Merge branch 'i2c/for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "Quite some driver updates:
   - piix4 can now handle multiplexed adapters
   - brcmstb, xlr, eg20t, designware drivers support more SoCs
   - emev2 gained i2c slave support
   - img-scb and rcar got bigger refactoring to remove issues
   - lots of common driver updates

  i2c core changes:
   - new quirk flag when an adapter does not support clock stretching,
     so clients can be configured to avoid that if possible
   - added a helper function to retrieve timing parameters from firmware
     (with rcar being the first user)
   - "multi-master" DT binding added so drivers can adapt to this
     setting (like disabling PM to keep arbitration working)
   - RuntimePM for the logical adapter device is now always enabled by
     the core to ensure propagation from childs to the parent (the HW
     device)
   - new macro builtin_i2c_driver to reduce boilerplate"

* 'i2c/for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (70 commits)
  i2c: create builtin_i2c_driver to avoid registration boilerplate
  i2c: imx: fix i2c resource leak with dma transfer
  dt-bindings: i2c: eeprom: add another EEPROM device
  dt-bindings: move I2C eeprom descriptions to the proper file
  i2c: designware: Do not require clock when SSCN and FFCN are provided
  DT: i2c: trivial-devices: Add Epson RX8010 and MPL3115
  i2c: s3c2410: remove superfluous runtime PM calls
  i2c: always enable RuntimePM for the adapter device
  i2c: designware: retry transfer on transient failure
  i2c: ibm_iic: rename i2c_timings struct due to clash with generic version
  i2c: designware: Add support for AMD Seattle I2C
  i2c: imx: Remove unneeded comments
  i2c: st: use to_platform_device()
  i2c: designware: use to_pci_dev()
  i2c: brcmstb: Adding support for CM and DSL SoCs
  i2c: mediatek: fix i2c multi transfer issue in high speed mode
  i2c: imx: improve code readability
  i2c: imx: Improve message log when DMA is not used
  i2c: imx: add runtime pm support to improve the performance
  i2c: imx: init bus recovery info before adding i2c adapter
  ...

Documentation/devicetree/bindings/eeprom/eeprom.txt

@@ -2,11 +2,22 @@ EEPROMs (I2C)
 
 Required properties:
 
-  - compatible : should be "<manufacturer>,<type>"
-		 If there is no specific driver for <manufacturer>, a generic
-		 driver based on <type> is selected. Possible types are:
-		 24c00, 24c01, 24c02, 24c04, 24c08, 24c16, 24c32, 24c64,
-		 24c128, 24c256, 24c512, 24c1024, spd
+  - compatible : should be "<manufacturer>,<type>", like these:
+
+	"atmel,24c00", "atmel,24c01", "atmel,24c02", "atmel,24c04",
+	"atmel,24c08", "atmel,24c16", "atmel,24c32", "atmel,24c64",
+	"atmel,24c128", "atmel,24c256", "atmel,24c512", "atmel,24c1024"
+
+	"catalyst,24c32"
+
+	"ramtron,24c64"
+
+	"renesas,r1ex24002"
+
+	 If there is no specific driver for <manufacturer>, a generic
+	 driver based on <type> is selected. Possible types are:
+	 "24c00", "24c01", "24c02", "24c04", "24c08", "24c16", "24c32", "24c64",
+	 "24c128", "24c256", "24c512", "24c1024", "spd"
 
   - reg : the I2C address of the EEPROM
 

Documentation/devicetree/bindings/i2c/i2c-at91.txt

@@ -3,7 +3,7 @@ I2C for Atmel platforms
 Required properties :
 - compatible : Must be "atmel,at91rm9200-i2c", "atmel,at91sam9261-i2c",
      "atmel,at91sam9260-i2c", "atmel,at91sam9g20-i2c", "atmel,at91sam9g10-i2c",
-     "atmel,at91sam9x5-i2c" or "atmel,sama5d2-i2c"
+     "atmel,at91sam9x5-i2c", "atmel,sama5d4-i2c" or "atmel,sama5d2-i2c"
 - reg: physical base address of the controller and length of memory mapped
      region.
 - interrupts: interrupt number to the cpu.
@@ -17,6 +17,8 @@ Optional properties:
 - dma-names: should contain "tx" and "rx".
 - atmel,fifo-size: maximum number of data the RX and TX FIFOs can store for FIFO
   capable I2C controllers.
+- i2c-sda-hold-time-ns: TWD hold time, only available for "atmel,sama5d4-i2c"
+  and "atmel,sama5d2-i2c".
 - Child nodes conforming to i2c bus binding
 
 Examples :
@@ -52,6 +54,7 @@ i2c0: i2c@f8034600 {
 	#size-cells = <0>;
 	clocks = <&flx0>;
 	atmel,fifo-size = <16>;
+	i2c-sda-hold-time-ns = <336>;
 
 	wm8731: wm8731@1a {
 		compatible = "wm8731";

Documentation/devicetree/bindings/i2c/i2c-brcmstb.txt

@@ -2,7 +2,7 @@ Broadcom stb bsc iic master controller
 
 Required properties:
 
-- compatible: should be "brcm,brcmstb-i2c"
+- compatible: should be "brcm,brcmstb-i2c" or "brcm,brcmper-i2c"
 - clock-frequency: 32-bit decimal value of iic master clock freqency in Hz
 		   valid values are 375000, 390000, 187500, 200000
 		   93750, 97500, 46875 and 50000

Documentation/devicetree/bindings/i2c/i2c-rcar.txt

@@ -20,6 +20,10 @@ Optional properties:
   propoerty indicates the default frequency 100 kHz.
 - clocks: clock specifier.
 
+- i2c-scl-falling-time-ns: see i2c.txt
+- i2c-scl-internal-delay-ns: see i2c.txt
+- i2c-scl-rising-time-ns: see i2c.txt
+
 Examples :
 
 i2c0: i2c@e6508000 {

Documentation/devicetree/bindings/i2c/i2c.txt

@@ -29,12 +29,38 @@ Optional properties
 These properties may not be supported by all drivers. However, if a driver
 wants to support one of the below features, it should adapt the bindings below.
 
-- clock-frequency	- frequency of bus clock in Hz.
-- wakeup-source		- device can be used as a wakeup source.
+- clock-frequency
+	frequency of bus clock in Hz.
 
-- interrupts		- interrupts used by the device.
-- interrupt-names	- "irq" and "wakeup" names are recognized by I2C core,
-			  other names are left to individual drivers.
+- i2c-scl-falling-time-ns
+	Number of nanoseconds the SCL signal takes to fall; t(f) in the I2C
+	specification.
+
+- i2c-scl-internal-delay-ns
+	Number of nanoseconds the IP core additionally needs to setup SCL.
+
+- i2c-scl-rising-time-ns
+	Number of nanoseconds the SCL signal takes to rise; t(r) in the I2C
+	specification.
+
+- i2c-sda-falling-time-ns
+	Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
+	specification.
+
+- interrupts
+	interrupts used by the device.
+
+- interrupt-names
+	"irq" and "wakeup" names are recognized by I2C core, other names are
+	left to individual drivers.
+
+- multi-master
+	states that there is another master active on this bus. The OS can use
+	this information to adapt power management to keep the arbitration awake
+	all the time, for example.
+
+- wakeup-source
+	device can be used as a wakeup source.
 
 Binding may contain optional "interrupts" property, describing interrupts
 used by the device. I2C core will assign "irq" interrupt (or the very first

Documentation/devicetree/bindings/i2c/trivial-devices.txt

@@ -22,21 +22,9 @@ adi,adxl345		Three-Axis Digital Accelerometer
 adi,adxl346		Three-Axis Digital Accelerometer (backward-compatibility value "adi,adxl345" must be listed too)
 ams,iaq-core		AMS iAQ-Core VOC Sensor
 at,24c08		i2c serial eeprom  (24cxx)
-atmel,24c00		i2c serial eeprom  (24cxx)
-atmel,24c01		i2c serial eeprom  (24cxx)
-atmel,24c02		i2c serial eeprom  (24cxx)
-atmel,24c04		i2c serial eeprom  (24cxx)
-atmel,24c16		i2c serial eeprom  (24cxx)
-atmel,24c32		i2c serial eeprom  (24cxx)
-atmel,24c64		i2c serial eeprom  (24cxx)
-atmel,24c128		i2c serial eeprom  (24cxx)
-atmel,24c256		i2c serial eeprom  (24cxx)
-atmel,24c512		i2c serial eeprom  (24cxx)
-atmel,24c1024		i2c serial eeprom  (24cxx)
 atmel,at97sc3204t	i2c trusted platform module (TPM)
 capella,cm32181		CM32181: Ambient Light Sensor
 capella,cm3232		CM3232: Ambient Light Sensor
-catalyst,24c32		i2c serial eeprom
 cirrus,cs42l51		Cirrus Logic CS42L51 audio codec
 dallas,ds1307		64 x 8, Serial, I2C Real-Time Clock
 dallas,ds1338		I2C RTC with 56-Byte NV RAM
@@ -50,11 +38,13 @@ dallas,ds4510		CPU Supervisor with Nonvolatile Memory and Programmable I/O
 dallas,ds75		Digital Thermometer and Thermostat
 dlg,da9053		DA9053: flexible system level PMIC with multicore support
 dlg,da9063		DA9063: system PMIC for quad-core application processors
+epson,rx8010		I2C-BUS INTERFACE REAL TIME CLOCK MODULE
 epson,rx8025		High-Stability. I2C-Bus INTERFACE REAL TIME CLOCK MODULE
 epson,rx8581		I2C-BUS INTERFACE REAL TIME CLOCK MODULE
 fsl,mag3110		MAG3110: Xtrinsic High Accuracy, 3D Magnetometer
 fsl,mc13892		MC13892: Power Management Integrated Circuit (PMIC) for i.MX35/51
 fsl,mma8450		MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer
+fsl,mpl3115		MPL3115: Absolute Digital Pressure Sensor
 fsl,mpr121		MPR121: Proximity Capacitive Touch Sensor Controller
 fsl,sgtl5000		SGTL5000: Ultra Low-Power Audio Codec
 gmt,g751		G751: Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface
@@ -81,7 +71,6 @@ ovti,ov5642		OV5642: Color CMOS QSXGA (5-megapixel) Image Sensor with OmniBSI an
 pericom,pt7c4338	Real-time Clock Module
 plx,pex8648		48-Lane, 12-Port PCI Express Gen 2 (5.0 GT/s) Switch
 pulsedlight,lidar-lite-v2	Pulsedlight LIDAR range-finding sensor
-ramtron,24c64		i2c serial eeprom  (24cxx)
 ricoh,r2025sd		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
 ricoh,r2221tl		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
 ricoh,rs5c372a		I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC

drivers/i2c/algos/i2c-algo-bit.c

@@ -617,6 +617,10 @@ const struct i2c_algorithm i2c_bit_algo = {
 };
 EXPORT_SYMBOL(i2c_bit_algo);
 
+const struct i2c_adapter_quirks i2c_bit_quirk_no_clk_stretch = {
+	.flags = I2C_AQ_NO_CLK_STRETCH,
+};
+
 /*
  * registering functions to load algorithms at runtime
  */
@@ -635,6 +639,8 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap,
 	/* register new adapter to i2c module... */
 	adap->algo = &i2c_bit_algo;
 	adap->retries = 3;
+	if (bit_adap->getscl == NULL)
+		adap->quirks = &i2c_bit_quirk_no_clk_stretch;
 
 	ret = add_adapter(adap);
 	if (ret < 0)

drivers/i2c/busses/Kconfig

@@ -516,7 +516,7 @@ config I2C_EFM32
 
 config I2C_EG20T
 	tristate "Intel EG20T PCH/LAPIS Semicon IOH(ML7213/ML7223/ML7831) I2C"
-	depends on PCI && (X86_32 || COMPILE_TEST)
+	depends on PCI && (X86_32 || MIPS || COMPILE_TEST)
 	help
 	  This driver is for PCH(Platform controller Hub) I2C of EG20T which
 	  is an IOH(Input/Output Hub) for x86 embedded processor.
@@ -532,6 +532,7 @@ config I2C_EG20T
 config I2C_EMEV2
 	tristate "EMMA Mobile series I2C adapter"
 	depends on HAVE_CLK
+	select I2C_SLAVE
 	help
 	  If you say yes to this option, support will be included for the
 	  I2C interface on the Renesas Electronics EM/EV family of processors.
@@ -963,11 +964,11 @@ config I2C_XILINX
 	  will be called xilinx_i2c.
 
 config I2C_XLR
-	tristate "XLR I2C support"
-	depends on CPU_XLR
+	tristate "Netlogic XLR and Sigma Designs I2C support"
+	depends on CPU_XLR || ARCH_TANGOX
 	help
 	  This driver enables support for the on-chip I2C interface of
-	  the Netlogic XLR/XLS MIPS processors.
+	  the Netlogic XLR/XLS MIPS processors and Sigma Designs SOCs.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-xlr.

drivers/i2c/busses/i2c-at91.c

@@ -64,6 +64,8 @@
 #define	AT91_TWI_IADR		0x000c	/* Internal Address Register */
 
 #define	AT91_TWI_CWGR		0x0010	/* Clock Waveform Generator Reg */
+#define	AT91_TWI_CWGR_HOLD_MAX	0x1f
+#define	AT91_TWI_CWGR_HOLD(x)	(((x) & AT91_TWI_CWGR_HOLD_MAX) << 24)
 
 #define	AT91_TWI_SR		0x0020	/* Status Register */
 #define	AT91_TWI_TXCOMP		BIT(0)	/* Transmission Complete */
@@ -110,6 +112,7 @@ struct at91_twi_pdata {
 	unsigned clk_offset;
 	bool has_unre_flag;
 	bool has_alt_cmd;
+	bool has_hold_field;
 	struct at_dma_slave dma_slave;
 };
 
@@ -187,10 +190,11 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev)
  */
 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
 {
-	int ckdiv, cdiv, div;
+	int ckdiv, cdiv, div, hold = 0;
 	struct at91_twi_pdata *pdata = dev->pdata;
 	int offset = pdata->clk_offset;
 	int max_ckdiv = pdata->clk_max_div;
+	u32 twd_hold_time_ns = 0;
 
 	div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
 				       2 * twi_clk) - offset);
@@ -204,8 +208,33 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
 		cdiv = 255;
 	}
 
-	dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
-	dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
+	if (pdata->has_hold_field) {
+		of_property_read_u32(dev->dev->of_node, "i2c-sda-hold-time-ns",
+				     &twd_hold_time_ns);
+
+		/*
+		 * hold time = HOLD + 3 x T_peripheral_clock
+		 * Use clk rate in kHz to prevent overflows when computing
+		 * hold.
+		 */
+		hold = DIV_ROUND_UP(twd_hold_time_ns
+				    * (clk_get_rate(dev->clk) / 1000), 1000000);
+		hold -= 3;
+		if (hold < 0)
+			hold = 0;
+		if (hold > AT91_TWI_CWGR_HOLD_MAX) {
+			dev_warn(dev->dev,
+				 "HOLD field set to its maximum value (%d instead of %d)\n",
+				 AT91_TWI_CWGR_HOLD_MAX, hold);
+			hold = AT91_TWI_CWGR_HOLD_MAX;
+		}
+	}
+
+	dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
+			    | AT91_TWI_CWGR_HOLD(hold);
+
+	dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns)\n",
+		cdiv, ckdiv, hold, twd_hold_time_ns);
 }
 
 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
@@ -797,6 +826,7 @@ static struct at91_twi_pdata at91rm9200_config = {
 	.clk_offset = 3,
 	.has_unre_flag = true,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
 };
 
 static struct at91_twi_pdata at91sam9261_config = {
@@ -804,6 +834,7 @@ static struct at91_twi_pdata at91sam9261_config = {
 	.clk_offset = 4,
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
 };
 
 static struct at91_twi_pdata at91sam9260_config = {
@@ -811,6 +842,7 @@ static struct at91_twi_pdata at91sam9260_config = {
 	.clk_offset = 4,
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
 };
 
 static struct at91_twi_pdata at91sam9g20_config = {
@@ -818,6 +850,7 @@ static struct at91_twi_pdata at91sam9g20_config = {
 	.clk_offset = 4,
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
 };
 
 static struct at91_twi_pdata at91sam9g10_config = {
@@ -825,6 +858,7 @@ static struct at91_twi_pdata at91sam9g10_config = {
 	.clk_offset = 4,
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
 };
 
 static const struct platform_device_id at91_twi_devtypes[] = {
@@ -854,6 +888,15 @@ static struct at91_twi_pdata at91sam9x5_config = {
 	.clk_offset = 4,
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
+	.has_hold_field = false,
+};
+
+static struct at91_twi_pdata sama5d4_config = {
+	.clk_max_div = 7,
+	.clk_offset = 4,
+	.has_unre_flag = false,
+	.has_alt_cmd = false,
+	.has_hold_field = true,
 };
 
 static struct at91_twi_pdata sama5d2_config = {
@@ -861,6 +904,7 @@ static struct at91_twi_pdata sama5d2_config = {
 	.clk_offset = 4,
 	.has_unre_flag = true,
 	.has_alt_cmd = true,
+	.has_hold_field = true,
 };
 
 static const struct of_device_id atmel_twi_dt_ids[] = {
@@ -882,6 +926,9 @@ static const struct of_device_id atmel_twi_dt_ids[] = {
 	}, {
 		.compatible = "atmel,at91sam9x5-i2c",
 		.data = &at91sam9x5_config,
+	}, {
+		.compatible = "atmel,sama5d4-i2c",
+		.data = &sama5d4_config,
 	}, {
 		.compatible = "atmel,sama5d2-i2c",
 		.data = &sama5d2_config,

drivers/i2c/busses/i2c-bcm2835.c

@@ -222,6 +222,15 @@ static const struct i2c_algorithm bcm2835_i2c_algo = {
 	.functionality	= bcm2835_i2c_func,
 };
 
+/*
+ * This HW was reported to have problems with clock stretching:
+ * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html
+ * https://www.raspberrypi.org/forums/viewtopic.php?p=146272
+ */
+static const struct i2c_adapter_quirks bcm2835_i2c_quirks = {
+	.flags = I2C_AQ_NO_CLK_STRETCH,
+};
+
 static int bcm2835_i2c_probe(struct platform_device *pdev)
 {
 	struct bcm2835_i2c_dev *i2c_dev;
@@ -293,6 +302,7 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 	adap->algo = &bcm2835_i2c_algo;
 	adap->dev.parent = &pdev->dev;
 	adap->dev.of_node = pdev->dev.of_node;
+	adap->quirks = &bcm2835_i2c_quirks;
 
 	bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0);
 

drivers/i2c/busses/i2c-brcmstb.c

@@ -25,13 +25,16 @@
 #include <linux/version.h>
 
 #define N_DATA_REGS					8
-#define N_DATA_BYTES					(N_DATA_REGS * 4)
 
-/* BSC count register field definitions */
-#define BSC_CNT_REG1_MASK				0x0000003f
-#define BSC_CNT_REG1_SHIFT				0
-#define BSC_CNT_REG2_MASK				0x00000fc0
-#define BSC_CNT_REG2_SHIFT				6
+/*
+ * PER_I2C/BSC count register mask depends on 1 byte/4 byte data register
+ * size. Cable modem and DSL SoCs with Peripheral i2c cores use 1 byte per
+ * data register whereas STB SoCs use 4 byte per data register transfer,
+ * account for this difference in total count per transaction and mask to
+ * use.
+ */
+#define BSC_CNT_REG1_MASK(nb)	(nb == 1 ? GENMASK(3, 0) : GENMASK(5, 0))
+#define BSC_CNT_REG1_SHIFT	0
 
 /* BSC CTL register field definitions */
 #define BSC_CTL_REG_DTF_MASK				0x00000003
@@ -41,7 +44,7 @@
 #define BSC_CTL_REG_INT_EN_SHIFT			6
 #define BSC_CTL_REG_DIV_CLK_MASK			0x00000080
 
-/* BSC_IIC_ENABLE r/w enable and interrupt field defintions */
+/* BSC_IIC_ENABLE r/w enable and interrupt field definitions */
 #define BSC_IIC_EN_RESTART_MASK				0x00000040
 #define BSC_IIC_EN_NOSTART_MASK				0x00000020
 #define BSC_IIC_EN_NOSTOP_MASK				0x00000010
@@ -169,6 +172,7 @@ struct brcmstb_i2c_dev {
 	struct completion done;
 	bool is_suspended;
 	u32 clk_freq_hz;
+	int data_regsz;
 };
 
 /* register accessors for both be and le cpu arch */
@@ -186,6 +190,16 @@ struct brcmstb_i2c_dev {
 #define bsc_writel(_dev, _val, _reg)					\
 	__bsc_writel(_val, _dev->base + offsetof(struct bsc_regs, _reg))
 
+static inline int brcmstb_i2c_get_xfersz(struct brcmstb_i2c_dev *dev)
+{
+	return (N_DATA_REGS * dev->data_regsz);
+}
+
+static inline int brcmstb_i2c_get_data_regsz(struct brcmstb_i2c_dev *dev)
+{
+	return dev->data_regsz;
+}
+
 static void brcmstb_i2c_enable_disable_irq(struct brcmstb_i2c_dev *dev,
 					   bool int_en)
 {
@@ -323,14 +337,16 @@ static int brcmstb_i2c_xfer_bsc_data(struct brcmstb_i2c_dev *dev,
 				     u8 *buf, unsigned int len,
 				     struct i2c_msg *pmsg)
 {
-	int cnt, byte, rc;
+	int cnt, byte, i, rc;
 	enum bsc_xfer_cmd cmd;
 	u32 ctl_reg;
 	struct bsc_regs *pi2creg = dev->bsc_regmap;
 	int no_ack = pmsg->flags & I2C_M_IGNORE_NAK;
+	int data_regsz = brcmstb_i2c_get_data_regsz(dev);
+	int xfersz = brcmstb_i2c_get_xfersz(dev);
 
 	/* see if the transaction needs to check NACK conditions */
-	if (no_ack || len <= N_DATA_BYTES) {
+	if (no_ack || len <= xfersz) {
 		cmd = (pmsg->flags & I2C_M_RD) ? CMD_RD_NOACK
 			: CMD_WR_NOACK;
 		pi2creg->ctlhi_reg |= BSC_CTLHI_REG_IGNORE_ACK_MASK;
@@ -348,20 +364,22 @@ static int brcmstb_i2c_xfer_bsc_data(struct brcmstb_i2c_dev *dev,
 		pi2creg->ctl_reg = ctl_reg | DTF_RD_MASK;
 
 	/* set the read/write length */
-	bsc_writel(dev, BSC_CNT_REG1_MASK & (len << BSC_CNT_REG1_SHIFT),
-		   cnt_reg);
+	bsc_writel(dev, BSC_CNT_REG1_MASK(data_regsz) &
+		   (len << BSC_CNT_REG1_SHIFT), cnt_reg);
 
 	/* Write data into data_in register */
+
 	if (cmd == CMD_WR || cmd == CMD_WR_NOACK) {
-		for (cnt = 0; cnt < len; cnt += 4) {
+		for (cnt = 0, i = 0; cnt < len; cnt += data_regsz, i++) {
 			u32 word = 0;
 
-			for (byte = 0; byte < 4; byte++) {
-				word >>= 8;
+			for (byte = 0; byte < data_regsz; byte++) {
+				word >>= BITS_PER_BYTE;
 				if ((cnt + byte) < len)
-					word |= buf[cnt + byte] << 24;
+					word |= buf[cnt + byte] <<
+					(BITS_PER_BYTE * (data_regsz - 1));
 			}
-			bsc_writel(dev, word, data_in[cnt >> 2]);
+			bsc_writel(dev, word, data_in[i]);
 		}
 	}
 
@@ -373,14 +391,15 @@ static int brcmstb_i2c_xfer_bsc_data(struct brcmstb_i2c_dev *dev,
 		return rc;
 	}
 
+	/* Read data from data_out register */
 	if (cmd == CMD_RD || cmd == CMD_RD_NOACK) {
-		for (cnt = 0; cnt < len; cnt += 4) {
-			u32 data = bsc_readl(dev, data_out[cnt >> 2]);
+		for (cnt = 0, i = 0; cnt < len; cnt += data_regsz, i++) {
+			u32 data = bsc_readl(dev, data_out[i]);
 
-			for (byte = 0; byte < 4 &&
+			for (byte = 0; byte < data_regsz &&
 				     (byte + cnt) < len; byte++) {
 				buf[cnt + byte] = data & 0xff;
-				data >>= 8;
+				data >>= BITS_PER_BYTE;
 			}
 		}
 	}
@@ -448,6 +467,7 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
 	int bytes_to_xfer;
 	u8 *tmp_buf;
 	int len = 0;
+	int xfersz = brcmstb_i2c_get_xfersz(dev);
 
 	if (dev->is_suspended)
 		return -EBUSY;
@@ -482,9 +502,9 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
 
 		/* Perform data transfer */
 		while (len) {
-			bytes_to_xfer = min(len, N_DATA_BYTES);
+			bytes_to_xfer = min(len, xfersz);
 
-			if (len <= N_DATA_BYTES && i == (num - 1))
+			if (len <= xfersz && i == (num - 1))
 				brcmstb_set_i2c_start_stop(dev,
 							   ~(COND_START_STOP));
 
@@ -542,8 +562,12 @@ static void brcmstb_i2c_set_bus_speed(struct brcmstb_i2c_dev *dev)
 
 static void brcmstb_i2c_set_bsc_reg_defaults(struct brcmstb_i2c_dev *dev)
 {
-	/* 4 byte data register */
-	dev->bsc_regmap->ctlhi_reg = BSC_CTLHI_REG_DATAREG_SIZE_MASK;
+	if (brcmstb_i2c_get_data_regsz(dev) == sizeof(u32))
+		/* set 4 byte data in/out xfers  */
+		dev->bsc_regmap->ctlhi_reg = BSC_CTLHI_REG_DATAREG_SIZE_MASK;
+	else
+		dev->bsc_regmap->ctlhi_reg &= ~BSC_CTLHI_REG_DATAREG_SIZE_MASK;
+
 	bsc_writel(dev, dev->bsc_regmap->ctlhi_reg, ctlhi_reg);
 	/* set bus speed */
 	brcmstb_i2c_set_bus_speed(dev);
@@ -608,6 +632,13 @@ static int brcmstb_i2c_probe(struct platform_device *pdev)
 		dev->clk_freq_hz = bsc_clk[0].hz;
 	}
 
+	/* set the data in/out register size for compatible SoCs */
+	if (of_device_is_compatible(dev->device->of_node,
+				    "brcmstb,brcmper-i2c"))
+		dev->data_regsz = sizeof(u8);
+	else
+		dev->data_regsz = sizeof(u32);
+
 	brcmstb_i2c_set_bsc_reg_defaults(dev);
 
 	/* Add the i2c adapter */
@@ -674,6 +705,7 @@ static SIMPLE_DEV_PM_OPS(brcmstb_i2c_pm, brcmstb_i2c_suspend,
 
 static const struct of_device_id brcmstb_i2c_of_match[] = {
 	{.compatible = "brcm,brcmstb-i2c"},
+	{.compatible = "brcm,brcmper-i2c"},
 	{},
 };
 MODULE_DEVICE_TABLE(of, brcmstb_i2c_of_match);

drivers/i2c/busses/i2c-cadence.c

@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
+#include <linux/pm_runtime.h>
 
 /* Register offsets for the I2C device. */
 #define CDNS_I2C_CR_OFFSET		0x00 /* Control Register, RW */
@@ -96,6 +97,8 @@
 					 CDNS_I2C_IXR_COMP)
 
 #define CDNS_I2C_TIMEOUT		msecs_to_jiffies(1000)
+/* timeout for pm runtime autosuspend */
+#define CNDS_I2C_PM_TIMEOUT		1000	/* ms */
 
 #define CDNS_I2C_FIFO_DEPTH		16
 /* FIFO depth at which the DATA interrupt occurs */
@@ -128,7 +131,6 @@
  * @xfer_done:		Transfer complete status
  * @p_send_buf:		Pointer to transmit buffer
  * @p_recv_buf:		Pointer to receive buffer
- * @suspended:		Flag holding the device's PM status
  * @send_count:		Number of bytes still expected to send
  * @recv_count:		Number of bytes still expected to receive
  * @curr_recv_count:	Number of bytes to be received in current transfer
@@ -141,6 +143,7 @@
  * @quirks:		flag for broken hold bit usage in r1p10
  */
 struct cdns_i2c {
+	struct device		*dev;
 	void __iomem *membase;
 	struct i2c_adapter adap;
 	struct i2c_msg *p_msg;
@@ -148,7 +151,6 @@ struct cdns_i2c {
 	struct completion xfer_done;
 	unsigned char *p_send_buf;
 	unsigned char *p_recv_buf;
-	u8 suspended;
 	unsigned int send_count;
 	unsigned int recv_count;
 	unsigned int curr_recv_count;
@@ -569,9 +571,14 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	struct cdns_i2c *id = adap->algo_data;
 	bool hold_quirk;
 
+	ret = pm_runtime_get_sync(id->dev);
+	if (ret < 0)
+		return ret;
 	/* Check if the bus is free */
-	if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA)
-		return -EAGAIN;
+	if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA) {
+		ret = -EAGAIN;
+		goto out;
+	}
 
 	hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
 	/*
@@ -590,7 +597,8 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 			if (msgs[count].flags & I2C_M_RD) {
 				dev_warn(adap->dev.parent,
 					 "Can't do repeated start after a receive message\n");
-				return -EOPNOTSUPP;
+				ret = -EOPNOTSUPP;
+				goto out;
 			}
 		}
 		id->bus_hold_flag = 1;
@@ -608,20 +616,26 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 
 		ret = cdns_i2c_process_msg(id, msgs, adap);
 		if (ret)
-			return ret;
+			goto out;
 
 		/* Report the other error interrupts to application */
 		if (id->err_status) {
 			cdns_i2c_master_reset(adap);
 
-			if (id->err_status & CDNS_I2C_IXR_NACK)
-				return -ENXIO;
-
-			return -EIO;
+			if (id->err_status & CDNS_I2C_IXR_NACK) {
+				ret = -ENXIO;
+				goto out;
+			}
+			ret = -EIO;
+			goto out;
 		}
 	}
 
-	return num;
+	ret = num;
+out:
+	pm_runtime_mark_last_busy(id->dev);
+	pm_runtime_put_autosuspend(id->dev);
+	return ret;
 }
 
 /**
@@ -760,7 +774,7 @@ static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
 	struct clk_notifier_data *ndata = data;
 	struct cdns_i2c *id = to_cdns_i2c(nb);
 
-	if (id->suspended)
+	if (pm_runtime_suspended(id->dev))
 		return NOTIFY_OK;
 
 	switch (event) {
@@ -808,14 +822,12 @@ static int cdns_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
  *
  * Return: 0 always
  */
-static int __maybe_unused cdns_i2c_suspend(struct device *_dev)
+static int __maybe_unused cdns_i2c_runtime_suspend(struct device *dev)
 {
-	struct platform_device *pdev = container_of(_dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct cdns_i2c *xi2c = platform_get_drvdata(pdev);
 
 	clk_disable(xi2c->clk);
-	xi2c->suspended = 1;
 
 	return 0;
 }
@@ -828,26 +840,25 @@ static int __maybe_unused cdns_i2c_suspend(struct device *_dev)
  *
  * Return: 0 on success and error value on error
  */
-static int __maybe_unused cdns_i2c_resume(struct device *_dev)
+static int __maybe_unused cdns_i2c_runtime_resume(struct device *dev)
 {
-	struct platform_device *pdev = container_of(_dev,
-			struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct cdns_i2c *xi2c = platform_get_drvdata(pdev);
 	int ret;
 
 	ret = clk_enable(xi2c->clk);
 	if (ret) {
-		dev_err(_dev, "Cannot enable clock.\n");
+		dev_err(dev, "Cannot enable clock.\n");
 		return ret;
 	}
 
-	xi2c->suspended = 0;
-
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(cdns_i2c_dev_pm_ops, cdns_i2c_suspend,
-			 cdns_i2c_resume);
+static const struct dev_pm_ops cdns_i2c_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(cdns_i2c_runtime_suspend,
+			   cdns_i2c_runtime_resume, NULL)
+};
 
 static const struct cdns_platform_data r1p10_i2c_def = {
 	.quirks = CDNS_I2C_BROKEN_HOLD_BIT,
@@ -881,6 +892,7 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 	if (!id)
 		return -ENOMEM;
 
+	id->dev = &pdev->dev;
 	platform_set_drvdata(pdev, id);
 
 	match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node);
@@ -913,10 +925,14 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 		return PTR_ERR(id->clk);
 	}
 	ret = clk_prepare_enable(id->clk);
-	if (ret) {
+	if (ret)
 		dev_err(&pdev->dev, "Unable to enable clock.\n");
-		return ret;
-	}
+
+	pm_runtime_enable(id->dev);
+	pm_runtime_set_autosuspend_delay(id->dev, CNDS_I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(id->dev);
+	pm_runtime_set_active(id->dev);
+
 	id->clk_rate_change_nb.notifier_call = cdns_i2c_clk_notifier_cb;
 	if (clk_notifier_register(id->clk, &id->clk_rate_change_nb))
 		dev_warn(&pdev->dev, "Unable to register clock notifier.\n");
@@ -966,6 +982,8 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 
 err_clk_dis:
 	clk_disable_unprepare(id->clk);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
 	return ret;
 }
 
@@ -984,6 +1002,7 @@ static int cdns_i2c_remove(struct platform_device *pdev)
 	i2c_del_adapter(&id->adap);
 	clk_notifier_unregister(id->clk, &id->clk_rate_change_nb);
 	clk_disable_unprepare(id->clk);
+	pm_runtime_disable(&pdev->dev);
 
 	return 0;
 }

drivers/i2c/busses/i2c-designware-core.c

@@ -271,6 +271,17 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
 		 enable ? "en" : "dis");
 }
 
+static unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev)
+{
+	/*
+	 * Clock is not necessary if we got LCNT/HCNT values directly from
+	 * the platform code.
+	 */
+	if (WARN_ON_ONCE(!dev->get_clk_rate_khz))
+		return 0;
+	return dev->get_clk_rate_khz(dev);
+}
+
 /**
  * i2c_dw_init() - initialize the designware i2c master hardware
  * @dev: device private data
@@ -281,7 +292,6 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
  */
 int i2c_dw_init(struct dw_i2c_dev *dev)
 {
-	u32 input_clock_khz;
 	u32 hcnt, lcnt;
 	u32 reg;
 	u32 sda_falling_time, scl_falling_time;
@@ -295,8 +305,6 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 		}
 	}
 
-	input_clock_khz = dev->get_clk_rate_khz(dev);
-
 	reg = dw_readl(dev, DW_IC_COMP_TYPE);
 	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
 		/* Configure register endianess access */
@@ -325,12 +333,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 		hcnt = dev->ss_hcnt;
 		lcnt = dev->ss_lcnt;
 	} else {
-		hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+		hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
 					4000,	/* tHD;STA = tHIGH = 4.0 us */
 					sda_falling_time,
 					0,	/* 0: DW default, 1: Ideal */
 					0);	/* No offset */
-		lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+		lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
 					4700,	/* tLOW = 4.7 us */
 					scl_falling_time,
 					0);	/* No offset */
@@ -344,12 +352,12 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 		hcnt = dev->fs_hcnt;
 		lcnt = dev->fs_lcnt;
 	} else {
-		hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+		hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
 					600,	/* tHD;STA = tHIGH = 0.6 us */
 					sda_falling_time,
 					0,	/* 0: DW default, 1: Ideal */
 					0);	/* No offset */
-		lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+		lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
 					1300,	/* tLOW = 1.3 us */
 					scl_falling_time,
 					0);	/* No offset */
@@ -860,6 +868,7 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
 
 	snprintf(adap->name, sizeof(adap->name),
 		 "Synopsys DesignWare I2C adapter");
+	adap->retries = 3;
 	adap->algo = &i2c_dw_algo;
 	adap->dev.parent = dev->dev;
 	i2c_set_adapdata(adap, dev);

drivers/i2c/busses/i2c-designware-pcidrv.c

@@ -162,7 +162,7 @@ static struct dw_pci_controller dw_pci_controllers[] = {
 #ifdef CONFIG_PM
 static int i2c_dw_pci_suspend(struct device *dev)
 {
-	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+	struct pci_dev *pdev = to_pci_dev(dev);
 
 	i2c_dw_disable(pci_get_drvdata(pdev));
 	return 0;
@@ -170,7 +170,7 @@ static int i2c_dw_pci_suspend(struct device *dev)
 
 static int i2c_dw_pci_resume(struct device *dev)
 {
-	struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
+	struct pci_dev *pdev = to_pci_dev(dev);
 
 	return i2c_dw_init(pci_get_drvdata(pdev));
 }

drivers/i2c/busses/i2c-designware-platdrv.c

@@ -123,6 +123,7 @@ static const struct acpi_device_id dw_i2c_acpi_match[] = {
 	{ "80860F41", 0 },
 	{ "808622C1", 0 },
 	{ "AMD0010", ACCESS_INTR_MASK },
+	{ "AMDI0510", 0 },
 	{ "APMC0D0F", 0 },
 	{ }
 };
@@ -134,6 +135,18 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 }
 #endif
 
+static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
+{
+	if (IS_ERR(i_dev->clk))
+		return PTR_ERR(i_dev->clk);
+
+	if (prepare)
+		return clk_prepare_enable(i_dev->clk);
+
+	clk_disable_unprepare(i_dev->clk);
+	return 0;
+}
+
 static int dw_i2c_plat_probe(struct platform_device *pdev)
 {
 	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
@@ -206,16 +219,13 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 			DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
 
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
-	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
-	if (IS_ERR(dev->clk))
-		return PTR_ERR(dev->clk);
-	clk_prepare_enable(dev->clk);
+	if (!i2c_dw_plat_prepare_clk(dev, true)) {
+		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
 
-	if (!dev->sda_hold_time && ht) {
-		u32 ic_clk = dev->get_clk_rate_khz(dev);
-
-		dev->sda_hold_time = div_u64((u64)ic_clk * ht + 500000,
-					     1000000);
+		if (!dev->sda_hold_time && ht)
+			dev->sda_hold_time = div_u64(
+				(u64)dev->get_clk_rate_khz(dev) * ht + 500000,
+				1000000);
 	}
 
 	if (!dev->tx_fifo_depth) {
@@ -297,7 +307,7 @@ static int dw_i2c_plat_suspend(struct device *dev)
 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
 
 	i2c_dw_disable(i_dev);
-	clk_disable_unprepare(i_dev->clk);
+	i2c_dw_plat_prepare_clk(i_dev, false);
 
 	return 0;
 }
@@ -307,7 +317,7 @@ static int dw_i2c_plat_resume(struct device *dev)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
 
-	clk_prepare_enable(i_dev->clk);
+	i2c_dw_plat_prepare_clk(i_dev, true);
 
 	if (!i_dev->pm_runtime_disabled)
 		i2c_dw_init(i_dev);

drivers/i2c/busses/i2c-eg20t.c

@@ -795,6 +795,7 @@ static int pch_i2c_probe(struct pci_dev *pdev,
 		/* base_addr + offset; */
 		adap_info->pch_data[i].pch_base_address = base_addr + 0x100 * i;
 
+		pch_adap->dev.of_node = pdev->dev.of_node;
 		pch_adap->dev.parent = &pdev->dev;
 
 		pch_i2c_init(&adap_info->pch_data[i]);

drivers/i2c/busses/i2c-emev2.c

@@ -71,6 +71,7 @@ struct em_i2c_device {
 	struct i2c_adapter adap;
 	struct completion msg_done;
 	struct clk *sclk;
+	struct i2c_client *slave;
 };
 
 static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg)
@@ -226,22 +227,131 @@ static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	return num;
 }
 
+static bool em_i2c_slave_irq(struct em_i2c_device *priv)
+{
+	u8 status, value;
+	enum i2c_slave_event event;
+	int ret;
+
+	if (!priv->slave)
+		return false;
+
+	status = readb(priv->base + I2C_OFS_IICSE0);
+
+	/* Extension code, do not participate */
+	if (status & I2C_BIT_EXC0) {
+		em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0);
+		return true;
+	}
+
+	/* Stop detected, we don't know if it's for slave or master */
+	if (status & I2C_BIT_SPD0) {
+		/* Notify slave device */
+		i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
+		/* Pretend we did not handle the interrupt */
+		return false;
+	}
+
+	/* Only handle interrupts addressed to us */
+	if (!(status & I2C_BIT_COI0))
+		return false;
+
+	/* Enable stop interrupts */
+	em_clear_set_bit(priv, 0, I2C_BIT_SPIE0, I2C_OFS_IICC0);
+
+	/* Transmission or Reception */
+	if (status & I2C_BIT_TRC0) {
+		if (status & I2C_BIT_ACKD0) {
+			/* 9 bit interrupt mode */
+			em_clear_set_bit(priv, 0, I2C_BIT_WTIM0, I2C_OFS_IICC0);
+
+			/* Send data */
+			event = status & I2C_BIT_STD0 ?
+				I2C_SLAVE_READ_REQUESTED :
+				I2C_SLAVE_READ_PROCESSED;
+			i2c_slave_event(priv->slave, event, &value);
+			writeb(value, priv->base + I2C_OFS_IIC0);
+		} else {
+			/* NACK, stop transmitting */
+			em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0);
+		}
+	} else {
+		/* 8 bit interrupt mode */
+		em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_ACKE0,
+				I2C_OFS_IICC0);
+		em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_WREL0,
+				I2C_OFS_IICC0);
+
+		if (status & I2C_BIT_STD0) {
+			i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED,
+					&value);
+		} else {
+			/* Recv data */
+			value = readb(priv->base + I2C_OFS_IIC0);
+			ret = i2c_slave_event(priv->slave,
+					I2C_SLAVE_WRITE_RECEIVED, &value);
+			if (ret < 0)
+				em_clear_set_bit(priv, I2C_BIT_ACKE0, 0,
+						I2C_OFS_IICC0);
+		}
+	}
+
+	return true;
+}
+
 static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id)
 {
 	struct em_i2c_device *priv = dev_id;
 
+	if (em_i2c_slave_irq(priv))
+		return IRQ_HANDLED;
+
 	complete(&priv->msg_done);
+
 	return IRQ_HANDLED;
 }
 
 static u32 em_i2c_func(struct i2c_adapter *adap)
 {
-	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE;
+}
+
+static int em_i2c_reg_slave(struct i2c_client *slave)
+{
+	struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter);
+
+	if (priv->slave)
+		return -EBUSY;
+
+	if (slave->flags & I2C_CLIENT_TEN)
+		return -EAFNOSUPPORT;
+
+	priv->slave = slave;
+
+	/* Set slave address */
+	writeb(slave->addr << 1, priv->base + I2C_OFS_SVA0);
+
+	return 0;
+}
+
+static int em_i2c_unreg_slave(struct i2c_client *slave)
+{
+	struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter);
+
+	WARN_ON(!priv->slave);
+
+	writeb(0, priv->base + I2C_OFS_SVA0);
+
+	priv->slave = NULL;
+
+	return 0;
 }
 
 static struct i2c_algorithm em_i2c_algo = {
 	.master_xfer = em_i2c_xfer,
 	.functionality = em_i2c_func,
+	.reg_slave      = em_i2c_reg_slave,
+	.unreg_slave    = em_i2c_unreg_slave,
 };
 
 static int em_i2c_probe(struct platform_device *pdev)

drivers/i2c/busses/i2c-ibm_iic.c

@@ -99,7 +99,7 @@ static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
 #endif
 
 /* Bus timings (in ns) for bit-banging */
-static struct i2c_timings {
+static struct ibm_iic_timings {
 	unsigned int hd_sta;
 	unsigned int su_sto;
 	unsigned int low;
@@ -241,7 +241,7 @@ static int iic_dc_wait(volatile struct iic_regs __iomem *iic, u8 mask)
 static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p)
 {
 	volatile struct iic_regs __iomem *iic = dev->vaddr;
-	const struct i2c_timings* t = &timings[dev->fast_mode ? 1 : 0];
+	const struct ibm_iic_timings *t = &timings[dev->fast_mode ? 1 : 0];
 	u8 mask, v, sda;
 	int i, res;
 

drivers/i2c/busses/i2c-img-scb.c

@@ -151,10 +151,11 @@
 #define INT_FIFO_EMPTYING		BIT(12)
 #define INT_TRANSACTION_DONE		BIT(15)
 #define INT_SLAVE_EVENT			BIT(16)
+#define INT_MASTER_HALTED		BIT(17)
 #define INT_TIMING			BIT(18)
+#define INT_STOP_DETECTED		BIT(19)
 
 #define INT_FIFO_FULL_FILLING	(INT_FIFO_FULL  | INT_FIFO_FILLING)
-#define INT_FIFO_EMPTY_EMPTYING	(INT_FIFO_EMPTY | INT_FIFO_EMPTYING)
 
 /* Level interrupts need clearing after handling instead of before */
 #define INT_LEVEL			0x01e00
@@ -177,7 +178,8 @@
 					 INT_FIFO_FULL        | \
 					 INT_FIFO_FILLING     | \
 					 INT_FIFO_EMPTY       | \
-					 INT_FIFO_EMPTYING)
+					 INT_MASTER_HALTED    | \
+					 INT_STOP_DETECTED)
 
 #define INT_ENABLE_MASK_WAITSTOP	(INT_SLAVE_EVENT      | \
 					 INT_ADDR_ACK_ERR     | \
@@ -511,7 +513,17 @@ static void img_i2c_soft_reset(struct img_i2c *i2c)
 		       SCB_CONTROL_CLK_ENABLE | SCB_CONTROL_SOFT_RESET);
 }
 
-/* enable or release transaction halt for control of repeated starts */
+/*
+ * Enable or release transaction halt for control of repeated starts.
+ * In version 3.3 of the IP when transaction halt is set, an interrupt
+ * will be generated after each byte of a transfer instead of after
+ * every transfer but before the stop bit.
+ * Due to this behaviour we have to be careful that every time we
+ * release the transaction halt we have to re-enable it straight away
+ * so that we only process a single byte, not doing so will result in
+ * all remaining bytes been processed and a stop bit being issued,
+ * which will prevent us having a repeated start.
+ */
 static void img_i2c_transaction_halt(struct img_i2c *i2c, bool t_halt)
 {
 	u32 val;
@@ -580,7 +592,6 @@ static void img_i2c_read(struct img_i2c *i2c)
 	img_i2c_writel(i2c, SCB_READ_ADDR_REG, i2c->msg.addr);
 	img_i2c_writel(i2c, SCB_READ_COUNT_REG, i2c->msg.len);
 
-	img_i2c_transaction_halt(i2c, false);
 	mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
 }
 
@@ -594,7 +605,6 @@ static void img_i2c_write(struct img_i2c *i2c)
 	img_i2c_writel(i2c, SCB_WRITE_ADDR_REG, i2c->msg.addr);
 	img_i2c_writel(i2c, SCB_WRITE_COUNT_REG, i2c->msg.len);
 
-	img_i2c_transaction_halt(i2c, false);
 	mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
 	img_i2c_write_fifo(i2c);
 
@@ -750,7 +760,9 @@ static unsigned int img_i2c_atomic(struct img_i2c *i2c,
 			next_cmd = CMD_RET_ACK;
 		break;
 	case CMD_RET_ACK:
-		if (i2c->line_status & LINESTAT_ACK_DET) {
+		if (i2c->line_status & LINESTAT_ACK_DET ||
+		    (i2c->line_status & LINESTAT_NACK_DET &&
+		    i2c->msg.flags & I2C_M_IGNORE_NAK)) {
 			if (i2c->msg.len == 0) {
 				next_cmd = CMD_GEN_STOP;
 			} else if (i2c->msg.flags & I2C_M_RD) {
@@ -858,34 +870,42 @@ static unsigned int img_i2c_auto(struct img_i2c *i2c,
 
 	/* Enable transaction halt on start bit */
 	if (!i2c->last_msg && line_status & LINESTAT_START_BIT_DET) {
-		img_i2c_transaction_halt(i2c, true);
+		img_i2c_transaction_halt(i2c, !i2c->last_msg);
 		/* we're no longer interested in the slave event */
 		i2c->int_enable &= ~INT_SLAVE_EVENT;
 	}
 
 	mod_timer(&i2c->check_timer, jiffies + msecs_to_jiffies(1));
 
+	if (int_status & INT_STOP_DETECTED) {
+		/* Drain remaining data in FIFO and complete transaction */
+		if (i2c->msg.flags & I2C_M_RD)
+			img_i2c_read_fifo(i2c);
+		return ISR_COMPLETE(0);
+	}
+
 	if (i2c->msg.flags & I2C_M_RD) {
-		if (int_status & INT_FIFO_FULL_FILLING) {
+		if (int_status & (INT_FIFO_FULL_FILLING | INT_MASTER_HALTED)) {
 			img_i2c_read_fifo(i2c);
 			if (i2c->msg.len == 0)
 				return ISR_WAITSTOP;
 		}
 	} else {
-		if (int_status & INT_FIFO_EMPTY_EMPTYING) {
-			/*
-			 * The write fifo empty indicates that we're in the
-			 * last byte so it's safe to start a new write
-			 * transaction without losing any bytes from the
-			 * previous one.
-			 * see 2.3.7 Repeated Start Transactions.
-			 */
+		if (int_status & (INT_FIFO_EMPTY | INT_MASTER_HALTED)) {
 			if ((int_status & INT_FIFO_EMPTY) &&
 			    i2c->msg.len == 0)
 				return ISR_WAITSTOP;
 			img_i2c_write_fifo(i2c);
 		}
 	}
+	if (int_status & INT_MASTER_HALTED) {
+		/*
+		 * Release and then enable transaction halt, to
+		 * allow only a single byte to proceed.
+		 */
+		img_i2c_transaction_halt(i2c, false);
+		img_i2c_transaction_halt(i2c, !i2c->last_msg);
+	}
 
 	return 0;
 }
@@ -1017,20 +1037,23 @@ static int img_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 		return -EIO;
 
 	for (i = 0; i < num; i++) {
-		if (likely(msgs[i].len))
-			continue;
 		/*
 		 * 0 byte reads are not possible because the slave could try
 		 * and pull the data line low, preventing a stop bit.
 		 */
-		if (unlikely(msgs[i].flags & I2C_M_RD))
+		if (!msgs[i].len && msgs[i].flags & I2C_M_RD)
 			return -EIO;
 		/*
 		 * 0 byte writes are possible and used for probing, but we
 		 * cannot do them in automatic mode, so use atomic mode
 		 * instead.
+		 *
+		 * Also, the I2C_M_IGNORE_NAK mode can only be implemented
+		 * in atomic mode.
 		 */
-		atomic = true;
+		if (!msgs[i].len ||
+		    (msgs[i].flags & I2C_M_IGNORE_NAK))
+			atomic = true;
 	}
 
 	ret = clk_prepare_enable(i2c->scb_clk);
@@ -1069,12 +1092,31 @@ static int img_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 		img_i2c_writel(i2c, SCB_INT_CLEAR_REG, ~0);
 		img_i2c_writel(i2c, SCB_CLEAR_REG, ~0);
 
-		if (atomic)
+		if (atomic) {
 			img_i2c_atomic_start(i2c);
-		else if (msg->flags & I2C_M_RD)
-			img_i2c_read(i2c);
-		else
-			img_i2c_write(i2c);
+		} else {
+			/*
+			 * Enable transaction halt if not the last message in
+			 * the queue so that we can control repeated starts.
+			 */
+			img_i2c_transaction_halt(i2c, !i2c->last_msg);
+
+			if (msg->flags & I2C_M_RD)
+				img_i2c_read(i2c);
+			else
+				img_i2c_write(i2c);
+
+			/*
+			 * Release and then enable transaction halt, to
+			 * allow only a single byte to proceed.
+			 * This doesn't have an effect on the initial transfer
+			 * but will allow the following transfers to start
+			 * processing if the previous transfer was marked as
+			 * complete while the i2c block was halted.
+			 */
+			img_i2c_transaction_halt(i2c, false);
+			img_i2c_transaction_halt(i2c, !i2c->last_msg);
+		}
 		spin_unlock_irqrestore(&i2c->lock, flags);
 
 		time_left = wait_for_completion_timeout(&i2c->msg_complete,

drivers/i2c/busses/i2c-imx.c

@@ -29,9 +29,6 @@
  *
  */
 
-/** Includes *******************************************************************
-*******************************************************************************/
-
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
@@ -53,12 +50,10 @@
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_data/i2c-imx.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 
-/** Defines ********************************************************************
-*******************************************************************************/
-
 /* This will be the driver name the kernel reports */
 #define DRIVER_NAME "imx-i2c"
 
@@ -120,8 +115,7 @@
 #define I2CR_IEN_OPCODE_0	0x0
 #define I2CR_IEN_OPCODE_1	I2CR_IEN
 
-/** Variables ******************************************************************
-*******************************************************************************/
+#define I2C_PM_TIMEOUT		10 /* ms */
 
 /*
  * sorted list of clock divider, register value pairs
@@ -346,7 +340,7 @@ fail_tx:
 	dma_release_channel(dma->chan_tx);
 fail_al:
 	devm_kfree(dev, dma);
-	dev_info(dev, "can't use DMA\n");
+	dev_info(dev, "can't use DMA, using PIO instead.\n");
 }
 
 static void i2c_imx_dma_callback(void *arg)
@@ -393,6 +387,7 @@ static int i2c_imx_dma_xfer(struct imx_i2c_struct *i2c_imx,
 	return 0;
 
 err_submit:
+	dmaengine_terminate_all(dma->chan_using);
 err_desc:
 	dma_unmap_single(chan_dev, dma->dma_buf,
 			dma->dma_len, dma->dma_data_dir);
@@ -416,9 +411,6 @@ static void i2c_imx_dma_free(struct imx_i2c_struct *i2c_imx)
 	dma->chan_using = NULL;
 }
 
-/** Functions for IMX I2C adapter driver ***************************************
-*******************************************************************************/
-
 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
 {
 	unsigned long orig_jiffies = jiffies;
@@ -527,9 +519,6 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
 
 	i2c_imx_set_clk(i2c_imx);
 
-	result = clk_prepare_enable(i2c_imx->clk);
-	if (result)
-		return result;
 	imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
 	/* Enable I2C controller */
 	imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
@@ -582,7 +571,6 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 	/* Disable I2C controller */
 	temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
 	imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
-	clk_disable_unprepare(i2c_imx->clk);
 }
 
 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
@@ -901,6 +889,10 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
 
 	dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 
+	result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
+	if (result < 0)
+		goto out;
+
 	/* Start I2C transfer */
 	result = i2c_imx_start(i2c_imx);
 	if (result) {
@@ -964,6 +956,10 @@ fail0:
 	/* Stop I2C transfer */
 	i2c_imx_stop(i2c_imx);
 
+	pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
+	pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);
+
+out:
 	dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
 		(result < 0) ? "error" : "success msg",
 			(result < 0) ? result : num);
@@ -997,10 +993,8 @@ static void i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
 			PINCTRL_STATE_DEFAULT);
 	i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
 			"gpio");
-	rinfo->sda_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
-			"sda-gpios", 0, NULL);
-	rinfo->scl_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
-			"scl-gpios", 0, NULL);
+	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
+	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
 
 	if (!gpio_is_valid(rinfo->sda_gpio) ||
 	    !gpio_is_valid(rinfo->scl_gpio) ||
@@ -1083,7 +1077,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
 
 	ret = clk_prepare_enable(i2c_imx->clk);
 	if (ret) {
-		dev_err(&pdev->dev, "can't enable I2C clock\n");
+		dev_err(&pdev->dev, "can't enable I2C clock, ret=%d\n", ret);
 		return ret;
 	}
 
@@ -1107,6 +1101,18 @@ static int i2c_imx_probe(struct platform_device *pdev)
 	/* Set up adapter data */
 	i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
 
+	/* Set up platform driver data */
+	platform_set_drvdata(pdev, i2c_imx);
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0)
+		goto rpm_disable;
+
 	/* Set up clock divider */
 	i2c_imx->bitrate = IMX_I2C_BIT_RATE;
 	ret = of_property_read_u32(pdev->dev.of_node,
@@ -1125,12 +1131,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
 	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "registration failed\n");
-		goto clk_disable;
+		goto rpm_disable;
 	}
 
-	/* Set up platform driver data */
-	platform_set_drvdata(pdev, i2c_imx);
-	clk_disable_unprepare(i2c_imx->clk);
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
 
 	dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq);
 	dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res);
@@ -1143,6 +1148,12 @@ static int i2c_imx_probe(struct platform_device *pdev)
 
 	return 0;   /* Return OK */
 
+rpm_disable:
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+
 clk_disable:
 	clk_disable_unprepare(i2c_imx->clk);
 	return ret;
@@ -1151,6 +1162,11 @@ clk_disable:
 static int i2c_imx_remove(struct platform_device *pdev)
 {
 	struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0)
+		return ret;
 
 	/* remove adapter */
 	dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
@@ -1165,17 +1181,54 @@ static int i2c_imx_remove(struct platform_device *pdev)
 	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
 	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
 
+	clk_disable_unprepare(i2c_imx->clk);
+
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int i2c_imx_runtime_suspend(struct device *dev)
+{
+	struct imx_i2c_struct *i2c_imx  = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(i2c_imx->clk);
+
 	return 0;
 }
 
+static int i2c_imx_runtime_resume(struct device *dev)
+{
+	struct imx_i2c_struct *i2c_imx  = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(i2c_imx->clk);
+	if (ret)
+		dev_err(dev, "can't enable I2C clock, ret=%d\n", ret);
+
+	return ret;
+}
+
+static const struct dev_pm_ops i2c_imx_pm_ops = {
+	SET_RUNTIME_PM_OPS(i2c_imx_runtime_suspend,
+			   i2c_imx_runtime_resume, NULL)
+};
+#define I2C_IMX_PM_OPS (&i2c_imx_pm_ops)
+#else
+#define I2C_IMX_PM_OPS NULL
+#endif /* CONFIG_PM */
+
 static struct platform_driver i2c_imx_driver = {
 	.probe = i2c_imx_probe,
 	.remove = i2c_imx_remove,
-	.driver	= {
-		.name	= DRIVER_NAME,
+	.driver = {
+		.name = DRIVER_NAME,
+		.pm = I2C_IMX_PM_OPS,
 		.of_match_table = i2c_imx_dt_ids,
 	},
-	.id_table	= imx_i2c_devtype,
+	.id_table = imx_i2c_devtype,
 };
 
 static int __init i2c_adap_imx_init(void)

drivers/i2c/busses/i2c-mt65xx.c

@@ -132,6 +132,7 @@ struct mtk_i2c_compatible {
 	unsigned char pmic_i2c: 1;
 	unsigned char dcm: 1;
 	unsigned char auto_restart: 1;
+	unsigned char aux_len_reg: 1;
 };
 
 struct mtk_i2c {
@@ -153,6 +154,8 @@ struct mtk_i2c {
 	enum mtk_trans_op op;
 	u16 timing_reg;
 	u16 high_speed_reg;
+	unsigned char auto_restart;
+	bool ignore_restart_irq;
 	const struct mtk_i2c_compatible *dev_comp;
 };
 
@@ -178,6 +181,7 @@ static const struct mtk_i2c_compatible mt6577_compat = {
 	.pmic_i2c = 0,
 	.dcm = 1,
 	.auto_restart = 0,
+	.aux_len_reg = 0,
 };
 
 static const struct mtk_i2c_compatible mt6589_compat = {
@@ -185,6 +189,7 @@ static const struct mtk_i2c_compatible mt6589_compat = {
 	.pmic_i2c = 1,
 	.dcm = 0,
 	.auto_restart = 0,
+	.aux_len_reg = 0,
 };
 
 static const struct mtk_i2c_compatible mt8173_compat = {
@@ -192,6 +197,7 @@ static const struct mtk_i2c_compatible mt8173_compat = {
 	.pmic_i2c = 0,
 	.dcm = 1,
 	.auto_restart = 1,
+	.aux_len_reg = 1,
 };
 
 static const struct of_device_id mtk_i2c_of_match[] = {
@@ -373,7 +379,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 
 	i2c->irq_stat = 0;
 
-	if (i2c->dev_comp->auto_restart)
+	if (i2c->auto_restart)
 		restart_flag = I2C_RS_TRANSFER;
 
 	reinit_completion(&i2c->msg_complete);
@@ -411,8 +417,14 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 
 	/* Set transfer and transaction len */
 	if (i2c->op == I2C_MASTER_WRRD) {
-		writew(msgs->len | ((msgs + 1)->len) << 8,
-		       i2c->base + OFFSET_TRANSFER_LEN);
+		if (i2c->dev_comp->aux_len_reg) {
+			writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
+			writew((msgs + 1)->len, i2c->base +
+			       OFFSET_TRANSFER_LEN_AUX);
+		} else {
+			writew(msgs->len | ((msgs + 1)->len) << 8,
+			       i2c->base + OFFSET_TRANSFER_LEN);
+		}
 		writew(I2C_WRRD_TRANAC_VALUE, i2c->base + OFFSET_TRANSAC_LEN);
 	} else {
 		writew(msgs->len, i2c->base + OFFSET_TRANSFER_LEN);
@@ -461,7 +473,7 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
 
 	writel(I2C_DMA_START_EN, i2c->pdmabase + OFFSET_EN);
 
-	if (!i2c->dev_comp->auto_restart) {
+	if (!i2c->auto_restart) {
 		start_reg = I2C_TRANSAC_START;
 	} else {
 		start_reg = I2C_TRANSAC_START | I2C_RS_MUL_TRIG;
@@ -518,6 +530,24 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
 	if (ret)
 		return ret;
 
+	i2c->auto_restart = i2c->dev_comp->auto_restart;
+
+	/* checking if we can skip restart and optimize using WRRD mode */
+	if (i2c->auto_restart && num == 2) {
+		if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) &&
+		    msgs[0].addr == msgs[1].addr) {
+			i2c->auto_restart = 0;
+		}
+	}
+
+	if (i2c->auto_restart && num >= 2 && i2c->speed_hz > MAX_FS_MODE_SPEED)
+		/* ignore the first restart irq after the master code,
+		 * otherwise the first transfer will be discarded.
+		 */
+		i2c->ignore_restart_irq = true;
+	else
+		i2c->ignore_restart_irq = false;
+
 	while (left_num--) {
 		if (!msgs->buf) {
 			dev_dbg(i2c->dev, "data buffer is NULL.\n");
@@ -530,7 +560,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
 		else
 			i2c->op = I2C_MASTER_WR;
 
-		if (!i2c->dev_comp->auto_restart) {
+		if (!i2c->auto_restart) {
 			if (num > 1) {
 				/* combined two messages into one transaction */
 				i2c->op = I2C_MASTER_WRRD;
@@ -559,7 +589,7 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 	u16 restart_flag = 0;
 	u16 intr_stat;
 
-	if (i2c->dev_comp->auto_restart)
+	if (i2c->auto_restart)
 		restart_flag = I2C_RS_TRANSFER;
 
 	intr_stat = readw(i2c->base + OFFSET_INTR_STAT);
@@ -571,8 +601,16 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
 	 * i2c->irq_stat need keep the two interrupt value.
 	 */
 	i2c->irq_stat |= intr_stat;
-	if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
-		complete(&i2c->msg_complete);
+
+	if (i2c->ignore_restart_irq && (i2c->irq_stat & restart_flag)) {
+		i2c->ignore_restart_irq = false;
+		i2c->irq_stat = 0;
+		writew(I2C_RS_MUL_CNFG | I2C_RS_MUL_TRIG | I2C_TRANSAC_START,
+		       i2c->base + OFFSET_START);
+	} else {
+		if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
+			complete(&i2c->msg_complete);
+	}
 
 	return IRQ_HANDLED;
 }

drivers/i2c/busses/i2c-piix4.c

@@ -23,6 +23,9 @@
 
    Note: we assume there can only be one device, with one or more
    SMBus interfaces.
+   The device can register multiple i2c_adapters (up to PIIX4_MAX_ADAPTERS).
+   For devices supporting multiple ports the i2c_adapter should provide
+   an i2c_algorithm to access them.
 */
 
 #include <linux/module.h>
@@ -37,6 +40,7 @@
 #include <linux/dmi.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
+#include <linux/mutex.h>
 
 
 /* PIIX4 SMBus address offsets */
@@ -75,6 +79,16 @@
 #define PIIX4_WORD_DATA		0x0C
 #define PIIX4_BLOCK_DATA	0x14
 
+/* Multi-port constants */
+#define PIIX4_MAX_ADAPTERS 4
+
+/* SB800 constants */
+#define SB800_PIIX4_SMB_IDX		0xcd6
+
+/* SB800 port is selected by bits 2:1 of the smb_en register (0x2c) */
+#define SB800_PIIX4_PORT_IDX		0x2c
+#define SB800_PIIX4_PORT_IDX_MASK	0x06
+
 /* insmod parameters */
 
 /* If force is set to anything different from 0, we forcibly enable the
@@ -122,8 +136,19 @@ static const struct dmi_system_id piix4_dmi_ibm[] = {
 	{ },
 };
 
+/* SB800 globals */
+static const char *piix4_main_port_names_sb800[PIIX4_MAX_ADAPTERS] = {
+	"SDA0", "SDA2", "SDA3", "SDA4"
+};
+static const char *piix4_aux_port_name_sb800 = "SDA1";
+
 struct i2c_piix4_adapdata {
 	unsigned short smba;
+
+	/* SB800 */
+	bool sb800_main;
+	unsigned short port;
+	struct mutex *mutex;
 };
 
 static int piix4_setup(struct pci_dev *PIIX4_dev,
@@ -229,7 +254,6 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 			     const struct pci_device_id *id, u8 aux)
 {
 	unsigned short piix4_smba;
-	unsigned short smba_idx = 0xcd6;
 	u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
 	u8 i2ccfg, i2ccfg_offset = 0x10;
 
@@ -251,16 +275,10 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev,
 	else
 		smb_en = (aux) ? 0x28 : 0x2c;
 
-	if (!request_region(smba_idx, 2, "smba_idx")) {
-		dev_err(&PIIX4_dev->dev, "SMBus base address index region "
-			"0x%x already in use!\n", smba_idx);
-		return -EBUSY;
-	}
-	outb_p(smb_en, smba_idx);
-	smba_en_lo = inb_p(smba_idx + 1);
-	outb_p(smb_en + 1, smba_idx);
-	smba_en_hi = inb_p(smba_idx + 1);
-	release_region(smba_idx, 2);
+	outb_p(smb_en, SB800_PIIX4_SMB_IDX);
+	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
+	outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
+	smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
 
 	if (!smb_en) {
 		smb_en_status = smba_en_lo & 0x10;
@@ -483,7 +501,7 @@ static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
 			if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 				return -EINVAL;
 			outb_p(len, SMBHSTDAT0);
-			i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
+			inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
 			for (i = 1; i <= len; i++)
 				outb_p(data->block[i], SMBBLKDAT);
 		}
@@ -516,7 +534,7 @@ static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
 		data->block[0] = inb_p(SMBHSTDAT0);
 		if (data->block[0] == 0 || data->block[0] > I2C_SMBUS_BLOCK_MAX)
 			return -EPROTO;
-		i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
+		inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
 		for (i = 1; i <= data->block[0]; i++)
 			data->block[i] = inb_p(SMBBLKDAT);
 		break;
@@ -524,6 +542,43 @@ static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
 	return 0;
 }
 
+/*
+ * Handles access to multiple SMBus ports on the SB800.
+ * The port is selected by bits 2:1 of the smb_en register (0x2c).
+ * Returns negative errno on error.
+ *
+ * Note: The selected port must be returned to the initial selection to avoid
+ * problems on certain systems.
+ */
+static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr,
+		 unsigned short flags, char read_write,
+		 u8 command, int size, union i2c_smbus_data *data)
+{
+	struct i2c_piix4_adapdata *adapdata = i2c_get_adapdata(adap);
+	u8 smba_en_lo;
+	u8 port;
+	int retval;
+
+	mutex_lock(adapdata->mutex);
+
+	outb_p(SB800_PIIX4_PORT_IDX, SB800_PIIX4_SMB_IDX);
+	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
+
+	port = adapdata->port;
+	if ((smba_en_lo & SB800_PIIX4_PORT_IDX_MASK) != (port << 1))
+		outb_p((smba_en_lo & ~SB800_PIIX4_PORT_IDX_MASK) | (port << 1),
+		       SB800_PIIX4_SMB_IDX + 1);
+
+	retval = piix4_access(adap, addr, flags, read_write,
+			      command, size, data);
+
+	outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1);
+
+	mutex_unlock(adapdata->mutex);
+
+	return retval;
+}
+
 static u32 piix4_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
@@ -536,6 +591,11 @@ static const struct i2c_algorithm smbus_algorithm = {
 	.functionality	= piix4_func,
 };
 
+static const struct i2c_algorithm piix4_smbus_algorithm_sb800 = {
+	.smbus_xfer	= piix4_access_sb800,
+	.functionality	= piix4_func,
+};
+
 static const struct pci_device_id piix4_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_3) },
@@ -561,11 +621,11 @@ static const struct pci_device_id piix4_ids[] = {
 
 MODULE_DEVICE_TABLE (pci, piix4_ids);
 
-static struct i2c_adapter *piix4_main_adapter;
+static struct i2c_adapter *piix4_main_adapters[PIIX4_MAX_ADAPTERS];
 static struct i2c_adapter *piix4_aux_adapter;
 
 static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
-			     struct i2c_adapter **padap)
+			     const char *name, struct i2c_adapter **padap)
 {
 	struct i2c_adapter *adap;
 	struct i2c_piix4_adapdata *adapdata;
@@ -594,7 +654,7 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 	adap->dev.parent = &dev->dev;
 
 	snprintf(adap->name, sizeof(adap->name),
-		"SMBus PIIX4 adapter at %04x", smba);
+		"SMBus PIIX4 adapter %s at %04x", name, smba);
 
 	i2c_set_adapdata(adap, adapdata);
 
@@ -611,6 +671,54 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
 	return 0;
 }
 
+static int piix4_add_adapters_sb800(struct pci_dev *dev, unsigned short smba)
+{
+	struct mutex *mutex;
+	struct i2c_piix4_adapdata *adapdata;
+	int port;
+	int retval;
+
+	mutex = kzalloc(sizeof(*mutex), GFP_KERNEL);
+	if (mutex == NULL)
+		return -ENOMEM;
+
+	mutex_init(mutex);
+
+	for (port = 0; port < PIIX4_MAX_ADAPTERS; port++) {
+		retval = piix4_add_adapter(dev, smba,
+					   piix4_main_port_names_sb800[port],
+					   &piix4_main_adapters[port]);
+		if (retval < 0)
+			goto error;
+
+		piix4_main_adapters[port]->algo = &piix4_smbus_algorithm_sb800;
+
+		adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
+		adapdata->sb800_main = true;
+		adapdata->port = port;
+		adapdata->mutex = mutex;
+	}
+
+	return retval;
+
+error:
+	dev_err(&dev->dev,
+		"Error setting up SB800 adapters. Unregistering!\n");
+	while (--port >= 0) {
+		adapdata = i2c_get_adapdata(piix4_main_adapters[port]);
+		if (adapdata->smba) {
+			i2c_del_adapter(piix4_main_adapters[port]);
+			kfree(adapdata);
+			kfree(piix4_main_adapters[port]);
+			piix4_main_adapters[port] = NULL;
+		}
+	}
+
+	kfree(mutex);
+
+	return retval;
+}
+
 static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
 	int retval;
@@ -618,20 +726,41 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if ((dev->vendor == PCI_VENDOR_ID_ATI &&
 	     dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
 	     dev->revision >= 0x40) ||
-	    dev->vendor == PCI_VENDOR_ID_AMD)
+	    dev->vendor == PCI_VENDOR_ID_AMD) {
+		if (!request_region(SB800_PIIX4_SMB_IDX, 2, "smba_idx")) {
+			dev_err(&dev->dev,
+			"SMBus base address index region 0x%x already in use!\n",
+			SB800_PIIX4_SMB_IDX);
+			return -EBUSY;
+		}
+
 		/* base address location etc changed in SB800 */
 		retval = piix4_setup_sb800(dev, id, 0);
-	else
-		retval = piix4_setup(dev, id);
+		if (retval < 0) {
+			release_region(SB800_PIIX4_SMB_IDX, 2);
+			return retval;
+		}
 
-	/* If no main SMBus found, give up */
-	if (retval < 0)
-		return retval;
+		/*
+		 * Try to register multiplexed main SMBus adapter,
+		 * give up if we can't
+		 */
+		retval = piix4_add_adapters_sb800(dev, retval);
+		if (retval < 0) {
+			release_region(SB800_PIIX4_SMB_IDX, 2);
+			return retval;
+		}
+	} else {
+		retval = piix4_setup(dev, id);
+		if (retval < 0)
+			return retval;
 
-	/* Try to register main SMBus adapter, give up if we can't */
-	retval = piix4_add_adapter(dev, retval, &piix4_main_adapter);
-	if (retval < 0)
-		return retval;
+		/* Try to register main SMBus adapter, give up if we can't */
+		retval = piix4_add_adapter(dev, retval, "main",
+					   &piix4_main_adapters[0]);
+		if (retval < 0)
+			return retval;
+	}
 
 	/* Check for auxiliary SMBus on some AMD chipsets */
 	retval = -ENODEV;
@@ -654,7 +783,8 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (retval > 0) {
 		/* Try to add the aux adapter if it exists,
 		 * piix4_add_adapter will clean up if this fails */
-		piix4_add_adapter(dev, retval, &piix4_aux_adapter);
+		piix4_add_adapter(dev, retval, piix4_aux_port_name_sb800,
+				  &piix4_aux_adapter);
 	}
 
 	return 0;
@@ -666,7 +796,13 @@ static void piix4_adap_remove(struct i2c_adapter *adap)
 
 	if (adapdata->smba) {
 		i2c_del_adapter(adap);
-		release_region(adapdata->smba, SMBIOSIZE);
+		if (adapdata->port == 0) {
+			release_region(adapdata->smba, SMBIOSIZE);
+			if (adapdata->sb800_main) {
+				kfree(adapdata->mutex);
+				release_region(SB800_PIIX4_SMB_IDX, 2);
+			}
+		}
 		kfree(adapdata);
 		kfree(adap);
 	}
@@ -674,9 +810,13 @@ static void piix4_adap_remove(struct i2c_adapter *adap)
 
 static void piix4_remove(struct pci_dev *dev)
 {
-	if (piix4_main_adapter) {
-		piix4_adap_remove(piix4_main_adapter);
-		piix4_main_adapter = NULL;
+	int port = PIIX4_MAX_ADAPTERS;
+
+	while (--port >= 0) {
+		if (piix4_main_adapters[port]) {
+			piix4_adap_remove(piix4_main_adapters[port]);
+			piix4_main_adapters[port] = NULL;
+		}
 	}
 
 	if (piix4_aux_adapter) {

drivers/i2c/busses/i2c-rcar.c

@@ -1,7 +1,8 @@
 /*
  * Driver for the Renesas RCar I2C unit
  *
- * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2011-2015 Renesas Electronics Corporation
  *
  * Copyright (C) 2012-14 Renesas Solutions Corp.
  * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
@@ -9,9 +10,6 @@
  * This file is based on the drivers/i2c/busses/i2c-sh7760.c
  * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
  *
- * This file used out-of-tree driver i2c-rcar.c
- * Copyright (C) 2011-2012 Renesas Electronics Corporation
- *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; version 2 of the License.
@@ -33,7 +31,6 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
-#include <linux/spinlock.h>
 
 /* register offsets */
 #define ICSCR	0x00	/* slave ctrl */
@@ -84,6 +81,7 @@
 
 #define RCAR_BUS_PHASE_START	(MDBS | MIE | ESG)
 #define RCAR_BUS_PHASE_DATA	(MDBS | MIE)
+#define RCAR_BUS_MASK_DATA	(~(ESG | FSB) & 0xFF)
 #define RCAR_BUS_PHASE_STOP	(MDBS | MIE | FSB)
 
 #define RCAR_IRQ_SEND	(MNR | MAL | MST | MAT | MDE)
@@ -94,10 +92,13 @@
 #define RCAR_IRQ_ACK_RECV	(~(MAT | MDR) & 0xFF)
 
 #define ID_LAST_MSG	(1 << 0)
-#define ID_IOERROR	(1 << 1)
+#define ID_FIRST_MSG	(1 << 1)
 #define ID_DONE		(1 << 2)
 #define ID_ARBLOST	(1 << 3)
 #define ID_NACK		(1 << 4)
+/* persistent flags */
+#define ID_P_PM_BLOCKED	(1 << 31)
+#define ID_P_MASK	ID_P_PM_BLOCKED
 
 enum rcar_i2c_type {
 	I2C_RCAR_GEN1,
@@ -108,10 +109,10 @@ enum rcar_i2c_type {
 struct rcar_i2c_priv {
 	void __iomem *io;
 	struct i2c_adapter adap;
-	struct i2c_msg	*msg;
+	struct i2c_msg *msg;
+	int msgs_left;
 	struct clk *clk;
 
-	spinlock_t lock;
 	wait_queue_head_t wait;
 
 	int pos;
@@ -124,9 +125,6 @@ struct rcar_i2c_priv {
 #define rcar_i2c_priv_to_dev(p)		((p)->adap.dev.parent)
 #define rcar_i2c_is_recv(p)		((p)->msg->flags & I2C_M_RD)
 
-#define rcar_i2c_flags_set(p, f)	((p)->flags |= (f))
-#define rcar_i2c_flags_has(p, f)	((p)->flags & (f))
-
 #define LOOP_TIMEOUT	1024
 
 
@@ -144,9 +142,10 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv)
 {
 	/* reset master mode */
 	rcar_i2c_write(priv, ICMIER, 0);
-	rcar_i2c_write(priv, ICMCR, 0);
+	rcar_i2c_write(priv, ICMCR, MDBS);
 	rcar_i2c_write(priv, ICMSR, 0);
-	rcar_i2c_write(priv, ICMAR, 0);
+	/* start clock */
+	rcar_i2c_write(priv, ICCCR, priv->icccr);
 }
 
 static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
@@ -163,15 +162,17 @@ static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
 	return -EBUSY;
 }
 
-static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
-				    u32 bus_speed,
-				    struct device *dev)
+static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timings *t)
 {
-	u32 scgd, cdf;
-	u32 round, ick;
-	u32 scl;
-	u32 cdf_width;
+	u32 scgd, cdf, round, ick, sum, scl, cdf_width;
 	unsigned long rate;
+	struct device *dev = rcar_i2c_priv_to_dev(priv);
+
+	/* Fall back to previously used values if not supplied */
+	t->bus_freq_hz = t->bus_freq_hz ?: 100000;
+	t->scl_fall_ns = t->scl_fall_ns ?: 35;
+	t->scl_rise_ns = t->scl_rise_ns ?: 200;
+	t->scl_int_delay_ns = t->scl_int_delay_ns ?: 50;
 
 	switch (priv->devtype) {
 	case I2C_RCAR_GEN1:
@@ -195,9 +196,9 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
 	 * SCL	= ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
 	 *
 	 * ick  : I2C internal clock < 20 MHz
-	 * ticf : I2C SCL falling time  =  35 ns here
-	 * tr   : I2C SCL rising  time  = 200 ns here
-	 * intd : LSI internal delay    =  50 ns here
+	 * ticf : I2C SCL falling time
+	 * tr   : I2C SCL rising  time
+	 * intd : LSI internal delay
 	 * clkp : peripheral_clk
 	 * F[]  : integer up-valuation
 	 */
@@ -213,12 +214,12 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
 	 * it is impossible to calculate large scale
 	 * number on u32. separate it
 	 *
-	 * F[(ticf + tr + intd) * ick]
-	 *  = F[(35 + 200 + 50)ns * ick]
-	 *  = F[285 * ick / 1000000000]
-	 *  = F[(ick / 1000000) * 285 / 1000]
+	 * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
+	 *  = F[sum * ick / 1000000000]
+	 *  = F[(ick / 1000000) * sum / 1000]
 	 */
-	round = (ick + 500000) / 1000000 * 285;
+	sum = t->scl_fall_ns + t->scl_rise_ns + t->scl_int_delay_ns;
+	round = (ick + 500000) / 1000000 * sum;
 	round = (round + 500) / 1000;
 
 	/*
@@ -235,7 +236,7 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
 	 */
 	for (scgd = 0; scgd < 0x40; scgd++) {
 		scl = ick / (20 + (scgd * 8) + round);
-		if (scl <= bus_speed)
+		if (scl <= t->bus_freq_hz)
 			goto scgd_find;
 	}
 	dev_err(dev, "it is impossible to calculate best SCL\n");
@@ -243,11 +244,9 @@ static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv,
 
 scgd_find:
 	dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
-		scl, bus_speed, clk_get_rate(priv->clk), round, cdf, scgd);
+		scl, t->bus_freq_hz, clk_get_rate(priv->clk), round, cdf, scgd);
 
-	/*
-	 * keep icccr value
-	 */
+	/* keep icccr value */
 	priv->icccr = scgd << cdf_width | cdf;
 
 	return 0;
@@ -257,33 +256,44 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
 {
 	int read = !!rcar_i2c_is_recv(priv);
 
+	priv->pos = 0;
+	if (priv->msgs_left == 1)
+		priv->flags |= ID_LAST_MSG;
+
 	rcar_i2c_write(priv, ICMAR, (priv->msg->addr << 1) | read);
-	rcar_i2c_write(priv, ICMSR, 0);
-	rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+	/*
+	 * We don't have a testcase but the HW engineers say that the write order
+	 * of ICMSR and ICMCR depends on whether we issue START or REP_START. Since
+	 * it didn't cause a drawback for me, let's rather be safe than sorry.
+	 */
+	if (priv->flags & ID_FIRST_MSG) {
+		rcar_i2c_write(priv, ICMSR, 0);
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+	} else {
+		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
+		rcar_i2c_write(priv, ICMSR, 0);
+	}
 	rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
 }
 
+static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
+{
+	priv->msg++;
+	priv->msgs_left--;
+	priv->flags &= ID_P_MASK;
+	rcar_i2c_prepare_msg(priv);
+}
+
 /*
  *		interrupt functions
  */
-static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
+static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
 {
 	struct i2c_msg *msg = priv->msg;
 
-	/*
-	 * FIXME
-	 * sometimes, unknown interrupt happened.
-	 * Do nothing
-	 */
+	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
 	if (!(msr & MDE))
-		return 0;
-
-	/*
-	 * If address transfer phase finished,
-	 * goto data phase.
-	 */
-	if (msr & MAT)
-		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
+		return;
 
 	if (priv->pos < msg->len) {
 		/*
@@ -305,67 +315,50 @@ static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
 		 * [ICRXTX] -> [SHIFT] -> [I2C bus]
 		 */
 
-		if (priv->flags & ID_LAST_MSG)
+		if (priv->flags & ID_LAST_MSG) {
 			/*
 			 * If current msg is the _LAST_ msg,
 			 * prepare stop condition here.
 			 * ID_DONE will be set on STOP irq.
 			 */
 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
-		else
-			/*
-			 * If current msg is _NOT_ last msg,
-			 * it doesn't call stop phase.
-			 * thus, there is no STOP irq.
-			 * return ID_DONE here.
-			 */
-			return ID_DONE;
+		} else {
+			rcar_i2c_next_msg(priv);
+			return;
+		}
 	}
 
 	rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND);
-
-	return 0;
 }
 
-static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
+static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
 {
 	struct i2c_msg *msg = priv->msg;
 
-	/*
-	 * FIXME
-	 * sometimes, unknown interrupt happened.
-	 * Do nothing
-	 */
+	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
 	if (!(msr & MDR))
-		return 0;
+		return;
 
 	if (msr & MAT) {
-		/*
-		 * Address transfer phase finished,
-		 * but, there is no data at this point.
-		 * Do nothing.
-		 */
+		/* Address transfer phase finished, but no data at this point. */
 	} else if (priv->pos < msg->len) {
-		/*
-		 * get received data
-		 */
+		/* get received data */
 		msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX);
 		priv->pos++;
 	}
 
 	/*
-	 * If next received data is the _LAST_,
-	 * go to STOP phase,
-	 * otherwise, go to DATA phase.
+	 * If next received data is the _LAST_, go to STOP phase. Might be
+	 * overwritten by REP START when setting up a new msg. Not elegant
+	 * but the only stable sequence for REP START I have found so far.
 	 */
 	if (priv->pos + 1 >= msg->len)
 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
-	else
-		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
-
-	rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
 
-	return 0;
+	if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG))
+		rcar_i2c_next_msg(priv);
+	else
+		rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
 }
 
 static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
@@ -426,62 +419,57 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
 static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
 {
 	struct rcar_i2c_priv *priv = ptr;
-	irqreturn_t result = IRQ_HANDLED;
-	u32 msr;
-
-	/*-------------- spin lock -----------------*/
-	spin_lock(&priv->lock);
+	u32 msr, val;
 
-	if (rcar_i2c_slave_irq(priv))
-		goto exit;
+	/* Clear START or STOP as soon as we can */
+	val = rcar_i2c_read(priv, ICMCR);
+	rcar_i2c_write(priv, ICMCR, val & RCAR_BUS_MASK_DATA);
 
 	msr = rcar_i2c_read(priv, ICMSR);
 
 	/* Only handle interrupts that are currently enabled */
 	msr &= rcar_i2c_read(priv, ICMIER);
 	if (!msr) {
-		result = IRQ_NONE;
-		goto exit;
+		if (rcar_i2c_slave_irq(priv))
+			return IRQ_HANDLED;
+
+		return IRQ_NONE;
 	}
 
 	/* Arbitration lost */
 	if (msr & MAL) {
-		rcar_i2c_flags_set(priv, (ID_DONE | ID_ARBLOST));
+		priv->flags |= ID_DONE | ID_ARBLOST;
 		goto out;
 	}
 
 	/* Nack */
 	if (msr & MNR) {
-		/* go to stop phase */
-		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
+		/* HW automatically sends STOP after received NACK */
 		rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
-		rcar_i2c_flags_set(priv, ID_NACK);
+		priv->flags |= ID_NACK;
 		goto out;
 	}
 
 	/* Stop */
 	if (msr & MST) {
-		rcar_i2c_flags_set(priv, ID_DONE);
+		priv->msgs_left--; /* The last message also made it */
+		priv->flags |= ID_DONE;
 		goto out;
 	}
 
 	if (rcar_i2c_is_recv(priv))
-		rcar_i2c_flags_set(priv, rcar_i2c_irq_recv(priv, msr));
+		rcar_i2c_irq_recv(priv, msr);
 	else
-		rcar_i2c_flags_set(priv, rcar_i2c_irq_send(priv, msr));
+		rcar_i2c_irq_send(priv, msr);
 
 out:
-	if (rcar_i2c_flags_has(priv, ID_DONE)) {
+	if (priv->flags & ID_DONE) {
 		rcar_i2c_write(priv, ICMIER, 0);
 		rcar_i2c_write(priv, ICMSR, 0);
 		wake_up(&priv->wait);
 	}
 
-exit:
-	spin_unlock(&priv->lock);
-	/*-------------- spin unlock -----------------*/
-
-	return result;
+	return IRQ_HANDLED;
 }
 
 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
@@ -490,22 +478,11 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 {
 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
 	struct device *dev = rcar_i2c_priv_to_dev(priv);
-	unsigned long flags;
 	int i, ret;
-	long timeout;
+	long time_left;
 
 	pm_runtime_get_sync(dev);
 
-	/*-------------- spin lock -----------------*/
-	spin_lock_irqsave(&priv->lock, flags);
-
-	rcar_i2c_init(priv);
-	/* start clock */
-	rcar_i2c_write(priv, ICCCR, priv->icccr);
-
-	spin_unlock_irqrestore(&priv->lock, flags);
-	/*-------------- spin unlock -----------------*/
-
 	ret = rcar_i2c_bus_barrier(priv);
 	if (ret < 0)
 		goto out;
@@ -514,48 +491,27 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 		/* This HW can't send STOP after address phase */
 		if (msgs[i].len == 0) {
 			ret = -EOPNOTSUPP;
-			break;
-		}
-
-		/*-------------- spin lock -----------------*/
-		spin_lock_irqsave(&priv->lock, flags);
-
-		/* init each data */
-		priv->msg	= &msgs[i];
-		priv->pos	= 0;
-		priv->flags	= 0;
-		if (i == num - 1)
-			rcar_i2c_flags_set(priv, ID_LAST_MSG);
-
-		rcar_i2c_prepare_msg(priv);
-
-		spin_unlock_irqrestore(&priv->lock, flags);
-		/*-------------- spin unlock -----------------*/
-
-		timeout = wait_event_timeout(priv->wait,
-					     rcar_i2c_flags_has(priv, ID_DONE),
-					     adap->timeout);
-		if (!timeout) {
-			ret = -ETIMEDOUT;
-			break;
-		}
-
-		if (rcar_i2c_flags_has(priv, ID_NACK)) {
-			ret = -ENXIO;
-			break;
-		}
-
-		if (rcar_i2c_flags_has(priv, ID_ARBLOST)) {
-			ret = -EAGAIN;
-			break;
-		}
-
-		if (rcar_i2c_flags_has(priv, ID_IOERROR)) {
-			ret = -EIO;
-			break;
+			goto out;
 		}
+	}
 
-		ret = i + 1; /* The number of transfer */
+	/* init first message */
+	priv->msg = msgs;
+	priv->msgs_left = num;
+	priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG;
+	rcar_i2c_prepare_msg(priv);
+
+	time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
+				     num * adap->timeout);
+	if (!time_left) {
+		rcar_i2c_init(priv);
+		ret = -ETIMEDOUT;
+	} else if (priv->flags & ID_NACK) {
+		ret = -ENXIO;
+	} else if (priv->flags & ID_ARBLOST) {
+		ret = -EAGAIN;
+	} else {
+		ret = num - priv->msgs_left; /* The number of transfer */
 	}
 out:
 	pm_runtime_put(dev);
@@ -637,7 +593,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	struct i2c_adapter *adap;
 	struct resource *res;
 	struct device *dev = &pdev->dev;
-	u32 bus_speed;
+	struct i2c_timings i2c_t;
 	int irq, ret;
 
 	priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
@@ -650,23 +606,13 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->clk);
 	}
 
-	bus_speed = 100000; /* default 100 kHz */
-	of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed);
-
-	priv->devtype = (enum rcar_i2c_type)of_match_device(rcar_i2c_dt_ids, dev)->data;
-
-	ret = rcar_i2c_clock_calculate(priv, bus_speed, dev);
-	if (ret < 0)
-		return ret;
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->io = devm_ioremap_resource(dev, res);
 	if (IS_ERR(priv->io))
 		return PTR_ERR(priv->io);
 
-	irq = platform_get_irq(pdev, 0);
+	priv->devtype = (enum rcar_i2c_type)of_match_device(rcar_i2c_dt_ids, dev)->data;
 	init_waitqueue_head(&priv->wait);
-	spin_lock_init(&priv->lock);
 
 	adap = &priv->adap;
 	adap->nr = pdev->id;
@@ -678,26 +624,47 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	i2c_set_adapdata(adap, priv);
 	strlcpy(adap->name, pdev->name, sizeof(adap->name));
 
-	ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0,
-			       dev_name(dev), priv);
+	i2c_parse_fw_timings(dev, &i2c_t, false);
+
+	pm_runtime_enable(dev);
+	pm_runtime_get_sync(dev);
+	ret = rcar_i2c_clock_calculate(priv, &i2c_t);
+	if (ret < 0)
+		goto out_pm_put;
+
+	rcar_i2c_init(priv);
+
+	/* Don't suspend when multi-master to keep arbitration working */
+	if (of_property_read_bool(dev->of_node, "multi-master"))
+		priv->flags |= ID_P_PM_BLOCKED;
+	else
+		pm_runtime_put(dev);
+
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv);
 	if (ret < 0) {
 		dev_err(dev, "cannot get irq %d\n", irq);
-		return ret;
+		goto out_pm_disable;
 	}
 
-	pm_runtime_enable(dev);
 	platform_set_drvdata(pdev, priv);
 
 	ret = i2c_add_numbered_adapter(adap);
 	if (ret < 0) {
 		dev_err(dev, "reg adap failed: %d\n", ret);
-		pm_runtime_disable(dev);
-		return ret;
+		goto out_pm_disable;
 	}
 
 	dev_info(dev, "probed\n");
 
 	return 0;
+
+ out_pm_put:
+	pm_runtime_put(dev);
+ out_pm_disable:
+	pm_runtime_disable(dev);
+	return ret;
 }
 
 static int rcar_i2c_remove(struct platform_device *pdev)
@@ -706,6 +673,8 @@ static int rcar_i2c_remove(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 
 	i2c_del_adapter(&priv->adap);
+	if (priv->flags & ID_P_PM_BLOCKED)
+		pm_runtime_put(dev);
 	pm_runtime_disable(dev);
 
 	return 0;

drivers/i2c/busses/i2c-s3c2410.c

@@ -784,7 +784,6 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 	int retry;
 	int ret;
 
-	pm_runtime_get_sync(&adap->dev);
 	ret = clk_enable(i2c->clk);
 	if (ret)
 		return ret;
@@ -795,7 +794,6 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 
 		if (ret != -EAGAIN) {
 			clk_disable(i2c->clk);
-			pm_runtime_put(&adap->dev);
 			return ret;
 		}
 
@@ -805,7 +803,6 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 	}
 
 	clk_disable(i2c->clk);
-	pm_runtime_put(&adap->dev);
 	return -EREMOTEIO;
 }
 
@@ -1256,8 +1253,6 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	pm_runtime_enable(&i2c->adap.dev);
-
 	dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
 	return 0;
 }
@@ -1273,7 +1268,6 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
 
 	clk_unprepare(i2c->clk);
 
-	pm_runtime_disable(&i2c->adap.dev);
 	pm_runtime_disable(&pdev->dev);
 
 	s3c24xx_i2c_deregister_cpufreq(i2c);

drivers/i2c/busses/i2c-st.c

@@ -708,8 +708,7 @@ static int st_i2c_xfer(struct i2c_adapter *i2c_adap,
 #ifdef CONFIG_PM_SLEEP
 static int st_i2c_suspend(struct device *dev)
 {
-	struct platform_device *pdev =
-		container_of(dev, struct platform_device, dev);
+	struct platform_device *pdev = to_platform_device(dev);
 	struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 
 	if (i2c_dev->busy)

drivers/i2c/busses/i2c-taos-evm.c

@@ -130,7 +130,13 @@ static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 			return 0;
 	} else {
 		if (p[0] == 'x') {
-			data->byte = simple_strtol(p + 1, NULL, 16);
+			/*
+			 * Voluntarily dropping error code of kstrtou8 since all
+			 * error code that it could return are invalid according
+			 * to Documentation/i2c/fault-codes.
+			 */
+			if (kstrtou8(p + 1, 16, &data->byte))
+				return -EPROTO;
 			return 0;
 		}
 	}

drivers/i2c/busses/i2c-uniphier-f.c

@@ -466,6 +466,11 @@ static int uniphier_fi2c_clk_init(struct device *dev,
 	if (of_property_read_u32(np, "clock-frequency", &bus_speed))
 		bus_speed = UNIPHIER_FI2C_DEFAULT_SPEED;
 
+	if (!bus_speed) {
+		dev_err(dev, "clock-freqyency should not be zero\n");
+		return -EINVAL;
+	}
+
 	if (bus_speed > UNIPHIER_FI2C_MAX_SPEED)
 		bus_speed = UNIPHIER_FI2C_MAX_SPEED;
 
@@ -481,6 +486,10 @@ static int uniphier_fi2c_clk_init(struct device *dev,
 		return ret;
 
 	clk_rate = clk_get_rate(priv->clk);
+	if (!clk_rate) {
+		dev_err(dev, "input clock rate should not be zero\n");
+		return -EINVAL;
+	}
 
 	uniphier_fi2c_reset(priv);
 
@@ -531,7 +540,7 @@ static int uniphier_fi2c_probe(struct platform_device *pdev)
 
 	ret = uniphier_fi2c_clk_init(dev, priv);
 	if (ret)
-		return ret;
+		goto err;
 
 	ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
 			       pdev->name, priv);

drivers/i2c/busses/i2c-uniphier.c

@@ -327,6 +327,11 @@ static int uniphier_i2c_clk_init(struct device *dev,
 	if (of_property_read_u32(np, "clock-frequency", &bus_speed))
 		bus_speed = UNIPHIER_I2C_DEFAULT_SPEED;
 
+	if (!bus_speed) {
+		dev_err(dev, "clock-freqyency should not be zero\n");
+		return -EINVAL;
+	}
+
 	if (bus_speed > UNIPHIER_I2C_MAX_SPEED)
 		bus_speed = UNIPHIER_I2C_MAX_SPEED;
 
@@ -342,6 +347,10 @@ static int uniphier_i2c_clk_init(struct device *dev,
 		return ret;
 
 	clk_rate = clk_get_rate(priv->clk);
+	if (!clk_rate) {
+		dev_err(dev, "input clock rate should not be zero\n");
+		return -EINVAL;
+	}
 
 	uniphier_i2c_reset(priv, true);
 
@@ -388,7 +397,7 @@ static int uniphier_i2c_probe(struct platform_device *pdev)
 
 	ret = uniphier_i2c_clk_init(dev, priv);
 	if (ret)
-		return ret;
+		goto err;
 
 	ret = devm_request_irq(dev, irq, uniphier_i2c_interrupt, 0, pdev->name,
 			       priv);

drivers/i2c/busses/i2c-xiic.c

@@ -70,7 +70,7 @@ struct xiic_i2c {
 	wait_queue_head_t	wait;
 	struct i2c_adapter	adap;
 	struct i2c_msg		*tx_msg;
-	spinlock_t		lock;
+	struct mutex		lock;
 	unsigned int		tx_pos;
 	unsigned int		nmsgs;
 	enum xilinx_i2c_state	state;
@@ -369,7 +369,7 @@ static irqreturn_t xiic_process(int irq, void *dev_id)
 	 * To find which interrupts are pending; AND interrupts pending with
 	 * interrupts masked.
 	 */
-	spin_lock(&i2c->lock);
+	mutex_lock(&i2c->lock);
 	isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
 	ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
 	pend = isr & ier;
@@ -497,7 +497,7 @@ out:
 	dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr);
 
 	xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr);
-	spin_unlock(&i2c->lock);
+	mutex_unlock(&i2c->lock);
 	return IRQ_HANDLED;
 }
 
@@ -662,10 +662,10 @@ static void __xiic_start_xfer(struct xiic_i2c *i2c)
 
 static void xiic_start_xfer(struct xiic_i2c *i2c)
 {
-	spin_lock(&i2c->lock);
+	mutex_lock(&i2c->lock);
 	xiic_reinit(i2c);
 	__xiic_start_xfer(i2c);
-	spin_unlock(&i2c->lock);
+	mutex_unlock(&i2c->lock);
 }
 
 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
@@ -745,7 +745,7 @@ static int xiic_i2c_probe(struct platform_device *pdev)
 	i2c->adap.dev.parent = &pdev->dev;
 	i2c->adap.dev.of_node = pdev->dev.of_node;
 
-	spin_lock_init(&i2c->lock);
+	mutex_init(&i2c->lock);
 	init_waitqueue_head(&i2c->wait);
 
 	ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr,

drivers/i2c/busses/i2c-xlr.c

@@ -17,6 +17,10 @@
 #include <linux/i2c.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
 
 /* XLR I2C REGISTERS */
 #define XLR_I2C_CFG		0x00
@@ -30,6 +34,10 @@
 #define XLR_I2C_BYTECNT		0x08
 #define XLR_I2C_HDSTATIM	0x09
 
+/* Sigma Designs additional registers */
+#define XLR_I2C_INT_EN		0x09
+#define XLR_I2C_INT_STAT	0x0a
+
 /* XLR I2C REGISTERS FLAGS */
 #define XLR_I2C_BUS_BUSY	0x01
 #define XLR_I2C_SDOEMPTY	0x02
@@ -63,11 +71,98 @@ static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg)
 	return __raw_readl(base + reg);
 }
 
+#define XLR_I2C_FLAG_IRQ	1
+
+struct xlr_i2c_config {
+	u32 flags;		/* optional feature support */
+	u32 status_busy;	/* value of STATUS[0] when busy */
+	u32 cfg_extra;		/* extra CFG bits to set */
+};
+
 struct xlr_i2c_private {
 	struct i2c_adapter adap;
 	u32 __iomem *iobase;
+	int irq;
+	int pos;
+	struct i2c_msg *msg;
+	const struct xlr_i2c_config *cfg;
+	wait_queue_head_t wait;
+	struct clk *clk;
 };
 
+static int xlr_i2c_busy(struct xlr_i2c_private *priv, u32 status)
+{
+	return (status & XLR_I2C_BUS_BUSY) == priv->cfg->status_busy;
+}
+
+static int xlr_i2c_idle(struct xlr_i2c_private *priv)
+{
+	return !xlr_i2c_busy(priv, xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS));
+}
+
+static int xlr_i2c_wait(struct xlr_i2c_private *priv, unsigned long timeout)
+{
+	int status;
+	int t;
+
+	t = wait_event_timeout(priv->wait, xlr_i2c_idle(priv),
+				msecs_to_jiffies(timeout));
+	if (!t)
+		return -ETIMEDOUT;
+
+	status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+
+	return status & XLR_I2C_ACK_ERR ? -EIO : 0;
+}
+
+static void xlr_i2c_tx_irq(struct xlr_i2c_private *priv, u32 status)
+{
+	struct i2c_msg *msg = priv->msg;
+
+	if (status & XLR_I2C_SDOEMPTY)
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT,
+				msg->buf[priv->pos++]);
+}
+
+static void xlr_i2c_rx_irq(struct xlr_i2c_private *priv, u32 status)
+{
+	struct i2c_msg *msg = priv->msg;
+
+	if (status & XLR_I2C_RXRDY)
+		msg->buf[priv->pos++] =
+			xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
+}
+
+static irqreturn_t xlr_i2c_irq(int irq, void *dev_id)
+{
+	struct xlr_i2c_private *priv = dev_id;
+	struct i2c_msg *msg = priv->msg;
+	u32 int_stat, status;
+
+	int_stat = xlr_i2c_rdreg(priv->iobase, XLR_I2C_INT_STAT);
+	if (!int_stat)
+		return IRQ_NONE;
+
+	xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, int_stat);
+
+	if (!msg)
+		return IRQ_HANDLED;
+
+	status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+
+	if (priv->pos < msg->len) {
+		if (msg->flags & I2C_M_RD)
+			xlr_i2c_rx_irq(priv, status);
+		else
+			xlr_i2c_tx_irq(priv, status);
+	}
+
+	if (!xlr_i2c_busy(priv, status))
+		wake_up(&priv->wait);
+
+	return IRQ_HANDLED;
+}
+
 static int xlr_i2c_tx(struct xlr_i2c_private *priv,  u16 len,
 	u8 *buf, u16 addr)
 {
@@ -75,37 +170,48 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv,  u16 len,
 	unsigned long timeout, stoptime, checktime;
 	u32 i2c_status;
 	int pos, timedout;
-	u8 offset, byte;
+	u8 offset;
+	u32 xfer;
+
+	if (!len)
+		return -EOPNOTSUPP;
 
 	offset = buf[0];
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
-	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR);
-	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
+	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,
+			XLR_I2C_CFG_ADDR | priv->cfg->cfg_extra);
 
 	timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
 	stoptime = jiffies + timeout;
 	timedout = 0;
-	pos = 1;
-retry:
+
 	if (len == 1) {
-		xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
-				XLR_I2C_STARTXFR_ND);
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
+		xfer = XLR_I2C_STARTXFR_ND;
+		pos = 1;
 	} else {
-		xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos]);
-		xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
-				XLR_I2C_STARTXFR_WR);
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 2);
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[1]);
+		xfer = XLR_I2C_STARTXFR_WR;
+		pos = 2;
 	}
 
+	priv->pos = pos;
+
+retry:
+	/* retry can only happen on the first byte */
+	xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, xfer);
+
+	if (priv->irq > 0)
+		return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len);
+
 	while (!timedout) {
 		checktime = jiffies;
 		i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
 
-		if (i2c_status & XLR_I2C_SDOEMPTY) {
-			pos++;
-			/* need to do a empty dataout after the last byte */
-			byte = (pos < len) ? buf[pos] : 0;
-			xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, byte);
+		if ((i2c_status & XLR_I2C_SDOEMPTY) && pos < len) {
+			xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos++]);
 
 			/* reset timeout on successful xmit */
 			stoptime = jiffies + timeout;
@@ -121,7 +227,7 @@ retry:
 		if (i2c_status & XLR_I2C_ACK_ERR)
 			return -EIO;
 
-		if ((i2c_status & XLR_I2C_BUS_BUSY) == 0 && pos >= len)
+		if (!xlr_i2c_busy(priv, i2c_status) && pos >= len)
 			return 0;
 	}
 	dev_err(&adap->dev, "I2C transmit timeout\n");
@@ -134,12 +240,17 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
 	u32 i2c_status;
 	unsigned long timeout, stoptime, checktime;
 	int nbytes, timedout;
-	u8 byte;
 
-	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR);
-	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);
+	if (!len)
+		return -EOPNOTSUPP;
+
+	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,
+			XLR_I2C_CFG_NOADDR | priv->cfg->cfg_extra);
+	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
 
+	priv->pos = 0;
+
 	timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
 	stoptime = jiffies + timeout;
 	timedout = 0;
@@ -147,18 +258,18 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
 retry:
 	xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, XLR_I2C_STARTXFR_RD);
 
+	if (priv->irq > 0)
+		return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len);
+
 	while (!timedout) {
 		checktime = jiffies;
 		i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
 		if (i2c_status & XLR_I2C_RXRDY) {
-			if (nbytes > len)
+			if (nbytes >= len)
 				return -EIO;	/* should not happen */
 
-			/* we need to do a dummy datain when nbytes == len */
-			byte = xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
-			if (nbytes < len)
-				buf[nbytes] = byte;
-			nbytes++;
+			buf[nbytes++] =
+				xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
 
 			/* reset timeout on successful read */
 			stoptime = jiffies + timeout;
@@ -174,7 +285,7 @@ retry:
 		if (i2c_status & XLR_I2C_ACK_ERR)
 			return -EIO;
 
-		if ((i2c_status & XLR_I2C_BUS_BUSY) == 0)
+		if (!xlr_i2c_busy(priv, i2c_status))
 			return 0;
 	}
 
@@ -190,8 +301,17 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap,
 	int ret = 0;
 	struct xlr_i2c_private *priv = i2c_get_adapdata(adap);
 
+	ret = clk_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	if (priv->irq)
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0xf);
+
+
 	for (i = 0; ret == 0 && i < num; i++) {
 		msg = &msgs[i];
+		priv->msg = msg;
 		if (msg->flags & I2C_M_RD)
 			ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0],
 					msg->addr);
@@ -200,13 +320,19 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap,
 					msg->addr);
 	}
 
+	if (priv->irq)
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0);
+
+	clk_disable(priv->clk);
+	priv->msg = NULL;
+
 	return (ret != 0) ? ret : num;
 }
 
 static u32 xlr_func(struct i2c_adapter *adap)
 {
 	/* Emulate SMBUS over I2C */
-	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
+	return (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | I2C_FUNC_I2C;
 }
 
 static struct i2c_algorithm xlr_i2c_algo = {
@@ -214,22 +340,89 @@ static struct i2c_algorithm xlr_i2c_algo = {
 	.functionality	= xlr_func,
 };
 
+static const struct xlr_i2c_config xlr_i2c_config_default = {
+	.status_busy	= XLR_I2C_BUS_BUSY,
+	.cfg_extra	= 0,
+};
+
+static const struct xlr_i2c_config xlr_i2c_config_tangox = {
+	.flags		= XLR_I2C_FLAG_IRQ,
+	.status_busy	= 0,
+	.cfg_extra	= 1 << 8,
+};
+
+static const struct of_device_id xlr_i2c_dt_ids[] = {
+	{
+		.compatible	= "sigma,smp8642-i2c",
+		.data		= &xlr_i2c_config_tangox,
+	},
+	{ }
+};
+
 static int xlr_i2c_probe(struct platform_device *pdev)
 {
+	const struct of_device_id *match;
 	struct xlr_i2c_private  *priv;
 	struct resource *res;
+	struct clk *clk;
+	unsigned long clk_rate;
+	unsigned long clk_div;
+	u32 busfreq;
+	int irq;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
+	match = of_match_device(xlr_i2c_dt_ids, &pdev->dev);
+	if (match)
+		priv->cfg = match->data;
+	else
+		priv->cfg = &xlr_i2c_config_default;
+
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->iobase = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(priv->iobase))
 		return PTR_ERR(priv->iobase);
 
+	irq = platform_get_irq(pdev, 0);
+
+	if (irq > 0 && (priv->cfg->flags & XLR_I2C_FLAG_IRQ)) {
+		priv->irq = irq;
+
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0);
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, 0xf);
+
+		ret = devm_request_irq(&pdev->dev, priv->irq, xlr_i2c_irq,
+					IRQF_SHARED, dev_name(&pdev->dev),
+					priv);
+		if (ret)
+			return ret;
+
+		init_waitqueue_head(&priv->wait);
+	}
+
+	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+				 &busfreq))
+		busfreq = 100000;
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(clk)) {
+		ret = clk_prepare_enable(clk);
+		if (ret)
+			return ret;
+
+		clk_rate = clk_get_rate(clk);
+		clk_div = DIV_ROUND_UP(clk_rate, 2 * busfreq);
+		xlr_i2c_wreg(priv->iobase, XLR_I2C_CLKDIV, clk_div);
+
+		clk_disable(clk);
+		priv->clk = clk;
+	}
+
 	priv->adap.dev.parent = &pdev->dev;
+	priv->adap.dev.of_node	= pdev->dev.of_node;
 	priv->adap.owner	= THIS_MODULE;
 	priv->adap.algo_data	= priv;
 	priv->adap.algo		= &xlr_i2c_algo;
@@ -255,6 +448,8 @@ static int xlr_i2c_remove(struct platform_device *pdev)
 
 	priv = platform_get_drvdata(pdev);
 	i2c_del_adapter(&priv->adap);
+	clk_unprepare(priv->clk);
+
 	return 0;
 }
 
@@ -263,6 +458,7 @@ static struct platform_driver xlr_i2c_driver = {
 	.remove = xlr_i2c_remove,
 	.driver = {
 		.name   = "xlr-i2cbus",
+		.of_match_table	= xlr_i2c_dt_ids,
 	},
 };
 

drivers/i2c/i2c-core.c

@@ -53,6 +53,7 @@
 #include <linux/jump_label.h>
 #include <asm/uaccess.h>
 #include <linux/err.h>
+#include <linux/property.h>
 
 #include "i2c-core.h"
 
@@ -1563,6 +1564,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
 
 	pm_runtime_no_callbacks(&adap->dev);
+	pm_runtime_enable(&adap->dev);
 
 #ifdef CONFIG_I2C_COMPAT
 	res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
@@ -1817,6 +1819,8 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 	/* device name is gone after device_unregister */
 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
 
+	pm_runtime_disable(&adap->dev);
+
 	/* wait until all references to the device are gone
 	 *
 	 * FIXME: This is old code and should ideally be replaced by an
@@ -1839,6 +1843,58 @@ void i2c_del_adapter(struct i2c_adapter *adap)
 }
 EXPORT_SYMBOL(i2c_del_adapter);
 
+/**
+ * i2c_parse_fw_timings - get I2C related timing parameters from firmware
+ * @dev: The device to scan for I2C timing properties
+ * @t: the i2c_timings struct to be filled with values
+ * @use_defaults: bool to use sane defaults derived from the I2C specification
+ *		  when properties are not found, otherwise use 0
+ *
+ * Scan the device for the generic I2C properties describing timing parameters
+ * for the signal and fill the given struct with the results. If a property was
+ * not found and use_defaults was true, then maximum timings are assumed which
+ * are derived from the I2C specification. If use_defaults is not used, the
+ * results will be 0, so drivers can apply their own defaults later. The latter
+ * is mainly intended for avoiding regressions of existing drivers which want
+ * to switch to this function. New drivers almost always should use the defaults.
+ */
+
+void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
+{
+	int ret;
+
+	memset(t, 0, sizeof(*t));
+
+	ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
+	if (ret && use_defaults)
+		t->bus_freq_hz = 100000;
+
+	ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
+	if (ret && use_defaults) {
+		if (t->bus_freq_hz <= 100000)
+			t->scl_rise_ns = 1000;
+		else if (t->bus_freq_hz <= 400000)
+			t->scl_rise_ns = 300;
+		else
+			t->scl_rise_ns = 120;
+	}
+
+	ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
+	if (ret && use_defaults) {
+		if (t->bus_freq_hz <= 400000)
+			t->scl_fall_ns = 300;
+		else
+			t->scl_fall_ns = 120;
+	}
+
+	device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
+
+	ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
+	if (ret && use_defaults)
+		t->sda_fall_ns = t->scl_fall_ns;
+}
+EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
+
 /* ------------------------------------------------------------------------- */
 
 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))

include/linux/i2c.h

@@ -413,6 +413,22 @@ struct i2c_algorithm {
 #endif
 };
 
+/**
+ * struct i2c_timings - I2C timing information
+ * @bus_freq_hz: the bus frequency in Hz
+ * @scl_rise_ns: time SCL signal takes to rise in ns; t(r) in the I2C specification
+ * @scl_fall_ns: time SCL signal takes to fall in ns; t(f) in the I2C specification
+ * @scl_int_delay_ns: time IP core additionally needs to setup SCL in ns
+ * @sda_fall_ns: time SDA signal takes to fall in ns; t(f) in the I2C specification
+ */
+struct i2c_timings {
+	u32 bus_freq_hz;
+	u32 scl_rise_ns;
+	u32 scl_fall_ns;
+	u32 scl_int_delay_ns;
+	u32 sda_fall_ns;
+};
+
 /**
  * struct i2c_bus_recovery_info - I2C bus recovery information
  * @recover_bus: Recover routine. Either pass driver's recover_bus() routine, or
@@ -493,6 +509,8 @@ struct i2c_adapter_quirks {
 /* convenience macro for typical write-then read case */
 #define I2C_AQ_COMB_WRITE_THEN_READ	(I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | \
 					 I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
+/* clock stretching is not supported */
+#define I2C_AQ_NO_CLK_STRETCH		BIT(4)
 
 /*
  * i2c_adapter is the structure used to identify a physical i2c bus along
@@ -602,6 +620,7 @@ extern void i2c_clients_command(struct i2c_adapter *adap,
 extern struct i2c_adapter *i2c_get_adapter(int nr);
 extern void i2c_put_adapter(struct i2c_adapter *adap);
 
+void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults);
 
 /* Return the functionality mask */
 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
@@ -615,6 +634,20 @@ static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 	return (func & i2c_get_functionality(adap)) == func;
 }
 
+/**
+ * i2c_check_quirks() - Function for checking the quirk flags in an i2c adapter
+ * @adap: i2c adapter
+ * @quirks: quirk flags
+ *
+ * Return: true if the adapter has all the specified quirk flags, false if not
+ */
+static inline bool i2c_check_quirks(struct i2c_adapter *adap, u64 quirks)
+{
+	if (!adap->quirks)
+		return false;
+	return (adap->quirks->flags & quirks) == quirks;
+}
+
 /* Return the adapter number for a specific adapter */
 static inline int i2c_adapter_id(struct i2c_adapter *adap)
 {
@@ -622,7 +655,7 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap)
 }
 
 /**
- * module_i2c_driver() - Helper macro for registering a I2C driver
+ * module_i2c_driver() - Helper macro for registering a modular I2C driver
  * @__i2c_driver: i2c_driver struct
  *
  * Helper macro for I2C drivers which do not do anything special in module
@@ -633,6 +666,17 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap)
 	module_driver(__i2c_driver, i2c_add_driver, \
 			i2c_del_driver)
 
+/**
+ * builtin_i2c_driver() - Helper macro for registering a builtin I2C driver
+ * @__i2c_driver: i2c_driver struct
+ *
+ * Helper macro for I2C drivers which do not do anything special in their
+ * init. This eliminates a lot of boilerplate. Each driver may only
+ * use this macro once, and calling it replaces device_initcall().
+ */
+#define builtin_i2c_driver(__i2c_driver) \
+	builtin_driver(__i2c_driver, i2c_add_driver)
+
 #endif /* I2C */
 
 #if IS_ENABLED(CONFIG_OF)
@@ -644,6 +688,7 @@ extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 
 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
+
 #else
 
 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)