Merge tag 'pwm/for-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "This set of changes improve some aspects of the atomic API as well as
  make use of this new API in the regulator framework to allow properly
  dealing with critical regulators controlled by a PWM.

  Aside from that there's a bunch of updates and cleanups for existing
  drivers, as well as the addition of new drivers for the Broadcom
  iProc, STMPE and ChromeOS EC controllers"

* tag 'pwm/for-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (44 commits)
  regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range
  regulator: pwm: Support extra continuous mode cases
  pwm: Add ChromeOS EC PWM driver
  dt-bindings: pwm: Add binding for ChromeOS EC PWM
  mfd: cros_ec: Add EC_PWM function definitions
  mfd: cros_ec: Add cros_ec_cmd_xfer_status() helper
  pwm: atmel: Use of_device_get_match_data()
  pwm: atmel: Fix checkpatch warnings
  pwm: atmel: Fix disabling of PWM channels
  dt-bindings: pwm: Add R-Car H3 device tree bindings
  pwm: rcar: Use ARCH_RENESAS
  pwm: tegra: Add support for Tegra186
  dt-bindings: pwm: tegra: Add compatible string for Tegra186
  pwm: tegra: Avoid overflow when calculating duty cycle
  pwm: tegra: Allow 100 % duty cycle
  pwm: tegra: Add support for reset control
  pwm: tegra: Rename mmio_base to regs
  pwm: tegra: Remove useless padding
  pwm: tegra: Drop NUM_PWM macro
  pwm: lpc32xx: Set PWM_PIN_LEVEL bit to default value
  ...

Documentation/ABI/testing/sysfs-class-pwm

@@ -77,3 +77,12 @@ Description:
 		Enable/disable the PWM signal.
 		0 is disabled
 		1 is enabled
+
+What:		/sys/class/pwm/pwmchipN/pwmX/capture
+Date:		June 2016
+KernelVersion:	4.8
+Contact:	Lee Jones <lee.jones@linaro.org>
+Description:
+		Capture information about a PWM signal. The output format is a
+		pair unsigned integers (period and duty cycle), separated by a
+		single space.

Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt

@@ -0,0 +1,21 @@
+Broadcom iProc PWM controller device tree bindings
+
+This controller has 4 channels.
+
+Required Properties :
+- compatible: must be "brcm,iproc-pwm"
+- reg: physical base address and length of the controller's registers
+- clocks: phandle + clock specifier pair for the external clock
+- #pwm-cells: Should be 3. See pwm.txt in this directory for a
+  description of the cells format.
+
+Refer to clocks/clock-bindings.txt for generic clock consumer properties.
+
+Example:
+
+pwm: pwm@18031000 {
+	compatible = "brcm,iproc-pwm";
+	reg = <0x18031000 0x28>;
+	clocks = <&osc>;
+	#pwm-cells = <3>;
+};

Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt

@@ -0,0 +1,23 @@
+* PWM controlled by ChromeOS EC
+
+Google's ChromeOS EC PWM is a simple PWM attached to the Embedded Controller
+(EC) and controlled via a host-command interface.
+
+An EC PWM node should be only found as a sub-node of the EC node (see
+Documentation/devicetree/bindings/mfd/cros-ec.txt).
+
+Required properties:
+- compatible: Must contain "google,cros-ec-pwm"
+- #pwm-cells: Should be 1. The cell specifies the PWM index.
+
+Example:
+	cros-ec@0 {
+		compatible = "google,cros-ec-spi";
+
+		...
+
+		cros_ec_pwm: ec-pwm {
+			compatible = "google,cros-ec-pwm";
+			#pwm-cells = <1>;
+		};
+	};

Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt

@@ -1,10 +1,14 @@
 Tegra SoC PWFM controller
 
 Required properties:
-- compatible: For Tegra20, must contain "nvidia,tegra20-pwm".  For Tegra30,
-  must contain "nvidia,tegra30-pwm".  Otherwise, must contain
-  "nvidia,<chip>-pwm", plus one of the above, where <chip> is tegra114,
-  tegra124, tegra132, or tegra210.
+- compatible: Must be:
+  - "nvidia,tegra20-pwm": for Tegra20
+  - "nvidia,tegra30-pwm", "nvidia,tegra20-pwm": for Tegra30
+  - "nvidia,tegra114-pwm", "nvidia,tegra20-pwm": for Tegra114
+  - "nvidia,tegra124-pwm", "nvidia,tegra20-pwm": for Tegra124
+  - "nvidia,tegra132-pwm", "nvidia,tegra20-pwm": for Tegra132
+  - "nvidia,tegra210-pwm", "nvidia,tegra20-pwm": for Tegra210
+  - "nvidia,tegra186-pwm": for Tegra186
 - reg: physical base address and length of the controller's registers
 - #pwm-cells: should be 2. See pwm.txt in this directory for a description of
   the cells format.

Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt

@@ -7,6 +7,7 @@ Required Properties:
  - "renesas,pwm-r8a7790": for R-Car H2
  - "renesas,pwm-r8a7791": for R-Car M2-W
  - "renesas,pwm-r8a7794": for R-Car E2
+ - "renesas,pwm-r8a7795": for R-Car H3
 - reg: base address and length of the registers block for the PWM.
 - #pwm-cells: should be 2. See pwm.txt in this directory for a description of
   the cells format.

Documentation/devicetree/bindings/pwm/st,stmpe-pwm.txt

@@ -0,0 +1,18 @@
+== ST STMPE PWM controller ==
+
+This is a PWM block embedded in the ST Microelectronics STMPE
+(ST Multi-Purpose Expander) chips. The PWM is registered as a
+subdevices of the STMPE MFD device.
+
+Required properties:
+- compatible: should be:
+  - "st,stmpe-pwm"
+- #pwm-cells: should be 2. See pwm.txt in this directory for a description of
+  the cells format.
+
+Example:
+
+pwm0: pwm {
+	compatible = "st,stmpe-pwm";
+	#pwm-cells = <2>;
+};

Documentation/devicetree/bindings/regulator/pwm-regulator.txt

@@ -34,6 +34,18 @@ Only required for Voltage Table Mode:
 			    First cell is voltage in microvolts (uV)
 			    Second cell is duty-cycle in percent (%)
 
+Optional properties for Continuous mode:
+- pwm-dutycycle-unit:	Integer value encoding the duty cycle unit. If not
+			defined, <100> is assumed, meaning that
+			pwm-dutycycle-range contains values expressed in
+			percent.
+
+- pwm-dutycycle-range:	Should contain 2 entries. The first entry is encoding
+			the dutycycle for regulator-min-microvolt and the
+			second one the dutycycle for regulator-max-microvolt.
+			Duty cycle values are expressed in pwm-dutycycle-unit.
+			If not defined, <0 100> is assumed.
+
 NB: To be clear, if voltage-table is provided, then the device will be used
 in Voltage Table Mode.  If no voltage-table is provided, then the device will
 be used in Continuous Voltage Mode.
@@ -53,6 +65,13 @@ Continuous Voltage With Enable GPIO Example:
 		regulator-min-microvolt = <1016000>;
 		regulator-max-microvolt = <1114000>;
 		regulator-name = "vdd_logic";
+		/* unit == per-mille */
+		pwm-dutycycle-unit = <1000>;
+		/*
+		 * Inverted PWM logic, and the duty cycle range is limited
+		 * to 30%-70%.
+		 */
+		pwm-dutycycle-range <700 300>; /* */
 	};
 
 Voltage Table Example:

drivers/platform/chrome/cros_ec_proto.c

@@ -380,3 +380,20 @@ int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 	return ret;
 }
 EXPORT_SYMBOL(cros_ec_cmd_xfer);
+
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+			    struct cros_ec_command *msg)
+{
+	int ret;
+
+	ret = cros_ec_cmd_xfer(ec_dev, msg);
+	if (ret < 0) {
+		dev_err(ec_dev->dev, "Command xfer error (err:%d)\n", ret);
+	} else if (msg->result != EC_RES_SUCCESS) {
+		dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
+		return -EPROTO;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cros_ec_cmd_xfer_status);

drivers/pwm/Kconfig

@@ -74,6 +74,16 @@ config PWM_ATMEL_TCB
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-atmel-tcb.
 
+config PWM_BCM_IPROC
+	tristate "iProc PWM support"
+	depends on ARCH_BCM_IPROC
+	help
+	  Generic PWM framework driver for Broadcom iProc PWM block. This
+	  block is used in Broadcom iProc SoC's.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-bcm-iproc.
+
 config PWM_BCM_KONA
 	tristate "Kona PWM support"
 	depends on ARCH_BCM_MOBILE
@@ -137,6 +147,13 @@ config PWM_CRC
 	  Generic PWM framework driver for Crystalcove (CRC) PMIC based PWM
 	  control.
 
+config PWM_CROS_EC
+	tristate "ChromeOS EC PWM driver"
+	depends on MFD_CROS_EC
+	help
+	  PWM driver for exposing a PWM attached to the ChromeOS Embedded
+	  Controller.
+
 config PWM_EP93XX
 	tristate "Cirrus Logic EP93xx PWM support"
 	depends on ARCH_EP93XX
@@ -305,7 +322,7 @@ config PWM_PXA
 
 config PWM_RCAR
 	tristate "Renesas R-Car PWM support"
-	depends on ARCH_RCAR_GEN1 || ARCH_RCAR_GEN2 || COMPILE_TEST
+	depends on ARCH_RENESAS || COMPILE_TEST
 	depends on HAS_IOMEM
 	help
 	  This driver exposes the PWM Timer controller found in Renesas
@@ -362,6 +379,13 @@ config PWM_STI
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-sti.
 
+config PWM_STMPE
+	bool "STMPE expander PWM export"
+	depends on MFD_STMPE
+	help
+	  This enables support for the PWMs found in the STMPE I/O
+	  expanders.
+
 config PWM_SUN4I
 	tristate "Allwinner PWM support"
 	depends on ARCH_SUNXI || COMPILE_TEST

drivers/pwm/Makefile

@@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
+obj-$(CONFIG_PWM_BCM_IPROC)	+= pwm-bcm-iproc.o
 obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o
 obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o
 obj-$(CONFIG_PWM_BERLIN)	+= pwm-berlin.o
@@ -11,6 +12,7 @@ obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_BRCMSTB)	+= pwm-brcmstb.o
 obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
 obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
+obj-$(CONFIG_PWM_CROS_EC)	+= pwm-cros-ec.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
 obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
 obj-$(CONFIG_PWM_IMG)		+= pwm-img.o
@@ -34,6 +36,7 @@ obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o
 obj-$(CONFIG_PWM_SPEAR)		+= pwm-spear.o
 obj-$(CONFIG_PWM_STI)		+= pwm-sti.o
+obj-$(CONFIG_PWM_STMPE)		+= pwm-stmpe.o
 obj-$(CONFIG_PWM_SUN4I)		+= pwm-sun4i.o
 obj-$(CONFIG_PWM_TEGRA)		+= pwm-tegra.o
 obj-$(CONFIG_PWM_TIECAP)	+= pwm-tiecap.o

drivers/pwm/core.c

@@ -525,6 +525,33 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 }
 EXPORT_SYMBOL_GPL(pwm_apply_state);
 
+/**
+ * pwm_capture() - capture and report a PWM signal
+ * @pwm: PWM device
+ * @result: structure to fill with capture result
+ * @timeout: time to wait, in milliseconds, before giving up on capture
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
+		unsigned long timeout)
+{
+	int err;
+
+	if (!pwm || !pwm->chip->ops)
+		return -EINVAL;
+
+	if (!pwm->chip->ops->capture)
+		return -ENOSYS;
+
+	mutex_lock(&pwm_lock);
+	err = pwm->chip->ops->capture(pwm->chip, pwm, result, timeout);
+	mutex_unlock(&pwm_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(pwm_capture);
+
 /**
  * pwm_adjust_config() - adjust the current PWM config to the PWM arguments
  * @pwm: PWM device

drivers/pwm/pwm-atmel.c

@@ -64,7 +64,8 @@ struct atmel_pwm_chip {
 	void __iomem *base;
 
 	unsigned int updated_pwms;
-	struct mutex isr_lock; /* ISR is cleared when read, ensure only one thread does that */
+	/* ISR is cleared when read, ensure only one thread does that */
+	struct mutex isr_lock;
 
 	void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
 		       unsigned long dty, unsigned long prd);
@@ -271,6 +272,16 @@ static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 	mutex_unlock(&atmel_pwm->isr_lock);
 	atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm);
 
+	/*
+	 * Wait for the PWM channel disable operation to be effective before
+	 * stopping the clock.
+	 */
+	timeout = jiffies + 2 * HZ;
+
+	while ((atmel_pwm_readl(atmel_pwm, PWM_SR) & (1 << pwm->hwpwm)) &&
+	       time_before(jiffies, timeout))
+		usleep_range(10, 100);
+
 	clk_disable(atmel_pwm->clk);
 }
 
@@ -324,21 +335,14 @@ MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
 static inline const struct atmel_pwm_data *
 atmel_pwm_get_driver_data(struct platform_device *pdev)
 {
-	if (pdev->dev.of_node) {
-		const struct of_device_id *match;
-
-		match = of_match_device(atmel_pwm_dt_ids, &pdev->dev);
-		if (!match)
-			return NULL;
+	const struct platform_device_id *id;
 
-		return match->data;
-	} else {
-		const struct platform_device_id *id;
+	if (pdev->dev.of_node)
+		return of_device_get_match_data(&pdev->dev);
 
-		id = platform_get_device_id(pdev);
+	id = platform_get_device_id(pdev);
 
-		return (struct atmel_pwm_data *)id->driver_data;
-	}
+	return (struct atmel_pwm_data *)id->driver_data;
 }
 
 static int atmel_pwm_probe(struct platform_device *pdev)

drivers/pwm/pwm-bcm-iproc.c

@@ -0,0 +1,277 @@
+/*
+ * Copyright (C) 2016 Broadcom
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define IPROC_PWM_CTRL_OFFSET			0x00
+#define IPROC_PWM_CTRL_TYPE_SHIFT(ch)		(15 + (ch))
+#define IPROC_PWM_CTRL_POLARITY_SHIFT(ch)	(8 + (ch))
+#define IPROC_PWM_CTRL_EN_SHIFT(ch)		(ch)
+
+#define IPROC_PWM_PERIOD_OFFSET(ch)		(0x04 + ((ch) << 3))
+#define IPROC_PWM_PERIOD_MIN			0x02
+#define IPROC_PWM_PERIOD_MAX			0xffff
+
+#define IPROC_PWM_DUTY_CYCLE_OFFSET(ch)		(0x08 + ((ch) << 3))
+#define IPROC_PWM_DUTY_CYCLE_MIN		0x00
+#define IPROC_PWM_DUTY_CYCLE_MAX		0xffff
+
+#define IPROC_PWM_PRESCALE_OFFSET		0x24
+#define IPROC_PWM_PRESCALE_BITS			0x06
+#define IPROC_PWM_PRESCALE_SHIFT(ch)		((3 - (ch)) * \
+						 IPROC_PWM_PRESCALE_BITS)
+#define IPROC_PWM_PRESCALE_MASK(ch)		(IPROC_PWM_PRESCALE_MAX << \
+						 IPROC_PWM_PRESCALE_SHIFT(ch))
+#define IPROC_PWM_PRESCALE_MIN			0x00
+#define IPROC_PWM_PRESCALE_MAX			0x3f
+
+struct iproc_pwmc {
+	struct pwm_chip chip;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip)
+{
+	return container_of(chip, struct iproc_pwmc, chip);
+}
+
+static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel)
+{
+	u32 value;
+
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+	value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel);
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	/* must be a 400 ns delay between clearing and setting enable bit */
+	ndelay(400);
+}
+
+static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel)
+{
+	u32 value;
+
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+	value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel));
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	/* must be a 400 ns delay between clearing and setting enable bit */
+	ndelay(400);
+}
+
+static void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				 struct pwm_state *state)
+{
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	u64 tmp, multi, rate;
+	u32 value, prescale;
+
+	rate = clk_get_rate(ip->clk);
+
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
+		state->enabled = true;
+	else
+		state->enabled = false;
+
+	if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)))
+		state->polarity = PWM_POLARITY_NORMAL;
+	else
+		state->polarity = PWM_POLARITY_INVERSED;
+
+	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+	prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
+	prescale &= IPROC_PWM_PRESCALE_MAX;
+
+	multi = NSEC_PER_SEC * (prescale + 1);
+
+	value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
+	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
+	state->period = div64_u64(tmp, rate);
+
+	value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
+	tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
+	state->duty_cycle = div64_u64(tmp, rate);
+}
+
+static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    struct pwm_state *state)
+{
+	unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	u32 value, period, duty;
+	u64 rate;
+
+	rate = clk_get_rate(ip->clk);
+
+	/*
+	 * Find period count, duty count and prescale to suit duty_cycle and
+	 * period. This is done according to formulas described below:
+	 *
+	 * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
+	 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+	 *
+	 * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
+	 * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
+	 */
+	while (1) {
+		u64 value, div;
+
+		div = NSEC_PER_SEC * (prescale + 1);
+		value = rate * state->period;
+		period = div64_u64(value, div);
+		value = rate * state->duty_cycle;
+		duty = div64_u64(value, div);
+
+		if (period < IPROC_PWM_PERIOD_MIN ||
+		    duty < IPROC_PWM_DUTY_CYCLE_MIN)
+			return -EINVAL;
+
+		if (period <= IPROC_PWM_PERIOD_MAX &&
+		     duty <= IPROC_PWM_DUTY_CYCLE_MAX)
+			break;
+
+		/* Otherwise, increase prescale and recalculate counts */
+		if (++prescale > IPROC_PWM_PRESCALE_MAX)
+			return -EINVAL;
+	}
+
+	iproc_pwmc_disable(ip, pwm->hwpwm);
+
+	/* Set prescale */
+	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+	value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm);
+	value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
+	writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
+
+	/* set period and duty cycle */
+	writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
+	writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
+
+	/* set polarity */
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	if (state->polarity == PWM_POLARITY_NORMAL)
+		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm);
+	else
+		value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm));
+
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	if (state->enabled)
+		iproc_pwmc_enable(ip, pwm->hwpwm);
+
+	return 0;
+}
+
+static const struct pwm_ops iproc_pwm_ops = {
+	.apply = iproc_pwmc_apply,
+	.get_state = iproc_pwmc_get_state,
+};
+
+static int iproc_pwmc_probe(struct platform_device *pdev)
+{
+	struct iproc_pwmc *ip;
+	struct resource *res;
+	unsigned int i;
+	u32 value;
+	int ret;
+
+	ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);
+	if (!ip)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ip);
+
+	ip->chip.dev = &pdev->dev;
+	ip->chip.ops = &iproc_pwm_ops;
+	ip->chip.base = -1;
+	ip->chip.npwm = 4;
+	ip->chip.of_xlate = of_pwm_xlate_with_flags;
+	ip->chip.of_pwm_n_cells = 3;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ip->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ip->base))
+		return PTR_ERR(ip->base);
+
+	ip->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ip->clk)) {
+		dev_err(&pdev->dev, "failed to get clock: %ld\n",
+			PTR_ERR(ip->clk));
+		return PTR_ERR(ip->clk);
+	}
+
+	ret = clk_prepare_enable(ip->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	/* Set full drive and normal polarity for all channels */
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	for (i = 0; i < ip->chip.npwm; i++) {
+		value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i));
+		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i);
+	}
+
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	ret = pwmchip_add(&ip->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+		clk_disable_unprepare(ip->clk);
+	}
+
+	return ret;
+}
+
+static int iproc_pwmc_remove(struct platform_device *pdev)
+{
+	struct iproc_pwmc *ip = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(ip->clk);
+
+	return pwmchip_remove(&ip->chip);
+}
+
+static const struct of_device_id bcm_iproc_pwmc_dt[] = {
+	{ .compatible = "brcm,iproc-pwm" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
+
+static struct platform_driver iproc_pwmc_driver = {
+	.driver = {
+		.name = "bcm-iproc-pwm",
+		.of_match_table = bcm_iproc_pwmc_dt,
+	},
+	.probe = iproc_pwmc_probe,
+	.remove = iproc_pwmc_remove,
+};
+module_platform_driver(iproc_pwmc_driver);
+
+MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom iProc PWM driver");
+MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-cros-ec.c

@@ -0,0 +1,260 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2, as published by
+ * the Free Software Foundation.
+ *
+ * Expose a PWM controlled by the ChromeOS EC to the host processor.
+ */
+
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+/**
+ * struct cros_ec_pwm_device - Driver data for EC PWM
+ *
+ * @dev: Device node
+ * @ec: Pointer to EC device
+ * @chip: PWM controller chip
+ */
+struct cros_ec_pwm_device {
+	struct device *dev;
+	struct cros_ec_device *ec;
+	struct pwm_chip chip;
+};
+
+static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c)
+{
+	return container_of(c, struct cros_ec_pwm_device, chip);
+}
+
+static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)
+{
+	struct {
+		struct cros_ec_command msg;
+		struct ec_params_pwm_set_duty params;
+	} buf;
+	struct ec_params_pwm_set_duty *params = &buf.params;
+	struct cros_ec_command *msg = &buf.msg;
+
+	memset(&buf, 0, sizeof(buf));
+
+	msg->version = 0;
+	msg->command = EC_CMD_PWM_SET_DUTY;
+	msg->insize = 0;
+	msg->outsize = sizeof(*params);
+
+	params->duty = duty;
+	params->pwm_type = EC_PWM_TYPE_GENERIC;
+	params->index = index;
+
+	return cros_ec_cmd_xfer_status(ec, msg);
+}
+
+static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,
+				  u32 *result)
+{
+	struct {
+		struct cros_ec_command msg;
+		union {
+			struct ec_params_pwm_get_duty params;
+			struct ec_response_pwm_get_duty resp;
+		};
+	} buf;
+	struct ec_params_pwm_get_duty *params = &buf.params;
+	struct ec_response_pwm_get_duty *resp = &buf.resp;
+	struct cros_ec_command *msg = &buf.msg;
+	int ret;
+
+	memset(&buf, 0, sizeof(buf));
+
+	msg->version = 0;
+	msg->command = EC_CMD_PWM_GET_DUTY;
+	msg->insize = sizeof(*params);
+	msg->outsize = sizeof(*resp);
+
+	params->pwm_type = EC_PWM_TYPE_GENERIC;
+	params->index = index;
+
+	ret = cros_ec_cmd_xfer_status(ec, msg);
+	if (result)
+		*result = msg->result;
+	if (ret < 0)
+		return ret;
+
+	return resp->duty;
+}
+
+static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)
+{
+	return __cros_ec_pwm_get_duty(ec, index, NULL);
+}
+
+static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     struct pwm_state *state)
+{
+	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
+	int duty_cycle;
+
+	/* The EC won't let us change the period */
+	if (state->period != EC_PWM_MAX_DUTY)
+		return -EINVAL;
+
+	/*
+	 * EC doesn't separate the concept of duty cycle and enabled, but
+	 * kernel does. Translate.
+	 */
+	duty_cycle = state->enabled ? state->duty_cycle : 0;
+
+	return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);
+}
+
+static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				  struct pwm_state *state)
+{
+	struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip);
+	int ret;
+
+	ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);
+	if (ret < 0) {
+		dev_err(chip->dev, "error getting initial duty: %d\n", ret);
+		return;
+	}
+
+	state->enabled = (ret > 0);
+	state->period = EC_PWM_MAX_DUTY;
+
+	/* Note that "disabled" and "duty cycle == 0" are treated the same */
+	state->duty_cycle = ret;
+}
+
+static struct pwm_device *
+cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
+{
+	struct pwm_device *pwm;
+
+	if (args->args[0] >= pc->npwm)
+		return ERR_PTR(-EINVAL);
+
+	pwm = pwm_request_from_chip(pc, args->args[0], NULL);
+	if (IS_ERR(pwm))
+		return pwm;
+
+	/* The EC won't let us change the period */
+	pwm->args.period = EC_PWM_MAX_DUTY;
+
+	return pwm;
+}
+
+static const struct pwm_ops cros_ec_pwm_ops = {
+	.get_state	= cros_ec_pwm_get_state,
+	.apply		= cros_ec_pwm_apply,
+	.owner		= THIS_MODULE,
+};
+
+static int cros_ec_num_pwms(struct cros_ec_device *ec)
+{
+	int i, ret;
+
+	/* The index field is only 8 bits */
+	for (i = 0; i <= U8_MAX; i++) {
+		u32 result = 0;
+
+		ret = __cros_ec_pwm_get_duty(ec, i, &result);
+		/* We want to parse EC protocol errors */
+		if (ret < 0 && !(ret == -EPROTO && result))
+			return ret;
+
+		/*
+		 * We look for SUCCESS, INVALID_COMMAND, or INVALID_PARAM
+		 * responses; everything else is treated as an error.
+		 */
+		if (result == EC_RES_INVALID_COMMAND)
+			return -ENODEV;
+		else if (result == EC_RES_INVALID_PARAM)
+			return i;
+		else if (result)
+			return -EPROTO;
+	}
+
+	return U8_MAX;
+}
+
+static int cros_ec_pwm_probe(struct platform_device *pdev)
+{
+	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct cros_ec_pwm_device *ec_pwm;
+	struct pwm_chip *chip;
+	int ret;
+
+	if (!ec) {
+		dev_err(dev, "no parent EC device\n");
+		return -EINVAL;
+	}
+
+	ec_pwm = devm_kzalloc(dev, sizeof(*ec_pwm), GFP_KERNEL);
+	if (!ec_pwm)
+		return -ENOMEM;
+	chip = &ec_pwm->chip;
+	ec_pwm->ec = ec;
+
+	/* PWM chip */
+	chip->dev = dev;
+	chip->ops = &cros_ec_pwm_ops;
+	chip->of_xlate = cros_ec_pwm_xlate;
+	chip->of_pwm_n_cells = 1;
+	chip->base = -1;
+	ret = cros_ec_num_pwms(ec);
+	if (ret < 0) {
+		dev_err(dev, "Couldn't find PWMs: %d\n", ret);
+		return ret;
+	}
+	chip->npwm = ret;
+	dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);
+
+	ret = pwmchip_add(chip);
+	if (ret < 0) {
+		dev_err(dev, "cannot register PWM: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, ec_pwm);
+
+	return ret;
+}
+
+static int cros_ec_pwm_remove(struct platform_device *dev)
+{
+	struct cros_ec_pwm_device *ec_pwm = platform_get_drvdata(dev);
+	struct pwm_chip *chip = &ec_pwm->chip;
+
+	return pwmchip_remove(chip);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cros_ec_pwm_of_match[] = {
+	{ .compatible = "google,cros-ec-pwm" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cros_ec_pwm_of_match);
+#endif
+
+static struct platform_driver cros_ec_pwm_driver = {
+	.probe = cros_ec_pwm_probe,
+	.remove = cros_ec_pwm_remove,
+	.driver = {
+		.name = "cros-ec-pwm",
+		.of_match_table = of_match_ptr(cros_ec_pwm_of_match),
+	},
+};
+module_platform_driver(cros_ec_pwm_driver);
+
+MODULE_ALIAS("platform:cros-ec-pwm");
+MODULE_DESCRIPTION("ChromeOS EC PWM driver");
+MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-lpc32xx.c

@@ -25,6 +25,7 @@ struct lpc32xx_pwm_chip {
 };
 
 #define PWM_ENABLE	BIT(31)
+#define PWM_PIN_LEVEL	BIT(30)
 
 #define to_lpc32xx_pwm_chip(_chip) \
 	container_of(_chip, struct lpc32xx_pwm_chip, chip)
@@ -103,6 +104,7 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
 	struct lpc32xx_pwm_chip *lpc32xx;
 	struct resource *res;
 	int ret;
+	u32 val;
 
 	lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
 	if (!lpc32xx)
@@ -128,6 +130,11 @@ static int lpc32xx_pwm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* When PWM is disable, configure the output to the default value */
+	val = readl(lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
+	val &= ~PWM_PIN_LEVEL;
+	writel(val, lpc32xx->base + (lpc32xx->chip.pwms[0].hwpwm << 2));
+
 	platform_set_drvdata(pdev, lpc32xx);
 
 	return 0;

drivers/pwm/pwm-lpss-pci.c

@@ -76,6 +76,7 @@ static const struct pci_device_id pwm_lpss_pci_ids[] = {
 	{ PCI_VDEVICE(INTEL, 0x0ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&pwm_lpss_byt_info},
 	{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&pwm_lpss_byt_info},
+	{ PCI_VDEVICE(INTEL, 0x11a5), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&pwm_lpss_bsw_info},
 	{ PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&pwm_lpss_bsw_info},

drivers/pwm/pwm-lpss.c

@@ -27,7 +27,6 @@
 #define PWM_SW_UPDATE			BIT(30)
 #define PWM_BASE_UNIT_SHIFT		8
 #define PWM_ON_TIME_DIV_MASK		0x000000ff
-#define PWM_DIVISION_CORRECTION		0x2
 
 /* Size of each PWM register space if multiple */
 #define PWM_SIZE			0x400
@@ -92,8 +91,8 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			   int duty_ns, int period_ns)
 {
 	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
-	u8 on_time_div;
-	unsigned long c, base_unit_range;
+	unsigned long long on_time_div;
+	unsigned long c = lpwm->info->clk_rate, base_unit_range;
 	unsigned long long base_unit, freq = NSEC_PER_SEC;
 	u32 ctrl;
 
@@ -101,21 +100,18 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	/*
 	 * The equation is:
-	 * base_unit = ((freq / c) * base_unit_range) + correction
+	 * base_unit = round(base_unit_range * freq / c)
 	 */
 	base_unit_range = BIT(lpwm->info->base_unit_bits);
-	base_unit = freq * base_unit_range;
+	freq *= base_unit_range;
 
-	c = lpwm->info->clk_rate;
-	if (!c)
-		return -EINVAL;
-
-	do_div(base_unit, c);
-	base_unit += PWM_DIVISION_CORRECTION;
+	base_unit = DIV_ROUND_CLOSEST_ULL(freq, c);
 
 	if (duty_ns <= 0)
 		duty_ns = 1;
-	on_time_div = 255 - (255 * duty_ns / period_ns);
+	on_time_div = 255ULL * duty_ns;
+	do_div(on_time_div, period_ns);
+	on_time_div = 255ULL - on_time_div;
 
 	pm_runtime_get_sync(chip->dev);
 
@@ -169,6 +165,7 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
 				     const struct pwm_lpss_boardinfo *info)
 {
 	struct pwm_lpss_chip *lpwm;
+	unsigned long c;
 	int ret;
 
 	lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
@@ -180,6 +177,11 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
 		return ERR_CAST(lpwm->regs);
 
 	lpwm->info = info;
+
+	c = lpwm->info->clk_rate;
+	if (!c)
+		return ERR_PTR(-EINVAL);
+
 	lpwm->chip.dev = dev;
 	lpwm->chip.ops = &pwm_lpss_ops;
 	lpwm->chip.base = -1;

drivers/pwm/pwm-rockchip.c

@@ -47,10 +47,14 @@ struct rockchip_pwm_regs {
 struct rockchip_pwm_data {
 	struct rockchip_pwm_regs regs;
 	unsigned int prescaler;
+	bool supports_polarity;
 	const struct pwm_ops *ops;
 
 	void (*set_enable)(struct pwm_chip *chip,
-			   struct pwm_device *pwm, bool enable);
+			   struct pwm_device *pwm, bool enable,
+			   enum pwm_polarity polarity);
+	void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
+			  struct pwm_state *state);
 };
 
 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
@@ -59,7 +63,8 @@ static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
 }
 
 static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
-				       struct pwm_device *pwm, bool enable)
+				       struct pwm_device *pwm, bool enable,
+				       enum pwm_polarity polarity)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
@@ -75,15 +80,29 @@ static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
 	writel_relaxed(val, pc->base + pc->data->regs.ctrl);
 }
 
+static void rockchip_pwm_get_state_v1(struct pwm_chip *chip,
+				      struct pwm_device *pwm,
+				      struct pwm_state *state)
+{
+	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+	u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
+	u32 val;
+
+	val = readl_relaxed(pc->base + pc->data->regs.ctrl);
+	if ((val & enable_conf) == enable_conf)
+		state->enabled = true;
+}
+
 static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
-				       struct pwm_device *pwm, bool enable)
+				       struct pwm_device *pwm, bool enable,
+				       enum pwm_polarity polarity)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
 			  PWM_CONTINUOUS;
 	u32 val;
 
-	if (pwm_get_polarity(pwm) == PWM_POLARITY_INVERSED)
+	if (polarity == PWM_POLARITY_INVERSED)
 		enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSITIVE;
 	else
 		enable_conf |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
@@ -98,13 +117,59 @@ static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
 	writel_relaxed(val, pc->base + pc->data->regs.ctrl);
 }
 
+static void rockchip_pwm_get_state_v2(struct pwm_chip *chip,
+				      struct pwm_device *pwm,
+				      struct pwm_state *state)
+{
+	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+	u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
+			  PWM_CONTINUOUS;
+	u32 val;
+
+	val = readl_relaxed(pc->base + pc->data->regs.ctrl);
+	if ((val & enable_conf) != enable_conf)
+		return;
+
+	state->enabled = true;
+
+	if (!(val & PWM_DUTY_POSITIVE))
+		state->polarity = PWM_POLARITY_INVERSED;
+}
+
+static void rockchip_pwm_get_state(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   struct pwm_state *state)
+{
+	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+	unsigned long clk_rate;
+	u64 tmp;
+	int ret;
+
+	ret = clk_enable(pc->clk);
+	if (ret)
+		return;
+
+	clk_rate = clk_get_rate(pc->clk);
+
+	tmp = readl_relaxed(pc->base + pc->data->regs.period);
+	tmp *= pc->data->prescaler * NSEC_PER_SEC;
+	state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+	tmp = readl_relaxed(pc->base + pc->data->regs.duty);
+	tmp *= pc->data->prescaler * NSEC_PER_SEC;
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+	pc->data->get_state(chip, pwm, state);
+
+	clk_disable(pc->clk);
+}
+
 static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			       int duty_ns, int period_ns)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 	unsigned long period, duty;
 	u64 clk_rate, div;
-	int ret;
 
 	clk_rate = clk_get_rate(pc->clk);
 
@@ -114,74 +179,72 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * default prescaler value for all practical clock rate values.
 	 */
 	div = clk_rate * period_ns;
-	do_div(div, pc->data->prescaler * NSEC_PER_SEC);
-	period = div;
+	period = DIV_ROUND_CLOSEST_ULL(div,
+				       pc->data->prescaler * NSEC_PER_SEC);
 
 	div = clk_rate * duty_ns;
-	do_div(div, pc->data->prescaler * NSEC_PER_SEC);
-	duty = div;
-
-	ret = clk_enable(pc->clk);
-	if (ret)
-		return ret;
+	duty = DIV_ROUND_CLOSEST_ULL(div, pc->data->prescaler * NSEC_PER_SEC);
 
 	writel(period, pc->base + pc->data->regs.period);
 	writel(duty, pc->base + pc->data->regs.duty);
-	writel(0, pc->base + pc->data->regs.cntr);
-
-	clk_disable(pc->clk);
-
-	return 0;
-}
-
-static int rockchip_pwm_set_polarity(struct pwm_chip *chip,
-				     struct pwm_device *pwm,
-				     enum pwm_polarity polarity)
-{
-	/*
-	 * No action needed here because pwm->polarity will be set by the core
-	 * and the core will only change polarity when the PWM is not enabled.
-	 * We'll handle things in set_enable().
-	 */
 
 	return 0;
 }
 
-static int rockchip_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			      struct pwm_state *state)
 {
 	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+	struct pwm_state curstate;
+	bool enabled;
 	int ret;
 
+	pwm_get_state(pwm, &curstate);
+	enabled = curstate.enabled;
+
 	ret = clk_enable(pc->clk);
 	if (ret)
 		return ret;
 
-	pc->data->set_enable(chip, pwm, true);
+	if (state->polarity != curstate.polarity && enabled) {
+		pc->data->set_enable(chip, pwm, false, state->polarity);
+		enabled = false;
+	}
 
-	return 0;
-}
+	ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
+	if (ret) {
+		if (enabled != curstate.enabled)
+			pc->data->set_enable(chip, pwm, !enabled,
+					     state->polarity);
 
-static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+		goto out;
+	}
+
+	if (state->enabled != enabled)
+		pc->data->set_enable(chip, pwm, state->enabled,
+				     state->polarity);
 
-	pc->data->set_enable(chip, pwm, false);
+	/*
+	 * Update the state with the real hardware, which can differ a bit
+	 * because of period/duty_cycle approximation.
+	 */
+	rockchip_pwm_get_state(chip, pwm, state);
 
+out:
 	clk_disable(pc->clk);
+
+	return ret;
 }
 
 static const struct pwm_ops rockchip_pwm_ops_v1 = {
-	.config = rockchip_pwm_config,
-	.enable = rockchip_pwm_enable,
-	.disable = rockchip_pwm_disable,
+	.get_state = rockchip_pwm_get_state,
+	.apply = rockchip_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
 static const struct pwm_ops rockchip_pwm_ops_v2 = {
-	.config = rockchip_pwm_config,
-	.set_polarity = rockchip_pwm_set_polarity,
-	.enable = rockchip_pwm_enable,
-	.disable = rockchip_pwm_disable,
+	.get_state = rockchip_pwm_get_state,
+	.apply = rockchip_pwm_apply,
 	.owner = THIS_MODULE,
 };
 
@@ -195,6 +258,7 @@ static const struct rockchip_pwm_data pwm_data_v1 = {
 	.prescaler = 2,
 	.ops = &rockchip_pwm_ops_v1,
 	.set_enable = rockchip_pwm_set_enable_v1,
+	.get_state = rockchip_pwm_get_state_v1,
 };
 
 static const struct rockchip_pwm_data pwm_data_v2 = {
@@ -205,8 +269,10 @@ static const struct rockchip_pwm_data pwm_data_v2 = {
 		.ctrl = 0x0c,
 	},
 	.prescaler = 1,
+	.supports_polarity = true,
 	.ops = &rockchip_pwm_ops_v2,
 	.set_enable = rockchip_pwm_set_enable_v2,
+	.get_state = rockchip_pwm_get_state_v2,
 };
 
 static const struct rockchip_pwm_data pwm_data_vop = {
@@ -217,8 +283,10 @@ static const struct rockchip_pwm_data pwm_data_vop = {
 		.ctrl = 0x00,
 	},
 	.prescaler = 1,
+	.supports_polarity = true,
 	.ops = &rockchip_pwm_ops_v2,
 	.set_enable = rockchip_pwm_set_enable_v2,
+	.get_state = rockchip_pwm_get_state_v2,
 };
 
 static const struct of_device_id rockchip_pwm_dt_ids[] = {
@@ -253,7 +321,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pc->clk))
 		return PTR_ERR(pc->clk);
 
-	ret = clk_prepare(pc->clk);
+	ret = clk_prepare_enable(pc->clk);
 	if (ret)
 		return ret;
 
@@ -265,7 +333,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	pc->chip.base = -1;
 	pc->chip.npwm = 1;
 
-	if (pc->data->ops->set_polarity) {
+	if (pc->data->supports_polarity) {
 		pc->chip.of_xlate = of_pwm_xlate_with_flags;
 		pc->chip.of_pwm_n_cells = 3;
 	}
@@ -276,6 +344,10 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 	}
 
+	/* Keep the PWM clk enabled if the PWM appears to be up and running. */
+	if (!pwm_is_enabled(pc->chip.pwms))
+		clk_disable(pc->clk);
+
 	return ret;
 }
 
@@ -283,6 +355,20 @@ static int rockchip_pwm_remove(struct platform_device *pdev)
 {
 	struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
 
+	/*
+	 * Disable the PWM clk before unpreparing it if the PWM device is still
+	 * running. This should only happen when the last PWM user left it
+	 * enabled, or when nobody requested a PWM that was previously enabled
+	 * by the bootloader.
+	 *
+	 * FIXME: Maybe the core should disable all PWM devices in
+	 * pwmchip_remove(). In this case we'd only have to call
+	 * clk_unprepare() after pwmchip_remove().
+	 *
+	 */
+	if (pwm_is_enabled(pc->chip.pwms))
+		clk_disable(pc->clk);
+
 	clk_unprepare(pc->clk);
 
 	return pwmchip_remove(&pc->chip);

drivers/pwm/pwm-stmpe.c

@@ -0,0 +1,319 @@
+/*
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * Author: Linus Walleij <linus.walleij@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/mfd/stmpe.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define STMPE24XX_PWMCS		0x30
+#define PWMCS_EN_PWM0		BIT(0)
+#define PWMCS_EN_PWM1		BIT(1)
+#define PWMCS_EN_PWM2		BIT(2)
+#define STMPE24XX_PWMIC0	0x38
+#define STMPE24XX_PWMIC1	0x39
+#define STMPE24XX_PWMIC2	0x3a
+
+#define STMPE_PWM_24XX_PINBASE	21
+
+struct stmpe_pwm {
+	struct stmpe *stmpe;
+	struct pwm_chip chip;
+	u8 last_duty;
+};
+
+static inline struct stmpe_pwm *to_stmpe_pwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct stmpe_pwm, chip);
+}
+
+static int stmpe_24xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
+	u8 value;
+	int ret;
+
+	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
+	if (ret < 0) {
+		dev_err(chip->dev, "error reading PWM#%u control\n",
+			pwm->hwpwm);
+		return ret;
+	}
+
+	value = ret | BIT(pwm->hwpwm);
+
+	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
+	if (ret) {
+		dev_err(chip->dev, "error writing PWM#%u control\n",
+			pwm->hwpwm);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void stmpe_24xx_pwm_disable(struct pwm_chip *chip,
+				   struct pwm_device *pwm)
+{
+	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
+	u8 value;
+	int ret;
+
+	ret = stmpe_reg_read(stmpe_pwm->stmpe, STMPE24XX_PWMCS);
+	if (ret < 0) {
+		dev_err(chip->dev, "error reading PWM#%u control\n",
+			pwm->hwpwm);
+		return;
+	}
+
+	value = ret & ~BIT(pwm->hwpwm);
+
+	ret = stmpe_reg_write(stmpe_pwm->stmpe, STMPE24XX_PWMCS, value);
+	if (ret) {
+		dev_err(chip->dev, "error writing PWM#%u control\n",
+			pwm->hwpwm);
+		return;
+	}
+}
+
+/* STMPE 24xx PWM instructions */
+#define SMAX		0x007f
+#define SMIN		0x00ff
+#define GTS		0x0000
+#define LOAD		BIT(14) /* Only available on 2403 */
+#define RAMPUP		0x0000
+#define RAMPDOWN	BIT(7)
+#define PRESCALE_512	BIT(14)
+#define STEPTIME_1	BIT(8)
+#define BRANCH		(BIT(15) | BIT(13))
+
+static int stmpe_24xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+				 int duty_ns, int period_ns)
+{
+	struct stmpe_pwm *stmpe_pwm = to_stmpe_pwm(chip);
+	unsigned int i, pin;
+	u16 program[3] = {
+		SMAX,
+		GTS,
+		GTS,
+	};
+	u8 offset;
+	int ret;
+
+	/* Make sure we are disabled */
+	if (pwm_is_enabled(pwm)) {
+		stmpe_24xx_pwm_disable(chip, pwm);
+	} else {
+		/* Connect the PWM to the pin */
+		pin = pwm->hwpwm;
+
+		/* On STMPE2401 and 2403 pins 21,22,23 are used */
+		if (stmpe_pwm->stmpe->partnum == STMPE2401 ||
+		    stmpe_pwm->stmpe->partnum == STMPE2403)
+			pin += STMPE_PWM_24XX_PINBASE;
+
+		ret = stmpe_set_altfunc(stmpe_pwm->stmpe, BIT(pin),
+					STMPE_BLOCK_PWM);
+		if (ret) {
+			dev_err(chip->dev, "unable to connect PWM#%u to pin\n",
+				pwm->hwpwm);
+			return ret;
+		}
+	}
+
+	/* STMPE24XX */
+	switch (pwm->hwpwm) {
+	case 0:
+		offset = STMPE24XX_PWMIC0;
+		break;
+
+	case 1:
+		offset = STMPE24XX_PWMIC1;
+		break;
+
+	case 2:
+		offset = STMPE24XX_PWMIC1;
+		break;
+
+	default:
+		/* Should not happen as npwm is 3 */
+		return -ENODEV;
+	}
+
+	dev_dbg(chip->dev, "PWM#%u: config duty %d ns, period %d ns\n",
+		pwm->hwpwm, duty_ns, period_ns);
+
+	if (duty_ns == 0) {
+		if (stmpe_pwm->stmpe->partnum == STMPE2401)
+			program[0] = SMAX; /* off all the time */
+
+		if (stmpe_pwm->stmpe->partnum == STMPE2403)
+			program[0] = LOAD | 0xff; /* LOAD 0xff */
+
+		stmpe_pwm->last_duty = 0x00;
+	} else if (duty_ns == period_ns) {
+		if (stmpe_pwm->stmpe->partnum == STMPE2401)
+			program[0] = SMIN; /* on all the time */
+
+		if (stmpe_pwm->stmpe->partnum == STMPE2403)
+			program[0] = LOAD | 0x00; /* LOAD 0x00 */
+
+		stmpe_pwm->last_duty = 0xff;
+	} else {
+		u8 value, last = stmpe_pwm->last_duty;
+		unsigned long duty;
+
+		/*
+		 * Counter goes from 0x00 to 0xff repeatedly at 32768 Hz,
+		 * (means a period of 30517 ns) then this is compared to the
+		 * counter from the ramp, if this is >= PWM counter the output
+		 * is high. With LOAD we can define how much of the cycle it
+		 * is on.
+		 *
+		 * Prescale = 0 -> 2 kHz -> T = 1/f = 488281.25 ns
+		 */
+
+		/* Scale to 0..0xff */
+		duty = duty_ns * 256;
+		duty = DIV_ROUND_CLOSEST(duty, period_ns);
+		value = duty;
+
+		if (value == last) {
+			/* Run the old program */
+			if (pwm_is_enabled(pwm))
+				stmpe_24xx_pwm_enable(chip, pwm);
+
+			return 0;
+		} else if (stmpe_pwm->stmpe->partnum == STMPE2403) {
+			/* STMPE2403 can simply set the right PWM value */
+			program[0] = LOAD | value;
+			program[1] = 0x0000;
+		} else if (stmpe_pwm->stmpe->partnum == STMPE2401) {
+			/* STMPE2401 need a complex program */
+			u16 incdec = 0x0000;
+
+			if (last < value)
+				/* Count up */
+				incdec = RAMPUP | (value - last);
+			else
+				/* Count down */
+				incdec = RAMPDOWN | (last - value);
+
+			/* Step to desired value, smoothly */
+			program[0] = PRESCALE_512 | STEPTIME_1 | incdec;
+
+			/* Loop eternally to 0x00 */
+			program[1] = BRANCH;
+		}
+
+		dev_dbg(chip->dev,
+			"PWM#%u: value = %02x, last_duty = %02x, program=%04x,%04x,%04x\n",
+			pwm->hwpwm, value, last, program[0], program[1],
+			program[2]);
+		stmpe_pwm->last_duty = value;
+	}
+
+	/*
+	 * We can write programs of up to 64 16-bit words into this channel.
+	 */
+	for (i = 0; i < ARRAY_SIZE(program); i++) {
+		u8 value;
+
+		value = (program[i] >> 8) & 0xff;
+
+		ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
+		if (ret) {
+			dev_err(chip->dev, "error writing register %02x: %d\n",
+				offset, ret);
+			return ret;
+		}
+
+		value = program[i] & 0xff;
+
+		ret = stmpe_reg_write(stmpe_pwm->stmpe, offset, value);
+		if (ret) {
+			dev_err(chip->dev, "error writing register %02x: %d\n",
+				offset, ret);
+			return ret;
+		}
+	}
+
+	/* If we were enabled, re-enable this PWM */
+	if (pwm_is_enabled(pwm))
+		stmpe_24xx_pwm_enable(chip, pwm);
+
+	/* Sleep for 200ms so we're sure it will take effect */
+	msleep(200);
+
+	dev_dbg(chip->dev, "programmed PWM#%u, %u bytes\n", pwm->hwpwm, i);
+
+	return 0;
+}
+
+static const struct pwm_ops stmpe_24xx_pwm_ops = {
+	.config = stmpe_24xx_pwm_config,
+	.enable = stmpe_24xx_pwm_enable,
+	.disable = stmpe_24xx_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int __init stmpe_pwm_probe(struct platform_device *pdev)
+{
+	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
+	struct stmpe_pwm *pwm;
+	int ret;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->stmpe = stmpe;
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.base = -1;
+
+	if (stmpe->partnum == STMPE2401 || stmpe->partnum == STMPE2403) {
+		pwm->chip.ops = &stmpe_24xx_pwm_ops;
+		pwm->chip.npwm = 3;
+	} else {
+		if (stmpe->partnum == STMPE1601)
+			dev_err(&pdev->dev, "STMPE1601 not yet supported\n");
+		else
+			dev_err(&pdev->dev, "Unknown STMPE PWM\n");
+
+		return -ENODEV;
+	}
+
+	ret = stmpe_enable(stmpe, STMPE_BLOCK_PWM);
+	if (ret)
+		return ret;
+
+	ret = pwmchip_add(&pwm->chip);
+	if (ret) {
+		stmpe_disable(stmpe, STMPE_BLOCK_PWM);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+
+	return 0;
+}
+
+static struct platform_driver stmpe_pwm_driver = {
+	.driver = {
+		.name = "stmpe-pwm",
+	},
+};
+builtin_platform_driver_probe(stmpe_pwm_driver, stmpe_pwm_probe);

drivers/pwm/pwm-tegra.c

@@ -26,9 +26,11 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/pwm.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/reset.h>
 
 #define PWM_ENABLE	(1 << 31)
 #define PWM_DUTY_WIDTH	8
@@ -36,15 +38,20 @@
 #define PWM_SCALE_WIDTH	13
 #define PWM_SCALE_SHIFT	0
 
-#define NUM_PWM 4
+struct tegra_pwm_soc {
+	unsigned int num_channels;
+};
 
 struct tegra_pwm_chip {
-	struct pwm_chip		chip;
-	struct device		*dev;
+	struct pwm_chip chip;
+	struct device *dev;
+
+	struct clk *clk;
+	struct reset_control*rst;
 
-	struct clk		*clk;
+	void __iomem *regs;
 
-	void __iomem		*mmio_base;
+	const struct tegra_pwm_soc *soc;
 };
 
 static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
@@ -54,20 +61,20 @@ static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
 
 static inline u32 pwm_readl(struct tegra_pwm_chip *chip, unsigned int num)
 {
-	return readl(chip->mmio_base + (num << 4));
+	return readl(chip->regs + (num << 4));
 }
 
 static inline void pwm_writel(struct tegra_pwm_chip *chip, unsigned int num,
 			     unsigned long val)
 {
-	writel(val, chip->mmio_base + (num << 4));
+	writel(val, chip->regs + (num << 4));
 }
 
 static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			    int duty_ns, int period_ns)
 {
 	struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
-	unsigned long long c;
+	unsigned long long c = duty_ns;
 	unsigned long rate, hz;
 	u32 val = 0;
 	int err;
@@ -77,7 +84,8 @@ static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * per (1 << PWM_DUTY_WIDTH) cycles and make sure to round to the
 	 * nearest integer during division.
 	 */
-	c = duty_ns * ((1 << PWM_DUTY_WIDTH) - 1) + period_ns / 2;
+	c *= (1 << PWM_DUTY_WIDTH);
+	c += period_ns / 2;
 	do_div(c, period_ns);
 
 	val = (u32)c << PWM_DUTY_SHIFT;
@@ -176,12 +184,13 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 	if (!pwm)
 		return -ENOMEM;
 
+	pwm->soc = of_device_get_match_data(&pdev->dev);
 	pwm->dev = &pdev->dev;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
-	if (IS_ERR(pwm->mmio_base))
-		return PTR_ERR(pwm->mmio_base);
+	pwm->regs = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(pwm->regs))
+		return PTR_ERR(pwm->regs);
 
 	platform_set_drvdata(pdev, pwm);
 
@@ -189,14 +198,24 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
+	pwm->rst = devm_reset_control_get(&pdev->dev, "pwm");
+	if (IS_ERR(pwm->rst)) {
+		ret = PTR_ERR(pwm->rst);
+		dev_err(&pdev->dev, "Reset control is not found: %d\n", ret);
+		return ret;
+	}
+
+	reset_control_deassert(pwm->rst);
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &tegra_pwm_ops;
 	pwm->chip.base = -1;
-	pwm->chip.npwm = NUM_PWM;
+	pwm->chip.npwm = pwm->soc->num_channels;
 
 	ret = pwmchip_add(&pwm->chip);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		reset_control_assert(pwm->rst);
 		return ret;
 	}
 
@@ -206,12 +225,17 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 static int tegra_pwm_remove(struct platform_device *pdev)
 {
 	struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
-	int i;
+	unsigned int i;
+	int err;
 
 	if (WARN_ON(!pc))
 		return -ENODEV;
 
-	for (i = 0; i < NUM_PWM; i++) {
+	err = clk_prepare_enable(pc->clk);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < pc->chip.npwm; i++) {
 		struct pwm_device *pwm = &pc->chip.pwms[i];
 
 		if (!pwm_is_enabled(pwm))
@@ -223,12 +247,23 @@ static int tegra_pwm_remove(struct platform_device *pdev)
 		clk_disable_unprepare(pc->clk);
 	}
 
+	reset_control_assert(pc->rst);
+	clk_disable_unprepare(pc->clk);
+
 	return pwmchip_remove(&pc->chip);
 }
 
+static const struct tegra_pwm_soc tegra20_pwm_soc = {
+	.num_channels = 4,
+};
+
+static const struct tegra_pwm_soc tegra186_pwm_soc = {
+	.num_channels = 1,
+};
+
 static const struct of_device_id tegra_pwm_of_match[] = {
-	{ .compatible = "nvidia,tegra20-pwm" },
-	{ .compatible = "nvidia,tegra30-pwm" },
+	{ .compatible = "nvidia,tegra20-pwm", .data = &tegra20_pwm_soc },
+	{ .compatible = "nvidia,tegra186-pwm", .data = &tegra186_pwm_soc },
 	{ }
 };
 

drivers/pwm/pwm-tiecap.c

@@ -27,8 +27,6 @@
 #include <linux/pwm.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
 /* ECAP registers and bits definitions */
 #define CAP1			0x08
 #define CAP2			0x0C
@@ -195,6 +193,7 @@ static const struct pwm_ops ecap_pwm_ops = {
 };
 
 static const struct of_device_id ecap_of_match[] = {
+	{ .compatible	= "ti,am3352-ecap" },
 	{ .compatible	= "ti,am33xx-ecap" },
 	{},
 };
@@ -202,17 +201,24 @@ MODULE_DEVICE_TABLE(of, ecap_of_match);
 
 static int ecap_pwm_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	int ret;
 	struct resource *r;
 	struct clk *clk;
 	struct ecap_pwm_chip *pc;
-	u16 status;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
 		return -ENOMEM;
 
 	clk = devm_clk_get(&pdev->dev, "fck");
+	if (IS_ERR(clk)) {
+		if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
+			dev_warn(&pdev->dev, "Binding is obsolete.\n");
+			clk = devm_clk_get(pdev->dev.parent, "fck");
+		}
+	}
+
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "failed to get clock\n");
 		return PTR_ERR(clk);
@@ -243,40 +249,15 @@ static int ecap_pwm_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(&pdev->dev);
-	pm_runtime_get_sync(&pdev->dev);
-
-	status = pwmss_submodule_state_change(pdev->dev.parent,
-			PWMSS_ECAPCLK_EN);
-	if (!(status & PWMSS_ECAPCLK_EN_ACK)) {
-		dev_err(&pdev->dev, "PWMSS config space clock enable failed\n");
-		ret = -EINVAL;
-		goto pwmss_clk_failure;
-	}
-
-	pm_runtime_put_sync(&pdev->dev);
 
 	platform_set_drvdata(pdev, pc);
 	return 0;
-
-pwmss_clk_failure:
-	pm_runtime_put_sync(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-	pwmchip_remove(&pc->chip);
-	return ret;
 }
 
 static int ecap_pwm_remove(struct platform_device *pdev)
 {
 	struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
 
-	pm_runtime_get_sync(&pdev->dev);
-	/*
-	 * Due to hardware misbehaviour, acknowledge of the stop_req
-	 * is missing. Hence checking of the status bit skipped.
-	 */
-	pwmss_submodule_state_change(pdev->dev.parent, PWMSS_ECAPCLK_STOP_REQ);
-	pm_runtime_put_sync(&pdev->dev);
-
 	pm_runtime_disable(&pdev->dev);
 	return pwmchip_remove(&pc->chip);
 }

drivers/pwm/pwm-tiehrpwm.c

@@ -27,8 +27,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
 /* EHRPWM registers and bits definitions */
 
 /* Time base module registers */
@@ -426,6 +424,7 @@ static const struct pwm_ops ehrpwm_pwm_ops = {
 };
 
 static const struct of_device_id ehrpwm_of_match[] = {
+	{ .compatible	= "ti,am3352-ehrpwm" },
 	{ .compatible	= "ti,am33xx-ehrpwm" },
 	{},
 };
@@ -433,17 +432,24 @@ MODULE_DEVICE_TABLE(of, ehrpwm_of_match);
 
 static int ehrpwm_pwm_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	int ret;
 	struct resource *r;
 	struct clk *clk;
 	struct ehrpwm_pwm_chip *pc;
-	u16 status;
 
 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 	if (!pc)
 		return -ENOMEM;
 
 	clk = devm_clk_get(&pdev->dev, "fck");
+	if (IS_ERR(clk)) {
+		if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
+			dev_warn(&pdev->dev, "Binding is obsolete.\n");
+			clk = devm_clk_get(pdev->dev.parent, "fck");
+		}
+	}
+
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "failed to get clock\n");
 		return PTR_ERR(clk);
@@ -487,27 +493,9 @@ static int ehrpwm_pwm_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(&pdev->dev);
-	pm_runtime_get_sync(&pdev->dev);
-
-	status = pwmss_submodule_state_change(pdev->dev.parent,
-			PWMSS_EPWMCLK_EN);
-	if (!(status & PWMSS_EPWMCLK_EN_ACK)) {
-		dev_err(&pdev->dev, "PWMSS config space clock enable failed\n");
-		ret = -EINVAL;
-		goto pwmss_clk_failure;
-	}
-
-	pm_runtime_put_sync(&pdev->dev);
 
 	platform_set_drvdata(pdev, pc);
 	return 0;
-
-pwmss_clk_failure:
-	pm_runtime_put_sync(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-	pwmchip_remove(&pc->chip);
-	clk_unprepare(pc->tbclk);
-	return ret;
 }
 
 static int ehrpwm_pwm_remove(struct platform_device *pdev)
@@ -516,14 +504,6 @@ static int ehrpwm_pwm_remove(struct platform_device *pdev)
 
 	clk_unprepare(pc->tbclk);
 
-	pm_runtime_get_sync(&pdev->dev);
-	/*
-	 * Due to hardware misbehaviour, acknowledge of the stop_req
-	 * is missing. Hence checking of the status bit skipped.
-	 */
-	pwmss_submodule_state_change(pdev->dev.parent, PWMSS_EPWMCLK_STOP_REQ);
-	pm_runtime_put_sync(&pdev->dev);
-
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	return pwmchip_remove(&pc->chip);

drivers/pwm/pwm-tipwmss.c

@@ -22,32 +22,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/of_device.h>
 
-#include "pwm-tipwmss.h"
-
-#define PWMSS_CLKCONFIG		0x8	/* Clock gating reg */
-#define PWMSS_CLKSTATUS		0xc	/* Clock gating status reg */
-
-struct pwmss_info {
-	void __iomem	*mmio_base;
-	struct mutex	pwmss_lock;
-	u16		pwmss_clkconfig;
-};
-
-u16 pwmss_submodule_state_change(struct device *dev, int set)
-{
-	struct pwmss_info *info = dev_get_drvdata(dev);
-	u16 val;
-
-	mutex_lock(&info->pwmss_lock);
-	val = readw(info->mmio_base + PWMSS_CLKCONFIG);
-	val |= set;
-	writew(val , info->mmio_base + PWMSS_CLKCONFIG);
-	mutex_unlock(&info->pwmss_lock);
-
-	return readw(info->mmio_base + PWMSS_CLKSTATUS);
-}
-EXPORT_SYMBOL(pwmss_submodule_state_change);
-
 static const struct of_device_id pwmss_of_match[] = {
 	{ .compatible	= "ti,am33xx-pwmss" },
 	{},
@@ -57,24 +31,10 @@ MODULE_DEVICE_TABLE(of, pwmss_of_match);
 static int pwmss_probe(struct platform_device *pdev)
 {
 	int ret;
-	struct resource *r;
-	struct pwmss_info *info;
 	struct device_node *node = pdev->dev.of_node;
 
-	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
-
-	mutex_init(&info->pwmss_lock);
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
-	if (IS_ERR(info->mmio_base))
-		return PTR_ERR(info->mmio_base);
-
 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
-	platform_set_drvdata(pdev, info);
 
 	/* Populate all the child nodes here... */
 	ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
@@ -86,30 +46,21 @@ static int pwmss_probe(struct platform_device *pdev)
 
 static int pwmss_remove(struct platform_device *pdev)
 {
-	struct pwmss_info *info = platform_get_drvdata(pdev);
-
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-	mutex_destroy(&info->pwmss_lock);
 	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
 static int pwmss_suspend(struct device *dev)
 {
-	struct pwmss_info *info = dev_get_drvdata(dev);
-
-	info->pwmss_clkconfig = readw(info->mmio_base + PWMSS_CLKCONFIG);
 	pm_runtime_put_sync(dev);
 	return 0;
 }
 
 static int pwmss_resume(struct device *dev)
 {
-	struct pwmss_info *info = dev_get_drvdata(dev);
-
 	pm_runtime_get_sync(dev);
-	writew(info->pwmss_clkconfig, info->mmio_base + PWMSS_CLKCONFIG);
 	return 0;
 }
 #endif

drivers/pwm/pwm-tipwmss.h

@@ -1,39 +0,0 @@
-/*
- * TI PWM Subsystem driver
- *
- * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
- *
- * 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; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
-
-#ifndef __TIPWMSS_H
-#define __TIPWMSS_H
-
-/* PWM substem clock gating */
-#define PWMSS_ECAPCLK_EN	BIT(0)
-#define PWMSS_ECAPCLK_STOP_REQ	BIT(1)
-#define PWMSS_EPWMCLK_EN	BIT(8)
-#define PWMSS_EPWMCLK_STOP_REQ	BIT(9)
-
-#define PWMSS_ECAPCLK_EN_ACK	BIT(0)
-#define PWMSS_EPWMCLK_EN_ACK	BIT(8)
-
-#ifdef CONFIG_PWM_TIPWMSS
-extern u16 pwmss_submodule_state_change(struct device *dev, int set);
-#else
-static inline u16 pwmss_submodule_state_change(struct device *dev, int set)
-{
-	/* return success status value */
-	return 0xFFFF;
-}
-#endif
-#endif	/* __TIPWMSS_H */

drivers/pwm/sysfs.c

@@ -208,16 +208,33 @@ static ssize_t polarity_store(struct device *child,
 	return ret ? : size;
 }
 
+static ssize_t capture_show(struct device *child,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_capture result;
+	int ret;
+
+	ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
+}
+
 static DEVICE_ATTR_RW(period);
 static DEVICE_ATTR_RW(duty_cycle);
 static DEVICE_ATTR_RW(enable);
 static DEVICE_ATTR_RW(polarity);
+static DEVICE_ATTR_RO(capture);
 
 static struct attribute *pwm_attrs[] = {
 	&dev_attr_period.attr,
 	&dev_attr_duty_cycle.attr,
 	&dev_attr_enable.attr,
 	&dev_attr_polarity.attr,
+	&dev_attr_capture.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(pwm);

drivers/regulator/pwm-regulator.c

@@ -22,6 +22,12 @@
 #include <linux/pwm.h>
 #include <linux/gpio/consumer.h>
 
+struct pwm_continuous_reg_data {
+	unsigned int min_uV_dutycycle;
+	unsigned int max_uV_dutycycle;
+	unsigned int dutycycle_unit;
+};
+
 struct pwm_regulator_data {
 	/*  Shared */
 	struct pwm_device *pwm;
@@ -29,6 +35,9 @@ struct pwm_regulator_data {
 	/* Voltage table */
 	struct pwm_voltages *duty_cycle_table;
 
+	/* Continuous mode info */
+	struct pwm_continuous_reg_data continuous;
+
 	/* regulator descriptor */
 	struct regulator_desc desc;
 
@@ -37,9 +46,6 @@ struct pwm_regulator_data {
 
 	int state;
 
-	/* Continuous voltage */
-	int volt_uV;
-
 	/* Enable GPIO */
 	struct gpio_desc *enb_gpio;
 };
@@ -52,10 +58,31 @@ struct pwm_voltages {
 /**
  * Voltage table call-backs
  */
+static void pwm_regulator_init_state(struct regulator_dev *rdev)
+{
+	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	struct pwm_state pwm_state;
+	unsigned int dutycycle;
+	int i;
+
+	pwm_get_state(drvdata->pwm, &pwm_state);
+	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
+
+	for (i = 0; i < rdev->desc->n_voltages; i++) {
+		if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
+			drvdata->state = i;
+			return;
+		}
+	}
+}
+
 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 
+	if (drvdata->state < 0)
+		pwm_regulator_init_state(rdev);
+
 	return drvdata->state;
 }
 
@@ -63,16 +90,14 @@ static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
 					 unsigned selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
-	struct pwm_args pargs;
-	int dutycycle;
+	struct pwm_state pstate;
 	int ret;
 
-	pwm_get_args(drvdata->pwm, &pargs);
-
-	dutycycle = (pargs.period *
-		    drvdata->duty_cycle_table[selector].dutycycle) / 100;
+	pwm_init_state(drvdata->pwm, &pstate);
+	pwm_set_relative_duty_cycle(&pstate,
+			drvdata->duty_cycle_table[selector].dutycycle, 100);
 
-	ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
+	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
@@ -129,57 +154,90 @@ static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
+	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
+	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
+	int min_uV = rdev->constraints->min_uV;
+	int max_uV = rdev->constraints->max_uV;
+	int diff_uV = max_uV - min_uV;
+	struct pwm_state pstate;
+	unsigned int diff_duty;
+	unsigned int voltage;
+
+	pwm_get_state(drvdata->pwm, &pstate);
+
+	voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
+
+	/*
+	 * The dutycycle for min_uV might be greater than the one for max_uV.
+	 * This is happening when the user needs an inversed polarity, but the
+	 * PWM device does not support inversing it in hardware.
+	 */
+	if (max_uV_duty < min_uV_duty) {
+		voltage = min_uV_duty - voltage;
+		diff_duty = min_uV_duty - max_uV_duty;
+	} else {
+		voltage = voltage - min_uV_duty;
+		diff_duty = max_uV_duty - min_uV_duty;
+	}
 
-	return drvdata->volt_uV;
+	voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
+
+	return voltage + min_uV;
 }
 
 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
-					int min_uV, int max_uV,
-					unsigned *selector)
+				     int req_min_uV, int req_max_uV,
+				     unsigned int *selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
+	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
+	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
+	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 	unsigned int ramp_delay = rdev->constraints->ramp_delay;
-	struct pwm_args pargs;
-	unsigned int req_diff = min_uV - rdev->constraints->min_uV;
-	unsigned int diff;
-	unsigned int duty_pulse;
-	u64 req_period;
-	u32 rem;
+	int min_uV = rdev->constraints->min_uV;
+	int max_uV = rdev->constraints->max_uV;
+	int diff_uV = max_uV - min_uV;
+	struct pwm_state pstate;
 	int old_uV = pwm_regulator_get_voltage(rdev);
+	unsigned int diff_duty;
+	unsigned int dutycycle;
 	int ret;
 
-	pwm_get_args(drvdata->pwm, &pargs);
-	diff = rdev->constraints->max_uV - rdev->constraints->min_uV;
+	pwm_init_state(drvdata->pwm, &pstate);
 
-	/* First try to find out if we get the iduty cycle time which is
-	 * factor of PWM period time. If (request_diff_to_min * pwm_period)
-	 * is perfect divided by voltage_range_diff then it is possible to
-	 * get duty cycle time which is factor of PWM period. This will help
-	 * to get output voltage nearer to requested value as there is no
-	 * calculation loss.
+	/*
+	 * The dutycycle for min_uV might be greater than the one for max_uV.
+	 * This is happening when the user needs an inversed polarity, but the
+	 * PWM device does not support inversing it in hardware.
 	 */
-	req_period = req_diff * pargs.period;
-	div_u64_rem(req_period, diff, &rem);
-	if (!rem) {
-		do_div(req_period, diff);
-		duty_pulse = (unsigned int)req_period;
-	} else {
-		duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
-	}
+	if (max_uV_duty < min_uV_duty)
+		diff_duty = min_uV_duty - max_uV_duty;
+	else
+		diff_duty = max_uV_duty - min_uV_duty;
+
+	dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
+					  diff_duty,
+					  diff_uV);
+
+	if (max_uV_duty < min_uV_duty)
+		dutycycle = min_uV_duty - dutycycle;
+	else
+		dutycycle = min_uV_duty + dutycycle;
+
+	pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 
-	ret = pwm_config(drvdata->pwm, duty_pulse, pargs.period);
+	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
 	}
 
-	drvdata->volt_uV = min_uV;
-
 	if ((ramp_delay == 0) || !pwm_regulator_is_enabled(rdev))
 		return 0;
 
 	/* Ramp delay is in uV/uS. Adjust to uS and delay */
-	ramp_delay = DIV_ROUND_UP(abs(min_uV - old_uV), ramp_delay);
+	ramp_delay = DIV_ROUND_UP(abs(req_min_uV - old_uV), ramp_delay);
 	usleep_range(ramp_delay, ramp_delay + DIV_ROUND_UP(ramp_delay, 10));
 
 	return 0;
@@ -239,6 +297,7 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 		return ret;
 	}
 
+	drvdata->state			= -EINVAL;
 	drvdata->duty_cycle_table	= duty_cycle_table;
 	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 	       sizeof(drvdata->ops));
@@ -251,11 +310,28 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 					 struct pwm_regulator_data *drvdata)
 {
+	u32 dutycycle_range[2] = { 0, 100 };
+	u32 dutycycle_unit = 100;
+
 	memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 	       sizeof(drvdata->ops));
 	drvdata->desc.ops = &drvdata->ops;
 	drvdata->desc.continuous_voltage_range = true;
 
+	of_property_read_u32_array(pdev->dev.of_node,
+				   "pwm-dutycycle-range",
+				   dutycycle_range, 2);
+	of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
+			     &dutycycle_unit);
+
+	if (dutycycle_range[0] > dutycycle_unit ||
+	    dutycycle_range[1] > dutycycle_unit)
+		return -EINVAL;
+
+	drvdata->continuous.dutycycle_unit = dutycycle_unit;
+	drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
+	drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
+
 	return 0;
 }
 
@@ -316,11 +392,9 @@ static int pwm_regulator_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	/*
-	 * FIXME: pwm_apply_args() should be removed when switching to the
-	 * atomic PWM API.
-	 */
-	pwm_apply_args(drvdata->pwm);
+	ret = pwm_adjust_config(drvdata->pwm);
+	if (ret)
+		return ret;
 
 	regulator = devm_regulator_register(&pdev->dev,
 					    &drvdata->desc, &config);

include/linux/mfd/cros_ec.h

@@ -225,6 +225,21 @@ int cros_ec_check_result(struct cros_ec_device *ec_dev,
 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 		     struct cros_ec_command *msg);
 
+/**
+ * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC
+ *
+ * This function is identical to cros_ec_cmd_xfer, except it returns success
+ * status only if both the command was transmitted successfully and the EC
+ * replied with success status. It's not necessary to check msg->result when
+ * using this function.
+ *
+ * @ec_dev: EC device
+ * @msg: Message to write
+ * @return: Num. of bytes transferred on success, <0 on failure
+ */
+int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
+			    struct cros_ec_command *msg);
+
 /**
  * cros_ec_remove - Remove a ChromeOS EC
  *

include/linux/mfd/cros_ec_commands.h

@@ -949,6 +949,37 @@ struct ec_params_pwm_set_fan_duty {
 	uint32_t percent;
 } __packed;
 
+#define EC_CMD_PWM_SET_DUTY 0x25
+/* 16 bit duty cycle, 0xffff = 100% */
+#define EC_PWM_MAX_DUTY 0xffff
+
+enum ec_pwm_type {
+	/* All types, indexed by board-specific enum pwm_channel */
+	EC_PWM_TYPE_GENERIC = 0,
+	/* Keyboard backlight */
+	EC_PWM_TYPE_KB_LIGHT,
+	/* Display backlight */
+	EC_PWM_TYPE_DISPLAY_LIGHT,
+	EC_PWM_TYPE_COUNT,
+};
+
+struct ec_params_pwm_set_duty {
+	uint16_t duty;     /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
+	uint8_t pwm_type;  /* ec_pwm_type */
+	uint8_t index;     /* Type-specific index, or 0 if unique */
+} __packed;
+
+#define EC_CMD_PWM_GET_DUTY 0x26
+
+struct ec_params_pwm_get_duty {
+	uint8_t pwm_type;  /* ec_pwm_type */
+	uint8_t index;     /* Type-specific index, or 0 if unique */
+} __packed;
+
+struct ec_response_pwm_get_duty {
+	uint16_t duty;     /* Duty cycle, EC_PWM_MAX_DUTY = 100% */
+} __packed;
+
 /*****************************************************************************/
 /*
  * Lightbar commands. This looks worse than it is. Since we only use one HOST

include/linux/pwm.h

@@ -5,7 +5,9 @@
 #include <linux/mutex.h>
 #include <linux/of.h>
 
+struct pwm_capture;
 struct seq_file;
+
 struct pwm_chip;
 
 /**
@@ -147,12 +149,101 @@ static inline void pwm_get_args(const struct pwm_device *pwm,
 	*args = pwm->args;
 }
 
+/**
+ * pwm_init_state() - prepare a new state to be applied with pwm_apply_state()
+ * @pwm: PWM device
+ * @state: state to fill with the prepared PWM state
+ *
+ * This functions prepares a state that can later be tweaked and applied
+ * to the PWM device with pwm_apply_state(). This is a convenient function
+ * that first retrieves the current PWM state and the replaces the period
+ * and polarity fields with the reference values defined in pwm->args.
+ * Once the function returns, you can adjust the ->enabled and ->duty_cycle
+ * fields according to your needs before calling pwm_apply_state().
+ *
+ * ->duty_cycle is initially set to zero to avoid cases where the current
+ * ->duty_cycle value exceed the pwm_args->period one, which would trigger
+ * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle
+ * first.
+ */
+static inline void pwm_init_state(const struct pwm_device *pwm,
+				  struct pwm_state *state)
+{
+	struct pwm_args args;
+
+	/* First get the current state. */
+	pwm_get_state(pwm, state);
+
+	/* Then fill it with the reference config */
+	pwm_get_args(pwm, &args);
+
+	state->period = args.period;
+	state->polarity = args.polarity;
+	state->duty_cycle = 0;
+}
+
+/**
+ * pwm_get_relative_duty_cycle() - Get a relative duty cycle value
+ * @state: PWM state to extract the duty cycle from
+ * @scale: target scale of the relative duty cycle
+ *
+ * This functions converts the absolute duty cycle stored in @state (expressed
+ * in nanosecond) into a value relative to the period.
+ *
+ * For example if you want to get the duty_cycle expressed in percent, call:
+ *
+ * pwm_get_state(pwm, &state);
+ * duty = pwm_get_relative_duty_cycle(&state, 100);
+ */
+static inline unsigned int
+pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale)
+{
+	if (!state->period)
+		return 0;
+
+	return DIV_ROUND_CLOSEST_ULL((u64)state->duty_cycle * scale,
+				     state->period);
+}
+
+/**
+ * pwm_set_relative_duty_cycle() - Set a relative duty cycle value
+ * @state: PWM state to fill
+ * @duty_cycle: relative duty cycle value
+ * @scale: scale in which @duty_cycle is expressed
+ *
+ * This functions converts a relative into an absolute duty cycle (expressed
+ * in nanoseconds), and puts the result in state->duty_cycle.
+ *
+ * For example if you want to configure a 50% duty cycle, call:
+ *
+ * pwm_init_state(pwm, &state);
+ * pwm_set_relative_duty_cycle(&state, 50, 100);
+ * pwm_apply_state(pwm, &state);
+ *
+ * This functions returns -EINVAL if @duty_cycle and/or @scale are
+ * inconsistent (@scale == 0 or @duty_cycle > @scale).
+ */
+static inline int
+pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
+			    unsigned int scale)
+{
+	if (!scale || duty_cycle > scale)
+		return -EINVAL;
+
+	state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_cycle *
+						  state->period,
+						  scale);
+
+	return 0;
+}
+
 /**
  * struct pwm_ops - PWM controller operations
  * @request: optional hook for requesting a PWM
  * @free: optional hook for freeing a PWM
  * @config: configure duty cycles and period length for this PWM
  * @set_polarity: configure the polarity of this PWM
+ * @capture: capture and report PWM signal
  * @enable: enable PWM output toggling
  * @disable: disable PWM output toggling
  * @apply: atomically apply a new PWM config. The state argument
@@ -172,6 +263,8 @@ struct pwm_ops {
 		      int duty_ns, int period_ns);
 	int (*set_polarity)(struct pwm_chip *chip, struct pwm_device *pwm,
 			    enum pwm_polarity polarity);
+	int (*capture)(struct pwm_chip *chip, struct pwm_device *pwm,
+		       struct pwm_capture *result, unsigned long timeout);
 	int (*enable)(struct pwm_chip *chip, struct pwm_device *pwm);
 	void (*disable)(struct pwm_chip *chip, struct pwm_device *pwm);
 	int (*apply)(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -212,6 +305,16 @@ struct pwm_chip {
 	bool can_sleep;
 };
 
+/**
+ * struct pwm_capture - PWM capture data
+ * @period: period of the PWM signal (in nanoseconds)
+ * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
+ */
+struct pwm_capture {
+	unsigned int period;
+	unsigned int duty_cycle;
+};
+
 #if IS_ENABLED(CONFIG_PWM)
 /* PWM user APIs */
 struct pwm_device *pwm_request(int pwm_id, const char *label);
@@ -323,8 +426,9 @@ static inline void pwm_disable(struct pwm_device *pwm)
 	pwm_apply_state(pwm, &state);
 }
 
-
 /* PWM provider APIs */
+int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
+		unsigned long timeout);
 int pwm_set_chip_data(struct pwm_device *pwm, void *data);
 void *pwm_get_chip_data(struct pwm_device *pwm);
 
@@ -376,6 +480,13 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
 	return -EINVAL;
 }
 
+static inline int pwm_capture(struct pwm_device *pwm,
+			      struct pwm_capture *result,
+			      unsigned long timeout)
+{
+	return -EINVAL;
+}
+
 static inline int pwm_set_polarity(struct pwm_device *pwm,
 				   enum pwm_polarity polarity)
 {