i2c: designware: Convert to use unified device property API

With ACPI _DSD (introduced in ACPI v5.1) it is now possible to pass device
configuration information from ACPI in addition to DT. In order to support
this, convert the driver to use the unified device property accessors
instead of DT specific.

Change to ordering a bit so that we first try platform data and if that's
not available look from device properties. ACPI *CNT methods are then used
as last resort to override everything else.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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

@@ -36,6 +36,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
@@ -129,10 +130,10 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 
 static int dw_i2c_plat_probe(struct platform_device *pdev)
 {
+	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	struct dw_i2c_dev *dev;
 	struct i2c_adapter *adap;
 	struct resource *mem;
-	struct dw_i2c_platform_data *pdata;
 	int irq, r;
 	u32 clk_freq, ht = 0;
 
@@ -156,33 +157,28 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	/* fast mode by default because of legacy reasons */
 	clk_freq = 400000;
 
-	if (has_acpi_companion(&pdev->dev)) {
-		dw_i2c_acpi_configure(pdev);
-	} else if (pdev->dev.of_node) {
-		of_property_read_u32(pdev->dev.of_node,
-					"i2c-sda-hold-time-ns", &ht);
-
-		of_property_read_u32(pdev->dev.of_node,
-				     "i2c-sda-falling-time-ns",
-				     &dev->sda_falling_time);
-		of_property_read_u32(pdev->dev.of_node,
-				     "i2c-scl-falling-time-ns",
-				     &dev->scl_falling_time);
-
-		of_property_read_u32(pdev->dev.of_node, "clock-frequency",
-				     &clk_freq);
-
-		/* Only standard mode at 100kHz and fast mode at 400kHz
-		 * are supported.
-		 */
-		if (clk_freq != 100000 && clk_freq != 400000) {
-			dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
-			return -EINVAL;
-		}
+	if (pdata) {
+		clk_freq = pdata->i2c_scl_freq;
 	} else {
-		pdata = dev_get_platdata(&pdev->dev);
-		if (pdata)
-			clk_freq = pdata->i2c_scl_freq;
+		device_property_read_u32(&pdev->dev, "i2c-sda-hold-time-ns",
+					 &ht);
+		device_property_read_u32(&pdev->dev, "i2c-sda-falling-time-ns",
+					 &dev->sda_falling_time);
+		device_property_read_u32(&pdev->dev, "i2c-scl-falling-time-ns",
+					 &dev->scl_falling_time);
+		device_property_read_u32(&pdev->dev, "clock-frequency",
+					 &clk_freq);
+	}
+
+	if (has_acpi_companion(&pdev->dev))
+		dw_i2c_acpi_configure(pdev);
+
+	/*
+	 * Only standard mode at 100kHz and fast mode at 400kHz are supported.
+	 */
+	if (clk_freq != 100000 && clk_freq != 400000) {
+		dev_err(&pdev->dev, "Only 100kHz and 400kHz supported");
+		return -EINVAL;
 	}
 
 	r = i2c_dw_eval_lock_support(dev);