pwm: renesas-tpu: Add DT support

Specify DT bindings for the TPU PWM controller and add OF support to the
driver.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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

+* Renesas R-Car Timer Pulse Unit PWM Controller
+
+Required Properties:
+
+  - compatible: should be one of the following.
+    - "renesas,tpu-r8a73a4": for R8A77A4 (R-Mobile APE6) compatible PWM controller.
+    - "renesas,tpu-r8a7740": for R8A7740 (R-Mobile A1) compatible PWM controller.
+    - "renesas,tpu-r8a7790": for R8A7790 (R-Car H2) compatible PWM controller.
+    - "renesas,tpu-sh7372": for SH7372 (SH-Mobile AP4) compatible PWM controller.
+    - "renesas,tpu": for generic R-Car TPU PWM controller.
+
+  - reg: Base address and length of each memory resource used by the PWM
+    controller hardware module.
+
+  - #pwm-cells: should be 3. See pwm.txt in this directory for a description of
+    the cells format. The only third cell flag supported by this binding is
+    PWM_POLARITY_INVERTED.
+
+Please refer to pwm.txt in this directory for details of the common PWM bindings
+used by client devices.
+
+Example: R8A7740 (R-Car A1) TPU controller node
+
+	tpu: pwm@e6600000 {
+		compatible = "renesas,tpu-r8a7740", "renesas,tpu";
+		reg = <0xe6600000 0x100>;
+		#pwm-cells = <3>;
+	};

drivers/pwm/pwm-renesas-tpu.c

@@ -20,6 +20,7 @@
 #include <linux/ioport.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 #include <linux/platform_data/pwm-renesas-tpu.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
@@ -86,7 +87,7 @@ struct tpu_pwm_device {
 
 struct tpu_device {
 	struct platform_device *pdev;
-	struct tpu_pwm_platform_data *pdata;
+	enum pwm_polarity polarities[TPU_CHANNEL_MAX];
 	struct pwm_chip chip;
 	spinlock_t lock;
 
@@ -228,8 +229,7 @@ static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm)
 
 	pwm->tpu = tpu;
 	pwm->channel = _pwm->hwpwm;
-	pwm->polarity = tpu->pdata ? tpu->pdata->channels[pwm->channel].polarity
-		      : PWM_POLARITY_NORMAL;
+	pwm->polarity = tpu->polarities[pwm->channel];
 	pwm->prescaler = 0;
 	pwm->period = 0;
 	pwm->duty = 0;
@@ -388,6 +388,16 @@ static const struct pwm_ops tpu_pwm_ops = {
  * Probe and remove
  */
 
+static void tpu_parse_pdata(struct tpu_device *tpu)
+{
+	struct tpu_pwm_platform_data *pdata = tpu->pdev->dev.platform_data;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(tpu->polarities); ++i)
+		tpu->polarities[i] = pdata ? pdata->channels[i].polarity
+				   : PWM_POLARITY_NORMAL;
+}
+
 static int tpu_probe(struct platform_device *pdev)
 {
 	struct tpu_device *tpu;
@@ -400,7 +410,11 @@ static int tpu_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	tpu->pdata = pdev->dev.platform_data;
+	spin_lock_init(&tpu->lock);
+	tpu->pdev = pdev;
+
+	/* Initialize device configuration from platform data. */
+	tpu_parse_pdata(tpu);
 
 	/* Map memory, get clock and pin control. */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -422,11 +436,10 @@ static int tpu_probe(struct platform_device *pdev)
 	/* Initialize and register the device. */
 	platform_set_drvdata(pdev, tpu);
 
-	spin_lock_init(&tpu->lock);
-	tpu->pdev = pdev;
-
 	tpu->chip.dev = &pdev->dev;
 	tpu->chip.ops = &tpu_pwm_ops;
+	tpu->chip.of_xlate = of_pwm_xlate_with_flags;
+	tpu->chip.of_pwm_n_cells = 3;
 	tpu->chip.base = -1;
 	tpu->chip.npwm = TPU_CHANNEL_MAX;
 
@@ -457,12 +470,26 @@ static int tpu_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id tpu_of_table[] = {
+	{ .compatible = "renesas,tpu-r8a73a4", },
+	{ .compatible = "renesas,tpu-r8a7740", },
+	{ .compatible = "renesas,tpu-r8a7790", },
+	{ .compatible = "renesas,tpu-sh7372", },
+	{ .compatible = "renesas,tpu", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, tpu_of_table);
+#endif
+
 static struct platform_driver tpu_driver = {
 	.probe		= tpu_probe,
 	.remove		= tpu_remove,
 	.driver		= {
 		.name	= "renesas-tpu-pwm",
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(tpu_of_table),
 	}
 };