pwm: renesas-tpu: Make use of devm_pwmchip_alloc() function

This prepares the pwm-renesas-tpu driver to further changes of the pwm
core outlined in the commit introducing devm_pwmchip_alloc(). There is
no intended semantical change and the driver should behave as before.

Also convert the to_tpu_device() helper macro to a static inline to get
some type safety.

Link: https://lore.kernel.org/r/aac4a9546b0f474d991144aa925c83cfa7abe2c0.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-renesas-tpu.c

@@ -79,7 +79,6 @@ struct tpu_pwm_device {
 
 struct tpu_device {
 	struct platform_device *pdev;
-	struct pwm_chip chip;
 	spinlock_t lock;
 
 	void __iomem *base;
@@ -87,7 +86,10 @@ struct tpu_device {
 	struct tpu_pwm_device tpd[TPU_CHANNEL_MAX];
 };
 
-#define to_tpu_device(c)	container_of(c, struct tpu_device, chip)
+static inline struct tpu_device *to_tpu_device(struct pwm_chip *chip)
+{
+	return pwmchip_get_drvdata(chip);
+}
 
 static void tpu_pwm_write(struct tpu_pwm_device *tpd, int reg_nr, u16 value)
 {
@@ -438,12 +440,14 @@ static const struct pwm_ops tpu_pwm_ops = {
 
 static int tpu_probe(struct platform_device *pdev)
 {
+	struct pwm_chip *chip;
 	struct tpu_device *tpu;
 	int ret;
 
-	tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
-	if (tpu == NULL)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, TPU_CHANNEL_MAX, sizeof(*tpu));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	tpu = to_tpu_device(chip);
 
 	spin_lock_init(&tpu->lock);
 	tpu->pdev = pdev;
@@ -460,15 +464,13 @@ static int tpu_probe(struct platform_device *pdev)
 	/* Initialize and register the device. */
 	platform_set_drvdata(pdev, tpu);
 
-	tpu->chip.dev = &pdev->dev;
-	tpu->chip.ops = &tpu_pwm_ops;
-	tpu->chip.npwm = TPU_CHANNEL_MAX;
+	chip->ops = &tpu_pwm_ops;
 
 	ret = devm_pm_runtime_enable(&pdev->dev);
 	if (ret < 0)
 		return dev_err_probe(&pdev->dev, ret, "Failed to enable runtime PM\n");
 
-	ret = devm_pwmchip_add(&pdev->dev, &tpu->chip);
+	ret = devm_pwmchip_add(&pdev->dev, chip);
 	if (ret < 0)
 		return dev_err_probe(&pdev->dev, ret, "Failed to register PWM chip\n");