pwm: meson: Make use of devm_pwmchip_alloc() function

This prepares the pwm-meson 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.

Link: https://lore.kernel.org/r/6cc57880e910e6ffd8df15bc4a41c42fe9523293.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-meson.c

@@ -102,7 +102,6 @@ struct meson_pwm_data {
 };
 
 struct meson_pwm {
-	struct pwm_chip chip;
 	const struct meson_pwm_data *data;
 	struct meson_pwm_channel channels[MESON_NUM_PWMS];
 	void __iomem *base;
@@ -115,7 +114,7 @@ struct meson_pwm {
 
 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 {
-	return container_of(chip, struct meson_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -529,29 +528,29 @@ static int meson_pwm_init_channels(struct pwm_chip *chip)
 
 static int meson_pwm_probe(struct platform_device *pdev)
 {
+	struct pwm_chip *chip;
 	struct meson_pwm *meson;
 	int err;
 
-	meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
-	if (!meson)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, MESON_NUM_PWMS, sizeof(*meson));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	meson = to_meson_pwm(chip);
 
 	meson->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(meson->base))
 		return PTR_ERR(meson->base);
 
 	spin_lock_init(&meson->lock);
-	meson->chip.dev = &pdev->dev;
-	meson->chip.ops = &meson_pwm_ops;
-	meson->chip.npwm = MESON_NUM_PWMS;
+	chip->ops = &meson_pwm_ops;
 
 	meson->data = of_device_get_match_data(&pdev->dev);
 
-	err = meson_pwm_init_channels(&meson->chip);
+	err = meson_pwm_init_channels(chip);
 	if (err < 0)
 		return err;
 
-	err = devm_pwmchip_add(&pdev->dev, &meson->chip);
+	err = devm_pwmchip_add(&pdev->dev, chip);
 	if (err < 0)
 		return dev_err_probe(&pdev->dev, err,
 				     "failed to register PWM chip\n");