gpio: mvebu: Make use of devm_pwmchip_alloc() function

This prepares the pwm sub-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.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/2edc3adbb2c40b76b3b3dac82de82f3036bec1d5.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/gpio/gpio-mvebu.c

@@ -99,7 +99,6 @@ struct mvebu_pwm {
 	u32			 offset;
 	unsigned long		 clk_rate;
 	struct gpio_desc	*gpiod;
-	struct pwm_chip		 chip;
 	spinlock_t		 lock;
 	struct mvebu_gpio_chip	*mvchip;
 
@@ -615,7 +614,7 @@ static const struct regmap_config mvebu_gpio_regmap_config = {
  */
 static struct mvebu_pwm *to_mvebu_pwm(struct pwm_chip *chip)
 {
-	return container_of(chip, struct mvebu_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int mvebu_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -789,6 +788,7 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 {
 	struct device *dev = &pdev->dev;
 	struct mvebu_pwm *mvpwm;
+	struct pwm_chip *chip;
 	void __iomem *base;
 	u32 offset;
 	u32 set;
@@ -813,9 +813,11 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 	if (IS_ERR(mvchip->clk))
 		return PTR_ERR(mvchip->clk);
 
-	mvpwm = devm_kzalloc(dev, sizeof(struct mvebu_pwm), GFP_KERNEL);
-	if (!mvpwm)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(dev, mvchip->chip.ngpio, sizeof(*mvpwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	mvpwm = to_mvebu_pwm(chip);
+
 	mvchip->mvpwm = mvpwm;
 	mvpwm->mvchip = mvchip;
 	mvpwm->offset = offset;
@@ -868,13 +870,11 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
 		return -EINVAL;
 	}
 
-	mvpwm->chip.dev = dev;
-	mvpwm->chip.ops = &mvebu_pwm_ops;
-	mvpwm->chip.npwm = mvchip->chip.ngpio;
+	chip->ops = &mvebu_pwm_ops;
 
 	spin_lock_init(&mvpwm->lock);
 
-	return devm_pwmchip_add(dev, &mvpwm->chip);
+	return devm_pwmchip_add(dev, chip);
 }
 
 #ifdef CONFIG_DEBUG_FS