pwm: img: Make use of devm_pwmchip_alloc() function

This prepares the pwm-img 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/d99e00af2ff09cd3587d9a7c51dc8e0e13f85208.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-img.c

@@ -59,7 +59,6 @@ struct img_pwm_soc_data {
 };
 
 struct img_pwm_chip {
-	struct pwm_chip	chip;
 	struct clk	*pwm_clk;
 	struct clk	*sys_clk;
 	void __iomem	*base;
@@ -73,7 +72,7 @@ struct img_pwm_chip {
 
 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct img_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static inline void img_pwm_writel(struct img_pwm_chip *imgchip,
@@ -263,10 +262,10 @@ static int img_pwm_probe(struct platform_device *pdev)
 	struct pwm_chip *chip;
 	struct img_pwm_chip *imgchip;
 
-	imgchip = devm_kzalloc(&pdev->dev, sizeof(*imgchip), GFP_KERNEL);
-	if (!imgchip)
-		return -ENOMEM;
-	chip = &imgchip->chip;
+	chip = devm_pwmchip_alloc(&pdev->dev, IMG_PWM_NPWM, sizeof(*imgchip));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	imgchip = to_img_pwm_chip(chip);
 
 	imgchip->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(imgchip->base))
@@ -318,9 +317,7 @@ static int img_pwm_probe(struct platform_device *pdev)
 	do_div(val, clk_rate);
 	imgchip->min_period_ns = val;
 
-	chip->dev = &pdev->dev;
 	chip->ops = &img_pwm_ops;
-	chip->npwm = IMG_PWM_NPWM;
 
 	ret = pwmchip_add(chip);
 	if (ret < 0) {