pwm: twl: Make use of devm_pwmchip_alloc() function

This prepares the pwm-twol 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/c65e796d46df71cd8d0d0941921997b9501f1cb3.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-twl.c

@@ -46,7 +46,6 @@
 #define TWL6030_PWM_TOGGLE(pwm, x)	((x) << (pwm * 3))
 
 struct twl_pwm_chip {
-	struct pwm_chip chip;
 	struct mutex mutex;
 	u8 twl6030_toggle3;
 	u8 twl4030_pwm_mux;
@@ -54,7 +53,7 @@ struct twl_pwm_chip {
 
 static inline struct twl_pwm_chip *to_twl(struct pwm_chip *chip)
 {
-	return container_of(chip, struct twl_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int twl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -341,23 +340,22 @@ static const struct pwm_ops twl6030_pwm_ops = {
 
 static int twl_pwm_probe(struct platform_device *pdev)
 {
+	struct pwm_chip *chip;
 	struct twl_pwm_chip *twl;
 
-	twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
-	if (!twl)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*twl));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	twl = to_twl(chip);
 
 	if (twl_class_is_4030())
-		twl->chip.ops = &twl4030_pwm_ops;
+		chip->ops = &twl4030_pwm_ops;
 	else
-		twl->chip.ops = &twl6030_pwm_ops;
-
-	twl->chip.dev = &pdev->dev;
-	twl->chip.npwm = 2;
+		chip->ops = &twl6030_pwm_ops;
 
 	mutex_init(&twl->mutex);
 
-	return devm_pwmchip_add(&pdev->dev, &twl->chip);
+	return devm_pwmchip_add(&pdev->dev, chip);
 }
 
 #ifdef CONFIG_OF