pwm: sl28cpld: Make use of devm_pwmchip_alloc() function

This prepares the pwm-sl28cpld 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.

Reviewed-by: Michael Walle <[e-mail]>
Link: https://lore.kernel.org/r/ee68708[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-sl28cpld.c

···
 	regmap_write((priv)->regmap, (priv)->offset + (reg), (val))
 
 struct sl28cpld_pwm {
-	struct pwm_chip chip;
 	struct regmap *regmap;
 	u32 offset;
 };
 
 static inline struct sl28cpld_pwm *sl28cpld_pwm_from_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct sl28cpld_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int sl28cpld_pwm_get_state(struct pwm_chip *chip,
···
 		return -ENODEV;
 	}
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*priv));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	priv = sl28cpld_pwm_from_chip(chip);
 
 	priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 	if (!priv->regmap) {
···
 	}
 
 	/* Initialize the pwm_chip structure */
-	chip = &priv->chip;
-	chip->dev = &pdev->dev;
 	chip->ops = &sl28cpld_pwm_ops;
-	chip->npwm = 1;
 
 	ret = devm_pwmchip_add(&pdev->dev, chip);
 	if (ret) {