pwm: lp3943: Make use of devm_pwmchip_alloc() function

This prepares the pwm-lp3943 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/44a2d303bb511e49c6db8aaedd17986c3aedde44.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-lp3943.c

@@ -20,7 +20,6 @@
 #define LP3943_MAX_PERIOD		1600000
 
 struct lp3943_pwm {
-	struct pwm_chip chip;
 	struct lp3943 *lp3943;
 	struct lp3943_platform_data *pdata;
 	struct lp3943_pwm_map pwm_map[LP3943_NUM_PWMS];
@@ -28,7 +27,7 @@ struct lp3943_pwm {
 
 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip)
 {
-	return container_of(chip, struct lp3943_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static struct lp3943_pwm_map *
@@ -273,12 +272,14 @@ static int lp3943_pwm_parse_dt(struct device *dev,
 static int lp3943_pwm_probe(struct platform_device *pdev)
 {
 	struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);
+	struct pwm_chip *chip;
 	struct lp3943_pwm *lp3943_pwm;
 	int ret;
 
-	lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL);
-	if (!lp3943_pwm)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, LP3943_NUM_PWMS, sizeof(*lp3943_pwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	lp3943_pwm = to_lp3943_pwm(chip);
 
 	lp3943_pwm->pdata = lp3943->pdata;
 	if (!lp3943_pwm->pdata) {
@@ -292,11 +293,9 @@ static int lp3943_pwm_probe(struct platform_device *pdev)
 	}
 
 	lp3943_pwm->lp3943 = lp3943;
-	lp3943_pwm->chip.dev = &pdev->dev;
-	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
-	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
+	chip->ops = &lp3943_pwm_ops;
 
-	return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip);
+	return devm_pwmchip_add(&pdev->dev, chip);
 }
 
 #ifdef CONFIG_OF