pwm: lpc18xx-sct: Make use of devm_pwmchip_alloc() function

This prepares the pwm-lpc18xx-sct 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/d480891340e927705843cd09e5777d4daaa6c9cc.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-lpc18xx-sct.c

@@ -92,7 +92,6 @@ struct lpc18xx_pwm_data {
 };
 
 struct lpc18xx_pwm_chip {
-	struct pwm_chip chip;
 	void __iomem *base;
 	struct clk *pwm_clk;
 	unsigned long clk_rate;
@@ -109,7 +108,7 @@ struct lpc18xx_pwm_chip {
 static inline struct lpc18xx_pwm_chip *
 to_lpc18xx_pwm_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct lpc18xx_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static inline void lpc18xx_pwm_writel(struct lpc18xx_pwm_chip *lpc18xx_pwm,
@@ -353,11 +352,10 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
 	int ret;
 	u64 val;
 
-	lpc18xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*lpc18xx_pwm),
-				   GFP_KERNEL);
-	if (!lpc18xx_pwm)
-		return -ENOMEM;
-	chip = &lpc18xx_pwm->chip;
+	chip = devm_pwmchip_alloc(&pdev->dev, LPC18XX_NUM_PWMS, sizeof(*lpc18xx_pwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	lpc18xx_pwm = to_lpc18xx_pwm_chip(chip);
 
 	lpc18xx_pwm->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(lpc18xx_pwm->base))
@@ -388,9 +386,7 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
 	lpc18xx_pwm->min_period_ns = DIV_ROUND_UP(NSEC_PER_SEC,
 						  lpc18xx_pwm->clk_rate);
 
-	chip->dev = &pdev->dev;
 	chip->ops = &lpc18xx_pwm_ops;
-	chip->npwm = LPC18XX_NUM_PWMS;
 
 	/* SCT counter must be in unify (32 bit) mode */
 	lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_CONFIG,