pwm: bcm2835: Make use of devm_pwmchip_alloc() function

This prepares the pwm-bcm2835 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/441489772bdfbb2cd206fd534b36c63e8c50843a.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-bcm2835.c

@@ -24,7 +24,6 @@
 #define PERIOD_MIN		0x2
 
 struct bcm2835_pwm {
-	struct pwm_chip chip;
 	void __iomem *base;
 	struct clk *clk;
 	unsigned long rate;
@@ -32,7 +31,7 @@ struct bcm2835_pwm {
 
 static inline struct bcm2835_pwm *to_bcm2835_pwm(struct pwm_chip *chip)
 {
-	return container_of(chip, struct bcm2835_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int bcm2835_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -134,12 +133,14 @@ static void devm_clk_rate_exclusive_put(void *data)
 
 static int bcm2835_pwm_probe(struct platform_device *pdev)
 {
+	struct pwm_chip *chip;
 	struct bcm2835_pwm *pc;
 	int ret;
 
-	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
-	if (!pc)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*pc));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	pc = to_bcm2835_pwm(chip);
 
 	pc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pc->base))
@@ -165,14 +166,12 @@ static int bcm2835_pwm_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, -EINVAL,
 				     "failed to get clock rate\n");
 
-	pc->chip.dev = &pdev->dev;
-	pc->chip.ops = &bcm2835_pwm_ops;
-	pc->chip.atomic = true;
-	pc->chip.npwm = 2;
+	chip->ops = &bcm2835_pwm_ops;
+	chip->atomic = true;
 
 	platform_set_drvdata(pdev, pc);
 
-	ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
+	ret = devm_pwmchip_add(&pdev->dev, chip);
 	if (ret < 0)
 		return dev_err_probe(&pdev->dev, ret,
 				     "failed to add pwmchip\n");