pwm: stm32: Make use of devm_pwmchip_alloc() function

This prepares the pwm-stm32 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/59e5dfff2b878cc8590e286572672e4f10e35380.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-stm32.c

@@ -27,7 +27,6 @@ struct stm32_breakinput {
 };
 
 struct stm32_pwm {
-	struct pwm_chip chip;
 	struct mutex lock; /* protect pwm config/enable */
 	struct clk *clk;
 	struct regmap *regmap;
@@ -40,7 +39,7 @@ struct stm32_pwm {
 
 static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
 {
-	return container_of(chip, struct stm32_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static u32 active_channels(struct stm32_pwm *dev)
@@ -632,14 +631,16 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 	struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
 	struct pwm_chip *chip;
 	struct stm32_pwm *priv;
-	unsigned int num_enabled;
+	unsigned int npwm, num_enabled;
 	unsigned int i;
 	int ret;
 
-	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
-	chip = &priv->chip;
+	npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
+
+	chip = devm_pwmchip_alloc(dev, npwm, sizeof(*priv));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	priv = to_stm32_pwm_dev(chip);
 
 	mutex_init(&priv->lock);
 	priv->regmap = ddata->regmap;
@@ -655,9 +656,7 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 
 	stm32_pwm_detect_complementary(priv);
 
-	chip->dev = dev;
 	chip->ops = &stm32pwm_ops;
-	chip->npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
 
 	/* Initialize clock refcount to number of enabled PWM channels. */
 	for (i = 0; i < num_enabled; i++)