pwm: tegra: Make use of devm_pwmchip_alloc() function

This prepares the pwm-tegra 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/8719be3d57b0b5cf575b312e5ff41fe0717e3a43.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-tegra.c

@@ -65,8 +65,6 @@ struct tegra_pwm_soc {
 };
 
 struct tegra_pwm_chip {
-	struct pwm_chip chip;
-
 	struct clk *clk;
 	struct reset_control*rst;
 
@@ -80,7 +78,7 @@ struct tegra_pwm_chip {
 
 static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct tegra_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static inline u32 pwm_readl(struct tegra_pwm_chip *pc, unsigned int offset)
@@ -273,14 +271,17 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 {
 	struct pwm_chip *chip;
 	struct tegra_pwm_chip *pc;
+	const struct tegra_pwm_soc *soc;
 	int ret;
 
-	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
-	if (!pc)
-		return -ENOMEM;
-	chip = &pc->chip;
+	soc = of_device_get_match_data(&pdev->dev);
+
+	chip = devm_pwmchip_alloc(&pdev->dev, soc->num_channels, sizeof(*pc));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	pc = to_tegra_pwm_chip(chip);
 
-	pc->soc = of_device_get_match_data(&pdev->dev);
+	pc->soc = soc;
 
 	pc->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pc->regs))
@@ -328,9 +329,7 @@ static int tegra_pwm_probe(struct platform_device *pdev)
 
 	reset_control_deassert(pc->rst);
 
-	chip->dev = &pdev->dev;
 	chip->ops = &tegra_pwm_ops;
-	chip->npwm = pc->soc->num_channels;
 
 	ret = pwmchip_add(chip);
 	if (ret < 0) {