pwm: vt8500: Make use of devm_pwmchip_alloc() function

This prepares the pwm-vt8500 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.

Also convert the to_vt8500_chip() helper macro to a static inline to
get some type safety.

Link: https://lore.kernel.org/r/b203c4448db23ebad1165b7bce43ac41468c4e89.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <[email protected]>

Author: Uwe Kleine-König

drivers/pwm/pwm-vt8500.c

@@ -45,12 +45,14 @@
 #define STATUS_ALL_UPDATE	0x0F
 
 struct vt8500_chip {
-	struct pwm_chip chip;
 	void __iomem *base;
 	struct clk *clk;
 };
 
-#define to_vt8500_chip(chip)	container_of(chip, struct vt8500_chip, chip)
+static inline struct vt8500_chip *to_vt8500_chip(struct pwm_chip *chip)
+{
+	return pwmchip_get_drvdata(chip);
+}
 
 #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
 static inline void vt8500_pwm_busy_wait(struct pwm_chip *chip, int nr, u8 bitmask)
@@ -240,14 +242,12 @@ static int vt8500_pwm_probe(struct platform_device *pdev)
 	if (!np)
 		return dev_err_probe(&pdev->dev, -EINVAL, "invalid devicetree node\n");
 
-	vt8500 = devm_kzalloc(&pdev->dev, sizeof(*vt8500), GFP_KERNEL);
-	if (vt8500 == NULL)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, VT8500_NR_PWMS, sizeof(*vt8500));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	vt8500 = to_vt8500_chip(chip);
 
-	chip = &vt8500->chip;
-	chip->dev = &pdev->dev;
 	chip->ops = &vt8500_pwm_ops;
-	chip->npwm = VT8500_NR_PWMS;
 
 	vt8500->clk = devm_clk_get_prepared(&pdev->dev, NULL);
 	if (IS_ERR(vt8500->clk))