pwm: raspberrypi-poe: Make use of devm_pwmchip_alloc() function

This prepares the pwm-raspberrypi-poe 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/4654a64[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-raspberrypi-poe.c

···
 
 struct raspberrypi_pwm {
 	struct rpi_firmware *firmware;
-	struct pwm_chip chip;
 	unsigned int duty_cycle;
 };
 
···
 static inline
 struct raspberrypi_pwm *raspberrypi_pwm_from_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct raspberrypi_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int raspberrypi_pwm_set_property(struct rpi_firmware *firmware,
···
 	struct device_node *firmware_node;
 	struct device *dev = &pdev->dev;
 	struct rpi_firmware *firmware;
+	struct pwm_chip *chip;
 	struct raspberrypi_pwm *rpipwm;
 	int ret;
 
···
 		return dev_err_probe(dev, -EPROBE_DEFER,
 				     "Failed to get firmware handle\n");
 
-	rpipwm = devm_kzalloc(&pdev->dev, sizeof(*rpipwm), GFP_KERNEL);
-	if (!rpipwm)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(&pdev->dev, RASPBERRYPI_FIRMWARE_PWM_NUM,
+				  sizeof(*rpipwm));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	rpipwm = raspberrypi_pwm_from_chip(chip);
 
 	rpipwm->firmware = firmware;
-	rpipwm->chip.dev = dev;
-	rpipwm->chip.ops = &raspberrypi_pwm_ops;
-	rpipwm->chip.npwm = RASPBERRYPI_FIRMWARE_PWM_NUM;
+	chip->ops = &raspberrypi_pwm_ops;
 
 	ret = raspberrypi_pwm_get_property(rpipwm->firmware, RPI_PWM_CUR_DUTY_REG,
 					   &rpipwm->duty_cycle);
···
 		return ret;
 	}
 
-	return devm_pwmchip_add(dev, &rpipwm->chip);
+	return devm_pwmchip_add(dev, chip);
 }
 
 static const struct of_device_id raspberrypi_pwm_of_match[] = {