backlight: pwm_bl: Drop support for legacy PWM probing

There is no in-tree user left which relies on legacy probing. So drop
support for it which removes another user of the deprecated
pwm_request() function.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20221117072151.3789691-1-u.kleine-koenig@pengutronix.de

drivers/video/backlight/pwm_bl.c

@@ -28,7 +28,6 @@ struct pwm_bl_data {
 	struct regulator	*power_supply;
 	struct gpio_desc	*enable_gpio;
 	unsigned int		scale;
-	bool			legacy;
 	unsigned int		post_pwm_on_delay;
 	unsigned int		pwm_off_delay;
 	int			(*notify)(struct device *,
@@ -455,7 +454,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	struct platform_pwm_backlight_data defdata;
 	struct backlight_properties props;
 	struct backlight_device *bl;
-	struct device_node *node = pdev->dev.of_node;
 	struct pwm_bl_data *pb;
 	struct pwm_state state;
 	unsigned int i;
@@ -506,12 +504,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	}
 
 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
-	if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !node) {
-		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
-		pb->legacy = true;
-		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
-	}
-
 	if (IS_ERR(pb->pwm)) {
 		ret = PTR_ERR(pb->pwm);
 		if (ret != -EPROBE_DEFER)
@@ -604,8 +596,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	if (IS_ERR(bl)) {
 		dev_err(&pdev->dev, "failed to register backlight\n");
 		ret = PTR_ERR(bl);
-		if (pb->legacy)
-			pwm_free(pb->pwm);
 		goto err_alloc;
 	}
 
@@ -639,8 +629,6 @@ static int pwm_backlight_remove(struct platform_device *pdev)
 
 	if (pb->exit)
 		pb->exit(&pdev->dev);
-	if (pb->legacy)
-		pwm_free(pb->pwm);
 
 	return 0;
 }

include/linux/pwm_backlight.h

@@ -8,7 +8,6 @@
 #include <linux/backlight.h>
 
 struct platform_pwm_backlight_data {
-	int pwm_id;
 	unsigned int max_brightness;
 	unsigned int dft_brightness;
 	unsigned int lth_brightness;