backlight: Add controls_device callback to struct backlight_ops

Replace check_fb with controls_device in struct backlight_ops. The
new callback interface takes a Linux device instead of a framebuffer.
Resolves one of the dependencies of backlight.h on fb.h.

The few drivers that had custom implementations of check_fb can easily
use the framebuffer's Linux device instead. Update them accordingly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20240305162425.23845-11-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>

drivers/video/backlight/backlight.c

@@ -112,7 +112,7 @@ static int fb_notifier_callback(struct notifier_block *self,
 
 	if (!bd->ops)
 		goto out;
-	if (bd->ops->check_fb && !bd->ops->check_fb(bd, info))
+	if (bd->ops->controls_device && !bd->ops->controls_device(bd, info->device))
 		goto out;
 	if (fb_bd && fb_bd != bd)
 		goto out;

drivers/video/backlight/bd6107.c

@@ -99,18 +99,18 @@ static int bd6107_backlight_update_status(struct backlight_device *backlight)
 	return 0;
 }
 
-static int bd6107_backlight_check_fb(struct backlight_device *backlight,
-				       struct fb_info *info)
+static bool bd6107_backlight_controls_device(struct backlight_device *backlight,
+					     struct device *display_dev)
 {
 	struct bd6107 *bd = bl_get_data(backlight);
 
-	return !bd->pdata->dev || bd->pdata->dev == info->device;
+	return !bd->pdata->dev || bd->pdata->dev == display_dev;
 }
 
 static const struct backlight_ops bd6107_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= bd6107_backlight_update_status,
-	.check_fb	= bd6107_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = bd6107_backlight_update_status,
+	.controls_device = bd6107_backlight_controls_device,
 };
 
 static int bd6107_probe(struct i2c_client *client)

drivers/video/backlight/gpio_backlight.c

@@ -30,18 +30,18 @@ static int gpio_backlight_update_status(struct backlight_device *bl)
 	return 0;
 }
 
-static int gpio_backlight_check_fb(struct backlight_device *bl,
-				   struct fb_info *info)
+static bool gpio_backlight_controls_device(struct backlight_device *bl,
+					   struct device *display_dev)
 {
 	struct gpio_backlight *gbl = bl_get_data(bl);
 
-	return !gbl->dev || gbl->dev == info->device;
+	return !gbl->dev || gbl->dev == display_dev;
 }
 
 static const struct backlight_ops gpio_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= gpio_backlight_update_status,
-	.check_fb	= gpio_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = gpio_backlight_update_status,
+	.controls_device = gpio_backlight_controls_device,
 };
 
 static int gpio_backlight_probe(struct platform_device *pdev)

drivers/video/backlight/lv5207lp.c

@@ -62,18 +62,18 @@ static int lv5207lp_backlight_update_status(struct backlight_device *backlight)
 	return 0;
 }
 
-static int lv5207lp_backlight_check_fb(struct backlight_device *backlight,
-				       struct fb_info *info)
+static bool lv5207lp_backlight_controls_device(struct backlight_device *backlight,
+					       struct device *display_dev)
 {
 	struct lv5207lp *lv = bl_get_data(backlight);
 
-	return !lv->pdata->dev || lv->pdata->dev == info->device;
+	return !lv->pdata->dev || lv->pdata->dev == display_dev;
 }
 
 static const struct backlight_ops lv5207lp_backlight_ops = {
-	.options	= BL_CORE_SUSPENDRESUME,
-	.update_status	= lv5207lp_backlight_update_status,
-	.check_fb	= lv5207lp_backlight_check_fb,
+	.options	 = BL_CORE_SUSPENDRESUME,
+	.update_status	 = lv5207lp_backlight_update_status,
+	.controls_device = lv5207lp_backlight_controls_device,
 };
 
 static int lv5207lp_probe(struct i2c_client *client)

include/linux/backlight.h

@@ -13,6 +13,7 @@
 #include <linux/fb.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
+#include <linux/types.h>
 
 /**
  * enum backlight_update_reason - what method was used to update backlight
@@ -110,7 +111,6 @@ enum backlight_scale {
 };
 
 struct backlight_device;
-struct fb_info;
 
 /**
  * struct backlight_ops - backlight operations
@@ -160,18 +160,18 @@ struct backlight_ops {
 	int (*get_brightness)(struct backlight_device *);
 
 	/**
-	 * @check_fb: Check the framebuffer device.
+	 * @controls_device: Check against the display device
 	 *
-	 * Check if given framebuffer device is the one bound to this backlight.
-	 * This operation is optional and if not implemented it is assumed that the
-	 * fbdev is always the one bound to the backlight.
+	 * Check if the backlight controls the given display device. This
+	 * operation is optional and if not implemented it is assumed that
+	 * the display is always the one controlled by the backlight.
 	 *
 	 * RETURNS:
 	 *
-	 * If info is NULL or the info matches the fbdev bound to the backlight return true.
-	 * If info does not match the fbdev bound to the backlight return false.
+	 * If display_dev is NULL or display_dev matches the device controlled by
+	 * the backlight, return true. Otherwise return false.
 	 */
-	int (*check_fb)(struct backlight_device *bd, struct fb_info *info);
+	bool (*controls_device)(struct backlight_device *bd, struct device *display_dev);
 };
 
 /**