[PATCH 02/28] backlight: lcd: Test against struct fb_info.lcd_dev

[Thomas Zimmermann]

Add struct fb_info.lcd_dev for fbdev drivers to store a reference to
their lcd device. Update the lcd's fb_notifier_callback() to test for
this field. The lcd module can now detect if an lcd device belongs to
an fbdev device.

This works similar to the bl_dev for backlights and will allow for
the removal of the check_fb callback from several fbdev driver's lcd
devices.

Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
---
 drivers/video/backlight/lcd.c |  3 +++
 include/linux/fb.h            | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/drivers/video/backlight/lcd.c b/drivers/video/backlight/lcd.c
index 0cd0fa1b24f9..43a6752ec27f 100644
--- a/drivers/video/backlight/lcd.c
+++ b/drivers/video/backlight/lcd.c
@@ -30,6 +30,7 @@ static int fb_notifier_callback(struct notifier_block *self,
        struct lcd_device *ld;
        struct fb_event *evdata = data;
        struct fb_info *info = evdata->info;
+       struct lcd_device *fb_lcd = fb_lcd_device(info);
 
        ld = container_of(self, struct lcd_device, fb_notif);
        mutex_lock(&ld->ops_lock);
@@ -38,6 +39,8 @@ static int fb_notifier_callback(struct notifier_block *self,
                goto out;
        if (ld->ops->check_fb && !ld->ops->check_fb(ld, evdata->info))
                goto out;
+       if (fb_lcd && fb_lcd != ld)
+               goto out;
 
        if (event == FB_EVENT_BLANK) {
                if (ld->ops->set_power)
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 865dad03e73e..bf1893616e9c 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -21,6 +21,7 @@ struct fb_info;
 struct file;
 struct i2c_adapter;
 struct inode;
+struct lcd_device;
 struct module;
 struct notifier_block;
 struct page;
@@ -480,6 +481,13 @@ struct fb_info {
        struct mutex bl_curve_mutex;
        u8 bl_curve[FB_BACKLIGHT_LEVELS];
 #endif
+
+       /*
+        * Assigned LCD device; set before framebuffer
+        * registration, remove after unregister
+        */
+       struct lcd_device *lcd_dev;
+
 #ifdef CONFIG_FB_DEFERRED_IO
        struct delayed_work deferred_work;
        unsigned long npagerefs;
@@ -753,6 +761,11 @@ static inline struct backlight_device *fb_bl_device(struct 
fb_info *info)
 }
 #endif
 
+static inline struct lcd_device *fb_lcd_device(struct fb_info *info)
+{
+       return info->lcd_dev;
+}
+
 /* fbmon.c */
 #define FB_MAXTIMINGS          0
 #define FB_VSYNCTIMINGS                1
-- 
2.46.0