backlight: lcd: Add LCD_POWER_ constants for power states

Duplicate FB_BLANK_ constants as LCD_POWER_ constants in the lcd
header file. Allows lcd drivers to avoid including the fbdev header
file and removes a compile-time dependency between the two subsystems.

The new LCD_POWER_ constants have the same values as their
FB_BLANK_ counterparts. Hence semantics does not change and the lcd
drivers can be converted one by one. Each instance of FB_BLANK_UNBLANK
becomes LCD_POWER_ON, each of FB_BLANK_POWERDOWN becomes LCD_POWER_OFF,
FB_BLANK_NORMAL becomes LCD_POWER_REDUCED and FB_BLANK_VSYNC_SUSPEND
becomes LCD_POWER_REDUCED_VSYNC_SUSPEND.

Lcd code or drivers do not use FB_BLANK_HSYNC_SUSPEND, so no
new constants for this is being added. The tokens LCD_POWER_REDUCED
and LCD_POWER_REDUCED_VSYNC_SUSPEND are deprecated and drivers should
replace them with LCD_POWER_ON and LCD_POWER_OFF.

See also commit a1cacb8 ("backlight: Add BACKLIGHT_POWER_ constants
for power states"), which added similar constants for backlight drivers.

v2:
- fix typo in commit description

Signed-off-by: Thomas Zimmermann <[email protected]>
Reviewed-by: Daniel Thompson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lee Jones <[email protected]>

Author: tdz

drivers/video/backlight/lcd.c

@@ -20,6 +20,24 @@
 
 #if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
 			   defined(CONFIG_LCD_CLASS_DEVICE_MODULE))
+static int to_lcd_power(int fb_blank)
+{
+	switch (fb_blank) {
+	case FB_BLANK_UNBLANK:
+		return LCD_POWER_ON;
+	/* deprecated; TODO: should become 'off' */
+	case FB_BLANK_NORMAL:
+		return LCD_POWER_REDUCED;
+	case FB_BLANK_VSYNC_SUSPEND:
+		return LCD_POWER_REDUCED_VSYNC_SUSPEND;
+	/* 'off' */
+	case FB_BLANK_HSYNC_SUSPEND:
+	case FB_BLANK_POWERDOWN:
+	default:
+		return LCD_POWER_OFF;
+	}
+}
+
 /* This callback gets called when something important happens inside a
  * framebuffer driver. We're looking if that important event is blanking,
  * and if it is, we're switching lcd power as well ...
@@ -42,8 +60,10 @@ static int fb_notifier_callback(struct notifier_block *self,
 		return 0;
 
 	if (event == FB_EVENT_BLANK) {
+		int power = to_lcd_power(*(int *)evdata->data);
+
 		if (ld->ops->set_power)
-			ld->ops->set_power(ld, *(int *)evdata->data);
+			ld->ops->set_power(ld, power);
 	} else {
 		if (ld->ops->set_mode)
 			ld->ops->set_mode(ld, evdata->data);

include/linux/lcd.h

@@ -14,6 +14,11 @@
 #include <linux/notifier.h>
 #include <linux/fb.h>
 
+#define LCD_POWER_ON			(0)
+#define LCD_POWER_REDUCED		(1) // deprecated; don't use in new code
+#define LCD_POWER_REDUCED_VSYNC_SUSPEND	(2) // deprecated; don't use in new code
+#define LCD_POWER_OFF			(4)
+
 /* Notes on locking:
  *
  * lcd_device->ops_lock is an internal backlight lock protecting the ops