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ENGR00264855 backlight: Support backlight shared by multiple fbs

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One backlight device may shared by multiple framebuffers.
We don't hope blanking one of the framebuffers may turn the
backlight off for all the other framebuffers, since they are
likely active to show display content. This patch adds logic
to record each framebuffer's backlight usage to determine the
backlight device use count and whether the backlight should be
turned on or off.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit 37cbf741e4dff1f757f3ade6bb861d9a2af70693)
This commit is contained in:
Liu Ying
2013-05-30 13:56:17 +08:00
committed by Nitin Garg
parent cc02bcc198
commit 2cb66c2795
2 changed files with 22 additions and 5 deletions
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21
drivers/video/backlight/backlight.c
View File

@ -38,6 +38,7 @@ static int fb_notifier_callback(struct notifier_block *self,
{
struct backlight_device *bd;
struct fb_event *evdata = data;
int node = evdata->info->node;
/* If we aren't interested in this event, skip it immediately ... */
if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)
@ -49,11 +50,21 @@ static int fb_notifier_callback(struct notifier_block *self,
if (!bd->ops->check_fb ||
bd->ops->check_fb(bd, evdata->info)) {
bd->props.fb_blank = *(int *)evdata->data;
if (bd->props.fb_blank == FB_BLANK_UNBLANK)
bd->props.state &= ~BL_CORE_FBBLANK;
else
bd->props.state |= BL_CORE_FBBLANK;
backlight_update_status(bd);
if (bd->props.fb_blank == FB_BLANK_UNBLANK &&
!bd->fb_bl_on[node]) {
bd->fb_bl_on[node] = true;
if (!bd->use_count++) {
bd->props.state &= ~BL_CORE_FBBLANK;
backlight_update_status(bd);
}
} else if (bd->props.fb_blank != FB_BLANK_UNBLANK &&
bd->fb_bl_on[node]) {
bd->fb_bl_on[node] = false;
if (!(--bd->use_count)) {
bd->props.state |= BL_CORE_FBBLANK;
backlight_update_status(bd);
}
}
}
mutex_unlock(&bd->ops_lock);
return 0;

6
include/linux/backlight.h
View File

@ -9,6 +9,7 @@
#define _LINUX_BACKLIGHT_H
#include <linux/device.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
@ -101,6 +102,11 @@ struct backlight_device {
struct notifier_block fb_notif;
struct device dev;
/* Multiple framebuffers may share one backlight device */
bool fb_bl_on[FB_MAX];
int use_count;
};
static inline void backlight_update_status(struct backlight_device *bd)