backlight: Fix external uses of backlight internal semaphore
backlight_device->sem has a very specific use as documented in the
header file. The external users of this are using it for a different
reason, to serialise access to the update_status() method.
backlight users were supposed to implement their own internal
serialisation of update_status() if needed but everyone is doing
things differently and incorrectly. Therefore add a global mutex to
take care of serialisation for everyone, once and for all.
Locking for get_brightness remains optional since most users don't
need it.
Also update the lcd class in a similar way.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
diff --git a/drivers/macintosh/via-pmu-backlight.c b/drivers/macintosh/via-pmu-backlight.c
index db8bcc3..7ba2042 100644
--- a/drivers/macintosh/via-pmu-backlight.c
+++ b/drivers/macintosh/via-pmu-backlight.c
@@ -166,11 +166,9 @@
pmu_backlight_data.max_brightness / 15);
}
- down(&bd->sem);
bd->props->brightness = level;
bd->props->power = FB_BLANK_UNBLANK;
- bd->props->update_status(bd);
- up(&bd->sem);
+ backlight_update_status(bd);
mutex_lock(&pmac_backlight_mutex);
if (!pmac_backlight)