Subject: [PATCH 2/2] backlight: Fix blanking for L4F00242T03 LCD

From: [email-masked] (Marek Vasut)
Date: Sat, 5 Jun 2010 03:25:46 +0200

Dne P? 4. ?ervna 2010 09:29:43 Alberto Panizzo napsal(a):
> On ven, 2010-06-04 at 07:52 +0200, Marek Vasut wrote:
> > The LCD was turned on if the variable power was > 0, but that was
> > incorrect. The LCD has to be turned on in every case but POWERDOWN.
> > 
> > Signed-off-by: Marek Vasut <[email-masked]>
> 
> Ack
> 
> > ---
> > 
> >  drivers/video/backlight/l4f00242t03.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/video/backlight/l4f00242t03.c
> > b/drivers/video/backlight/l4f00242t03.c index 9093ef0..ac20b2e 100644
> > --- a/drivers/video/backlight/l4f00242t03.c
> > +++ b/drivers/video/backlight/l4f00242t03.c
> > @@ -78,7 +78,7 @@ static int l4f00242t03_lcd_power_set(struct lcd_device
> > *ld, int power)
> > 
> >  	const u16 slpin = 0x10;
> >  	const u16 disoff = 0x28;
> > 
> > -	if (power) {
> > +	if (power < FB_BLANK_POWERDOWN) {
> > 
> >  		if (priv->lcd_on)
> >  		
> >  			return 0;
> 
> lcd.h states:
> struct lcd_ops {
> 	/* Get the LCD panel power status (0: full on, 1..3: controller
> 	   power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
> 	int (*get_power)(struct lcd_device *);
> 	/* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) 
*/
> 	int (*set_power)(struct lcd_device *, int power);
> 
> AFAIK the gray area between FB_BLANK_NORMAL and FB_BLANK_HSYNC_SUSPEND
> can be chosen as needs.
> 
> Why not:
> 
> + #define POWER_IS_ON(pwr)	((pwr) <= FB_BLANK_NORMAL)
> 
> ...
> 
> -	if (power) {
> +	if (POWER_IS_ON(power)) {
>  		if (priv->lcd_on)
>  			return 0;
> 
> So with FB_BLANK_NORMAL the lcd is active and on -> low latencies
> in re-enabling the video out, but for !POWER_IS_ON(power) we will send
> the lcd to standby.
> 
> It have to be implemented for power == FB_BLANK_POWERDOWN to turn off the
> regulators of the lcd.
> 
> What do you think about?

Thanks! I sent a new (better) version. If you want credit in it, tell me how 
should I add you one ;-)
> Regards,