From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Date: Mon, 09 Jan 2012 16:17:18 +0000 Subject: Re: [PATCH 2/2] atmel_lcdfb: Use proper blanking on negative contrast Message-Id: <4F0B130E.10701@atmel.com> List-Id: References: <1317801598-23757-1-git-send-email-alexander.stein@systec-electronic.com> <1317801598-23757-2-git-send-email-alexander.stein@systec-electronic.com> In-Reply-To: <1317801598-23757-2-git-send-email-alexander.stein@systec-electronic.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On 10/05/2011 09:59 AM, Alexander Stein : > If used with negative polarity the PWM unit cannot be disabled. This would > result in a full contrast screen. > Instead let the PWM unit enabled using 0x0 as compare value which darkens > the display. > In result no power saving is possible if inverted contrast polarity > is used. Ok, this patch looks correct. > Signed-off-by: Alexander Stein Acked-by: Nicolas Ferre Florian, you can propagate this one upstream. Thanks you, best regards, > --- > drivers/video/atmel_lcdfb.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c > index 816d528..2bd75b5 100644 > --- a/drivers/video/atmel_lcdfb.c > +++ b/drivers/video/atmel_lcdfb.c > @@ -96,8 +96,11 @@ static int atmel_bl_update_status(struct backlight_device *bl) > brightness = 0; > > lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_VAL, brightness); > - lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, > + if (contrast_ctr & ATMEL_LCDC_POL_POSITIVE) > + lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, > brightness ? contrast_ctr : 0); > + else > + lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, contrast_ctr); > > bl->props.fb_blank = bl->props.power = sinfo->bl_power = power; > -- Nicolas Ferre