[PATCH] media: ov7670: Allow 32x maximum gain for yuv422.

[PATCH] media: ov7670: Allow 32x maximum gain for yuv422.

[Javier Martin]

4x gain ceiling is not enough to capture a decent image in conditions
of total darkness and only a LED light source. Allow a maximum gain
of 32x instead.

This doesn't have any drawback since the image quality in 'normal'
light conditions is the same.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
---
 drivers/media/video/ov7670.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/video/ov7670.c b/drivers/media/video/ov7670.c
index 5faa3d8..2ea9c51 100644
--- a/drivers/media/video/ov7670.c
+++ b/drivers/media/video/ov7670.c
@@ -366,7 +366,7 @@ static struct regval_list ov7670_fmt_yuv422[] = {
 	{ REG_RGB444, 0 },	/* No RGB444 please */
 	{ REG_COM1, 0 },	/* CCIR601 */
 	{ REG_COM15, COM15_R00FF },
-	{ REG_COM9, 0x18 }, /* 4x gain ceiling; 0x8 is reserved bit */
+	{ REG_COM9, 0x48 }, /* 32x gain ceiling; 0x8 is reserved bit */
 	{ 0x4f, 0x80 }, 	/* "matrix coefficient 1" */
 	{ 0x50, 0x80 }, 	/* "matrix coefficient 2" */
 	{ 0x51, 0    },		/* vb */
-- 
1.7.9.5

Re: [PATCH] media: ov7670: Allow 32x maximum gain for yuv422.

[Jonathan Corbet]

On Tue, 30 Oct 2012 17:04:23 +0100
Javier Martin <javier.martin@vista-silicon.com> wrote:

> 4x gain ceiling is not enough to capture a decent image in conditions
> of total darkness and only a LED light source. Allow a maximum gain
> of 32x instead.

The initial number surely came from OmniVision and was never really
thought about.  I can't test this at the moment, but I see no reason not
to take your word that it doesn't affect normal-light operation.

Acked-by: Jonathan Corbet <corbet@lwn.net>

jon