media: ov7670: Allow 32x maximum gain for yuv422.
Commit Message
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(-)
Comments
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
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@@ -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 */