V4L/DVB (5691): Ov7670: reset clkrc in rgb565 mode
A bug in the ov7670 sensor causes it to introduce noise unless the CLKRC
register is rewritten *after* setting the image mode. Naturally,
resetting CLKRC in this way will cause other modes to fail. So
carefully poke the register only when indicated.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/ov7670.c b/drivers/media/video/ov7670.c
index 03bc369..3ceb8a6 100644
--- a/drivers/media/video/ov7670.c
+++ b/drivers/media/video/ov7670.c
@@ -720,12 +720,22 @@
struct ov7670_format_struct *ovfmt;
struct ov7670_win_size *wsize;
struct ov7670_info *info = i2c_get_clientdata(c);
- unsigned char com7;
+ unsigned char com7, clkrc;
ret = ov7670_try_fmt(c, fmt, &ovfmt, &wsize);
if (ret)
return ret;
/*
+ * HACK: if we're running rgb565 we need to grab then rewrite
+ * CLKRC. If we're *not*, however, then rewriting clkrc hoses
+ * the colors.
+ */
+ if (fmt->fmt.pix.pixelformat == V4L2_PIX_FMT_RGB565) {
+ ret = ov7670_read(c, REG_CLKRC, &clkrc);
+ if (ret)
+ return ret;
+ }
+ /*
* COM7 is a pain in the ass, it doesn't like to be read then
* quickly written afterward. But we have everything we need
* to set it absolutely here, as long as the format-specific
@@ -744,7 +754,10 @@
if (wsize->regs)
ret = ov7670_write_array(c, wsize->regs);
info->fmt = ovfmt;
- return 0;
+
+ if (fmt->fmt.pix.pixelformat == V4L2_PIX_FMT_RGB565 && ret == 0)
+ ret = ov7670_write(c, REG_CLKRC, clkrc);
+ return ret;
}
/*
@@ -1267,7 +1280,9 @@
ret = ov7670_detect(client);
if (ret)
goto out_free_info;
- i2c_attach_client(client);
+ ret = i2c_attach_client(client);
+ if (ret)
+ goto out_free_info;
return 0;
out_free_info: