V4L/DVB: ov7670: Avoid reading clkrc
Reading the clkrc register creates flaky behavior in some situations, and
we can easily track its state separately.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/ov7670.c b/drivers/media/video/ov7670.c
index b44762a..b2e6f8e 100644
--- a/drivers/media/video/ov7670.c
+++ b/drivers/media/video/ov7670.c
@@ -198,6 +198,7 @@
struct ov7670_format_struct *fmt; /* Current format */
unsigned char sat; /* Saturation value */
int hue; /* Hue value */
+ u8 clkrc; /* Clock divider value */
};
static inline struct ov7670_info *to_state(struct v4l2_subdev *sd)
@@ -744,22 +745,12 @@
struct ov7670_format_struct *ovfmt;
struct ov7670_win_size *wsize;
struct ov7670_info *info = to_state(sd);
- unsigned char com7, clkrc = 0;
+ unsigned char com7;
ret = ov7670_try_fmt_internal(sd, 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(sd, 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
@@ -779,8 +770,14 @@
ret = ov7670_write_array(sd, wsize->regs);
info->fmt = ovfmt;
+ /*
+ * If we're running RGB565, we must rewrite clkrc after setting
+ * the other parameters or the image looks poor. If we're *not*
+ * doing RGB565, we must not rewrite clkrc or the image looks
+ * *really* poor.
+ */
if (fmt->fmt.pix.pixelformat == V4L2_PIX_FMT_RGB565 && ret == 0)
- ret = ov7670_write(sd, REG_CLKRC, clkrc);
+ ret = ov7670_write(sd, REG_CLKRC, info->clkrc);
return ret;
}
@@ -791,20 +788,17 @@
static int ov7670_g_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms)
{
struct v4l2_captureparm *cp = &parms->parm.capture;
- unsigned char clkrc;
- int ret;
+ struct ov7670_info *info = to_state(sd);
if (parms->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
return -EINVAL;
- ret = ov7670_read(sd, REG_CLKRC, &clkrc);
- if (ret < 0)
- return ret;
+
memset(cp, 0, sizeof(struct v4l2_captureparm));
cp->capability = V4L2_CAP_TIMEPERFRAME;
cp->timeperframe.numerator = 1;
cp->timeperframe.denominator = OV7670_FRAME_RATE;
- if ((clkrc & CLK_EXT) == 0 && (clkrc & CLK_SCALE) > 1)
- cp->timeperframe.denominator /= (clkrc & CLK_SCALE);
+ if ((info->clkrc & CLK_EXT) == 0 && (info->clkrc & CLK_SCALE) > 1)
+ cp->timeperframe.denominator /= (info->clkrc & CLK_SCALE);
return 0;
}
@@ -812,6 +806,7 @@
{
struct v4l2_captureparm *cp = &parms->parm.capture;
struct v4l2_fract *tpf = &cp->timeperframe;
+ struct ov7670_info *info = to_state(sd);
unsigned char clkrc;
int ret, div;
@@ -819,12 +814,7 @@
return -EINVAL;
if (cp->extendedmode != 0)
return -EINVAL;
- /*
- * CLKRC has a reserved bit, so let's preserve it.
- */
- ret = ov7670_read(sd, REG_CLKRC, &clkrc);
- if (ret < 0)
- return ret;
+
if (tpf->numerator == 0 || tpf->denominator == 0)
div = 1; /* Reset to full rate */
else
@@ -833,10 +823,10 @@
div = 1;
else if (div > CLK_SCALE)
div = CLK_SCALE;
- clkrc = (clkrc & 0x80) | div;
+ info->clkrc = (info->clkrc & 0x80) | div;
tpf->numerator = 1;
tpf->denominator = OV7670_FRAME_RATE/div;
- return ov7670_write(sd, REG_CLKRC, clkrc);
+ return ov7670_write(sd, REG_CLKRC, info->clkrc);
}
@@ -1268,6 +1258,7 @@
info->fmt = &ov7670_formats[0];
info->sat = 128; /* Review this */
+ info->clkrc = 1; /* 30fps */
return 0;
}