Commit d8d20155 authored by Jonathan Corbet's avatar Jonathan Corbet Committed by Mauro Carvalho Chehab
Browse files

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: default avatarJonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 97693f91

drivers/media/video/ov7670.c

+18 −27
Original line number Diff line number Diff line
@@ -198,6 +198,7 @@ struct ov7670_info { 
	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)
@@ -744,21 +745,11 @@ static int ov7670_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt) 
	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
@@ -779,8 +770,14 @@ static int ov7670_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt) 
		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_s_fmt(struct v4l2_subdev *sd, struct v4l2_format *fmt) 
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 @@ static int ov7670_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms) 
{

	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 @@ static int ov7670_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms) 
		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 @@ static int ov7670_s_parm(struct v4l2_subdev *sd, struct v4l2_streamparm *parms) 
		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 @@ static int ov7670_probe(struct i2c_client *client, 


	info->fmt = &ov7670_formats[0];

	info->sat = 128;	/* Review this */

	info->clkrc = 1;	/* 30fps */



	return 0;

}