Commit 04ee6d92 authored by Javier Martin's avatar Javier Martin Committed by Mauro Carvalho Chehab
Browse files

[media] media: ov7670: add possibility to bypass pll for ov7675 



For a frame rate of 30 fps a pixclk of 24MHz is needed. For those
cases where the ov7670 has a clean 24MHz input (xvclk) the PLL
can be bypassed.
This will result in a value of clkrc of 1, which means that in practice
pixclk = xvclk (input clock)

Acked-by: default avatarJonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarJavier Martin <javier.martin@vista-silicon.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent f6dd927f

drivers/media/i2c/ov7670.c

+26 −2
Original line number Diff line number Diff line
@@ -230,6 +230,7 @@ struct ov7670_info { 
	int clock_speed;		/* External clock speed (MHz) */

	u8 clkrc;			/* Clock divider value */

	bool use_smbus;			/* Use smbus I/O instead of I2C */

	bool pll_bypass;

	const struct ov7670_devtype *devtype; /* Device specifics */

};
@@ -755,7 +756,12 @@ static void ov7675_get_framerate(struct v4l2_subdev *sd, 
{

	struct ov7670_info *info = to_state(sd);

	u32 clkrc = info->clkrc;

	u32 pll_factor = PLL_FACTOR;

	int pll_factor;



	if (info->pll_bypass)

		pll_factor = 1;

	else

		pll_factor = PLL_FACTOR;



	clkrc++;

	if (info->fmt->mbus_code == V4L2_MBUS_FMT_SBGGR8_1X8)
@@ -771,7 +777,7 @@ static int ov7675_set_framerate(struct v4l2_subdev *sd, 
{

	struct ov7670_info *info = to_state(sd);

	u32 clkrc;

	u32 pll_factor = PLL_FACTOR;

	int pll_factor;

	int ret;



	/*
@@ -781,6 +787,16 @@ static int ov7675_set_framerate(struct v4l2_subdev *sd, 
	 * pixclk = clock_speed / (clkrc + 1) * PLLfactor

	 *

	 */

	if (info->pll_bypass) {

		pll_factor = 1;

		ret = ov7670_write(sd, REG_DBLV, DBLV_BYPASS);

	} else {

		pll_factor = PLL_FACTOR;

		ret = ov7670_write(sd, REG_DBLV, DBLV_X4);

	}

	if (ret < 0)

		return ret;



	if (tpf->numerator == 0 || tpf->denominator == 0) {

		clkrc = 0;

	} else {
@@ -808,6 +824,7 @@ static int ov7675_set_framerate(struct v4l2_subdev *sd, 
	ret = ov7670_write(sd, REG_CLKRC, info->clkrc);

	if (ret < 0)

		return ret;



	return ov7670_write(sd, REG_DBLV, DBLV_X4);

}
@@ -1688,6 +1705,13 @@ static int ov7670_probe(struct i2c_client *client, 


		if (config->clock_speed)

			info->clock_speed = config->clock_speed;



		/*

		 * It should be allowed for ov7670 too when it is migrated to

		 * the new frame rate formula.

		 */

		if (config->pll_bypass && id->driver_data != MODEL_OV7670)

			info->pll_bypass = true;

	}



	/* Make sure it's an ov7670 */

include/media/ov7670.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ struct ov7670_config { 
	int min_height;			/* Filter out smaller sizes */

	int clock_speed;		/* External clock speed (MHz) */

	bool use_smbus;			/* Use smbus I/O instead of I2C */

	bool pll_bypass;		/* Choose whether to bypass the PLL */

};



#endif

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