[PATCH v4 0/3] media: i2c: ov772x: Enable BT656 mode and test pattern support

[PATCH v4 0/3] media: i2c: ov772x: Enable BT656 mode and test pattern support

[Lad Prabhakar]

Hi All,

This patch series adds support for BT656 mode in the ov772x sensor
and also enables color bar test pattern control.

Cheers,
Prabhakar

Changes for v4:
* New patch 1/3 to fallback in parallel mode.
* Switched to v4l2_fwnode_endpoint_alloc_parse() for parsing the ep.
* Dropped support for pdat for test pattern control.
* DT documentation patches [1].

Changes for v3:
* Dropped DT binding documentation patch as this is handled by Jacopo.
* Fixed review comments pointed by Jacopo.

[1] https://patchwork.kernel.org/project/linux-renesas-soc/list/?series=346809

Lad Prabhakar (3):
  media: i2c: ov772x: Parse endpoint properties
  media: i2c: ov772x: Add support for BT656 mode
  media: i2c: ov772x: Add test pattern control

 drivers/media/i2c/ov772x.c | 56 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

-- 
2.17.1

[PATCH v4 1/3] media: i2c: ov772x: Parse endpoint properties

[Lad Prabhakar]

Parse endpoint properties using v4l2_fwnode_endpoint_alloc_parse()
to determine bus-type and store it locally in priv data.

Also for backward compatibility with the existing DT where bus-type
isnt specified fallback to V4L2_MBUS_PARALLEL.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/media/i2c/ov772x.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index 2cc6a678069a..551082aa7026 100644
--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -31,6 +31,7 @@
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-event.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-image-sizes.h>
 #include <media/v4l2-subdev.h>
 
@@ -434,6 +435,7 @@ struct ov772x_priv {
 #ifdef CONFIG_MEDIA_CONTROLLER
 	struct media_pad pad;
 #endif
+	enum v4l2_mbus_type		  bus_type;
 };
 
 /*
@@ -1354,6 +1356,8 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = {
 
 static int ov772x_probe(struct i2c_client *client)
 {
+	struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
+	struct fwnode_handle	*ep;
 	struct ov772x_priv	*priv;
 	int			ret;
 	static const struct regmap_config ov772x_regmap_config = {
@@ -1415,6 +1419,26 @@ static int ov772x_probe(struct i2c_client *client)
 		goto error_clk_put;
 	}
 
+	ep = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev),
+					    NULL);
+	if (!ep) {
+		dev_err(&client->dev, "endpoint node not found\n");
+		ret = -EINVAL;
+		goto error_clk_put;
+	}
+
+	bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
+	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
+	priv->bus_type = bus_cfg.bus_type;
+	v4l2_fwnode_endpoint_free(&bus_cfg);
+	if (ret) {
+		/* For backward compatibility with the existing DT where
+		 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
+		 */
+		priv->bus_type = V4L2_MBUS_PARALLEL;
+		dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");
+	}
+
 	ret = ov772x_video_probe(priv);
 	if (ret < 0)
 		goto error_gpio_put;
-- 
2.17.1

Re: [PATCH v4 1/3] media: i2c: ov772x: Parse endpoint properties

[Sakari Ailus]

Hi Prabhakar,

Thanks for the patchset.

On Sun, Sep 13, 2020 at 07:42:45PM +0100, Lad Prabhakar wrote:
> Parse endpoint properties using v4l2_fwnode_endpoint_alloc_parse()
> to determine bus-type and store it locally in priv data.
> 
> Also for backward compatibility with the existing DT where bus-type
> isnt specified fallback to V4L2_MBUS_PARALLEL.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/media/i2c/ov772x.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> index 2cc6a678069a..551082aa7026 100644
> --- a/drivers/media/i2c/ov772x.c
> +++ b/drivers/media/i2c/ov772x.c
> @@ -31,6 +31,7 @@
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-event.h>
> +#include <media/v4l2-fwnode.h>
>  #include <media/v4l2-image-sizes.h>
>  #include <media/v4l2-subdev.h>
>  
> @@ -434,6 +435,7 @@ struct ov772x_priv {
>  #ifdef CONFIG_MEDIA_CONTROLLER
>  	struct media_pad pad;
>  #endif
> +	enum v4l2_mbus_type		  bus_type;
>  };
>  
>  /*
> @@ -1354,6 +1356,8 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = {
>  
>  static int ov772x_probe(struct i2c_client *client)
>  {
> +	struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
> +	struct fwnode_handle	*ep;
>  	struct ov772x_priv	*priv;
>  	int			ret;
>  	static const struct regmap_config ov772x_regmap_config = {
> @@ -1415,6 +1419,26 @@ static int ov772x_probe(struct i2c_client *client)
>  		goto error_clk_put;
>  	}
>  
> +	ep = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev),
> +					    NULL);
> +	if (!ep) {
> +		dev_err(&client->dev, "endpoint node not found\n");
> +		ret = -EINVAL;
> +		goto error_clk_put;
> +	}
> +
> +	bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
> +	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> +	priv->bus_type = bus_cfg.bus_type;
> +	v4l2_fwnode_endpoint_free(&bus_cfg);
> +	if (ret) {
> +		/* For backward compatibility with the existing DT where
> +		 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL

"isn't", "fall back", and a period, please.

> +		 */
> +		priv->bus_type = V4L2_MBUS_PARALLEL;
> +		dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");

I'd just use dev_dbg().

> +	}
> +
>  	ret = ov772x_video_probe(priv);
>  	if (ret < 0)
>  		goto error_gpio_put;

-- 
Regards,

Sakari Ailus

Re: [PATCH v4 1/3] media: i2c: ov772x: Parse endpoint properties

[Lad, Prabhakar]

Hi Sakari,

THank you for the review.

On Mon, Sep 14, 2020 at 7:54 AM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Prabhakar,
>
> Thanks for the patchset.
>
> On Sun, Sep 13, 2020 at 07:42:45PM +0100, Lad Prabhakar wrote:
> > Parse endpoint properties using v4l2_fwnode_endpoint_alloc_parse()
> > to determine bus-type and store it locally in priv data.
> >
> > Also for backward compatibility with the existing DT where bus-type
> > isnt specified fallback to V4L2_MBUS_PARALLEL.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> >  drivers/media/i2c/ov772x.c | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> > index 2cc6a678069a..551082aa7026 100644
> > --- a/drivers/media/i2c/ov772x.c
> > +++ b/drivers/media/i2c/ov772x.c
> > @@ -31,6 +31,7 @@
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-device.h>
> >  #include <media/v4l2-event.h>
> > +#include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-image-sizes.h>
> >  #include <media/v4l2-subdev.h>
> >
> > @@ -434,6 +435,7 @@ struct ov772x_priv {
> >  #ifdef CONFIG_MEDIA_CONTROLLER
> >       struct media_pad pad;
> >  #endif
> > +     enum v4l2_mbus_type               bus_type;
> >  };
> >
> >  /*
> > @@ -1354,6 +1356,8 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = {
> >
> >  static int ov772x_probe(struct i2c_client *client)
> >  {
> > +     struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
> > +     struct fwnode_handle    *ep;
> >       struct ov772x_priv      *priv;
> >       int                     ret;
> >       static const struct regmap_config ov772x_regmap_config = {
> > @@ -1415,6 +1419,26 @@ static int ov772x_probe(struct i2c_client *client)
> >               goto error_clk_put;
> >       }
> >
> > +     ep = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev),
> > +                                         NULL);
> > +     if (!ep) {
> > +             dev_err(&client->dev, "endpoint node not found\n");
> > +             ret = -EINVAL;
> > +             goto error_clk_put;
> > +     }
> > +
> > +     bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
> > +     ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> > +     priv->bus_type = bus_cfg.bus_type;
> > +     v4l2_fwnode_endpoint_free(&bus_cfg);
> > +     if (ret) {
> > +             /* For backward compatibility with the existing DT where
> > +              * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
>
> "isn't", "fall back", and a period, please.
>
Will fix that.

> > +              */
> > +             priv->bus_type = V4L2_MBUS_PARALLEL;
> > +             dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");
>
> I'd just use dev_dbg().
>
OK will switch to dev_dbg()

Cheers,
Prabhakar

Re: [PATCH v4 1/3] media: i2c: ov772x: Parse endpoint properties

[Jacopo Mondi]

Hi Prabhakar,

On Sun, Sep 13, 2020 at 07:42:45PM +0100, Lad Prabhakar wrote:
> Parse endpoint properties using v4l2_fwnode_endpoint_alloc_parse()
> to determine bus-type and store it locally in priv data.
>
> Also for backward compatibility with the existing DT where bus-type
> isnt specified fallback to V4L2_MBUS_PARALLEL.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>  drivers/media/i2c/ov772x.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> index 2cc6a678069a..551082aa7026 100644
> --- a/drivers/media/i2c/ov772x.c
> +++ b/drivers/media/i2c/ov772x.c
> @@ -31,6 +31,7 @@
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-event.h>
> +#include <media/v4l2-fwnode.h>
>  #include <media/v4l2-image-sizes.h>
>  #include <media/v4l2-subdev.h>
>
> @@ -434,6 +435,7 @@ struct ov772x_priv {
>  #ifdef CONFIG_MEDIA_CONTROLLER
>  	struct media_pad pad;
>  #endif
> +	enum v4l2_mbus_type		  bus_type;
>  };
>
>  /*
> @@ -1354,6 +1356,8 @@ static const struct v4l2_subdev_ops ov772x_subdev_ops = {
>
>  static int ov772x_probe(struct i2c_client *client)
>  {
> +	struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
> +	struct fwnode_handle	*ep;
>  	struct ov772x_priv	*priv;
>  	int			ret;
>  	static const struct regmap_config ov772x_regmap_config = {
> @@ -1415,6 +1419,26 @@ static int ov772x_probe(struct i2c_client *client)
>  		goto error_clk_put;
>  	}
>
> +	ep = fwnode_graph_get_next_endpoint(dev_fwnode(&client->dev),
> +					    NULL);
> +	if (!ep) {
> +		dev_err(&client->dev, "endpoint node not found\n");
> +		ret = -EINVAL;
> +		goto error_clk_put;
> +	}
> +
> +	bus_cfg.bus_type = V4L2_MBUS_PARALLEL;

Could you set the bus type when you declare bus_cfg ? There's no point
in setting it to UNKNOW and re-writing it here

> +	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);

Should you here fwnode_handle_put(ep) ?

Also, this driver does not support the 'link_frequency' property, as the
device does not support CSI-2. As commented on the previous version,
the 'alloc' version of v4l2_fwnode_endpoint_parse() reserves space for
that property, and requires a manual free like you have here below. So
using the 'alloc' version is not techincally wrong, but I don't think
it's required here.

> +	priv->bus_type = bus_cfg.bus_type;
> +	v4l2_fwnode_endpoint_free(&bus_cfg);
> +	if (ret) {

By reading the code in v4l2-fwnode it seems to me that, if you set
bus_cfg.bus_type:
1) The "bus_type" property is set in the fwnode and doesn't match the
requested one -> return -ENXIO
2) The "bus_type" property is not set in the fwnode: no error code is
returned and vep->bus_type is not changed.

> +		/* For backward compatibility with the existing DT where
> +		 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
> +		 */

This mean there's no need to fallback here, as at this point we only
support PARALLEL. If fwnode,bus_type is not set you won't faile, if
it's set and doesn't match you should fail as the DT is not correct
(at this point).

1) In this patch: try to parse as MBUS_PARALLEL, fail if -ENXIO,
assume parallel otherwise and continue.

2) When you introduce BT.656 in the next patch things become nasty.
Newer DTS will have bus_type mandatory once my series gets in. Old
ones do not and assume "parallel".
2.a) If you try to parse with "cfg.bus_type = MBUS_BT656" and there's
no 'bus_type' in the fwnode, the 'parallel' flags are simply cleared
at the end of v4l2_fwnode_endpoint_parse_parallel_bus(), but the
bus_type does not get changed. You won't detect the mismatch and
happily assume the bus type is BT.656. In other word, if you set
cfg.bus_type that's always authoritative unless the fwnode property
contradicts it (and if that's the case, it should be documented in
v4l2-fnode, unless it is and I missed it).
2.b) If the fwnode.bus_type is set, you try to parse one bus type
first, if -ENOXIO try the second. If it fails again, then return an
error.

In the next patch, to avoid the case described in 2.a I would:
- Parse the 'bus_type' property in the driver (mentioning it's for
  retrocompatibility).
-- If not present: Assume parallel and parse the fwnode. Enclose that
with a comment about "retrocompatibility" and proceed.
-- If present: Do what suggested in the 2.b case. Try one, then the
other, then eventually fail.

I hope this makes any sense, this part is such a gray area... and as a
note to "self" in the forthcoming "of_graph.yaml", let's make bus_type
mandatory for all endpoints!

Also, I might be mistaken in following the code and if you have tested
all cases and they work as intended please call me out on this :)

Thanks
  j

> +		priv->bus_type = V4L2_MBUS_PARALLEL;
> +		dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");
> +	}
> +
>  	ret = ov772x_video_probe(priv);
>  	if (ret < 0)
>  		goto error_gpio_put;
> --
> 2.17.1
>

[PATCH v4 2/3] media: i2c: ov772x: Add support for BT656 mode

[Lad Prabhakar]

Add support to read the bus-type for V4L2_MBUS_BT656 and
enable BT656 mode in the sensor if needed.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
---
 drivers/media/i2c/ov772x.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index 551082aa7026..edd7c4c22225 100644
--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -583,6 +583,13 @@ static int ov772x_s_stream(struct v4l2_subdev *sd, int enable)
 	if (priv->streaming == enable)
 		goto done;
 
+	if (priv->bus_type == V4L2_MBUS_BT656) {
+		ret = regmap_update_bits(priv->regmap, COM7, ITU656_ON_OFF,
+					 enable ? ITU656_ON_OFF : ~ITU656_ON_OFF);
+		if (ret)
+			goto done;
+	}
+
 	ret = regmap_update_bits(priv->regmap, COM2, SOFT_SLEEP_MODE,
 				 enable ? 0 : SOFT_SLEEP_MODE);
 	if (ret)
@@ -1427,16 +1434,24 @@ static int ov772x_probe(struct i2c_client *client)
 		goto error_clk_put;
 	}
 
-	bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
+	bus_cfg = (struct v4l2_fwnode_endpoint)
+		  { .bus_type = V4L2_MBUS_BT656 };
 	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
 	priv->bus_type = bus_cfg.bus_type;
 	v4l2_fwnode_endpoint_free(&bus_cfg);
 	if (ret) {
-		/* For backward compatibility with the existing DT where
-		 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
-		 */
-		priv->bus_type = V4L2_MBUS_PARALLEL;
-		dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");
+		bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
+		ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
+		priv->bus_type = bus_cfg.bus_type;
+		v4l2_fwnode_endpoint_free(&bus_cfg);
+		if (ret) {
+			/* For backward compatibility with the existing DT where
+			 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
+			 */
+			priv->bus_type = V4L2_MBUS_PARALLEL;
+			dev_notice(&client->dev,
+				   "Falling back to V4L2_MBUS_PARALLEL mode\n");
+		}
 	}
 
 	ret = ov772x_video_probe(priv);
-- 
2.17.1

Re: [PATCH v4 2/3] media: i2c: ov772x: Add support for BT656 mode

[Sergei Shtylyov]

Hello!

On 13.09.2020 21:42, Lad Prabhakar wrote:

> Add support to read the bus-type for V4L2_MBUS_BT656 and
> enable BT656 mode in the sensor if needed.

    Isn't it called BT.656?

> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
>   drivers/media/i2c/ov772x.c | 27 +++++++++++++++++++++------
>   1 file changed, 21 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
> index 551082aa7026..edd7c4c22225 100644
> --- a/drivers/media/i2c/ov772x.c
> +++ b/drivers/media/i2c/ov772x.c
[...]
> @@ -1427,16 +1434,24 @@ static int ov772x_probe(struct i2c_client *client)
>   		goto error_clk_put;
>   	}
>   
> -	bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
> +	bus_cfg = (struct v4l2_fwnode_endpoint)
> +		  { .bus_type = V4L2_MBUS_BT656 };
>   	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
>   	priv->bus_type = bus_cfg.bus_type;
>   	v4l2_fwnode_endpoint_free(&bus_cfg);
>   	if (ret) {
> -		/* For backward compatibility with the existing DT where
> -		 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
> -		 */
> -		priv->bus_type = V4L2_MBUS_PARALLEL;
> -		dev_notice(&client->dev, "Falling back to V4L2_MBUS_PARALLEL mode\n");
> +		bus_cfg.bus_type = V4L2_MBUS_PARALLEL;
> +		ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg);
> +		priv->bus_type = bus_cfg.bus_type;
> +		v4l2_fwnode_endpoint_free(&bus_cfg);
> +		if (ret) {
> +			/* For backward compatibility with the existing DT where
> +			 * bus-type isnt specified fallback to V4L2_MBUS_PARALLEL
                                     ^^^^ isn't
    Could be fixed, while at it?

> +			 */
> +			priv->bus_type = V4L2_MBUS_PARALLEL;
> +			dev_notice(&client->dev,
> +				   "Falling back to V4L2_MBUS_PARALLEL mode\n");
> +		}
>   	}
>   
>   	ret = ov772x_video_probe(priv);

MBR, Sergei

[PATCH v4 3/3] media: i2c: ov772x: Add test pattern control

[Lad Prabhakar]

Add support for test pattern control supported by the sensor.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
---
 drivers/media/i2c/ov772x.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/ov772x.c b/drivers/media/i2c/ov772x.c
index edd7c4c22225..2eeb11eae5f8 100644
--- a/drivers/media/i2c/ov772x.c
+++ b/drivers/media/i2c/ov772x.c
@@ -227,7 +227,7 @@
 
 /* COM3 */
 #define SWAP_MASK       (SWAP_RGB | SWAP_YUV | SWAP_ML)
-#define IMG_MASK        (VFLIP_IMG | HFLIP_IMG)
+#define IMG_MASK        (VFLIP_IMG | HFLIP_IMG | SCOLOR_TEST)
 
 #define VFLIP_IMG       0x80	/* Vertical flip image ON/OFF selection */
 #define HFLIP_IMG       0x40	/* Horizontal mirror image ON/OFF selection */
@@ -425,6 +425,7 @@ struct ov772x_priv {
 	const struct ov772x_win_size     *win;
 	struct v4l2_ctrl		 *vflip_ctrl;
 	struct v4l2_ctrl		 *hflip_ctrl;
+	unsigned int			  test_pattern;
 	/* band_filter = COM8[5] ? 256 - BDBASE : 0 */
 	struct v4l2_ctrl		 *band_filter_ctrl;
 	unsigned int			  fps;
@@ -540,6 +541,11 @@ static const struct ov772x_win_size ov772x_win_sizes[] = {
 	},
 };
 
+static const char * const ov772x_test_pattern_menu[] = {
+	"Disabled",
+	"Vertical Color Bar Type 1",
+};
+
 /*
  * frame rate settings lists
  */
@@ -809,6 +815,9 @@ static int ov772x_s_ctrl(struct v4l2_ctrl *ctrl)
 		}
 
 		return ret;
+	case V4L2_CID_TEST_PATTERN:
+		priv->test_pattern = ctrl->val;
+		return 0;
 	}
 
 	return -EINVAL;
@@ -1107,6 +1116,8 @@ static int ov772x_set_params(struct ov772x_priv *priv,
 		val ^= VFLIP_IMG;
 	if (priv->hflip_ctrl->val)
 		val ^= HFLIP_IMG;
+	if (priv->test_pattern)
+		val |= SCOLOR_TEST;
 
 	ret = regmap_update_bits(priv->regmap, COM3, SWAP_MASK | IMG_MASK, val);
 	if (ret < 0)
@@ -1405,6 +1416,10 @@ static int ov772x_probe(struct i2c_client *client)
 	priv->band_filter_ctrl = v4l2_ctrl_new_std(&priv->hdl, &ov772x_ctrl_ops,
 						   V4L2_CID_BAND_STOP_FILTER,
 						   0, 256, 1, 0);
+	v4l2_ctrl_new_std_menu_items(&priv->hdl, &ov772x_ctrl_ops,
+				     V4L2_CID_TEST_PATTERN,
+				     ARRAY_SIZE(ov772x_test_pattern_menu) - 1,
+				     0, 0, ov772x_test_pattern_menu);
 	priv->subdev.ctrl_handler = &priv->hdl;
 	if (priv->hdl.error) {
 		ret = priv->hdl.error;
-- 
2.17.1