[v2,11/11] media: i2c: ov5645: Report streams using frame descriptors

Commit Message

Lad, Prabhakar Sept. 10, 2024, 5:06 p.m. UTC

From: Lad Prabhakar <[e-mail]>

Implement the .get_frame_desc() subdev operation to report information
about streams to the connected CSI-2 receiver. This is required to let
the CSI-2 receiver driver know about virtual channels and data types for
each stream.

Signed-off-by: Lad Prabhakar <[e-mail]>
---
 drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Comments

Laurent Pinchart Sept. 25, 2024, 4:26 p.m. UTC | #1

Hi Prabhakar,

Thank you for the patch.

On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <[e-mail]>
> 
> Implement the .get_frame_desc() subdev operation to report information
> about streams to the connected CSI-2 receiver. This is required to let
> the CSI-2 receiver driver know about virtual channels and data types for
> each stream.
> 
> Signed-off-by: Lad Prabhakar <[e-mail]>
> ---
>  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> index 7f1133292ffc..c24eb6e7a7b5 100644
> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -28,6 +28,7 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
> +#include <media/mipi-csi2.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-event.h>
>  #include <media/v4l2-fwnode.h>
> @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
>  	.s_ctrl = ov5645_s_ctrl,
>  };
>  
> +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> +				 struct v4l2_mbus_frame_desc *fd)
> +{
> +	const struct v4l2_mbus_framefmt *fmt;
> +	struct v4l2_subdev_state *state;
> +
> +	if (pad != OV5645_PAD_SOURCE)
> +		return -EINVAL;
> +
> +	state = v4l2_subdev_lock_and_get_active_state(sd);
> +	fmt = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0);
> +	v4l2_subdev_unlock_state(state);

Once you unlock the state fmt could change, so you should instead do

	state = v4l2_subdev_lock_and_get_active_state(sd);
	code = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0)->code;
	v4l2_subdev_unlock_state(state);

Reviewed-by: Laurent Pinchart <[e-mail]>

> +
> +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> +	fd->num_entries = 1;
> +
> +	memset(fd->entry, 0, sizeof(fd->entry));
> +
> +	fd->entry[0].pixelcode = fmt->code;
> +	fd->entry[0].stream = 0;
> +	fd->entry[0].bus.csi2.vc = 0;
> +	fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_YUV422_8B;
> +
> +	return 0;
> +}
> +
>  static int ov5645_enum_mbus_code(struct v4l2_subdev *sd,
>  				 struct v4l2_subdev_state *sd_state,
>  				 struct v4l2_subdev_mbus_code_enum *code)
> @@ -1062,6 +1089,7 @@ static const struct v4l2_subdev_video_ops ov5645_video_ops = {
>  };
>  
>  static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> +	.get_frame_desc = ov5645_get_frame_desc,
>  	.enum_mbus_code = ov5645_enum_mbus_code,
>  	.enum_frame_size = ov5645_enum_frame_size,
>  	.get_fmt = v4l2_subdev_get_fmt,

Lad, Prabhakar Sept. 26, 2024, 10:16 a.m. UTC | #2

Hi Laurent,

Thank you for the review.

On Wed, Sep 25, 2024 at 5:26 PM Laurent Pinchart
<[e-mail]> wrote:
>
> Hi Prabhakar,
>
> Thank you for the patch.
>
> On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> > From: Lad Prabhakar <[e-mail]>
> >
> > Implement the .get_frame_desc() subdev operation to report information
> > about streams to the connected CSI-2 receiver. This is required to let
> > the CSI-2 receiver driver know about virtual channels and data types for
> > each stream.
> >
> > Signed-off-by: Lad Prabhakar <[e-mail]>
> > ---
> >  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
> >  1 file changed, 28 insertions(+)
> >
> > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > index 7f1133292ffc..c24eb6e7a7b5 100644
> > --- a/drivers/media/i2c/ov5645.c
> > +++ b/drivers/media/i2c/ov5645.c
> > @@ -28,6 +28,7 @@
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/slab.h>
> >  #include <linux/types.h>
> > +#include <media/mipi-csi2.h>
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-event.h>
> >  #include <media/v4l2-fwnode.h>
> > @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
> >       .s_ctrl = ov5645_s_ctrl,
> >  };
> >
> > +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> > +                              struct v4l2_mbus_frame_desc *fd)
> > +{
> > +     const struct v4l2_mbus_framefmt *fmt;
> > +     struct v4l2_subdev_state *state;
> > +
> > +     if (pad != OV5645_PAD_SOURCE)
> > +             return -EINVAL;
> > +
> > +     state = v4l2_subdev_lock_and_get_active_state(sd);
> > +     fmt = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0);
> > +     v4l2_subdev_unlock_state(state);
>
> Once you unlock the state fmt could change, so you should instead do
>
>         state = v4l2_subdev_lock_and_get_active_state(sd);
>         code = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0)->code;
>         v4l2_subdev_unlock_state(state);
>
Ok, I will update the above.

Cheers,
Prabhakar

> Reviewed-by: Laurent Pinchart <[e-mail]>
>
> > +
> > +     fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> > +     fd->num_entries = 1;
> > +
> > +     memset(fd->entry, 0, sizeof(fd->entry));
> > +
> > +     fd->entry[0].pixelcode = fmt->code;
> > +     fd->entry[0].stream = 0;
> > +     fd->entry[0].bus.csi2.vc = 0;
> > +     fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_YUV422_8B;
> > +
> > +     return 0;
> > +}
> > +
> >  static int ov5645_enum_mbus_code(struct v4l2_subdev *sd,
> >                                struct v4l2_subdev_state *sd_state,
> >                                struct v4l2_subdev_mbus_code_enum *code)
> > @@ -1062,6 +1089,7 @@ static const struct v4l2_subdev_video_ops ov5645_video_ops = {
> >  };
> >
> >  static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> > +     .get_frame_desc = ov5645_get_frame_desc,
> >       .enum_mbus_code = ov5645_enum_mbus_code,
> >       .enum_frame_size = ov5645_enum_frame_size,
> >       .get_fmt = v4l2_subdev_get_fmt,
>
> --
> Regards,
>
> Laurent Pinchart

Sakari Ailus Sept. 26, 2024, 3:45 p.m. UTC | #3

Hi Prabhakar,

Thanks for the set. It looks largely very nice to me, after addressing
Laurent's comments. A few comments here and possibly on other patches...

On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> From: Lad Prabhakar <[e-mail]>
> 
> Implement the .get_frame_desc() subdev operation to report information
> about streams to the connected CSI-2 receiver. This is required to let
> the CSI-2 receiver driver know about virtual channels and data types for
> each stream.
> 
> Signed-off-by: Lad Prabhakar <[e-mail]>
> ---
>  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> index 7f1133292ffc..c24eb6e7a7b5 100644
> --- a/drivers/media/i2c/ov5645.c
> +++ b/drivers/media/i2c/ov5645.c
> @@ -28,6 +28,7 @@
>  #include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
> +#include <media/mipi-csi2.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-event.h>
>  #include <media/v4l2-fwnode.h>
> @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
>  	.s_ctrl = ov5645_s_ctrl,
>  };
>  
> +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> +				 struct v4l2_mbus_frame_desc *fd)
> +{
> +	const struct v4l2_mbus_framefmt *fmt;
> +	struct v4l2_subdev_state *state;
> +
> +	if (pad != OV5645_PAD_SOURCE)
> +		return -EINVAL;

As you have a single source pad, and pretty much all sensor drivers will, I
think it'd be nice to add a check for this (that it's not an internal pad)
to the caller side in v4l2-subdev.c. And of course drop this one.

> +
> +	state = v4l2_subdev_lock_and_get_active_state(sd);
> +	fmt = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0);
> +	v4l2_subdev_unlock_state(state);
> +
> +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> +	fd->num_entries = 1;
> +
> +	memset(fd->entry, 0, sizeof(fd->entry));
> +
> +	fd->entry[0].pixelcode = fmt->code;
> +	fd->entry[0].stream = 0;
> +	fd->entry[0].bus.csi2.vc = 0;
> +	fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_YUV422_8B;
> +
> +	return 0;
> +}
> +
>  static int ov5645_enum_mbus_code(struct v4l2_subdev *sd,
>  				 struct v4l2_subdev_state *sd_state,
>  				 struct v4l2_subdev_mbus_code_enum *code)
> @@ -1062,6 +1089,7 @@ static const struct v4l2_subdev_video_ops ov5645_video_ops = {
>  };
>  
>  static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> +	.get_frame_desc = ov5645_get_frame_desc,
>  	.enum_mbus_code = ov5645_enum_mbus_code,
>  	.enum_frame_size = ov5645_enum_frame_size,
>  	.get_fmt = v4l2_subdev_get_fmt,
>

Laurent Pinchart Sept. 26, 2024, 5:48 p.m. UTC | #4

On Thu, Sep 26, 2024 at 03:45:26PM +0000, Sakari Ailus wrote:
> Hi Prabhakar,
> 
> Thanks for the set. It looks largely very nice to me, after addressing
> Laurent's comments. A few comments here and possibly on other patches...
> 
> On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> > From: Lad Prabhakar <[e-mail]>
> > 
> > Implement the .get_frame_desc() subdev operation to report information
> > about streams to the connected CSI-2 receiver. This is required to let
> > the CSI-2 receiver driver know about virtual channels and data types for
> > each stream.
> > 
> > Signed-off-by: Lad Prabhakar <[e-mail]>
> > ---
> >  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
> >  1 file changed, 28 insertions(+)
> > 
> > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > index 7f1133292ffc..c24eb6e7a7b5 100644
> > --- a/drivers/media/i2c/ov5645.c
> > +++ b/drivers/media/i2c/ov5645.c
> > @@ -28,6 +28,7 @@
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/slab.h>
> >  #include <linux/types.h>
> > +#include <media/mipi-csi2.h>
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-event.h>
> >  #include <media/v4l2-fwnode.h>
> > @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
> >  	.s_ctrl = ov5645_s_ctrl,
> >  };
> >  
> > +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> > +				 struct v4l2_mbus_frame_desc *fd)
> > +{
> > +	const struct v4l2_mbus_framefmt *fmt;
> > +	struct v4l2_subdev_state *state;
> > +
> > +	if (pad != OV5645_PAD_SOURCE)
> > +		return -EINVAL;
> 
> As you have a single source pad, and pretty much all sensor drivers will, I
> think it'd be nice to add a check for this (that it's not an internal pad)
> to the caller side in v4l2-subdev.c. And of course drop this one.

What check would you add, just verifying that the pad is a source pad ?

> > +
> > +	state = v4l2_subdev_lock_and_get_active_state(sd);
> > +	fmt = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0);
> > +	v4l2_subdev_unlock_state(state);
> > +
> > +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> > +	fd->num_entries = 1;
> > +
> > +	memset(fd->entry, 0, sizeof(fd->entry));
> > +
> > +	fd->entry[0].pixelcode = fmt->code;
> > +	fd->entry[0].stream = 0;
> > +	fd->entry[0].bus.csi2.vc = 0;
> > +	fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_YUV422_8B;
> > +
> > +	return 0;
> > +}
> > +
> >  static int ov5645_enum_mbus_code(struct v4l2_subdev *sd,
> >  				 struct v4l2_subdev_state *sd_state,
> >  				 struct v4l2_subdev_mbus_code_enum *code)
> > @@ -1062,6 +1089,7 @@ static const struct v4l2_subdev_video_ops ov5645_video_ops = {
> >  };
> >  
> >  static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> > +	.get_frame_desc = ov5645_get_frame_desc,
> >  	.enum_mbus_code = ov5645_enum_mbus_code,
> >  	.enum_frame_size = ov5645_enum_frame_size,
> >  	.get_fmt = v4l2_subdev_get_fmt,
> >

Sakari Ailus Sept. 26, 2024, 6:57 p.m. UTC | #5

On Thu, Sep 26, 2024 at 08:48:19PM +0300, Laurent Pinchart wrote:
> On Thu, Sep 26, 2024 at 03:45:26PM +0000, Sakari Ailus wrote:
> > Hi Prabhakar,
> > 
> > Thanks for the set. It looks largely very nice to me, after addressing
> > Laurent's comments. A few comments here and possibly on other patches...
> > 
> > On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> > > From: Lad Prabhakar <[e-mail]>
> > > 
> > > Implement the .get_frame_desc() subdev operation to report information
> > > about streams to the connected CSI-2 receiver. This is required to let
> > > the CSI-2 receiver driver know about virtual channels and data types for
> > > each stream.
> > > 
> > > Signed-off-by: Lad Prabhakar <[e-mail]>
> > > ---
> > >  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
> > >  1 file changed, 28 insertions(+)
> > > 
> > > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > > index 7f1133292ffc..c24eb6e7a7b5 100644
> > > --- a/drivers/media/i2c/ov5645.c
> > > +++ b/drivers/media/i2c/ov5645.c
> > > @@ -28,6 +28,7 @@
> > >  #include <linux/regulator/consumer.h>
> > >  #include <linux/slab.h>
> > >  #include <linux/types.h>
> > > +#include <media/mipi-csi2.h>
> > >  #include <media/v4l2-ctrls.h>
> > >  #include <media/v4l2-event.h>
> > >  #include <media/v4l2-fwnode.h>
> > > @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
> > >  	.s_ctrl = ov5645_s_ctrl,
> > >  };
> > >  
> > > +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> > > +				 struct v4l2_mbus_frame_desc *fd)
> > > +{
> > > +	const struct v4l2_mbus_framefmt *fmt;
> > > +	struct v4l2_subdev_state *state;
> > > +
> > > +	if (pad != OV5645_PAD_SOURCE)
> > > +		return -EINVAL;
> > 
> > As you have a single source pad, and pretty much all sensor drivers will, I
> > think it'd be nice to add a check for this (that it's not an internal pad)
> > to the caller side in v4l2-subdev.c. And of course drop this one.
> 
> What check would you add, just verifying that the pad is a source pad ?

I think you could add that, too, besides the absence of the internal flag.

Lad, Prabhakar Sept. 27, 2024, 3:31 p.m. UTC | #6

Hi Sakari and Laurent,

On Thu, Sep 26, 2024 at 7:57 PM Sakari Ailus
<[e-mail]> wrote:
>
> On Thu, Sep 26, 2024 at 08:48:19PM +0300, Laurent Pinchart wrote:
> > On Thu, Sep 26, 2024 at 03:45:26PM +0000, Sakari Ailus wrote:
> > > Hi Prabhakar,
> > >
> > > Thanks for the set. It looks largely very nice to me, after addressing
> > > Laurent's comments. A few comments here and possibly on other patches...
> > >
> > > On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> > > > From: Lad Prabhakar <[e-mail]>
> > > >
> > > > Implement the .get_frame_desc() subdev operation to report information
> > > > about streams to the connected CSI-2 receiver. This is required to let
> > > > the CSI-2 receiver driver know about virtual channels and data types for
> > > > each stream.
> > > >
> > > > Signed-off-by: Lad Prabhakar <[e-mail]>
> > > > ---
> > > >  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
> > > >  1 file changed, 28 insertions(+)
> > > >
> > > > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > > > index 7f1133292ffc..c24eb6e7a7b5 100644
> > > > --- a/drivers/media/i2c/ov5645.c
> > > > +++ b/drivers/media/i2c/ov5645.c
> > > > @@ -28,6 +28,7 @@
> > > >  #include <linux/regulator/consumer.h>
> > > >  #include <linux/slab.h>
> > > >  #include <linux/types.h>
> > > > +#include <media/mipi-csi2.h>
> > > >  #include <media/v4l2-ctrls.h>
> > > >  #include <media/v4l2-event.h>
> > > >  #include <media/v4l2-fwnode.h>
> > > > @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
> > > >   .s_ctrl = ov5645_s_ctrl,
> > > >  };
> > > >
> > > > +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> > > > +                          struct v4l2_mbus_frame_desc *fd)
> > > > +{
> > > > + const struct v4l2_mbus_framefmt *fmt;
> > > > + struct v4l2_subdev_state *state;
> > > > +
> > > > + if (pad != OV5645_PAD_SOURCE)
> > > > +         return -EINVAL;
> > >
> > > As you have a single source pad, and pretty much all sensor drivers will, I
> > > think it'd be nice to add a check for this (that it's not an internal pad)
> > > to the caller side in v4l2-subdev.c. And of course drop this one.
> >
> > What check would you add, just verifying that the pad is a source pad ?
>
> I think you could add that, too, besides the absence of the internal flag.
>
Checking only for the source flag should suffice, as the
MEDIA_PAD_FL_INTERNAL flag cannot be set for a source pad because
media_entity_pads_init() enforces this restriction.

Do you agree?

Cheers,
Prabhakar

Sakari Ailus Sept. 27, 2024, 4:01 p.m. UTC | #7

Hi Prabhakar,

On Fri, Sep 27, 2024 at 04:31:31PM +0100, Lad, Prabhakar wrote:
> Hi Sakari and Laurent,
> 
> On Thu, Sep 26, 2024 at 7:57 PM Sakari Ailus
> <[e-mail]> wrote:
> >
> > On Thu, Sep 26, 2024 at 08:48:19PM +0300, Laurent Pinchart wrote:
> > > On Thu, Sep 26, 2024 at 03:45:26PM +0000, Sakari Ailus wrote:
> > > > Hi Prabhakar,
> > > >
> > > > Thanks for the set. It looks largely very nice to me, after addressing
> > > > Laurent's comments. A few comments here and possibly on other patches...
> > > >
> > > > On Tue, Sep 10, 2024 at 06:06:10PM +0100, Prabhakar wrote:
> > > > > From: Lad Prabhakar <[e-mail]>
> > > > >
> > > > > Implement the .get_frame_desc() subdev operation to report information
> > > > > about streams to the connected CSI-2 receiver. This is required to let
> > > > > the CSI-2 receiver driver know about virtual channels and data types for
> > > > > each stream.
> > > > >
> > > > > Signed-off-by: Lad Prabhakar <[e-mail]>
> > > > > ---
> > > > >  drivers/media/i2c/ov5645.c | 28 ++++++++++++++++++++++++++++
> > > > >  1 file changed, 28 insertions(+)
> > > > >
> > > > > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > > > > index 7f1133292ffc..c24eb6e7a7b5 100644
> > > > > --- a/drivers/media/i2c/ov5645.c
> > > > > +++ b/drivers/media/i2c/ov5645.c
> > > > > @@ -28,6 +28,7 @@
> > > > >  #include <linux/regulator/consumer.h>
> > > > >  #include <linux/slab.h>
> > > > >  #include <linux/types.h>
> > > > > +#include <media/mipi-csi2.h>
> > > > >  #include <media/v4l2-ctrls.h>
> > > > >  #include <media/v4l2-event.h>
> > > > >  #include <media/v4l2-fwnode.h>
> > > > > @@ -829,6 +830,32 @@ static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
> > > > >   .s_ctrl = ov5645_s_ctrl,
> > > > >  };
> > > > >
> > > > > +static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> > > > > +                          struct v4l2_mbus_frame_desc *fd)
> > > > > +{
> > > > > + const struct v4l2_mbus_framefmt *fmt;
> > > > > + struct v4l2_subdev_state *state;
> > > > > +
> > > > > + if (pad != OV5645_PAD_SOURCE)
> > > > > +         return -EINVAL;
> > > >
> > > > As you have a single source pad, and pretty much all sensor drivers will, I
> > > > think it'd be nice to add a check for this (that it's not an internal pad)
> > > > to the caller side in v4l2-subdev.c. And of course drop this one.
> > >
> > > What check would you add, just verifying that the pad is a source pad ?
> >
> > I think you could add that, too, besides the absence of the internal flag.
> >
> Checking only for the source flag should suffice, as the
> MEDIA_PAD_FL_INTERNAL flag cannot be set for a source pad because
> media_entity_pads_init() enforces this restriction.
> 
> Do you agree?

Works for me.

Patch

diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
index 7f1133292ffc..c24eb6e7a7b5 100644
--- a/drivers/media/i2c/ov5645.c
+++ b/drivers/media/i2c/ov5645.c
@@ -28,6 +28,7 @@ 
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/types.h>
+#include <media/mipi-csi2.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-event.h>
 #include <media/v4l2-fwnode.h>
@@ -829,6 +830,32 @@  static const struct v4l2_ctrl_ops ov5645_ctrl_ops = {
 	.s_ctrl = ov5645_s_ctrl,
 };
 
+static int ov5645_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+				 struct v4l2_mbus_frame_desc *fd)
+{
+	const struct v4l2_mbus_framefmt *fmt;
+	struct v4l2_subdev_state *state;
+
+	if (pad != OV5645_PAD_SOURCE)
+		return -EINVAL;
+
+	state = v4l2_subdev_lock_and_get_active_state(sd);
+	fmt = v4l2_subdev_state_get_format(state, OV5645_PAD_SOURCE, 0);
+	v4l2_subdev_unlock_state(state);
+
+	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
+	fd->num_entries = 1;
+
+	memset(fd->entry, 0, sizeof(fd->entry));
+
+	fd->entry[0].pixelcode = fmt->code;
+	fd->entry[0].stream = 0;
+	fd->entry[0].bus.csi2.vc = 0;
+	fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_YUV422_8B;
+
+	return 0;
+}
+
 static int ov5645_enum_mbus_code(struct v4l2_subdev *sd,
 				 struct v4l2_subdev_state *sd_state,
 				 struct v4l2_subdev_mbus_code_enum *code)
@@ -1062,6 +1089,7 @@  static const struct v4l2_subdev_video_ops ov5645_video_ops = {
 };
 
 static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
+	.get_frame_desc = ov5645_get_frame_desc,
 	.enum_mbus_code = ov5645_enum_mbus_code,
 	.enum_frame_size = ov5645_enum_frame_size,
 	.get_fmt = v4l2_subdev_get_fmt,