Hi Sakari
On Mon, Apr 29, 2024 at 10:08:49PM +0300, Sakari Ailus wrote:
> v4l2_get_link_freq() accepts a V4L2 control handler for now, but it needs
> to take struct v4l2_subdev argument in order to obtain the link frequency
> using get_mbus_config() pad op. Prepare for this by allowing struct
> v4l2_subdev as well.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Nice! I need exactly something like this to avoid pre-computing a lot
a frequencies in a driver I'm working on.
> ---
> drivers/media/v4l2-core/v4l2-common.c | 19 ++++++++++++++++---
> include/media/v4l2-common.h | 14 +++++++++++---
> 2 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index 4165c815faef..7f69b5a025fa 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -464,8 +464,8 @@ int v4l2_fill_pixfmt(struct v4l2_pix_format *pixfmt, u32 pixelformat,
> }
> EXPORT_SYMBOL_GPL(v4l2_fill_pixfmt);
>
> -s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul,
> - unsigned int div)
> +s64 __v4l2_get_link_freq_ctrl(struct v4l2_ctrl_handler *handler,
> + unsigned int mul, unsigned int div)
> {
> struct v4l2_ctrl *ctrl;
> s64 freq;
> @@ -500,7 +500,20 @@ s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul,
>
> return freq > 0 ? freq : -EINVAL;
> }
> -EXPORT_SYMBOL_GPL(v4l2_get_link_freq);
> +EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_ctrl);
> +
> +s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul,
> + unsigned int div)
> +{
> + struct v4l2_subdev *sd;
> +
> + sd = media_entity_to_v4l2_subdev(pad->entity);
> + if (!sd)
> + return -ENODEV;
> +
> + return __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div);
> +}
> +EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_pad);
>
> /*
> * Simplify a fraction using a simple continued fraction decomposition. The
> diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
> index 63ad36f04f72..d7115cd61a38 100644
> --- a/include/media/v4l2-common.h
> +++ b/include/media/v4l2-common.h
> @@ -525,7 +525,8 @@ int v4l2_fill_pixfmt_mp(struct v4l2_pix_format_mplane *pixfmt, u32 pixelformat,
> /**
> * v4l2_get_link_freq - Get link rate from transmitter
> *
> - * @handler: The transmitter's control handler
> + * @pad: The transmitter's media pad (or control handler for compatibility
> + * reasons, don't use in new code)
> * @mul: The multiplier between pixel rate and link frequency. Bits per pixel on
> * D-PHY, samples per clock on parallel. 0 otherwise.
> * @div: The divisor between pixel rate and link frequency. Number of data lanes
> @@ -541,8 +542,15 @@ int v4l2_fill_pixfmt_mp(struct v4l2_pix_format_mplane *pixfmt, u32 pixelformat,
> * * %-ENOENT: Link frequency or pixel rate control not found
> * * %-EINVAL: Invalid link frequency value
> */
> -s64 v4l2_get_link_freq(struct v4l2_ctrl_handler *handler, unsigned int mul,
> - unsigned int div);
> +#define v4l2_get_link_freq(pad, mul, div) \
> + _Generic(pad, \
> + struct media_pad *: __v4l2_get_link_freq_pad, \
> + struct v4l2_ctrl_handler *: __v4l2_get_link_freq_ctrl) \
> + (pad, mul, div)
That's nice and elegant, but given that I count 10 drivers in mainline
using this function, wouldn't it be better to make them use a pad and
remove the ctrl_handler version completely to avoid it being used in
future ?
> +s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul,
> + unsigned int div);
> +s64 __v4l2_get_link_freq_ctrl(struct v4l2_ctrl_handler *handler,
> + unsigned int mul, unsigned int div);
>
> void v4l2_simplify_fraction(u32 *numerator, u32 *denominator,
> unsigned int n_terms, unsigned int threshold);
> --
> 2.39.2
>
>
