[libcamera-devel] [PATCH v2 03/10] libcamera: v4l2_subdevice: Extend [gs]etFormat() to specify format type
Jacopo Mondi
jacopo at jmondi.org
Tue Mar 17 13:22:43 CET 2020
HI Laurent,
On Mon, Mar 16, 2020 at 11:43:03PM +0200, Laurent Pinchart wrote:
> The V4L2 subdevice API exposes ACTIVE and TRY formats, but the
> V4L2Subdevice getFormat() and setFormat() operations only apply on
> ACTIVE formats. Extend them to support TRY formats as well.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
> src/libcamera/include/v4l2_subdevice.h | 11 +++++++++--
> src/libcamera/v4l2_subdevice.cpp | 23 +++++++++++++++++++----
> 2 files changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
> index 9c077674f997..4a04eadfb1f9 100644
> --- a/src/libcamera/include/v4l2_subdevice.h
> +++ b/src/libcamera/include/v4l2_subdevice.h
> @@ -32,6 +32,11 @@ struct V4L2SubdeviceFormat {
> class V4L2Subdevice : public V4L2Device
> {
> public:
> + enum Whence {
> + ActiveFormat,
> + TryFormat,
> + };
Just wondering if
ActiveFormat = V4L2_SUBDEV_FORMAT_ACTIVE,
TryFormat = V4L2_SUBDEV_FORMAT_TRY
would not save you the ternary operator in set/get functions
> +
> explicit V4L2Subdevice(const MediaEntity *entity);
> V4L2Subdevice(const V4L2Subdevice &) = delete;
> V4L2Subdevice &operator=(const V4L2Subdevice &) = delete;
> @@ -46,8 +51,10 @@ public:
>
> ImageFormats formats(unsigned int pad);
>
> - int getFormat(unsigned int pad, V4L2SubdeviceFormat *format);
> - int setFormat(unsigned int pad, V4L2SubdeviceFormat *format);
> + int getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> + Whence whence = ActiveFormat);
> + int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> + Whence whence = ActiveFormat);
This mimics the V4L2 APIs, so it's certainly safe, but considering the
use case for TRY is actually to set a try format to then get it back
to see how the driver changed it, have you considered a tryFormat()
function that does both steps in one call ?
>
> static V4L2Subdevice *fromEntityName(const MediaDevice *media,
> const std::string &entity);
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 8b9da81e8ab3..fb9bdbce2610 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -95,6 +95,15 @@ const std::string V4L2SubdeviceFormat::toString() const
> * any device left open will be closed, and any resources released.
> */
>
> +/**
> + * \enum V4L2Subdevice::Whence
> + * \brief Specify the type of format for getFormat() and setFormat() operations
> + * \var V4L2Subdevice::ActiveFormat
> + * \brief The format operation applies to ACTIVE formats
> + * \var V4L2Subdevice::TryFormat
> + * \brief The format operation applies to TRY formats
> + */
> +
> /**
> * \brief Create a V4L2 subdevice from a MediaEntity using its device node
> * path
> @@ -184,12 +193,15 @@ ImageFormats V4L2Subdevice::formats(unsigned int pad)
> * \brief Retrieve the image format set on one of the V4L2 subdevice pads
> * \param[in] pad The 0-indexed pad number the format is to be retrieved from
> * \param[out] format The image bus format
> + * \param[in] whence The format to retrieve, ACTIVE or TRY
> * \return 0 on success or a negative error code otherwise
> */
> -int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
> +int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> + Whence whence)
> {
> struct v4l2_subdev_format subdevFmt = {};
> - subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> + subdevFmt.which = whence == ActiveFormat ? V4L2_SUBDEV_FORMAT_ACTIVE
> + : V4L2_SUBDEV_FORMAT_TRY;
> subdevFmt.pad = pad;
>
> int ret = ioctl(VIDIOC_SUBDEV_G_FMT, &subdevFmt);
> @@ -211,6 +223,7 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
> * \brief Set an image format on one of the V4L2 subdevice pads
> * \param[in] pad The 0-indexed pad number the format is to be applied to
> * \param[inout] format The image bus format to apply to the subdevice's pad
> + * \param[in] whence The format to set, ACTIVE or TRY
Here and above "ActiveFormat or TryFormat".
If you could cross-reference to the enum it's even better
Thanks
j
> *
> * Apply the requested image format to the desired media pad and return the
> * actually applied format parameters, as \ref V4L2Subdevice::getFormat would
> @@ -218,10 +231,12 @@ int V4L2Subdevice::getFormat(unsigned int pad, V4L2SubdeviceFormat *format)
> *
> * \return 0 on success or a negative error code otherwise
> */
> -int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format)
> +int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
> + Whence whence)
> {
> struct v4l2_subdev_format subdevFmt = {};
> - subdevFmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> + subdevFmt.which = whence == ActiveFormat ? V4L2_SUBDEV_FORMAT_ACTIVE
> + : V4L2_SUBDEV_FORMAT_TRY;
> subdevFmt.pad = pad;
> subdevFmt.format.width = format->size.width;
> subdevFmt.format.height = format->size.height;
> --
> Regards,
>
> Laurent Pinchart
>
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