[libcamera-devel] [PATCH 1/6] libcamera: v4l2_device: Add setFd()
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Thu Aug 8 22:34:16 CEST 2019
Hi Kieran,
Thank you for the patch.
On Thu, Aug 08, 2019 at 04:12:16PM +0100, Kieran Bingham wrote:
> Provide a means for V4L2 device instances to set the fd_ explicitly.
> This allows for V4L2Devices to operate when they must use an external open() call.
Line wrap ?
>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
> src/libcamera/include/v4l2_device.h | 1 +
> src/libcamera/v4l2_device.cpp | 19 +++++++++++++++++++
> 2 files changed, 20 insertions(+)
>
> diff --git a/src/libcamera/include/v4l2_device.h b/src/libcamera/include/v4l2_device.h
> index e7e9829cb05f..7c3af5f6ebe0 100644
> --- a/src/libcamera/include/v4l2_device.h
> +++ b/src/libcamera/include/v4l2_device.h
> @@ -39,6 +39,7 @@ protected:
> int ioctl(unsigned long request, void *argp);
>
> int fd() { return fd_; }
> + int setFd(int fd);
>
> private:
> void listControls();
> diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
> index 9a00566a532b..120f68e49d7a 100644
> --- a/src/libcamera/v4l2_device.cpp
> +++ b/src/libcamera/v4l2_device.cpp
> @@ -308,6 +308,25 @@ int V4L2Device::ioctl(unsigned long request, void *argp)
> * \return The V4L2 device file descriptor, -1 if the device node is not open
> */
>
> +/**
> + * \brief Set the file descriptor of a V4L2 device.
s/\.$//
> + * \param[in] fd The file descriptor handle
> + *
> + * Allow a device to set the internal file descriptor rather than opening a
> + * device node directly.
How about the following ?
* This method allows a device to provide an already opened file descriptor
* referring to the V4L2 device node, instead of opening it with open(). This
* can be used for V4L2 M2M devices where a single video device node is used for
* both the output and capture devices, or when receiving an open file
* descriptor in a context that doesn't have permission to open the device node
* itself.
*
* This method and the open() method are mutually exclusive, only one of the two
* shall be used for a V4L2Device instance.
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> + *
> + * \return 0 on success or a negative error code otherwise
> + */
> +int V4L2Device::setFd(int fd)
> +{
> + if (fd_ != -1)
> + return -1;
> +
> + fd_ = fd;
> +
> + return 0;
> +}
> +
> /*
> * \brief List and store information about all controls supported by the
> * V4L2 device
--
Regards,
Laurent Pinchart
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