[libcamera-devel] [PATCH 1/6] libcamera: v4l2_device: Add setFd()

[Jacopo Mondi]

Hello,

On Thu, Aug 08, 2019 at 11:34:16PM +0300, Laurent Pinchart wrote:
> 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.

Thanks, this gives some more context on why this change is needed

Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
   j

>
> 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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> libcamera-devel at lists.libcamera.org
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