Hi Michael,
On Thursday 19 May 2011 16:24:29 Michael Jones wrote:
> On 05/19/2011 03:56 PM, Laurent Pinchart wrote:
> > On Thursday 19 May 2011 15:44:18 Michael Jones wrote:
> >> On 05/19/2011 03:02 PM, Laurent Pinchart wrote:
> >>> On Thursday 19 May 2011 14:51:16 Alex Gershgorin wrote:
> >>>> Thanks Laurent,
> >>>>
> >>>> My video source is not the video camera and performs many other
> >>>> functions. For this purpose I have RS232 port.
> >>>> As for the video, it runs continuously and is not subject to control
> >>>> except for the power supply.
> >>>
> >>> As a quick hack, you can create an I2C driver for your video source
> >>> that doesn't access the device and just returns fixed format and frame
> >>> size.
> >>>
> >>> The correct fix is to implement support for platform subdevs in the
> >>> V4L2 core.
> >>
> >> I recently implemented support for platform V4L2 subdevs. Now that it
> >> sounds like others would be interested in this, I will try to polish it
> >> up and submit the patch for review in the next week or so.
> >
> > Great. This has been discussed during the V4L meeting in Warsaw, here are
> > a couple of pointers, to make sure we're going in the same direction.
> >
> > Bridge drivers should not care whether the subdev sits on an I2C, SPI,
> > platform or other bus. To achieve that, an abstraction layer must be
> > provided by the V4L2 core. Here's what I got in one of my trees:
> >
> > /* V4L2 core */
> >
> > struct v4l2_subdev_i2c_board_info {
> >
> > struct i2c_board_info *board_info;
> > int i2c_adapter_id;
> >
> > };
> >
> > enum v4l2_subdev_bus_type {
> >
> > V4L2_SUBDEV_BUS_TYPE_NONE,
> > V4L2_SUBDEV_BUS_TYPE_I2C,
> > V4L2_SUBDEV_BUS_TYPE_SPI,
> >
> > };
> >
> > struct v4l2_subdev_board_info {
> >
> > enum v4l2_subdev_bus_type type;
> > union {
> >
> > struct v4l2_subdev_i2c_board_info i2c;
> > struct spi_board_info *spi;
> >
> > } info;
> >
> > };
> >
> > /* OMAP3 ISP */
> >
> > struct isp_v4l2_subdevs_group {
> >
> > struct v4l2_subdev_board_info *subdevs;
> > enum isp_interface_type interface;
> > union {
> >
> > struct isp_parallel_platform_data parallel;
> > struct isp_ccp2_platform_data ccp2;
> > struct isp_csi2_platform_data csi2;
> >
> > } bus; /* gcc < 4.6.0 chokes on anonymous union initializers */
> >
> > };
> >
> > struct isp_platform_data {
> >
> > struct isp_v4l2_subdevs_group *subdevs;
> >
> > };
> >
> > The V4L2 core would need to provide a function to register a subdev based
> > on a v4l2_subdev_board_info structure.
> >
> > Is that in line with what you've done ? I can provide a patch that
> > implements this for I2C and SPI, and let you add platform subdevs if
> > that can help you.
>
> Hi Laurent,
>
> Yes, that looks very similar to what I've done. I was going to submit
> SPI support, too, which I also have, but it sounds like you've already
> done that? I'm currently still using a 2.6.38 tree based on an older
> media branch of yours, so I'm not familiar with any new changes there yet.
>
> I just need to know what I should use as my baseline.
Please use mainline, now that the OMAP3 ISP driver has been merged :-)
> I don't need to step on toes and submit something you've already done, so
> maybe you want to point me to a branch with the SPI stuff, and I'll just put
> the platform stuff on top of it?
I'll send the SPI support patches to linux-media, as they haven't been
reviewed publicly yet.
--
Regards,
Laurent Pinchart
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