Re: FW: OMAP 3 ISP

[Michael Jones <michael.jones@matrix-vision.de>]

On 05/19/2011 03:56 PM, Laurent Pinchart wrote:
> Hi Michael,
> 
> 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.  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?

-Michael

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