Re: [Query] : DT: Adding mezzanine board

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Prabhakar,

On Wed, Feb 19, 2020 at 11:42:42AM +0000, Lad, Prabhakar wrote:
> Hi,
> 
> I am working Renesas RZ/Gx platforms, these boards have support for
> connecting MIPI adapter mezzanine board [1]. To enable this support I
> am planning to create a dtsi which will include the board file and
> enable the necessary VIN/CSI and the camera endpoint.
> 
> For example: to add support for G2E board I would create a file named
> r8a774c0-cat874-mipi-adapter.dtsi which will include the board file
> r8a774c0.dtsi and enable necessary VIN/CSI/Camera endpoint and when
> user wants to enable this support for the G2E board he could just
> include r8a774c0-cat874-mipi-adapter.dtsi to r8a774c0-cat874.dts
> 
> Would this be a good approach or is there an alternative way which I am missing.

DT overlays are another option. They can't be applied on a running
system though. It doesn't seem like the mezzanine boards can be detected
by the boot loader, so overlays can't be applied automatically before
the kernel is started. One option would still be to provide them to
U-Boot and apply a selected overlay based on environment variables.
Another option would be to apply overlays as part of the build process,
which shouldn't require modifying the DT sources to #include the .dtsi
file for the mezzanine board.

> [1] https://github.com/Kevin-WSCU/96Boards-Camera/blob/master/AISTARVISION%20MIPI%20Adapter%20V2.1/AISTARVISION%20MIPI%20Adapter%20V2.1.pdf

-- 
Regards,

Laurent Pinchart