Den 24.01.2022 17.42, skrev Rob Herring:
On Mon, Jan 24, 2022 at 10:28 AM Noralf Trønnes noralf@tronnes.org wrote:
Den 24.01.2022 17.08, skrev Rob Herring:
On Sun, Jan 23, 2022 at 11:25 AM Noralf Trønnes noralf@tronnes.org wrote:
Add binding for MIPI DBI compatible SPI panels.
I'm sure we already have MIPI DBI panels. What's this for?
It aims to use one driver to cover all MIPI DBI panels where the controller setup is loaded from userspace in a firmware file.
What's the solution when the user wants a splash screen in the bootloader and also wants multiple panels supported?
In that case the bootloader needs builtin support for the screen. The OS driver can then detect that the controller is configured and just skip the configure stage. I have yet to see someone implement suppport for such a SPI panel in a bootloader though.
Also, 1 driver doesn't dictate 1 compatible. A one to many relationship is fine and makes the decision entirely the OS's.
The cover letter points to the discussion where Maxime proposed this:
https://lore.kernel.org/dri-devel/20211129093946.xhp22mvdut3m67sc@houat/
The proposal there is:
compatible = "panel-spi"; model = "panel-from-random-place-42";
The same thing can be accomplished with this:
compatible = "panel-from-random-place-42", "panel-spi";
What's the advantage of hijacking 'model'?
That's what Maxime proposed, but having it in the compatible like this is even better. I suppose it's ok for the driver to use the compatible to load the firmware file?
Noralf.