Color lookup support for the atmel-hlcdc driver

[Boris Brezillon]

Hi Peter,

On Tue, 13 Jun 2017 16:34:25 +0200
Peter Rosin <peda at axentia.se> wrote:

> Hi!
> 
> I need color lookup support for the atmel-hlcdc driver, and had a peek
> at the code. I also looked at the drivers/gpu/drm/stm driver and came
> up with the below diff. It compiles, but I have not booted it for the
> simple reason that I can't imagine it will work.
> 
> Sure, the code fills the clut registers in the .load_lut helper function
> and I think it might even do the right thing when setting up the mode.
> I'm less sure DMA will work correctly? It might, but I haven't looked at
> it for many seconds...
> 
> The big question is how the color info gets into the new clut array
> I created in atmel_hlcdc_crtc? When I look at the stm driver, which does
> it just like this AFAICT I just don't see it. So, what I'm I missing?

You should look at drm_atomic_helper_legacy_gamma_set() and its users.

Regards,

Boris