[PATCH 1/3] RFT: drm/pl111: Support grayscale

[Adam Jackson]

On Tue, 2019-07-23 at 15:37 +0200, Linus Walleij wrote:
> Migrating the TI nspire calculators to use the PL111 driver for
> framebuffer requires grayscale support for the elder panel
> which uses 8bit grayscale only.
> 
> DRM does not support 8bit grayscale framebuffers in memory,
> but by defining the bus format to be MEDIA_BUS_FMT_Y8_1X8 we
> can get the hardware to turn on a grayscaling feature and
> convert the RGB framebuffer to grayscale for us.

What's wrong with DRM_FORMAT_R8? Yes the hardware is not really
"redscale", but it's still a single color channel and there's not
really any ambiguity.

- ajax