Re: [PATCH 0/2] drm/panel: Add support for the Sitronix ST7789V

Hi Noralf,

On Fri, Feb 03, 2017 at 07:48:51PM +0100, Noralf Trønnes wrote:

Den 03.02.2017 10.59, skrev Maxime Ripard:

quoted

Hi,

Here is an attempt at supporting the ST7789V LCD controller from Sitronix.

What happens if there's another panel driven by ST7789V that needs
a different controller initialization?

You know those panels / controllers much better than I do, but why
would that be the case?

Maybe it's better to name it after the panel, not the controller.

I guess you could also use that panel directly without the controller?

quoted

It is controlled through an SPI bus, with a twist, since each byte sent
must be prefixed by a bit, which needs an 9-bits-per-word SPI controller,
which is quite rare. Else, you would need to bitbang it.

It's possible to support SPI controllers that can't do 9-bit by using
8-bit mode and blocks of 9 bytes to send 8x 9-bit words padded with
zeroes. Zero is MIPI DCS no-op command.

Ah, yes, that makes sense. Thanks for the hint.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com