On Thu, Jan 27, 2022 at 3:36 AM Maxime Ripard <maxime@xxxxxxxxxx> wrote: > > Hi Rob, > > On Mon, Jan 24, 2022 at 10:42:37AM -0600, Rob Herring wrote: > > On Mon, Jan 24, 2022 at 10:28 AM Noralf Trønnes <noralf@xxxxxxxxxxx> wrote: > > > > > > > > > > > > Den 24.01.2022 17.08, skrev Rob Herring: > > > > On Sun, Jan 23, 2022 at 11:25 AM Noralf Trønnes <noralf@xxxxxxxxxxx> 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? > > > > 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'? > > So, the main issue is that a panel is essentially two things: a > controller and the actual panel. > > The controller has an initialization sequence of its own, and part of it > is parameters to match the panel. > > So you can have identical controllers that won't have the same > initialization sequence because they don't have the same panel. > > I was assuming that a compatible would be more about the controller, so > we needed something else, thus "model" We already have cases like that which have "foo,some-panel", "bar,a-ctrlr-ic". Rob
