On Mon, Aug 24, 2015 at 09:48:27AM -0500, Rob Herring wrote: > On Mon, Aug 24, 2015 at 7:57 AM, Russell King - ARM Linux > <linux@xxxxxxxxxxxxxxxx> wrote: > > On Sun, Aug 23, 2015 at 06:23:14PM -0500, Rob Herring wrote: > >> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote: > >> > + -analogix,color-depth: > >> > + number of bits per colour component. > >> > + COLOR_6 = 0, COLOR_8 = 1, COLOR_10 = 2, COLOR_12 = 3 > >> > >> This seems pretty generic. Just use 6, 8, 10, or 12 for values. And > >> drop the vendor prefix. > > > > Please think about this some more. What does "color-depth" mean? Does it > > mean the number of bits per colour _component_, or does it mean the total > > number of bits to represent a particular colour. It's confusing as it > > stands. > > Then "component-color-bpp" perhaps? There should be no need to have this in DT at all. The BPC is a property of the attached panel and it should come from the panel (either the panel driver or parsed from EDID if available). > > When we adopted the graph bindings for iMX DRM, I thought exactly at that > > time "it would be nice if this could become the standard for binding DRM > > components together" but I don't have the authority from either the DT > > perspective or the DRM perspective to mandate that. Neither does anyone > > else. That's the _real_ problem here. > > > > I've seen several DRM bindings go by which don't use the of-graph stuff, > > which means that they'll never be compatible with generic components > > which do use the of-graph stuff. > > It goes beyond bindings IMO. The use of the component framework or not > has been at the whim of driver writers as well. It is either used or > private APIs are created. I'm using components and my need for it > boils down to passing the struct drm_device pointer to the encoder. > Other components like panels and bridges have different ways to attach > to the DRM driver. I certainly support unification, but it needs to be reasonable. There are cases where a different structure for the binding work better than another and I think this always needs to be evaluated on a case by case basis. Because of that I think it makes sense to make all these framework bits opt-in, otherwise we could easily end up in a situation where drivers have to be rearchitected (or even DT bindings altered!) in order to be able to reuse code. Thierry
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