On Tuesday 25 February 2014 14:41:48 Sebastian Reichel wrote: > On Tue, Feb 25, 2014 at 12:39:21PM +0000, Russell King - ARM Linux wrote: > > > That compatible string is correct according to the latest series > > > posted by Tomi Valkeinen to add DT bindings for the OMAP Display > > > SubSystem (DSS) [0]. > > > > in which case: > > > > N N AA CCCC K K > > NN N A A C C K K > > N N N A A C KK > > N N N AAAAAA C KK > > N NN A A C C K K > > N N A A CCCC K K > > > > Yes, that's a very big nack. Two things: > > > > 1. OMAP really doesn't have the right to define a compatible string which > > is as generic as "hdmi-connector". > > AFAIK the idea was to have "hdmi-connector" as part of the common > display framework [1]. It's not really platform specific, since it's > just a connector. > > Since omapdss does not yet implement the common display framework, > but wants to keep a stable DT API it rewrites "hdmi-connector" to > "omapdss,hdmi-connector" for now. And since the common display framework has been pretty much nacked, we have no framework on which drivers can rely ;-) > > 2. Even with "omapdss," before it, the convention that DT people have > > adopted is for the prefix to be "companyname," and not a subsystem. > > > > I'm not the only one with this concern - I discussed it with Arnd last > > night and his comments were about it being "obviously bogus". > > > > > The property is added on this patch [1] and as far as I understood the > > > idea is that it could be a generic DT binding that can be used by > > > platform specific HDMI connectors like the omap dss HDMI connector [2]. > > > > Why do the physical connectors need a DT binding? > > This is the termination of the video bus and useful information for > xrandr. I don't think all physical connectors require a DT binding per-se, but they need to be represented in DT as they're part of the hardware. We could push connector-related information to the nodes of all chips that have interfaces wired directly to connectors, but that would result in more complex DT bindings and core. I believe modeling connectors using separate DT nodes is be best, and would allow easier support for more complex connectors that carry multiple streams/signals in parallel (video, audio, DDC, ...). > > Surely what needs the DT binding is the HDMI encoder - and that certainly > > should no way be a generic name, because there's no such thing as a > > generic HDMI encoder chip. > > The HDMI encoder and companion chips are described separatly and properly > prefixed [0]. > > [0] http://www.spinics.net/lists/linux-omap/msg102522.html > [1] https://lwn.net/Articles/563157/ -- Regards, Laurent Pinchart
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