On Tue, Feb 23, 2016 at 01:11:24PM +0200, Tomi Valkeinen wrote: > > > On 23/02/16 12:43, Archit Taneja wrote: > > > > > > On 02/23/2016 02:48 PM, Tomi Valkeinen wrote: > >> > >> On 22/02/16 22:10, Rob Herring wrote: > >> > >>>> If we want all DSI host controllers to use a common binding to describe > >>>> lanes, we'd need to go with the most flexible one, and the driver > >>>> restricts it to the subsets that we support. > >> > >> True, but I wonder if that's necessary. The lane property for the SoC > >> should be read by the SoC specific driver, right? So the DT property can > >> be anything. I'm not sure if there's ever a reason for a generic code to > >> observe the DSI lane setup. > > > > Yeah, it is very SoC specific. Agreed. > > The only place where it might matter is if a panel/bridge ever needs to > > know what pins implement what lanes on the platform. A common binding > > there might help us keep the panel driver generic. Although, this need > > itself is a bit hypothetical. > > My opinion here is that if the panel/bridge needs to know something > about the DSI lanes/pins, we should have that data in the > panel's/bridge's endpoint data. > > So if both SoC and the DSI peripheral need complex DSI pin/lane setup, > you might have very similar data on both sides. There's possibly some > duplication there, but I think it keeps things much simpler. > > For example, if the SoC needs OMAP style DSI pin data, and the DSI > peripheral needs to know the amount of DSI lanes used (but nothing > else), you might think it's nice if the DSI peripheral would peek at the > SoC side data, finding out about the DSI lanes. > > But I think in that case you should just add a "num-lanes" property to > the DSI peripheral. The DT data for a device should be private to the > driver handling the device, except for some special cases like following > the graph. num-lanes might not be enough. You could need to have a mask instead. Not sure if there is really any h/w like that though. Also, I think it is fine for a parent to look at standard properties in a child. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
