From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: Best practice device tree design for display subsystems/DRM Date: Tue, 2 Jul 2013 23:14:45 +0100 Message-ID: <20130702221445.GF13924@flint.arm.linux.org.uk> References: <20130702204255.2044c01b@armhf> <20130702191923.GD13924@flint.arm.linux.org.uk> <51D330AC.5060903@gmail.com> <20130702202548.GE13924@flint.arm.linux.org.uk> <20130702215048.GI516@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Dave Airlie Cc: Jean-Francois Moine , Daniel Drake , Sascha Hauer , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , Sebastian Hesselbarth List-Id: devicetree@vger.kernel.org On Wed, Jul 03, 2013 at 08:02:05AM +1000, Dave Airlie wrote: > Have you also considered how suspend/resume works in such a place, > where every driver is independent? The ChromeOS guys have bitched > before about the exynos driver which is has lots of sub-drivers, how > do you control the s/r ordering in a crazy system like that? I'd > prefer a central driver, otherwise there is too many moving parts. >>From earlier in the evolution of Armada DRM, that has also been my preferred idea - though probably not quite how people think. My idea was to have a separate "driver" assemble all the constituent parts, and then register the "armada-drm" platform device providing via platform resources and/or platform data all the necessary information (maybe not even bothering to decode the OF nodes but just provide a collection of nodes for each consituent part.) Such a thing could be turned into a generic solution for all the multi-part drivers. If we use Sebastian's idea of using phandles (it seems there's a precident for it with the direction v4l2 is going to solve a similar problem) then we likely have a standard way of describing component-ized display setups in DT. -- Russell King