From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Date: Fri, 13 Dec 2013 17:10:25 +0000 Subject: Re: [PATCH 13/26] ARM: omap3.dtsi: add omapdss information Message-Id: <20131213171025.GC28184@atomide.com> List-Id: References: <1386160133-24026-1-git-send-email-tomi.valkeinen@ti.com> <52A9760A.3000801@ti.com> <20131212215913.GB29072@muru.com> <1933495.zHe4JMYZyB@avalon> <52AADEF3.9040808@ti.com> In-Reply-To: <52AADEF3.9040808-l0cyMroinI0@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tomi Valkeinen Cc: Laurent Pinchart , linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Archit Taneja , Darren Etheridge * Tomi Valkeinen [131213 02:19]: > On 2013-12-13 05:27, Laurent Pinchart wrote: > > Hi Tony, > > > > On Thursday 12 December 2013 21:59:13 Tony Lindgren wrote: > >> On Thu, Dec 12, 2013 at 10:38:34AM +0200, Tomi Valkeinen wrote: > >>> On 2013-12-12 01:44, Laurent Pinchart wrote: > >>> > >>> So, are they independent? I don't know =). I think they lean on the > >>> independent side. dss_core is always needed for the submodules to work, > >>> but for example DSI could be used without DISPC, using system DMA to > >>> transfer data from memory to DSI. Not a very useful thing to do, but > >>> still, there are dedicated DMA channels for that. > >> > >> If they have separate hwmod entries, they should be considered separate > >> independent devices for sure. > >> > >> To summarize, here are few reasons why they need to be treated as > >> separate devices: > > > > Are you talking generally here, or about the DSS modules in particular ? > > > >> 1. The modules maybe clocked/powered/idled separately and can have their > >> own idle configuration so they can do the hardware based idling > >> separately. > > > > I don't think this applies to the DSS modules. > > The DSS submodules have their own SYSCONFIG register, and idle settings > can be set per module. So I think they idle separately, even if they are > in a common power domain. Yes. Please see the current omap_hwmod_*_data.c files, if they are separate entries there, that means we need to treat them as separate devices to avoid the issues I listed. We do have some entries still missing from omap_hwmod_*_data.c files, like the SSI entries as they are undocumented. But for the existing ones there please follow the same layout for the .dts entries. Regards, Tony