From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH V6 2/2] dmaengine: add helper function to request a slave DMA channel Date: Mon, 24 Sep 2012 17:25:47 -0500 Message-ID: <5060DDEB.4000600@ti.com> References: <1347662517-4210-1-git-send-email-jon-hunter@ti.com> <1347662517-4210-3-git-send-email-jon-hunter@ti.com> <1347852805.1943.130.camel@vkoul-udesk3> <201209171159.27359.arnd@arndb.de> <20120917223619.GC12445@n2100.arm.linux.org.uk> <1347938035.1943.162.camel@vkoul-udesk3> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1347938035.1943.162.camel@vkoul-udesk3> Sender: linux-omap-owner@vger.kernel.org To: Vinod Koul Cc: Russell King - ARM Linux , Arnd Bergmann , device-tree , linux-omap , linux-arm , Stephen Warren , Benoit Cousson , Nicolas Ferre , Rob Herring , Grant Likely , Dan Williams List-Id: devicetree@vger.kernel.org Hi Vinod, On 09/17/2012 10:13 PM, Vinod Koul wrote: > On Mon, 2012-09-17 at 23:36 +0100, Russell King - ARM Linux wrote: >>> >>> I believe that Jon is on vacation this week, so if this is the only issue >>> holding up the merge, maybe you can change this in his patch directly, or >>> I can send an updated version if you prefer. >> >> I worry that too much is going on here too quickly. We have some people >> working on changing the way DMA engine selects channels. Meanwhile we >> have other people trying to create an OF DMA engine API. >> >> It seems that Vinod's working on a way for platforms to specify bindings >> to the DMA engine code, and the DMA engine code itself selects the >> appropriate channel. This patch, on the other hand, introduces a set of >> translation functions which need to be provided by platform code, >> which returns the dma_chan pointer. >> >> This sounds like a recipe for a total abortion of interfaces. Only one >> of those two activities should be going on at any one time, or if they >> have to occur, they need coordination so that the we don't end up with >> two totally different schemes. >> >> In the mad rush to DTify everything, don't make hasty decisions, because >> it is very difficult to change it later - especially something like this >> which defines how DT encodes this information. > We discussed this in KS and IMHO we need to merge these two approaches. > > For DT bindings, I think the binding itself shouldn't change based on my > work but I would like these same bindings to help build the DMA engine > code mappings. > > Now would it make sense to NOT merge these changes for 3.7 and postpone > to 3.8. I can host these patches on a topic branch and merge them when > we are ready. I plan to spend some good amount of time on my work this > week so we should be ready pretty soon. > One these changes are merged, users can start moving to this scheme. I just wanted to see how things are progressing your side. Did you create a topic branch for this? If so let me know where I can find it, I did not find a branch on your infradead git tree. I wanted to pull in the latest patches for some testing. Cheers Jon