From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Abraham Subject: Re: [PATCH] mmc: dt: Add 'broken-cd' DT binding Date: Wed, 22 Aug 2012 16:21:33 +0530 Message-ID: References: <1345547371-6784-1-git-send-email-thomas.abraham@linaro.org> <87k3ws5uhs.fsf@octavius.laptop.org> <201208211208.49987.arnd@arndb.de> <87393g5mic.fsf@octavius.laptop.org> <5033A34E.7040201@gmail.com> <87pq6k46jg.fsf@octavius.laptop.org> <5033B0F0.7050506@gmail.com> <20120822055151.GT24242@S2101-09.ap.freescale.net> <877gsr5iz1.fsf@octavius.laptop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: <877gsr5iz1.fsf@octavius.laptop.org> Sender: linux-samsung-soc-owner@vger.kernel.org To: Chris Ball Cc: Shawn Guo , Rob Herring , Arnd Bergmann , linux-mmc@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-samsung-soc@vger.kernel.org, grant.likely@secretlab.ca, patches@linaro.org, Wolfram Sang List-Id: devicetree@vger.kernel.org On 22 August 2012 15:47, Chris Ball wrote: > Hi, > > On Wed, Aug 22 2012, Shawn Guo wrote: >> The following is what I have on my mind. >> >> broken-cd cd-gpios implication >> ------------------------------------------- >> no no SDHCI CD >> no yes GPIO CD >> yes no NO CD / Broken CD >> yes yes Invalid >> >> yes: property presents >> no: property does not present > > This matches Mitch's last suggestion exactly -- I think we're all agreed > on these properties now. The only remaining question is how to handle > the pinctrl for CD in Thomas's case. Hi Chris, For sdhci-s3c driver, the 'broken-cd' and 'cd-gpios' bindings are sufficient. But, are drivers free to use implementation specific behavior when using these bindings. Or do we strictly adhere to the table which Shawn has listed. For sdhci-s3c driver, I would like to deviate from the "implication" column listed above. On second thoughts, I now understand that gpio's terminate at the gpio controller, not at the card-detect pad of the mmc host controller. Those that terminate at the mmc controller pads are actually mux functions. I do agree that the long term solution for sdhci-s3c driver is to use the pinctrl driver. If sdhci-s3c has to strictly adhere to the Shawn's table above, then I prefer to postpone the device tree support in sdhci-s3c driver after having proper support for Samsung pinctrl driver. But then, sdhci-s3c driver is used on multiple Samsung SoC's, all of which might not get pinctrl driver support anytime soon. Hence, for sdhci-s3c driver, 'broken-cd' and 'cd-gpios' bindings are sufficient, but sdhci-s3c driver should be free to use these bindings in a implementation specific way. Thanks, Thomas.