From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [RFC v2 1/2] sdhci: Add device tree property broken-highspeed Date: Thu, 13 Oct 2016 11:27:23 +0900 Message-ID: <3a259c3a-6b5e-2464-8402-488b13f03730@samsung.com> References: <1476297656-7019-1-git-send-email-zach.brown@ni.com> <1476297656-7019-2-git-send-email-zach.brown@ni.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <1476297656-7019-2-git-send-email-zach.brown@ni.com> Sender: linux-kernel-owner@vger.kernel.org To: Zach Brown , ulf.hansson@linaro.org Cc: adrian.hunter@intel.com, robh+dt@kernel.org, mark.rutland@arm.com, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org On 10/13/2016 03:40 AM, Zach Brown wrote: > Certain board configurations can make highspeed malfuction due to timing > issues. In these cases a way is needed to force the controller and card > into standard speed even if they otherwise appear to be capable of > highspeed. I'm not sure "broken-hishspeed" property is relevant to only sdhci driver? otherwise on card side..? Subject looks like only sdhci driver..And your RFC patch should be supported only SDHCI driver. But your [patch 1/2] can cause the confusing in future..because there are just comment as "controller". Then developer who refer to mmc.txt will add the property "broken-highspeed". I'm not sure what is correct way..but to prevent confusing..you mentioned only "sdhci" driver or supporting other controller. Best Regards, Jaehoon Chung > > The broken-highspeed property will let the sdhci driver know that > highspeed will not work. > > Signed-off-by: Zach Brown > --- > Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt > index 8a37782..a2b298c 100644 > --- a/Documentation/devicetree/bindings/mmc/mmc.txt > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt > @@ -52,6 +52,8 @@ Optional properties: > - no-sdio: controller is limited to send sdio cmd during initialization > - no-sd: controller is limited to send sd cmd during initialization > - no-mmc: controller is limited to send mmc cmd during initialization > +- broken-highspeed: Highspeed is broken, even if the controller and card > + themselves claim they support highspeed. > > *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line > polarity properties, we have to fix the meaning of the "normal" and "inverted" >