From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [PATCH 6/7] pinctrl: tegra: Add DT binding for io pads control Date: Fri, 15 Apr 2016 22:01:52 +0530 Message-ID: <57111778.5030500@nvidia.com> References: <1460473007-11535-1-git-send-email-ldewangan@nvidia.com> <1460473007-11535-7-git-send-email-ldewangan@nvidia.com> <5711183F.1090003@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5711183F.1090003@wwwdotorg.org> Sender: linux-kernel-owner@vger.kernel.org To: Stephen Warren Cc: thierry.reding@gmail.com, linus.walleij@linaro.org, gnurou@gmail.com, robh+dt@kernel.org, mark.rutland@arm.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On Friday 15 April 2016 10:05 PM, Stephen Warren wrote: > On 04/12/2016 08:56 AM, Laxman Dewangan wrote: >> NVIDIA Tegra210 supports the IO pads which can operate at 1.8V >> or 3.3V I/O voltage levels. Also IO pads can be configured for >> power down state if it is not in used. SW needs to configure the >> voltage level of IO pads based on IO rail voltage and its power >> state based on platform usage. >> >> Add DT binding document for detailing the DT properties for >> configuring IO pads voltage levels and its power state. > > I hope that we only intend to use this in the case where Linux must > make dynamic changes to the IO voltage (e.g. SD cards switching > between speeds). > > All static settings, and good boot defaults, should be set up by > system FW. Perhaps not all FW does this on Tegra210 platforms:-( I > hope that on future chips, the same FW that sets up the static pinmux > sets up the static IO voltage configuration, in exactly the same way. Exactly yes.