From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laxman Dewangan Subject: Re: [PATCH 7/7] pinctrl: tegra: Add driver to configure voltage and power state of io pads Date: Fri, 15 Apr 2016 17:17:46 +0530 Message-ID: <5710D4E2.2030801@nvidia.com> References: <1460473007-11535-1-git-send-email-ldewangan@nvidia.com> <1460473007-11535-8-git-send-email-ldewangan@nvidia.com> <5710A8A4.90309@nvidia.com> <5710BA75.2010503@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linus Walleij Cc: Stephen Warren , Thierry Reding , Alexandre Courbot , Rob Herring , Mark Rutland , Jon Hunter , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-gpio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-gpio@vger.kernel.org On Friday 15 April 2016 04:45 PM, Linus Walleij wrote: > On Fri, Apr 15, 2016 at 11:55 AM, Laxman Dewangan wrote: >> On Friday 15 April 2016 02:55 PM, Linus Walleij wrote: >>> If the pin could actually set a voltage level it would have a regulator. >>> I don't believe that. I think it is selecting one of two rails which >>> could theoretically hold two totally different voltages. >>> >>> And that is what power-source is about. >> The IO rails connected to PMIC rail and connection does not get change. >> We change the voltage of PMIC rails via regulator calls. And then configure >> pads for the new voltage. > Aha I get it! So you adjust something in the I/O-cell so that it is adapted > for the new voltage. > > OK that seems to be something new. I suspect > power-voltage-select = ; where N i in uV would solve this? > (We should use uV since regulators use this.) Thanks for new property. I will make the unit and type same as the regulator framework. > > But to be sure we would like to know what is actually happening, > electronically speaking, when you set this up. Do you have any > idea? > From electronic point of view, the value of VIL, VIH, VOL, VOH (Input/output voltage level for low and high state) are different when talking for 0 t 1.8V and 0 to 3.3V.