From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vaibhav Hiremath Subject: Re: [RFC PATCH] pinctrl-single: Use of pinctrl-single for external device over I2C Date: Thu, 16 Jul 2015 19:46:03 +0530 Message-ID: <55A7BCA3.2010607@linaro.org> References: <1435855992-10312-1-git-send-email-vaibhav.hiremath@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org To: Linus Walleij Cc: "linux-arm-kernel@lists.infradead.org" , Rob Herring , Lee Jones , Will Deacon , Tony Lindgren , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Thursday 16 July 2015 06:28 PM, Linus Walleij wrote: > On Thu, Jul 2, 2015 at 6:53 PM, Vaibhav Hiremath > wrote: > >> In some usecases, the external device (in my case it PMIC over I2C) >> does support pin in multiple configuration, we may need to control/configure them >> during boot or runtime. > > What is missing from this patch is an explanation why pinctrl-single should > be used for this PMIC. > > Repeat: pinctrl-single: when you have exactly one register per pin, and > the description of the pins is delivered in an opaque ASIC-specific format > without developers knowing much about how the hardware actually works, > just "set these magic values". > > I strongly prefer that this PMIC has its own pin controller using standard > bindings with groups and functions, see eg. drivers/pinctrl/nomadik/pinctrl-ab* > for a PMIC pinctrl driver. > Thanks for the reference, good to know this. Let me check this driver before commenting anything further on this. Thanks, Vaibhav > Yours, > Linus Walleij >