Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755307AbbGPM6Q (ORCPT ); Thu, 16 Jul 2015 08:58:16 -0400 Received: from mail-oi0-f52.google.com ([209.85.218.52]:36461 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755190AbbGPM6O (ORCPT ); Thu, 16 Jul 2015 08:58:14 -0400 MIME-Version: 1.0 In-Reply-To: <1435855992-10312-1-git-send-email-vaibhav.hiremath@linaro.org> References: <1435855992-10312-1-git-send-email-vaibhav.hiremath@linaro.org> Date: Thu, 16 Jul 2015 14:58:13 +0200 Message-ID: Subject: Re: [RFC PATCH] pinctrl-single: Use of pinctrl-single for external device over I2C From: Linus Walleij To: Vaibhav Hiremath 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" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1067 Lines: 26 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. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/