From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939767AbcKNWPN (ORCPT ); Mon, 14 Nov 2016 17:15:13 -0500 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:48814 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933656AbcKNWPL (ORCPT ); Mon, 14 Nov 2016 17:15:11 -0500 User-Agent: K-9 Mail for Android In-Reply-To: References: <1478846078-22207-1-git-send-email-eraretuya@gmail.com> <1478846078-22207-2-git-send-email-eraretuya@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [PATCH 1/2] staging: iio: ad7606: replace range/range_available with corresponding scale From: Jonathan Cameron Date: Mon, 14 Nov 2016 22:15:04 +0000 To: Lars-Peter Clausen , Linus Walleij , Jonathan Cameron CC: Eva Rachel Retuya , "linux-iio@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Michael Hennerich , Hartmut Knaack , Peter Meerwald , Greg KH Message-ID: <0F7D932A-3232-4F33-9F46-98789442D721@jic23.retrosnub.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14 November 2016 18:53:28 GMT+00:00, Lars-Peter Clausen wrote: >On 11/14/2016 05:58 PM, Linus Walleij wrote: >> On Sat, Nov 12, 2016 at 3:24 PM, Jonathan Cameron >wrote: >> >>> Is it just me who thought, we need a fixed GPI like a fixed >regulator? Probably didn't help clarity that I described it as an input pin whereas it's kind of like having an output pin whose state you can't change... >>> Would allow this sort of fixed wiring to be simply defined. >>> >>> Linus, worth exploring? >> >> So if fixed regulator is for a voltage provider, this would be >> pretty much the inverse: deciding for a voltage range by switching >> a GPIO. > >It's about figuring out the setting of a "GPIO" that can't be changed >from >software. > >Devices sometimes, instead of a configuration bus like I2C or SPI, use >simple input pins, that can either be set to high or low, to allow >software >the state of the device. The GPIO API is typically used to configure >these pins. > >This works fine as long as the pin is connected to a GPIO. But >sometimes the >system designer decides that a settings does not need to be >configurable, in >this case the pin will be tied to logic low or high directly on the PCB >without any GPIO controller being involved. > >Sometimes a driver wants to know how the pin is wired up so it can >report to >userspace this part runs in the following mode and the mode can't be >changed. In a sense it is like a reverse GPIO hog. > >Considering that this is a common usecase the question was how this can >be >implemented in a driver independent way to avoid code duplication and >slightly different variations of what is effectively the same DT/ACPI >binding. > >E.g. lets say for a configurable pin you use > > range-gpio = <&gpio ...>; > >and for a static pin > > range-gpio-fixed = <1>; > >Or something similar. > >-- >To unsubscribe from this list: send the line "unsubscribe linux-iio" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html -- Sent from my Android device with K-9 Mail. Please excuse my brevity.