From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937496AbdAFRp3 (ORCPT ); Fri, 6 Jan 2017 12:45:29 -0500 Received: from vern.gendns.com ([206.190.152.46]:59043 "EHLO vern.gendns.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752579AbdAFRpT (ORCPT ); Fri, 6 Jan 2017 12:45:19 -0500 Subject: Re: [PATCH 3/3] Input: pwm-beeper: add optional enable gpio To: Andy Shevchenko References: <1483670635-25060-1-git-send-email-david@lechnology.com> <1483670635-25060-4-git-send-email-david@lechnology.com> Cc: Dmitry Torokhov , Rob Herring , Mark Rutland , linux-input , devicetree , "linux-kernel@vger.kernel.org" From: David Lechner Message-ID: <79167ff5-64c2-c753-6341-beef32d3bb54@lechnology.com> Date: Fri, 6 Jan 2017 11:45:15 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06/2017 11:28 AM, Andy Shevchenko wrote: > On Fri, Jan 6, 2017 at 4:43 AM, David Lechner wrote: >> This adds an optional enable gpio to the pwm-beeper device. This gpio is >> used in cases where the beeper needs to be switched on before using it. > > Isn't it a property of pin muxing? You may want to turn if off when not making a sound to save power. > >> For >> example, there may be an amplifier that is not always powered on. > > This looks like GPIO based fixed voltage regulator. Yes, I think a regulator could work here just as well. > >> >> Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through >> an amplifier. The amplifier has an enable pin that is connected to a gpio. >