From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933626AbdBPVPf (ORCPT ); Thu, 16 Feb 2017 16:15:35 -0500 Received: from smtp.exceet.ch ([77.245.33.226]:39946 "EHLO smtp.exceet.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932975AbdBPVPc (ORCPT ); Thu, 16 Feb 2017 16:15:32 -0500 Subject: Re: [PATCH v3 0/3] input: pwm-beeper: add feature to set volume level To: David Lechner , Dmitry Torokhov References: <0e2dec4d-7550-9495-f12a-020391183304@exceet.de> <20170119213700.GC13542@dtor-ws> <43679b65-8710-4255-2006-8c47dd755497@lechnology.com> CC: , , , , , , , From: Frieder Schrempf Message-ID: Date: Thu, 16 Feb 2017 22:15:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <43679b65-8710-4255-2006-8c47dd755497@lechnology.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [94.216.237.169] X-TM-AS-Product-Ver: SMEX-11.0.0.4255-8.100.1062-22890.002 X-TM-AS-Result: No--10.971300-5.000000-31 X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello David, On 20.01.2017 20:11, David Lechner wrote: > On 01/19/2017 03:37 PM, Dmitry Torokhov wrote: >> On Thu, Jan 19, 2017 at 04:24:07PM +0100, Frieder Schrempf wrote: >>> Make the driver accept switching volume levels via sysfs. >>> This can be helpful if the beep/bell sound intensity needs >>> to be adapted to the environment of the device. >>> >>> The number of volume levels available and their values can >>> be specified via device tree (similar to pwm-backlight). >>> >>> The volume adjustment is done by changing the duty cycle of >>> the pwm signal. >> >> I wonder how this all will mesh up with beepers that have dedicated >> amplifiers (support is being added by David Lechner). > > This will work very well with it. I fact, it is a feature I would like > to have but I was not sure about a good way to implement it. Please Cc: > me on future revisions of this series and I will be glad to test it. I have just send v4. > > One thing that would be nice would be for a more generic way to change > the volume from userspace. Having a sysfs attribute on the platform > device will work, but it requires very specific knowledge from any > userspace program that wants to control the volume. Would it be possible > to add an alsa mixer volume control or something like that? An alsa mixer control for the pwm-beeper volume sounds nice, but unfortunately I have no idea how one would implement this, or if this is even possible. >