From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754893AbcDKPWC (ORCPT ); Mon, 11 Apr 2016 11:22:02 -0400 Received: from mail.kernel.org ([198.145.29.136]:55392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754039AbcDKPWA (ORCPT ); Mon, 11 Apr 2016 11:22:00 -0400 Date: Mon, 11 Apr 2016 10:21:54 -0500 From: Rob Herring To: Schrempf Frieder Cc: "dmitry.torokhov@gmail.com" , "pawel.moll@arm.com" , "ijc+devicetree@hellion.org.uk" , "galak@codeaurora.org" , "luis@debethencourt.com" , "linux-input@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/1] input: pwm-beeper: add feature to set volume via sysfs Message-ID: <20160411152154.GA9736@rob-hp-laptop> References: <1460044644-12419-1-git-send-email-frieder.schrempf@exceet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1460044644-12419-1-git-send-email-frieder.schrempf@exceet.de> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 07, 2016 at 03:58:40PM +0000, Schrempf Frieder wrote: > Make the driver accept different volume levels via sysfs. > This can be helpful if the beep/bell sound intensity needs > to be adapted to the environment of the device. It is preferred that bindings be a separate patch. Also, this is 2 independent features: the sysfs interface and DT properties. So that is probably 3 patches. Also, sysfs interfaces are supposed to be documented. > > The number of volume levels available and their values can > be specified via device tree (similar to pwm-backlight). > > This patch was tested with linux-imx 3.10.17 and was > applied to current mainline without any changes. You need to test with something not 3 years old... > > Signed-off-by: Frieder Schrempf > --- > .../devicetree/bindings/input/pwm-beeper.txt | 20 ++++ > drivers/input/misc/pwm-beeper.c | 109 ++++++++++++++++++- > 2 files changed, 126 insertions(+), 3 deletions(-) > > diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt > index be332ae..153cd3f 100644 > --- a/Documentation/devicetree/bindings/input/pwm-beeper.txt > +++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt > @@ -5,3 +5,23 @@ Registers a PWM device as beeper. > Required properties: > - compatible: should be "pwm-beeper" > - pwms: phandle to the physical PWM device > +- volume-levels: Array of distinct volume levels. These need to be in the > + range of 0 to 500, while 0 means 0% duty cycle (mute) and 500 means > + 50% duty cycle (max volume). Where does the scale of 0-500 come from? It is tenth of a percent? How many array entries? > + Please note that the actual volume of most beepers is highly > + non-linear, which means that low volume levels are probably somewhere > + in the range of 1 to 30 (0.1-3% duty cycle). > +- default-volume-level: the default volume level (index into the > + array defined by the "volume-levels" property) > + > +The volume level can be set via sysfs under /sys/class/input/inputX/volume. > +The maximum volume level index can be read from /sys/class/input/inputX/max_volume_level. > + > +Example: > + > + pwm-beeper { > + compatible = "pwm-beeper"; > + pwms = <&pwm4 0 5000>; > + volume-levels = <0 8 20 40 500>; > + default-volume-level = <4>; > + };