linux-kernel - Re: [PATCH 3/3] Input: pwm-beeper: add optional enable gpio

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Message-ID: <79167ff5-64c2-c753-6341-beef32d3bb54@lechnology.com>
Date:   Fri, 6 Jan 2017 11:45:15 -0600
From:   David Lechner <david@...hnology.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-input <linux-input@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] Input: pwm-beeper: add optional enable gpio

On 01/06/2017 11:28 AM, Andy Shevchenko wrote:
> On Fri, Jan 6, 2017 at 4:43 AM, David Lechner <david@...hnology.com> 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.
>