From: David Lechner <david@lechnology.com>
To: Frieder Schrempf <frieder.schrempf@exceet.de>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: robh@kernel.org, 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 v3 0/3] input: pwm-beeper: add feature to set volume level
Date: Thu, 16 Feb 2017 15:44:01 -0600 [thread overview]
Message-ID: <5fc04e9d-7a92-2a34-e9cc-679106481e32@lechnology.com> (raw)
In-Reply-To: <fddaa3de-81a3-1078-65ac-29503419f1e6@exceet.de>
On 02/16/2017 03:15 PM, Frieder Schrempf wrote:
> 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.
>>
I know it is possible because I have done it. ;-)
https://github.com/ev3dev/lego-linux-drivers/blob/master/evb/evb_sound.c
The driver in the link above does PCM playback using PWM. But, it also
included an input device similar to pwm-beeper and it includes an ALSA
volume control specifically for the beeper.
next prev parent reply other threads:[~2017-02-16 21:44 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-07 15:58 [PATCH 1/1] input: pwm-beeper: add feature to set volume via sysfs Schrempf Frieder
2016-04-11 15:21 ` Rob Herring
2016-10-07 9:00 ` Schrempf Frieder
2016-10-07 9:08 ` [PATCH v2 0/3] input: pwm-beeper: add feature to set volume level Schrempf Frieder
2016-10-07 9:08 ` [PATCH v2 1/3] input: pwm-beeper: add feature to set volume via sysfs Schrempf Frieder
2016-10-07 9:08 ` [PATCH v2 2/3] input: pwm-beeper: add documentation for volume devicetree bindings Schrempf Frieder
2016-10-10 15:20 ` Rob Herring
2016-10-11 8:17 ` Schrempf Frieder
2016-10-11 13:39 ` Rob Herring
2017-01-19 14:40 ` Frieder Schrempf
2017-01-19 15:24 ` [PATCH v3 0/3] input: pwm-beeper: add feature to set volume level Frieder Schrempf
2017-01-19 15:24 ` [PATCH v3 1/3] input: pwm-beeper: add feature to set volume via sysfs Frieder Schrempf
2017-01-19 21:29 ` Dmitry Torokhov
2017-02-16 20:37 ` Frieder Schrempf
2017-01-19 15:24 ` [PATCH v3 2/3] input: pwm-beeper: add documentation for volume devicetree bindings Frieder Schrempf
2017-01-23 14:40 ` Rob Herring
2017-01-19 15:24 ` [PATCH v3 3/3] input: pwm-beeper: add devicetree bindings to set volume levels Frieder Schrempf
2017-01-19 21:30 ` Dmitry Torokhov
2017-02-16 20:40 ` Frieder Schrempf
2017-01-19 21:37 ` [PATCH v3 0/3] input: pwm-beeper: add feature to set volume level Dmitry Torokhov
2017-01-20 19:11 ` David Lechner
2017-02-16 21:15 ` Frieder Schrempf
2017-02-16 21:44 ` David Lechner [this message]
2017-02-17 10:01 ` Frieder Schrempf
2017-02-16 21:08 ` [PATCH v4 " Frieder Schrempf
2017-02-16 21:08 ` [PATCH v4 1/3] input: pwm-beeper: add feature to set volume via sysfs Frieder Schrempf
2017-02-16 21:08 ` [PATCH v4 2/3] input: pwm-beeper: add documentation for volume devicetree bindings Frieder Schrempf
2017-02-16 21:08 ` [PATCH v4 3/3] input: pwm-beeper: add devicetree bindings to set volume levels Frieder Schrempf
2017-02-16 23:07 ` kbuild test robot
2017-02-17 0:14 ` kbuild test robot
2017-02-17 9:54 ` [PATCH v5 0/3] input: pwm-beeper: add feature to set volume level Frieder Schrempf
2017-02-17 9:54 ` [PATCH v5 1/3] input: pwm-beeper: add feature to set volume via sysfs Frieder Schrempf
2017-02-17 9:54 ` [PATCH v5 2/3] input: pwm-beeper: add documentation for volume devicetree bindings Frieder Schrempf
2017-02-17 9:54 ` [PATCH v5 3/3] input: pwm-beeper: add devicetree bindings to set volume levels Frieder Schrempf
2016-10-07 9:08 ` [PATCH v2 " Schrempf Frieder
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