Re: [PATCH] Input: pwm-beeper: support customized freq for SND_BELL

Dmitry Torokhov
2017-02-14T04:27:55Z

On Wed, Feb 08, 2017 at 10:11:21AM +0000, Jonas Mark (ST-FIR/ENG1) wrote:
> Hello Dmitry,
>
> > > extend the pwm-beeper driver to support customized frequency
> > > for SND_BELL from device tree.
> >
> > No, SND_BELL is literally SND_TONE @1000Hz. There should be no
> > customizing. If applications want to use different frequency then should
> > be using SND_TONE.
>
> We are not aiming for an application shortcut here. Instead, changing
> the bell frequency shall be a system setting. That is, every
> application which wants to make a bell sound shall use the alternative
> frequency.
>
> The reason why we are deviating from the default 1000 Hz is that on
> our hardware we are using a loudspeaker which is rated for 2.7 kHz.
> That is, it will only sound at the specified volume and frequency if
> you feed it with a 2.7 kHz square wave. If you deviate from it, e.g.
> by using 1000 Hz, the output will be dim and squeaky. Worst case,
> SND_BELL would be completely silent on our system. So the only bell
> sound we can reliably generate on our system has 2.7 kHz.

OK, fair enough. Please address Rob's comments on binding and resend.

Also I am not sure why you needed to change the switch statement around,
you only need to replace 1000 with value from the attribute.

Oh, and please use device_property_*() API instead of of_*().

Thanks.

--
Dmitry