bcm2835-analog-audio: Is my driver PWM, ALSA or neither

Stefan Wahren stefan.wahren at i2se.com
Sun Mar 12 10:36:38 PDT 2017

> Michael Zoran <mzoran at crowfest.net> hat am 12. März 2017 um 11:37 geschrieben:
> I have submitted to ALSA a driver that uses the PWM hardware of the
> Raspbery PI(bcm2835) as an audio driver.
> http://mailman.alsa-project.org/pipermail/alsa-devel/2017-March/118652.
> html
> The driver is currently mutually exclusive with the standard PWM
> driver, mostly because the standard PWM interface is not adequate to
> have an audio driver written on top of it.  
> But as I think more, I see no reason the user needs to chose at boot
> time if they want traditional PWM or AUDIO. So I'm thinking of some how
> combining the two drivers.
> My question:
> 1. Is my driver a PWM driver that exposes an ALSA interface in additon
> to PWM?
> 2. Is my driver a ALSA driver that also exposes PWM.
> 3. Could my driver potentially go under misc or something new and
> expose both a PWM and ALSA interface.
> 4. Perhaps I should have both a PWM driver and a ALSA driver that both
> talk through a totally new but very small driver that controls access
> to the PWM hardware.  How would the function drivers get loaded in this
> case?

Sorry, i'm not a sound expert. But this sounds like a multi-function device driver (mfd) to me.

AFAIK this doesn't provide solution for your dynamic usage problem.

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