From: Pedro Coutin <pedroleandroc@gmail.com>
To: 9fans@9fans.net
Subject: [9fans] PWM and audio drivers for Raspberry Pi
Date: Sat, 23 Aug 2014 02:32:00 -0700 [thread overview]
Message-ID: <CA+wNSKZ6NM7u85wf1+c0EX8POsu=MPVFVg9GNWZGCpX433V8mg@mail.gmail.com> (raw)
Hello everyone,
I made a working audio driver for the Raspberry Pi by using the chipset's
PWM device directly.
The sound quality seems pretty acceptable to me. I managed to play music
and the Doom port from 9front with it.
Since it uses the PWM device, it only works for the TRS stereo jack. I
believe that the most sensible way to make HDMI audio work is to
make a VCHI(Q) driver, and then an audio driver that interfaces with
that. There's very little, if any, documentation available on this and
the Linux kernel code for it is pretty huge.
Tarball with changed files:
http://acsweb.ucsd.edu/~pcoutin/bcm-audio.tgz
Repository:
https://bitbucket.com/pcoutin/9pi-audio
Man page for PWM device:
http://acsweb.ucsd.edu/~pcoutin/bcmpwm.html
I guess I could extend the PWM driver so that the two channels can be
enabled/disabled separately.
next reply other threads:[~2014-08-23 9:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-23 9:32 Pedro Coutin [this message]
2014-08-23 9:52 ` dante
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