From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Sat, 23 Aug 2014 11:52:04 +0200 From: dante To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> In-Reply-To: References: Message-ID: <4da1f6793b81ec9012a55b338fc20a0a@posteo.de> User-Agent: Posteo Webmail Subject: Re: [9fans] PWM and audio drivers for Raspberry Pi Topicbox-Message-UUID: 12169416-ead9-11e9-9d60-3106f5b1d025 Hi Pedro, That's super-cool, thanks! Please consider submitting the patch through the right channels. Since I'm new here, I am not sure if this is correct, but here is what I found out: 1. as a patch(1) to the contributors. No idea if geoff or jmk are still working there: http://plan9.bell-labs.com/wiki/plan9/How_to_contribute/ 2. ask David du Colombier to accept and publish your patch: http://www.9legacy.org Cheers, Dante On 23.08.2014 11:32, Pedro Coutin wrote: > 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.