On Mon, Oct 20, 2008 at 3:02 PM, Mark Brown <broonie@xxxxxxxxxxxxx> wrote: > On Mon, Oct 20, 2008 at 02:51:04PM +0200, John Kacur wrote: >> On Mon, Oct 20, 2008 at 2:40 PM, Mark Brown <broonie@xxxxxxxxxxxxx> wrote: > >> >> There is however no sound card, thus no PCM device. Now the question >> >> is how to proceed? In other words what kind of minimal PCM layer do I >> >> need if any? > >> > Could you please clarify what you're attempting to do here? > >> On a simple level, I'm just trying to provide sound, by implementing >> an alsa driver. I've implemented a low-level library that can >> manipulate all my hardware's i2s registers, and I've been mirroring >> other alsa-soc drivers, and I'm at the point where I'm scratching my >> head over what to do about PCM. The confusion to me, is that the code >> seems to describe actually hardware - and the only thing I can think >> of it what my hardware i2s is capable of transmitting, does that sound >> right? > > I think you've misunderstood how this is supposed to work. None of the > drivers for I2S or DMA controllers are responsible for creating a sound > card by themselves. They provide support for the features of the I2S > or DMA controller but then rely on a separate machine driver to describe > how they are actually connected into the system. > > There's some documentation of the model that's being used here in: > > Documentation/sound/alsa/soc > > In your case you'll want to implement I2S and DMA drivers for your > platform and a codec driver for the MAX5556 (looking at the datasheet it > has no control of its own but you'll need to provide a DAI for it) and > then provide a machine driver which connects them together. > I've surely misunderstood a thing or two without question. :) However, I have read all of the documentation in Documentation/sound/alsa/soc, and more than once. And I've been reading the code for the ASoC drivers as well, and have been trying to emulate it, especially, the code in sound/soc/s3c24xx and sound/soc/pxa (as well as davinci at first until I realized that it was incomplete) ...but I'm still scratching my head when I look at files like sound/soc/s3c24xx/s3c24xx-pcm.c It appears to be part of the DAI that connects the i2s driver and codec together? So, back to my current source of confusion, do I need to implement some basic kind of pcm driver for my scenario? Thank again for taking the time to answer all my somewhat confused questions. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
