[alsa-devel] how to use mcbsp for i2s?

[Jarkko Nikula]

On Wed, Apr 1, 2009 at 9:29 PM, Ernesto Torres <skullmate at gmail.com> wrote:

> I'm currently working in adding an external codec to the beagleboard, so
> far
> the i2c control part is functional, now i want to use mcbsp3 to provide i2s
> transfers
>
> Is there any way to test the mcbsp to validate the connection?
>
> Also, I've done little modifications to the omap3beagle.c to change from
> mcbsp2 to mcbsp3, can someone validate this is correct?
>
> In:
> static int __init omap3beagle_soc_init(void)
>
> I changed to:
> *(unsigned int *)omap3beagle_dai.cpu_dai->private_data = 2; /* McBSP3 */
>
> It was:
> *(unsigned int *)omap3beagle_dai.cpu_dai->private_data = 1; /* McBSP2 */
>
> Is this correct? Or it should be changed in other places too?
>
> It is basically enough as well as setting correct DAI and clocking
configuration (if needed)
in omap3beagle_hw_params.

But by default McBSP1 and 3 which available in Beale pin header are muxed to
GPIO
so you need to mux those pins for McBSP by the bootloader and with
linux-omap
kernel multiplexing support.

I may have a hack patch somewhere... I'll try to find it and post it here
for reference.


Jarkko