[alsa-devel] Digital Audio Multiplexer of the i.MX27 processor

Juergen Beisert jbe at pengutronix.de
Wed May 28 10:42:53 CEST 2008


On Wednesday 28 May 2008 01:03, Peter Wurmsdobler wrote:
> > does anybody understand the DAM unit in the i.MX27 processor?
> Not that I really understand the AUDMUX unit, but the current Freescale
> BSP (19 Dec 2007) contains an audio/alsa driver which makes use of the
> AUDMUX, or DAM, in order to route audio streams to/from the mx27's SSI1
> and SSI2 to the PMIC's SSIs. PMIC is a the power management and audio
> chip which is on the ADS board. Unfortunately I do not have the file
> with me, it is called ./sound/arm/mxc-pmic-alsa.c I believe.
> I will be back in office next week, maybe we can have a chat then, if it
> is not too late.

Yes, I know this file. And I'm using the code from this file to setup my DAM 
hardware. But I'm not sure if I connect the right ports in the right way to 
each other. My external PMIC is connected to the processor's SSI1_* pins. And 
it provides i2s clock and frame signal. But the internal SSI unit does not 
send any data, so I believe it does not get these signals from the PMIC.

BTW: The last instruction in the DAM code in sound/arm/mxc-pmic-alsa.c is:
but the last valid register in the DAM unit is at AUDMUX_BASE_ADDR + 0x1C....

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