[alsa-devel] [PATCH 1/6] ASoC: OMAP mcbsp: Add DSP_A support

Peter Ujfalusi peter.ujfalusi at nokia.com
Mon Apr 6 14:37:58 CEST 2009

On Monday 06 April 2009 15:22:33 ext Mark Brown wrote:
> On Mon, Apr 06, 2009 at 03:19:27PM +0300, Peter Ujfalusi wrote:
> > Add SND_SOC_DAIFMT_DSP_A support for omap-mcbsp.
> > The configuration for DSP_A and DSP_B is the same.
> That doesn't sound right - the two formats do differ on the wire.  In
> mode B the MSB of data is transmitted along with the LRC pulse while in
> mode A it is transmitted after the trailing edge of the LRC pulse.

That is why I have asked previously about these... I'm still a bit confused, 
but at the end (I think) the configuration in omap-mcbsp is right for the 
regs->srgr2	|= FPER(wlen * channels - 1);
regs->srgr1	|= FWID(wlen * channels - 2);
/* 0-bit data delay */
regs->rcr2      |= RDATDLY(0);
regs->xcr2      |= XDATDLY(0);

I'll revisit this.


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