[alsa-devel] [PATCH 2/3] ASoC: omap-mcbsp: change the DSP_B mode to DSP_A mode

[Peter Ujfalusi]

On Thursday 09 April 2009 13:00:14 Nikula Jarkko (Nokia-D/Helsinki) wrote:
> On Thu, 9 Apr 2009 11:34:41 +0200
>
> "Ujfalusi Peter (Nokia-D/Tampere)" <peter.ujfalusi at nokia.com> wrote:
> > -	case SND_SOC_DAIFMT_DSP_B:
> > +	case SND_SOC_DAIFMT_DSP_A:
> >  		/* 0-bit data delay */
> >  		regs->rcr2      |= RDATDLY(0);
> >  		regs->xcr2      |= XDATDLY(0);
> > --
>
> Are you absolutely sure on this? According to WM9713, it's the DSP_A
> where MSB is valid after 1 bit clock period of the FS.

I think this is correct. The data is going to be valid exactly the same way, 
as the WM9713 data sheet describes.

As for the DSP_B mode: I think it can be implemented like this:
Invert the frame sync polarity, Then:
	case SND_SOC_DAIFMT_DSP_B:
		regs->srgr2	|= FPER(wlen * channels - 1);
		regs->srgr1	|= FWID(0); /* FS pulse width is 1 */
		break;

So the MSB will be in the correct place.

-- 
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