On Thursday 09 April 2009 13:16:55 Ujfalusi Peter (Nokia-D/Tampere) wrote:
> 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@xxxxxxxxx> 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.
BTW: I have draw it to paper the following to verified these:
1) how mcbsp would operate with the osk5912 config (as it was):
snd_soc_dai_set_fmt(codec_dai,
SND_SOC_DAIFMT_DSP_B |
SND_SOC_DAIFMT_NB_IF |
SND_SOC_DAIFMT_CBM_CFM);
Than after the change:
2) how mcbsp would operate with the osk5912 config (my proposal):
err = snd_soc_dai_set_fmt(codec_dai,
snd_soc_dai_set_fmt(codec_dai,
SND_SOC_DAIFMT_DSP_A |
SND_SOC_DAIFMT_IB_IF |
SND_SOC_DAIFMT_CBM_CFM);
3) how mcbsp would operate with the omap3beagle 4 channel mode:
fmt = SND_SOC_DAIFMT_DSP_A |
SND_SOC_DAIFMT_IB_NF |
SND_SOC_DAIFMT_CBM_CFM;
Than I compared these drawings to the pictures in the data sheets
(tlv320aic32, twl4030):
1) Does not match at all
2) 100% match
3) 100% match
I think if the osk5912 wants to use the codec with DSP_B mode it should have:
snd_soc_dai_set_fmt(codec_dai,
SND_SOC_DAIFMT_DSP_B |
SND_SOC_DAIFMT_NB_IF |
SND_SOC_DAIFMT_CBM_CFM);
Than in omap-mcbsp:
case SND_SOC_DAIFMT_DSP_B:
regs->srgr2 |= FPER(wlen * channels - 1);
regs->srgr1 |= FWID(0); /* FS pulse width is 1 */
break;
Than it would have been correct, I think. Probably I should send the DSP_B
support also in the series?
--
Péter
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
