On Tuesday 14 April 2009 11:20:16 Nikula Jarkko (Nokia-D/Helsinki) wrote: > On Tue, 14 Apr 2009 09:45:30 +0200 > > "Ujfalusi Peter (Nokia-D/Tampere)" <peter.ujfalusi@xxxxxxxxx> wrote: > > Use correct DSP_B mode configuration for omap-mcbsp. > > > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx> > > --- > > sound/soc/omap/omap-mcbsp.c | 2 +- > > 1 files changed, 1 insertions(+), 1 deletions(-) > > > > diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c > > index 9c09b94..4440bab 100644 > > --- a/sound/soc/omap/omap-mcbsp.c > > +++ b/sound/soc/omap/omap-mcbsp.c > > @@ -283,7 +283,7 @@ static int omap_mcbsp_dai_hw_params(struct > > snd_pcm_substream *substream, break; > > case SND_SOC_DAIFMT_DSP_B: > > regs->srgr2 |= FPER(wlen * channels - 1); > > - regs->srgr1 |= FWID(wlen * channels - 2); > > + regs->srgr1 |= FWID(0); > > break; > > } > > Grr, I have some practical problems with my Beagle refusing to mount my > SD card root but I give a test when I get it working. If you want to use the TWL codec to verify the DSP mode, than you will need to have the 4 channel support also. I'm planning to resend those as soon as this DSP_A/_B mode is settled. > > But I fear this change makes it into DSP_B with inverted FS polarity. > Register srgr1 defines the FS length and it's active low. I think this > will be correct if you switch the polarity in > omap_mcbsp_dai_set_dai_fmt. As I written in the introduction mail, one has to verify and pick the correct pair of DSP_A/_B mode and FS/clock polarity in order to have correct config... I think it is acceptable to assume, that whoever writes such a board file should have at least this level of understanding of the FS/bitclock and how the data is driven and how the data is sampled. Also I have provided sample configurations for the osk5912 board file - which is the only one at the moment using DSP mode on omap platform. > > At least defining pulse witdth with FWID(0) is more clear than FWID > (wlen * channels - 2) :-) I think this is the only way to implement the DSP_B mode correctly in omap- mcbsp. Again, you need to pick the correct FS/clock polarity, but that is kind of simple. > > > Jarkko -- Péter _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
