[alsa-devel] [PATCH 1/2] ASoC: omap-mcbsp: Correct the DSP_B mode

[Arun KS]

Hi,

I m not able to use my osk5912 to test this.
When i do an aplay with the latest kernel (linux-2.6.30-rc1) i am
getting an me i/o error.

Thanks,
Arun

On Tue, Apr 14, 2009 at 4:50 PM, Jarkko Nikula <jarkko.nikula at nokia.com> wrote:
> On Tue, 14 Apr 2009 12:34:33 +0200
> "Ujfalusi Peter (Nokia-D/Tampere)" <peter.ujfalusi at nokia.com> wrote:
>
>> Well, I think the mcbsp module is quite - maybe too - flexible...
>> To have the DSP_B mode correctly (for the tvl320aic32 codec used in osk5912 board) the FS polarity has to be handled by the mcbsp as it has been inverted. If we don't do this, there is no way to have the MSB at the correct place (it has to be available when the FS is high).
>>
>>
>> The DSP_A mode can use the FS polarity 'correctly' - as it is. Or we can also consider to require to invert the FS polarity, than add 1 bit delay for DSP_A mode.
>>
> I meant something like this below integrating your FWID(0) and temp_fmt from my earlier commit da6320becf31c40b60d4b1dc6b339c9a766b671c so that SND_SOC_DAIFMT_DSP_B | SND_SOC_DAIFMT_NB_NF will produce correct format.
>
> I tested this only with Beagle McBSP3 and oscilloscope but I like to verify it with real codecs as well :-)
>
>
> Jarkko
>
> diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
> index d6882be..c40ea21 100644
> --- a/sound/soc/omap/omap-mcbsp.c
> +++ b/sound/soc/omap/omap-mcbsp.c
> @@ -272,7 +272,7 @@ 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;
>        }
>
> @@ -291,6 +291,7 @@ static int omap_mcbsp_dai_set_dai_fmt(struct snd_soc_dai *cpu_dai,
>  {
>        struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
>        struct omap_mcbsp_reg_cfg *regs = &mcbsp_data->regs;
> +       unsigned int temp_fmt = fmt;
>
>        if (mcbsp_data->configured)
>                return 0;
> @@ -317,6 +318,8 @@ static int omap_mcbsp_dai_set_dai_fmt(struct snd_soc_dai *cpu_dai,
>                /* 0-bit data delay */
>                regs->rcr2      |= RDATDLY(0);
>                regs->xcr2      |= XDATDLY(0);
> +               /* Invert bit clock and FS polarity configuration */
> +               temp_fmt ^= SND_SOC_DAIFMT_IB_IF;
>                break;
>        default:
>                /* Unsupported data format */
> @@ -340,7 +343,7 @@ static int omap_mcbsp_dai_set_dai_fmt(struct snd_soc_dai *cpu_dai,
>        }
>
>        /* Set bit clock (CLKX/CLKR) and FS polarities */
> -       switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
> +       switch (temp_fmt & SND_SOC_DAIFMT_INV_MASK) {
>        case SND_SOC_DAIFMT_NB_NF:
>                /*
>                 * Normal BCLK + FS.
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