On Wed, Mar 4, 2009 at 9:17 PM, Daniel Mack <daniel@xxxxxxxx> wrote:
> This patch uses the SSP's PSP functionality to provide I2S timings. The
> particular problem is that even though the datasheets state it should be
> possbible, there is no mode which uses the network feature with its
> associated time slots in a sane way to do what we need.
>
> Hence, in order to have full 64 bit I2S on the wire, we need to fiddle
> around with the SSP and the timing paramters a lot. There are some
> constants left in the code which can't be replaced by names because the
> true meaning of their registers remains nebulous.
>
> Signed-off-by: Daniel Mack <daniel@xxxxxxxx>
> Signed-off-by: Tim Ruetz <tim@xxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
> Cc: Liam Girdwood <lrg@xxxxxxxxxx>
> Cc: Philipp Zabel <philipp.zabel@xxxxxxxxx>
> ---
> sound/soc/pxa/pxa-ssp.c | 39 +++++++++++++++++++++------------------
> 1 files changed, 21 insertions(+), 18 deletions(-)
>
> diff --git a/sound/soc/pxa/pxa-ssp.c b/sound/soc/pxa/pxa-ssp.c
> index 45fb600..97f11d6 100644
> --- a/sound/soc/pxa/pxa-ssp.c
> +++ b/sound/soc/pxa/pxa-ssp.c
> @@ -319,6 +319,7 @@ static int pxa_ssp_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
> break;
> case PXA_SSP_CLK_EXT:
> priv->sysclk = freq;
> + ssp_set_scr(&priv->dev, 4);
Shouldn't this be somehow set by set_dai_clkdiv instead?
> sscr0 |= SSCR0_ECS;
> break;
> case PXA_SSP_CLK_NET:
> @@ -551,17 +552,13 @@ static int pxa_ssp_set_dai_fmt(struct snd_soc_dai *cpu_dai,
>
> switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
> case SND_SOC_DAIFMT_I2S:
> - sscr0 |= SSCR0_MOD | SSCR0_PSP;
> + sscr0 |= SSCR0_PSP;
> sscr1 |= SSCR1_RWOT | SSCR1_TRAIL;
>
> switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
> case SND_SOC_DAIFMT_NB_NF:
> - sspsp |= SSPSP_FSRT;
> break;
> case SND_SOC_DAIFMT_NB_IF:
> - sspsp |= SSPSP_SFRMP | SSPSP_FSRT;
> - break;
> - case SND_SOC_DAIFMT_IB_IF:
> sspsp |= SSPSP_SFRMP;
> break;
Removal of SSPSP_FSRT from NB/IB selection seems to be correct from the docs.
Can you check if IB could be properly handled by setting SCMODE(1)?
> default:
> @@ -652,33 +649,39 @@ static int pxa_ssp_hw_params(struct snd_pcm_substream *substream,
> break;
> case SNDRV_PCM_FORMAT_S24_LE:
> sscr0 |= (SSCR0_EDSS | SSCR0_DataSize(8));
> - /* we must be in network mode (2 slots) for 24 bit stereo */
This is still dubious ...
S24_LE is 24-bit sound LSB-aligned in 32-bit frames, so DataSize
should be 32 here.
> break;
> case SNDRV_PCM_FORMAT_S32_LE:
> sscr0 |= (SSCR0_EDSS | SSCR0_DataSize(16));
> - /* we must be in network mode (2 slots) for 32 bit stereo */
How is it possible to send 64bit in one frame otherwise?
> break;
> }
> ssp_write_reg(ssp, SSCR0, sscr0);
>
> switch (priv->dai_fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
> case SND_SOC_DAIFMT_I2S:
> - /* Cleared when the DAI format is set */
> - sspsp = ssp_read_reg(ssp, SSPSP) | SSPSP_SFRMWDTH(width);
> + sspsp = ssp_read_reg(ssp, SSPSP);
> +
> + switch (priv->dai_fmt & SND_SOC_DAIFMT_FRAME_FORMAT_MASK) {
> + case SND_SOC_DAIFMT_FF_I2S_32:
> + /* These values are all found out by trying and
> + * failing a lot. PXA's SSP is all black magic and
> + * does not work like described in any datasheet.
> + */
> + sspsp |= SSPSP_SFRMWDTH(32);
> + sspsp |= SSPSP_SFRMDLY(32 * 2);
> + sspsp |= SSPSP_EDMYSTOP(3);
> + sspsp |= SSPSP_DMYSTOP(3);
> + sspsp |= SSPSP_DMYSTRT(1);
Wha?! Amazing. And this really works?
How the hell can this result in 16 bits of data followed by 16 bits of
zeroes, twice :)
> + break;
> + default:
> + /* Cleared when the DAI format is set */
> + sspsp |= SSPSP_SFRMWDTH(width);
Not good for DSP_A/B.
> + break;
> + }
> ssp_write_reg(ssp, SSPSP, sspsp);
> - break;
> default:
> break;
> }
>
> - /* We always use a network mode so we always require TDM slots
> - * - complain loudly and fail if they've not been set up yet.
> - */
> - if (!(ssp_read_reg(ssp, SSTSA) & 0xf)) {
> - dev_err(&ssp->pdev->dev, "No TDM timeslot configured\n");
> - return -EINVAL;
> - }
> -
> dump_registers(ssp);
>
> return 0;
> --
> 1.6.1.3
>
>
regards
Philipp
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