On 15/03/2024 13:27, Bastien Curutchet wrote:
> TDM is not supported by the McBSP driver. The McBSP datasheet does not
> name explicitly TDM as a supported format but it is possible to configure
> the McBSP to do TDM if all slots are used by McBSP.
>
> Add TDM support. It uses single-phase frame. Slot width is used to
> compute the McBSP's word length.
>
> Implement the set_tdm_slot() hook of snd_soc_dai_ops struct. It only
> supports TDM if all slots are used by McBSP.
>
> The snd_soc_dai_driver's capture.channels_max is updated from 2 to 128.
> 128 is the maximum frame length when using single-phase frame.
> playback.channels_max has not been updated as I could not test TDM on
> playbacks with my hardware.
>
> This was tested on platform designed off of DAVINCI/OMAP_L138 with BP_FC
> format so this is only supported format for TDM yet. A check is done in
> davinci_i2s_set_dai_fmt() to prevent TDM to be used with other formats
>
> Signed-off-by: Bastien Curutchet <bastien.curutchet@xxxxxxxxxxx>
> ---
> sound/soc/ti/davinci-i2s.c | 81 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 77 insertions(+), 4 deletions(-)
>
> diff --git a/sound/soc/ti/davinci-i2s.c b/sound/soc/ti/davinci-i2s.c
> index f4514d4dff07..4adaed010700 100644
> --- a/sound/soc/ti/davinci-i2s.c
> +++ b/sound/soc/ti/davinci-i2s.c
> @@ -160,6 +160,9 @@ struct davinci_mcbsp_dev {
> unsigned int fmt;
> int clk_div;
> bool i2s_accurate_sck;
> +
> + int tdm_slots;
> + int slot_width;
> };
>
> static inline void davinci_mcbsp_write_reg(struct davinci_mcbsp_dev *dev,
> @@ -213,6 +216,57 @@ static void davinci_mcbsp_stop(struct davinci_mcbsp_dev *dev, int playback)
> toggle_clock(dev, playback);
> }
>
> +static int davinci_i2s_tdm_word_length(int tdm_slot_width)
> +{
> + switch (tdm_slot_width) {
> + case 8:
> + return DAVINCI_MCBSP_WORD_8;
> + case 12:
> + return DAVINCI_MCBSP_WORD_12;
> + case 16:
> + return DAVINCI_MCBSP_WORD_16;
> + case 20:
> + return DAVINCI_MCBSP_WORD_20;
> + case 24:
> + return DAVINCI_MCBSP_WORD_24;
> + case 32:
> + return DAVINCI_MCBSP_WORD_32;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int davinci_i2s_set_tdm_slot(struct snd_soc_dai *cpu_dai,
> + unsigned int tx_mask,
> + unsigned int rx_mask,
> + int slots, int slot_width)
> +{
> + struct davinci_mcbsp_dev *dev = snd_soc_dai_get_drvdata(cpu_dai);
> +
> + dev_dbg(dev->dev, "%s - slots %d, slot_width %d\n", __func__, slots, slot_width);
The __func__ can be ommited, it is better to leave it for dynamic
debugging by adding "dyndbg=+pmf" module parameter if needed.
> +
> + if (slots > 128 || !slots) {
> + dev_err(dev->dev, "Invalid number of slots\n");
> + return -EINVAL;
> + }
> +
> + if (rx_mask != (1 << slots) - 1) {
> + dev_err(dev->dev, "Invalid RX mask (0x%08x) : all slots must be used by McBSP\n",
> + rx_mask);
> + return -EINVAL;
This is only a restriction for RX?
> + }
> +
> + if (davinci_i2s_tdm_word_length(slot_width) < 0) {
> + dev_err(dev->dev, "%s: Unsupported slot_width %d\n", __func__, slot_width);
> + return -EINVAL;
> + }
> +
> + dev->tdm_slots = slots;
> + dev->slot_width = slot_width;
> +
> + return 0;
> +}
> +
> #define DEFAULT_BITPERSAMPLE 16
>
> static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
> @@ -228,6 +282,13 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
> DAVINCI_MCBSP_SRGR_FWID(DEFAULT_BITPERSAMPLE - 1);
>
> dev->fmt = fmt;
> +
> + if ((dev->tdm_slots || dev->slot_width) &&
> + ((fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) != SND_SOC_DAIFMT_BP_FC)) {
> + dev_err(dev->dev, "TDM is only supported for BP_FC format\n");
> + return -EINVAL;
I think this is not a valid statement, Fsync can be generated internally
or coming from external source in TDM mode also.
> + }
> +
> /* set master/slave audio interface */
> switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
> case SND_SOC_DAIFMT_BP_FP:
> @@ -383,7 +444,13 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
>
> master = dev->fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK;
> fmt = params_format(params);
> - mcbsp_word_length = asp_word_length[fmt];
> + if (dev->slot_width)
> + mcbsp_word_length = davinci_i2s_tdm_word_length(dev->slot_width);
> + else
> + mcbsp_word_length = asp_word_length[fmt];
> +
> + if (mcbsp_word_length < 0)
> + return mcbsp_word_length;
>
> switch (master) {
> case SND_SOC_DAIFMT_BP_FP:
> @@ -483,8 +550,13 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
> switch (master) {
> case SND_SOC_DAIFMT_BP_FP:
> case SND_SOC_DAIFMT_BP_FC:
> - rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(0);
> - xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(0);
> + if (dev->tdm_slots > 0) {
> + rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(dev->tdm_slots - 1);
> + xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(dev->tdm_slots - 1);
> + } else {
> + rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(0);
> + xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(0);
> + }
> break;
> case SND_SOC_DAIFMT_BC_FC:
> case SND_SOC_DAIFMT_BC_FP:
> @@ -609,6 +681,7 @@ static const struct snd_soc_dai_ops davinci_i2s_dai_ops = {
> .hw_params = davinci_i2s_hw_params,
> .set_fmt = davinci_i2s_set_dai_fmt,
> .set_clkdiv = davinci_i2s_dai_set_clkdiv,
> + .set_tdm_slot = davinci_i2s_set_tdm_slot,
>
> };
>
> @@ -621,7 +694,7 @@ static struct snd_soc_dai_driver davinci_i2s_dai = {
> },
> .capture = {
> .channels_min = 2,
> - .channels_max = 2,
> + .channels_max = 128,
> .rates = DAVINCI_I2S_RATES,
> .formats = DAVINCI_I2S_FORMATS,
> },
--
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