ASoC: ti: davinci-i2s: Add TDM support

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 channels_max is updated from 2 to 128.

This was tested with BP_FC format on a platform designed off of
DAVINCI/OMAP_L138. A check is done in davinci_i2s_set_dai_fmt() to
prevent TDM to be used with BC_FC and BC_FP formats.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://msgid.link/r/20240402071213.11671-8-bastien.curutchet@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/ti/davinci-i2s.c b/sound/soc/ti/davinci-i2s.c
index a2c7c812ea5080e09d427c620edbd19e99725584..f9a67c2bc2f553aedc706527e6f6e298be38d1d9 100644 (file)
--- 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 +216,63 @@ 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, "slots %d, slot_width %d\n", slots, slot_width);
+
+       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;
+       }
+
+       if (tx_mask != (1 << slots) - 1) {
+               dev_err(dev->dev, "Invalid TX mask (0x%08x) : all slots must be used by McBSP\n",
+                       tx_mask);
+               return -EINVAL;
+       }
+
+       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,
@@ -238,6 +298,11 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
                        DAVINCI_MCBSP_PCR_CLKRM;
                break;
        case SND_SOC_DAIFMT_BC_FP:
+               if (dev->tdm_slots || dev->slot_width) {
+                       dev_err(dev->dev, "TDM is not supported for BC_FP format\n");
+                       return -EINVAL;
+               }
+
                /*
                 * McBSP CLKR pin is the input for the Sample Rate Generator.
                 * McBSP FSR and FSX are driven by the Sample Rate Generator.
@@ -246,6 +311,11 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
                pcr |= DAVINCI_MCBSP_PCR_SCLKME;
                break;
        case SND_SOC_DAIFMT_BC_FC:
+               if (dev->tdm_slots || dev->slot_width) {
+                       dev_err(dev->dev, "TDM is not supported for BC_FC format\n");
+                       return -EINVAL;
+               }
+
                /* codec is master */
                pcr = 0;
                break;
@@ -383,7 +453,13 @@ 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 +559,13 @@ 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:
@@ -609,19 +690,20 @@ 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,
 
 };
 
 static struct snd_soc_dai_driver davinci_i2s_dai = {
        .playback = {
                .channels_min = 2,
-               .channels_max = 2,
+               .channels_max = 128,
                .rates = DAVINCI_I2S_RATES,
                .formats = DAVINCI_I2S_FORMATS,
        },
        .capture = {
                .channels_min = 2,
-               .channels_max = 2,
+               .channels_max = 128,
                .rates = DAVINCI_I2S_RATES,
                .formats = DAVINCI_I2S_FORMATS,
        },