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);
+
+ 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 (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;
+ }
+
/* 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,
},
--
2.43.2
