On 5/7/26 5:51 AM, Srinivas Kandagatla wrote:
On 5/6/26 8:33 PM, Val Packett wrote:
Add support for TDM RX DAIs which are used on some devices to send audio
data to speaker amplifiers. Channels are assigned based on the codec
DAI names for a quad-speaker setup such as on the xiaomi-pipa tablet.
Signed-off-by: Val Packett <[email protected]>
---
sound/soc/qcom/sm8250.c | 141 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 141 insertions(+)
diff --git a/sound/soc/qcom/sm8250.c b/sound/soc/qcom/sm8250.c
index a675913da943..b64fd3970ba1 100644
--- a/sound/soc/qcom/sm8250.c
+++ b/sound/soc/qcom/sm8250.c
@@ -17,6 +17,10 @@
#include "sdw.h"
#define MI2S_BCLK_RATE 1536000
+#define TDM_BCLK_RATE 6144000
+#define NUM_TDM_SLOTS 8
+
+static unsigned int tdm_slot_offset[8] = {0, 4, 8, 12, 16, 20, 24, 28};
static const ?
ack
struct sm8250_snd_data {
bool stream_prepared[AFE_PORT_MAX];
@@ -55,6 +59,89 @@ static void sm8250_snd_exit(struct snd_soc_pcm_runtime *rtd)
}
+static int sm8250_tdm_snd_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params)
+{
+ struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
+ struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0);
+ struct snd_soc_dai *codec_dai;
+ unsigned int rx_mask;
+ int ret = 0, j;
+ int channels, slot_width;
+
+ switch (params_format(params)) {
+ case SNDRV_PCM_FORMAT_S16_LE:
+ slot_width = 16;
+ break;
Any reason only S16?
The entire driver is "locked" to S16 since 89be3c15a58b ("ASoC: qcom:
sm8250: explicitly set format in sm8250_be_hw_params_fixup()"). Which
was due to compressed playback, according to that commit message.. But
in reality there's also hardcoded MI2S_BCLK_RATE (so I did the same
thing for TDM for now).
I cooould try unhardcoding that, but this kind of thing is really
annoying to test with the whole combinatorial explosion of parameters x_x
+ default:
+ dev_err(rtd->dev, "%s: invalid param format 0x%x\n",
+ __func__, params_format(params));
+ return -EINVAL;
+ }
+
+ channels = params_channels(params);
+
+ if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+ ret = snd_soc_dai_set_tdm_slot(cpu_dai, 0, 0x3,
Please define the magic constants like 0x3 here.
+ 8, slot_width);
+ if (ret < 0) {
+ dev_err(rtd->dev, "%s: failed to set tdm slot,
err:%d\n",
+ __func__, ret);
+ goto end;
+ }
+
+ ret = snd_soc_dai_set_channel_map(cpu_dai, 0, NULL,
+ channels, tdm_slot_offset);
+ if (ret < 0) {
+ dev_err(rtd->dev, "%s: failed to set channel map,
err:%d\n",
+ __func__, ret);
+ goto end;
+ }
+ } else {
+ ret = snd_soc_dai_set_tdm_slot(cpu_dai, 0xf, 0,
+ 8, slot_width);
+ if (ret < 0) {
+ dev_err(rtd->dev, "%s: failed to set tdm slot,
err:%d\n",
+ __func__, ret);
+ goto end;
+ }
+
+ ret = snd_soc_dai_set_channel_map(cpu_dai, channels,
+ tdm_slot_offset, 0, NULL);
+ if (ret < 0) {
+ dev_err(rtd->dev, "%s: failed to set channel map,
err:%d\n",
+ __func__, ret);
+ goto end;
+ }
+ }
+
+ for_each_rtd_codec_dais(rtd, j, codec_dai) {
+ if (strstr(codec_dai->component->name_prefix, "PL")) {
name prefix can be null.
ack
+ rx_mask = BIT(0);
+ } else if (strstr(codec_dai->component->name_prefix, "PR")) {
name prefix comparision is fragile design, this will break very soon.
and this is not a binding too.
Right, but how would one even define a binding when this is supposed to
be(?) part of the sndcard and the prefixes themselves are set on codecs'
own nodes..?
I just copied what's been done for sdm845 so far, even though it doesn't
seem great to me either.
This also raises question about the using this generic driver for such
specific combination. Can these be made specific to compatible ?
Yeah, sure. I don't think we'll see other combinations in practice
though, for 2 channels regular I2S is used, the only reason for TDM is
to have 4 channels. Or more but I don't think any device has more than
4. (And surely no one has 3..)
+ rx_mask = BIT(1);
+ } else if (strstr(codec_dai->component->name_prefix, "SL")) {
+ rx_mask = BIT(2);
+ } else if (strstr(codec_dai->component->name_prefix, "SR")) {
+ rx_mask = BIT(3);
+ } else {
+ rx_mask = 0;
+ dev_warn(rtd->dev, "%s: codec DAI name '%s' not
recognized\n",
+ __func__, codec_dai->component->name_prefix);
+ }
+ ret = snd_soc_dai_set_tdm_slot(codec_dai, 0, rx_mask,
+ NUM_TDM_SLOTS, slot_width);
+ if (ret < 0) {
Can we handle -ENOSUPP?
By not erroring out here? Yeah
[..]
Thanks,
~val
