feat(audio): discover stream mute and volume controls

Inspect each associated Feature Unit during mount, cache master mute support and the common MIN, MAX, and RES volume range, and ignore units with neither control. Add typed asynchronous and synchronous mute and volume APIs and demonstrate them in the host example.

Signed-off-by: HiFiPHile <[email protected]>

1 files changed, 47 insertions, 26 deletions

diff --git a/examples/host/audio_host/src/audio_app.c b/examples/host/audio_host/src/audio_app.c
index 3102c28c9..9a1434284 100644
--- a/examples/host/audio_host/src/audio_app.c
+++ b/examples/host/audio_host/src/audio_app.c
@@ -28,11 +28,10 @@
 // - AUDIO_MAX_FRAME_COUNT: buffer holds up to 48 frames (1 ms of 48 kHz)
 // - AUDIO_MAX_CHANNELS: maximum channels of the capture/playback stream
 // - SAMPLE_RATES: sample rates tried in order, first match wins (44.1 kHz stereo by default)
-#define AUDIO_MAX_FRAME_COUNT 48
-#define AUDIO_MAX_CHANNELS    2
-#define SAMPLE_RATES          {48000, 44100}
-// UAC1 volume values are signed 1/256 dB; 0x0600 selects +6 dB.
-#define FEATURE_UNIT_VOLUME 0x0600
+#define AUDIO_MAX_FRAME_COUNT  48
+#define AUDIO_MAX_CHANNELS     2
+#define SAMPLE_RATES           {48000, 44100}
+#define FEATURE_UNIT_VOLUME_DB (-6 * 256)
 static uint8_t                   audio_idx      = TUSB_INDEX_INVALID_8; // index of the selected audio device
 static uint8_t                   cap_stream_idx = TUSB_INDEX_INVALID_8; // capture stream index
 static uint8_t                   spk_stream_idx = TUSB_INDEX_INVALID_8; // playback stream index
@@ -255,17 +254,6 @@ void led_blinking_task(void) {
   err_cb_count = 0;
 
 #endif
-#if 0
-  // Print the current Feature Unit volume, which is set to 0x0600 in mic_configured() and can be changed by the device.
-  uint16_t volume = 0x0001;
-  tuh_audio_feature_unit_get_sync(audio_idx, cap_stream_idx, AUDIO10_FU_CTRL_VOLUME, 0, &volume);
-  printf("  Feature Unit volume get: 0x%04x\r\n", (unsigned int)volume);
-  uint16_t mute = 0x0000;
-  tuh_audio_feature_unit_get_sync(audio_idx, cap_stream_idx, AUDIO10_FU_CTRL_MUTE, 0, &mute);
-  mute=!mute; // toggle mute for demonstration
-  tuh_audio_feature_unit_set_sync(audio_idx, cap_stream_idx, AUDIO10_FU_CTRL_MUTE, 0, mute);
-  printf("  Feature Unit mute set: 0x%04x\r\n", (unsigned int)mute);
-#endif
 }
 
 //--------------------------------------------------------------------+
@@ -377,6 +365,14 @@ static void print_stream_configs(uint8_t idx, uint8_t stream_idx) {
   const uint8_t               feature_unit_id = tuh_audio_get_feature_unit_id(idx, stream_idx);
   printf("  %s stream %u Feature Unit ID: %u, configurations: %u\r\n", dir_name, stream_idx, feature_unit_id,
          tuh_audio_config_count(idx, stream_idx));
+  tuh_audio_volume_range_t range;
+  if (tuh_audio_mute_supported(idx, stream_idx)) {
+    printf("    master mute supported\r\n");
+  }
+  if (tuh_audio_volume_range_get(idx, stream_idx, &range)) {
+    printf("    master volume range: min=%d max=%d res=%u (1/256 dB)\r\n", (int)range.min, (int)range.max,
+           (unsigned)range.res);
+  }
   for (uint8_t i = 0; i < tuh_audio_config_count(idx, stream_idx); i++) {
     tuh_audio_stream_config_t config;
     if (tuh_audio_config_get(idx, stream_idx, i, &config)) {
@@ -386,19 +382,44 @@ static void print_stream_configs(uint8_t idx, uint8_t stream_idx) {
   }
 }
 
-static void set_stream_volume(uint8_t idx, uint8_t stream_idx, const char *stream_name) {
+static void configure_stream_controls(uint8_t idx, uint8_t stream_idx, const char *stream_name) {
   const uint8_t feature_unit_id = tuh_audio_get_feature_unit_id(idx, stream_idx);
   if (feature_unit_id == 0) {
-    printf("  %s stream has no Feature Unit\r\n", stream_name);
+    printf("  %s stream has no master mute/volume Feature Unit\r\n", stream_name);
     return;
   }
 
-  uint16_t           volume = FEATURE_UNIT_VOLUME;
-  tusb_xfer_result_t result = tuh_audio_feature_unit_set_sync(idx, stream_idx, AUDIO10_FU_CTRL_VOLUME, 0, volume);
-  if (result == XFER_RESULT_SUCCESS) {
-    printf("  %s Feature Unit %u master volume set: 0x%04x\r\n", stream_name, feature_unit_id, (unsigned int)volume);
-  } else {
-    printf("  Setting %s Feature Unit %u volume failed: result=%u\r\n", stream_name, feature_unit_id, result);
+  if (tuh_audio_mute_supported(idx, stream_idx)) {
+    bool               mute;
+    tusb_xfer_result_t result = tuh_audio_mute_get_sync(idx, stream_idx, &mute);
+    if (result == XFER_RESULT_SUCCESS) {
+      printf("  %s Feature Unit %u master mute: %s\r\n", stream_name, feature_unit_id, mute ? "on" : "off");
+      result = tuh_audio_mute_set_sync(idx, stream_idx, false);
+    }
+    if (result != XFER_RESULT_SUCCESS) {
+      printf("  Accessing %s master mute failed: result=%u\r\n", stream_name, result);
+    }
+  }
+
+  tuh_audio_volume_range_t range;
+  if (tuh_audio_volume_range_get(idx, stream_idx, &range)) {
+    int16_t            volume;
+    tusb_xfer_result_t result = tuh_audio_volume_get_sync(idx, stream_idx, &volume);
+    if (result == XFER_RESULT_SUCCESS) {
+      printf("  %s Feature Unit %u master volume: %d (1/256 dB)\r\n", stream_name, feature_unit_id, volume);
+      int32_t target = FEATURE_UNIT_VOLUME_DB;
+      target         = TU_MAX(target, range.min);
+      target         = TU_MIN(target, range.max);
+      target         = range.min + ((target - range.min + range.res / 2) / range.res) * range.res;
+      target         = TU_MIN(target, range.max);
+      result         = tuh_audio_volume_set_sync(idx, stream_idx, (int16_t)target);
+      if (result == XFER_RESULT_SUCCESS) {
+        printf("  %s master volume set: %d (1/256 dB)\r\n", stream_name, (int)target);
+      }
+    }
+    if (result != XFER_RESULT_SUCCESS) {
+      printf("  Accessing %s master volume failed: result=%u\r\n", stream_name, result);
+    }
   }
 }
 
@@ -462,7 +483,7 @@ static void tuh_audio_mount_async(uintptr_t param) {
             // one ms of audio at the selected rate, rounded down to whole frames
             audio_frame_count = sample_rate / 1000;
             printf("  Microphone configured\r\n");
-            set_stream_volume(idx, stream_idx, "Microphone");
+            configure_stream_controls(idx, stream_idx, "Microphone");
             mic_ready     = tuh_audio_start(idx, stream_idx);
             capture_found = true;
             break;
@@ -519,7 +540,7 @@ static void tuh_audio_mount_async(uintptr_t param) {
   // playback-only device: set the frame cadence from the selected rate
   audio_frame_count = spk_config.sample_rate / 1000;
   sine_phase        = 0;
-  set_stream_volume(idx, spk_stream_idx, "Speaker");
+  configure_stream_controls(idx, spk_stream_idx, "Speaker");
 
   if (capture_found) {
     // Start in the mic-only phase without briefly activating playback first.