hal: Add volume control for pcm playback

Add stream specific volume control for pcm playback.
Used for Low latency and Deep buffer cases.

Change-Id: I0f9721f91a7926ab2c99de84e9bf9333ff0bd91d
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index 9ebe142..6df3f23 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -90,6 +90,7 @@
 #define DIRECT_PCM_NUM_FRAGMENTS 2
 #define COMPRESS_PLAYBACK_VOLUME_MAX 0x2000
 #define VOIP_PLAYBACK_VOLUME_MAX 0x2000
+#define PCM_PLAYBACK_VOLUME_MAX 0x2000
 #define DSD_VOLUME_MIN_DB (-110)
 
 #define PROXY_OPEN_RETRY_COUNT           100
@@ -443,6 +444,7 @@
 static int check_a2dp_restore_l(struct audio_device *adev, struct stream_out *out, bool restore);
 static int out_set_compr_volume(struct audio_stream_out *stream, float left, float right);
 static int out_set_voip_volume(struct audio_stream_out *stream, float left, float right);
+static int out_set_pcm_volume(struct audio_stream_out *stream, float left, float right);
 
 static bool may_use_noirq_mode(struct audio_device *adev, audio_usecase_t uc_id,
                                int flags __unused)
@@ -3094,6 +3096,8 @@
         // apply volume for voip playback after path is set up
         if (out->usecase == USECASE_AUDIO_PLAYBACK_VOIP)
             out_set_voip_volume(&out->stream, out->volume_l, out->volume_r);
+        else if ((out->usecase == USECASE_AUDIO_PLAYBACK_LOW_LATENCY || out->usecase == USECASE_AUDIO_PLAYBACK_DEEP_BUFFER))
+            out_set_pcm_volume(&out->stream, out->volume_l, out->volume_r);
     } else {
         platform_set_stream_channel_map(adev->platform, out->channel_mask,
                    out->pcm_device_id, &out->channel_map_param.channel_map[0]);
@@ -4150,6 +4154,33 @@
     return 0;
 }
 
+static int out_set_pcm_volume(struct audio_stream_out *stream, float left,
+                              float right)
+{
+    struct stream_out *out = (struct stream_out *)stream;
+    /* Volume control for pcm playback */
+    if (left != right) {
+        return -EINVAL;
+    } else {
+        char mixer_ctl_name [128];
+        struct audio_device *adev = out->dev;
+        struct mixer_ctl *ctl;
+        int pcm_device_id = platform_get_pcm_device_id(out->usecase, PCM_PLAYBACK);
+        snprintf(mixer_ctl_name, sizeof(mixer_ctl_name), "Playback %d Volume", pcm_device_id);
+        ctl = mixer_get_ctl_by_name(adev->mixer, mixer_ctl_name);
+        if (!ctl) {
+            ALOGE("%s : Could not get ctl for mixer cmd - %s", __func__, mixer_ctl_name);
+            return -EINVAL;
+        }
+        int volume = (int) (left * PCM_PLAYBACK_VOLUME_MAX);
+        mixer_ctl_set_value(ctl, 0, volume);
+
+        ALOGV("%s : Pcm set volume value %d", __func__, volume);
+
+        return 0;
+    }
+}
+
 static int out_set_volume(struct audio_stream_out *stream, float left,
                           float right)
 {
@@ -4199,6 +4230,13 @@
         out->volume_l = left;
         out->volume_r = right;
         return ret;
+    } else {
+        /* Volume control for pcm playback */
+        if (!out->standby)
+            ret = out_set_pcm_volume(stream, left, right);
+        out->volume_l = left;
+        out->volume_r = right;
+        return ret;
     }
 
     return -ENOSYS;