erosq: Switch to 32-bit PCM output, and do volume scaling in driver

Should improve audio output quality, especially at lower volumes.

Change-Id: I31c38f05fe4b554b092511f0fe7aaad9f346f6c5

4 files changed, 14 insertions, 12 deletions

diff --git a/firmware/drivers/audio/erosqlinux_codec.c b/firmware/drivers/audio/erosqlinux_codec.c
index b1c5aa0c4f..58104a61e6 100644
--- a/firmware/drivers/audio/erosqlinux_codec.c
+++ b/firmware/drivers/audio/erosqlinux_codec.c
@@ -169,6 +169,10 @@ void audiohw_set_frequency(int fsel)
     (void)fsel;
 }
 
+/* min/max for pcm volume */
+const int min_pcm = -430;
+const int max_pcm = 0;
+
 void audiohw_set_volume(int vol_l, int vol_r)
 {
     logf("hw vol %d %d", vol_l, vol_r);
@@ -179,7 +183,7 @@ void audiohw_set_volume(int vol_l, int vol_r)
     vol_r_hw = vol_r;
 
     if (lineout_inserted()) {
-        /* On the EROS Q/K hardware, line out is _very_ hot
+        /* On the EROS Q/K hardware, full scale line out is _very_ hot
            at ~5.8Vpp. As the hardware provides no way to reduce
            output gain, we have to back off on the PCM signal
            to avoid blowing out the signal.
@@ -190,10 +194,9 @@ void audiohw_set_volume(int vol_l, int vol_r)
         r = vol_r_hw;
     }
 
-    /* SW volume for <= 1.0 gain, HW at unity, < -740 == MUTE */
-    int sw_volume_l = l <= -740 ? PCM_MUTE_LEVEL : MIN(l, 0);
-    int sw_volume_r = r <= -740 ? PCM_MUTE_LEVEL : MIN(r, 0);
-    pcm_set_master_volume(sw_volume_l, sw_volume_r);
+    int sw_volume_l = l <= min_pcm ? min_pcm : MIN(l, max_pcm);
+    int sw_volume_r = r <= min_pcm ? min_pcm : MIN(r, max_pcm);
+    pcm_set_mixer_volume(sw_volume_l / 10, sw_volume_r / 10);
 }
 
 void audiohw_set_lineout_volume(int vol_l, int vol_r)
@@ -212,7 +215,7 @@ void audiohw_set_lineout_volume(int vol_l, int vol_r)
         r = vol_r_hw;
     }
 
-    int sw_volume_l = l <= -740 ? PCM_MUTE_LEVEL : MIN(l, 0);
-    int sw_volume_r = r <= -740 ? PCM_MUTE_LEVEL : MIN(r, 0);
-    pcm_set_master_volume(sw_volume_l, sw_volume_r);
+    int sw_volume_l = l <= min_pcm ? min_pcm : MIN(l, max_pcm);
+    int sw_volume_r = r <= min_pcm ? min_pcm : MIN(r, max_pcm);
+    pcm_set_mixer_volume(sw_volume_l / 10, sw_volume_r / 10);
 }
diff --git a/firmware/export/config/aigoerosq.h b/firmware/export/config/aigoerosq.h
index 6ae8ad049f..2d0f7a0cdf 100644
--- a/firmware/export/config/aigoerosq.h
+++ b/firmware/export/config/aigoerosq.h
@@ -36,8 +36,7 @@
 
 /* Audio codec */
 #define HAVE_EROSQ_LINUX_CODEC
-/* Rockbox has to handle the volume level */
-#define HAVE_SW_VOLUME_CONTROL
+#define HAVE_ALSA_32BIT
 
 /* We don't have hardware controls */
 #define HAVE_SW_TONE_CONTROLS
diff --git a/firmware/export/erosqlinux_codec.h b/firmware/export/erosqlinux_codec.h
index 1dd9b7e6c6..c337bb78c7 100644
--- a/firmware/export/erosqlinux_codec.h
+++ b/firmware/export/erosqlinux_codec.h
@@ -3,7 +3,7 @@
 
 #define AUDIOHW_CAPS (LINEOUT_CAP)
 
-AUDIOHW_SETTING(VOLUME, "dB", 0,  1, -74,   6, -25)
+AUDIOHW_SETTING(VOLUME, "dB", 0,  1, -43, 0, -20)
 
 //#define AUDIOHW_NEEDS_INITIAL_UNMUTE
 
diff --git a/firmware/target/hosted/pcm-alsa.c b/firmware/target/hosted/pcm-alsa.c
index 16f82bad5c..81c0a19a45 100644
--- a/firmware/target/hosted/pcm-alsa.c
+++ b/firmware/target/hosted/pcm-alsa.c
@@ -277,7 +277,7 @@ static int dig_vol_mult_r = 2 << 16; /* multiplicative factor to apply to each s
 void pcm_set_mixer_volume(int vol_db_l, int vol_db_r)
 {
     if(vol_db_l > 0 || vol_db_r > 0 || vol_db_l < -43 || vol_db_r < -43)
-        panicf("invalid pcm alsa volume");
+        panicf("invalid pcm alsa volume %d %d",   vol_db_l, vol_db_r);
     if(format != SND_PCM_FORMAT_S32_LE)
         panicf("this function assumes 32-bit sample size");
     vol_db_l += 48; /* -42dB .. 0dB => 5dB .. 48dB */