iBasso DX50: Digital filter roll off setting.

This patch enables "Settings -> Sound Settings -> DAC's filter roll-off" for the
iBasso DX50.

Confirmed working on iBasso DX50, firmware 1.6.

Change-Id: I901615541d8fa4f6550c5156cf8c6069f5bdf9d0

firmware/target/hosted/ibasso/dx50/audiohw-dx50.c

@@ -66,3 +66,14 @@ void audiohw_set_volume(int volume)
         DEBUGF("ERROR %s: Can not set volume.", __func__);
     }
 }
+
+
+void audiohw_set_filter_roll_off(int val)
+{
+    DEBUGF("DEBUG %s: val: %d", __func__, val);
+
+    if(! sysfs_set_char(SYSFS_ES9018_FILTER, (char) val))
+    {
+        DEBUGF("ERROR %s: Can not set roll off filter.", __func__);
+    }
+}

firmware/target/hosted/ibasso/dx50/codec-dx50.h

@@ -26,7 +26,7 @@
 #define _CODEC_DX50_H_
 
 
-#define AUDIOHW_CAPS MONO_VOL_CAP
+#define AUDIOHW_CAPS (MONO_VOL_CAP | FILTER_ROLL_OFF_CAP)
 
 
 /*
@@ -48,4 +48,8 @@
 AUDIOHW_SETTING(VOLUME, "dB", 0, 1, -128, 0, -30)
 
 
+/* 1: slow roll off, 0: sharp roll off, sharp roll off default */
+AUDIOHW_SETTING(FILTER_ROLL_OFF, "", 0, 1, 0, 1, 0)
+
+
 #endif

firmware/target/hosted/ibasso/sysfs-ibasso.c

@@ -43,6 +43,9 @@ static const char* SYSFS_PATHS[] =
     /* SYSFS_DX90_ES9018_VOLUME */
     "/sys/class/codec/es9018_volume",
 
+    /* SYSFS_ES9018_FILTER */
+    "/sys/class/codec/es9018_filter",
+
     /* SYSFS_MUTE */
     "/sys/class/codec/mute",
 
@@ -280,6 +283,7 @@ bool sysfs_set_char(enum sys_fs_interface_id id, char value)
     {
         case SYSFS_MUTE:
         case SYSFS_WM8740_MUTE:
+        case SYSFS_ES9018_FILTER:
         {
             break;
         }

firmware/target/hosted/ibasso/sysfs-ibasso.h

@@ -38,6 +38,7 @@ enum sys_fs_interface_id
     SYSFS_DX50_CODEC_VOLUME = 0,
     SYSFS_HOLDKEY,
     SYSFS_DX90_ES9018_VOLUME,
+    SYSFS_ES9018_FILTER,
     SYSFS_MUTE,
     SYSFS_WM8740_MUTE,
     SYSFS_BATTERY_CAPACITY,