iBasso DX50/DX90: User selectable freq scaling governor.

Depends on http://gerrit.rockbox.org/r/#/c/1043/.

This patch adds a new setting in Settings -> General
-> System: Freq Scaling Governor

Usable in Quickscreen and Shortcuts.

Possible settings are:
- Conservative: Slow frequency switching.
- Ondemand or Interactive: Fast frequency switching.
- Powersave: Allways lowest frequency.
- Performance: Allways highest frequency.

German translation provided.

This may be genric for Android kernel based devices but is only enabled
for iBasso Devices. Other maintainers may choose do adopt this.

Change-Id: I10296f5be9586ad3a409105db0cd03682a30e9c1

4 files changed, 146 insertions, 3 deletions

diff --git a/firmware/SOURCES b/firmware/SOURCES
index a67f866dcc..1bb8563f24 100644
--- a/firmware/SOURCES
+++ b/firmware/SOURCES
@@ -1841,6 +1841,7 @@ target/hosted/ibasso/button-ibasso.c
 #ifdef DEBUG
 target/hosted/ibasso/debug-ibasso.c
 #endif
+target/hosted/ibasso/governor-ibasso.c
 target/hosted/ibasso/hostfs-ibasso.c
 target/hosted/ibasso/lcd-ibasso.c
 target/hosted/ibasso/pcm-ibasso.c
diff --git a/firmware/target/hosted/ibasso/governor-ibasso.c b/firmware/target/hosted/ibasso/governor-ibasso.c
new file mode 100644
index 0000000000..b2d3cdf336
--- /dev/null
+++ b/firmware/target/hosted/ibasso/governor-ibasso.c
@@ -0,0 +1,90 @@
+/***************************************************************************
+ *             __________               __   ___
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Copyright (C) 2014 by Ilia Sergachev: Initial Rockbox port to iBasso DX50
+ * Copyright (C) 2014 by Mario Basister: iBasso DX90 port
+ * Copyright (C) 2014 by Simon Rothen: Initial Rockbox repository submission, additional features
+ * Copyright (C) 2014 by Udo Schläpfer: Code clean up, additional features
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+
+#include <stdio.h>
+
+#include "config.h"
+#include "cpufreq-linux.h"
+#include "debug.h"
+
+#include "debug-ibasso.h"
+#include "governor-ibasso.h"
+#include "sysfs-ibasso.h"
+
+
+/* Default governor at boot. */
+static int _last_governor = GOVERNOR_INTERACTIVE;
+
+
+void ibasso_set_governor(int governor)
+{
+    DEBUGF("DEBUG %s: _last_governor: %d, governor: %d.", __func__, _last_governor, governor);
+
+    if(_last_governor != governor)
+    {
+        switch(governor)
+        {
+            case GOVERNOR_CONSERVATIVE:
+            {
+                _last_governor = governor;
+                cpufreq_set_governor("conservative", CPUFREQ_ALL_CPUS);
+                break;
+            }
+
+            case GOVERNOR_ONDEMAND:
+            {
+                _last_governor = governor;
+                cpufreq_set_governor("ondemand", CPUFREQ_ALL_CPUS);
+                break;
+            }
+
+            case GOVERNOR_POWERSAVE:
+            {
+                _last_governor = governor;
+                cpufreq_set_governor("powersave", CPUFREQ_ALL_CPUS);
+                break;
+            }
+
+            case GOVERNOR_INTERACTIVE:
+            {
+                _last_governor = governor;
+                cpufreq_set_governor("interactive", CPUFREQ_ALL_CPUS);
+                break;
+            }
+
+            case GOVERNOR_PERFORMANCE:
+            {
+                _last_governor = governor;
+                cpufreq_set_governor("performance", CPUFREQ_ALL_CPUS);
+                break;
+            }
+
+            default:
+            {
+                DEBUGF("ERROR %s: Unknown governor: %d.", __func__, governor);
+                break;
+            }
+        }
+    }
+}
diff --git a/firmware/target/hosted/ibasso/governor-ibasso.h b/firmware/target/hosted/ibasso/governor-ibasso.h
new file mode 100644
index 0000000000..34781fde0b
--- /dev/null
+++ b/firmware/target/hosted/ibasso/governor-ibasso.h
@@ -0,0 +1,54 @@
+/***************************************************************************
+ *             __________               __   ___
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Copyright (C) 2014 by Ilia Sergachev: Initial Rockbox port to iBasso DX50
+ * Copyright (C) 2014 by Mario Basister: iBasso DX90 port
+ * Copyright (C) 2014 by Simon Rothen: Initial Rockbox repository submission, additional features
+ * Copyright (C) 2014 by Udo Schläpfer: Code clean up, additional features
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+
+#ifndef _GOVERNOR_IBASSO_H_
+#define _GOVERNOR_IBASSO_H_
+
+
+/* Supported freq scaling governors. */
+enum ibasso_governors
+{
+    /* Slow frequency switching. */
+    GOVERNOR_CONSERVATIVE = 0,
+
+    /* Fast frequency switching. */
+    GOVERNOR_ONDEMAND,
+    GOVERNOR_INTERACTIVE,
+
+    /* Allways lowest frequency. */
+    GOVERNOR_POWERSAVE,
+
+    /* Allways highest frequency. */
+    GOVERNOR_PERFORMANCE
+};
+
+
+/*
+    Set the active freq scaling governor.
+    governor: ibasso_governors
+*/
+void ibasso_set_governor(int governor);
+
+
+#endif
diff --git a/firmware/target/hosted/ibasso/system-ibasso.c b/firmware/target/hosted/ibasso/system-ibasso.c
index 00f8669ae0..a107af7a7f 100644
--- a/firmware/target/hosted/ibasso/system-ibasso.c
+++ b/firmware/target/hosted/ibasso/system-ibasso.c
@@ -27,7 +27,6 @@
 #include <sys/reboot.h>
 
 #include "config.h"
-#include "cpufreq-linux.h"
 #include "debug.h"
 
 #include "button-ibasso.h"
@@ -50,8 +49,7 @@ void system_init(void)
     volatile uintptr_t stack = 0;
     stackbegin = stackend = (uintptr_t*) &stack;
 
-    cpufreq_set_governor("powersave", CPUFREQ_ALL_CPUS);
-    vold_monitor_start();
+        vold_monitor_start();
     ibasso_set_usb_mode(USB_MODE_MASS_STORAGE);
 
     /*