Add option to use breathing led patterns

Adds two new runtime configuration values
* sw breathing enable flag
* sw breathing battery level limit

These can be modified with mcetool options
  --set-sw-breathing=<enabled|disabled>
  --set-sw-breathing-limit=<0 ... 100>

The led patterns that are configured to use the fully on / fully off
blinking mode supported by the pwm led controller will oscillate
smoothly along the first half of sine wave.

For the smooth transitions to work frequent timer wakeups are needed
and the device can't be suspended. As this will increase the battery
consumption the sw breathing happens only if breathing is enabled and
battery level exceeds the limit or the device is connected to charger.

[mce] Add option to use breathing led patterns. Contributes to JB#17229

builtin-gconf.c

@@ -1506,6 +1506,18 @@ static const setting_t gconf_defaults[] =
     .type = "b",
     .def  = "true",
   },
+  {
+    // no define; used by led module
+    .key  = "/system/osso/dsm/leds/sw_breath_enabled",
+    .type = "b",
+    .def  = "false",
+  },
+  {
+    // no define; used by led module
+    .key  = "/system/osso/dsm/leds/sw_breath_battery_limit",
+    .type = "i",
+    .def  = "90",
+  },
   {
     // MCE_GCONF_PROXIMITY_PS_ENABLED_PATH @ proximity.h
     .key  = "/system/osso/dsm/proximity/ps_enabled",

mce-hybris.c

@@ -530,6 +530,17 @@ bool mce_hybris_indicator_set_pattern(int r, int g, int b, int ms_on, int ms_off
   return !real ? false : real(r,g,b, ms_on, ms_off);
 }
 
+/** Enable/disable timer based led breathing
+ *
+ * @param enable true for smooth sw transitions, false for hw blinking only
+ */
+void mce_hybris_indicator_enable_breathing(bool enable)
+{
+  static void (*real)(bool) = 0;
+  RESOLVE;
+  if( real ) real(enable);
+}
+
 /* ------------------------------------------------------------------------- *
  * proximity sensor
  * ------------------------------------------------------------------------- */

mce-hybris.h

@@ -56,6 +56,7 @@ bool mce_hybris_keypad_init(void);
 bool mce_hybris_indicator_init(void);
 void mce_hybris_indicator_quit(void);
 bool mce_hybris_indicator_set_pattern(int r, int g, int b, int ms_on, int ms_off);
+void mce_hybris_indicator_enable_breathing(bool enable);
 
 /* - - - - - - - - - - - - - - - - - - - *
  * proximity sensor

mce.c

@@ -291,6 +291,7 @@ static void mce_cleanup_wakelocks(void)
 	wakelock_unlock("mce_powerkey_stm");
 	wakelock_unlock("mce_proximity_stm");
 	wakelock_unlock("mce_bluez_wait");
+	wakelock_unlock("mce_led_breathing");
 }
 #endif // ENABLE_WAKELOCKS