[buttonbacklight] Implement button backlight policy. JB#39838

Devices designed with Android in mind can have menu/home/back
buttons in front face. In some devices these buttons are
practically invisible unless the underlying button backlight is
turned on.

Add D-Bus interface that can used by applications and/or
lipstick for requesting and tracking button backlight state.

Implement policy that turns button backlight on when:
- Related sysfs controls have been defined in mce configuration
- At least one D-Bus client has requested backlight
- Display is powered up
- Lockscreen is not active

Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

.depend

@@ -570,6 +570,24 @@ modules/bluetooth.pic.o:\
 	mce-log.h\
 	mce.h\
 
+modules/buttonbacklight.o:\
+	modules/buttonbacklight.c\
+	builtin-gconf.h\
+	datapipe.h\
+	mce-conf.h\
+	mce-dbus.h\
+	mce-log.h\
+	mce.h\
+
+modules/buttonbacklight.pic.o:\
+	modules/buttonbacklight.c\
+	builtin-gconf.h\
+	datapipe.h\
+	mce-conf.h\
+	mce-dbus.h\
+	mce-log.h\
+	mce.h\
+
 modules/callstate.o:\
 	modules/callstate.c\
 	builtin-gconf.h\

Makefile

@@ -160,6 +160,7 @@ MODULES += $(MODULE_DIR)/battery-bme.so
 MODULES += $(MODULE_DIR)/battery-upower.so
 MODULES += $(MODULE_DIR)/bluetooth.so
 MODULES += $(MODULE_DIR)/battery-statefs.so
+MODULES += $(MODULE_DIR)/buttonbacklight.so
 MODULES += $(MODULE_DIR)/display.so
 MODULES += $(MODULE_DIR)/usbmode.so
 MODULES += $(MODULE_DIR)/doubletap.so
@@ -574,6 +575,7 @@ NORMALIZE_USES_SPC =\
 	modules/battery-upower.c\
 	modules/battery-statefs.c\
 	modules/bluetooth.c\
+	modules/buttonbacklight.c\
 	modules/callstate.c\
 	modules/callstate.h\
 	modules/camera.h\

inifiles/buttonbacklight.ini

@@ -0,0 +1,7 @@
+# Configuration file for MCE - android buttons backlight control
+
+[ButtonBacklight]
+
+ControlPath=/sys/class/leds/button-backlight/brightness
+ControlValueEnable=1
+ControlValueDisable=0

inifiles/mce.ini

@@ -16,7 +16,7 @@ ModulePath=/usr/lib/mce/modules
 # to avoid unnecessary brightness fluctuations on mce startup
 #
 # Note: the name should not include the "lib"-prefix
-Modules=radiostates;filter-brightness-als;display;keypad;led;battery-statefs;inactivity;alarm;callstate;audiorouting;proximity;powersavemode;cpu-keepalive;doubletap;packagekit;sensor-gestures;bluetooth;memnotify;usbmode
+Modules=radiostates;filter-brightness-als;display;keypad;led;battery-statefs;inactivity;alarm;callstate;audiorouting;proximity;powersavemode;cpu-keepalive;doubletap;packagekit;sensor-gestures;bluetooth;memnotify;usbmode;buttonbacklight
 
 [KeyPad]
 

mce-conf.h

@@ -45,4 +45,20 @@ const gchar * const *mce_conf_get_touchscreen_event_drivers(void);
 const gchar * const *mce_conf_get_keyboard_event_drivers(void);
 const gchar * const *mce_conf_get_blacklisted_event_drivers(void);
 
+/* ========================================================================= *
+ * Constant related to button backlight configuration
+ * ========================================================================= */
+
+/** Name of the display backlight configuration group */
+# define MCE_CONF_BUTTON_BACKLIGHT_GROUP                  "ButtonBacklight"
+
+/** Path to button backlight control file */
+# define MCE_CONF_BUTTON_BACKLIGHT_CONTROL_PATH           "ControlPath"
+
+/** Value to write when enabling button backlight */
+# define MCE_CONF_BUTTON_BACKLIGHT_CONTROL_VALUE_ENABLE   "ControlValueEnable"
+
+/** Value to write when disabling button backlight */
+# define MCE_CONF_BUTTON_BACKLIGHT_CONTROL_VALUE_DISABLE  "ControlValueDisable"
+
 #endif /* _MCE_CONF_H_ */