BackLight: Add support for button backlight.

Add function call to let framework layer could enable/disable the
button backlight.

Change-Id: I470ebb8953c5d3fdb72118dbaf06788c2079213e

1 files changed, 15 insertions, 0 deletions

diff --git a/liblight/lights.c b/liblight/lights.c
index eb71b742..ccfbe102 100644
--- a/liblight/lights.c
+++ b/liblight/lights.c
@@ -51,6 +51,9 @@ char const*const BLUE_LED_FILE
 char const*const LCD_FILE
         = "/sys/class/leds/lcd-backlight/brightness";
 
+char const*const BUTTON_FILE
+        = "/sys/class/leds/button-backlight/brightness";
+
 char const*const RED_BLINK_FILE
         = "/sys/class/leds/red/blink";
 
@@ -209,6 +212,16 @@ set_light_attention(struct light_device_t* dev,
     return 0;
 }
 
+static int
+set_light_buttons(struct light_device_t* dev,
+        struct light_state_t const* state)
+{
+    int err = 0;
+    pthread_mutex_lock(&g_lock);
+    err = write_int(BUTTON_FILE, state->color & 0xFF);
+    pthread_mutex_unlock(&g_lock);
+    return err;
+}
 
 /** Close the lights device */
 static int
@@ -238,6 +251,8 @@ static int open_lights(const struct hw_module_t* module, char const* name,
         set_light = set_light_backlight;
     else if (0 == strcmp(LIGHT_ID_NOTIFICATIONS, name))
         set_light = set_light_notifications;
+    else if (0 == strcmp(LIGHT_ID_BUTTONS, name))
+        set_light = set_light_buttons;
     else if (0 == strcmp(LIGHT_ID_ATTENTION, name))
         set_light = set_light_attention;
     else