liblights: Add support for variable touchkey brightness

Change-Id: Icc5c589e88dc342ae50b432187bae65a9b3a23d7

liblights/include/samsung_lights.h

@@ -30,6 +30,9 @@
 #define BUTTON_BRIGHTNESS_NODE "/sys/class/sec/sec_touchkey/brightness"
 #define LED_BLINK_NODE "/sys/class/sec/led/led_blink"
 
+// Set to 1 to enable variable button brightness
+#define VAR_BUTTON_BRIGHTNESS 0
+
 /*
  * Brightness adjustment factors
  *

liblights/lights.c

@@ -145,12 +145,13 @@ static int set_light_buttons(struct light_device_t* dev __unused,
                              struct light_state_t const* state)
 {
     int err = 0;
-    int on = (state->color & COLOR_MASK);
-
     pthread_mutex_lock(&g_lock);
+    int brightness = (state->color & COLOR_MASK) ? 1 : 0;
 
-    err = set_cur_button_brightness(on ? 1 : 0);
+#ifdef VAR_BUTTON_BRIGHTNESS
-
+    brightness = rgb_to_brightness(state);
+#endif
+    err = set_cur_button_brightness(brightness);
     pthread_mutex_unlock(&g_lock);
 
     return err;