breeze: lights: Detect maximum brightness dynamically

Change-Id: I9385be40a8598e1142bb3844446b6bbeb5aab008
Signed-off-by: SamarV-121 <samarvispute121@pm.me>
Signed-off-by: Sarthak Roy <sarthakroy2002@gmail.com>
Signed-off-by: SakthivelNadar <s2234nadar@gmail.com>

light/Light.cpp

@@ -32,7 +32,8 @@
 #define TRIGGER         "trigger"
 
 #define MAX_LED_BRIGHTNESS    13
-#define MAX_LCD_BRIGHTNESS    2047
+
+#define MAX_BRIGHTNESS "max_brightness"
 
 namespace {
 /*
@@ -53,6 +54,22 @@ static void set(std::string path, int value) {
     set(path, std::to_string(value));
 }
 
+/*
+ * Read max brightness from path and close file.
+ */
+static int getMaxBrightness(std::string path) {
+    std::ifstream file(path);
+    int value;
+
+    if (!file.is_open()) {
+        ALOGW("failed to read from %s", path.c_str());
+        return 0;
+    }
+
+    file >> value;
+    return value;
+}
+
 static uint32_t getBrightness(const LightState& state) {
     uint32_t alpha, red, green, blue;
 
@@ -87,7 +104,7 @@ static inline uint32_t getScaledBrightness(const LightState& state, uint32_t max
 }
 
 static void handleBacklight(const LightState& state) {
-    uint32_t brightness = getScaledBrightness(state, MAX_LCD_BRIGHTNESS);
+    uint32_t brightness = getScaledBrightness(state, getMaxBrightness(LCD_LED MAX_BRIGHTNESS));
     set(LCD_LED BRIGHTNESS, brightness);
 }