dumpstate: Add backlight information to bugreport output.

To help diagnose bugs b/2164183 and b/2164647

Change-Id: Ie80c3b205c231c485d8a24e68b0a9c5e025da479
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/cmds/dumpstate/dumpstate.c b/cmds/dumpstate/dumpstate.c
index 1f14726..4dda68c 100644
--- a/cmds/dumpstate/dumpstate.c
+++ b/cmds/dumpstate/dumpstate.c
@@ -111,6 +111,13 @@
                         "PANIC CONSOLE");
         dump_kernel_log("/data/dontpanic/apanic_threads",
                         "PANIC THREADS");
+
+        PRINT("------ BACKLIGHTS ------");
+        DUMP_PROMPT("LCD brightness=", "/sys/class/leds/lcd-backlight/brightness");
+        DUMP_PROMPT("Button brightness=", "/sys/class/leds/button-backlight/brightness");
+        DUMP_PROMPT("Keyboard brightness=", "/sys/class/leds/keyboard-backlight/brightness");
+        DUMP_PROMPT("ALS mode=", "/sys/class/leds/lcd-backlight/als");
+        DUMP_PROMPT("LCD driver registers:\n", "/sys/class/leds/lcd-backlight/registers");
     }
     PRINT("========================================================");
     PRINT("== build.prop");