davinci: power: Support event-based dt2w node

Change-Id: I08c874f3ca50fad1db820ddd85ef0f5d7ccf0ed2

power/Android.mk

@@ -20,6 +20,9 @@ include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := power-feature.c
 LOCAL_SHARED_LIBRARIES := liblog libcutils
+LOCAL_HEADER_LIBRARIES := \
+    generated_kernel_headers \
+    libhardware_headers
 
 LOCAL_MODULE := libpower_feature.davinci
 LOCAL_MODULE_TAGS := optional

power/power-feature.c

@@ -14,10 +14,25 @@
  * limitations under the License.
  */
 
+#include <fcntl.h>
+#include <unistd.h>
+
 #include "power-feature.h"
 
+#include <hardware/power.h>
+#include <linux/input.h>
 #include <log/log.h>
 
 void set_device_specific_feature(feature_t feature, int state) {
-    // stub
+    switch (feature) {
+        case POWER_FEATURE_DOUBLE_TAP_TO_WAKE: {
+            int fd = open(TAP_TO_WAKE_EVENT_NODE, O_WRONLY);
+            struct input_event ev;
+            ev.type = EV_SYN;
+            ev.code = SYN_CONFIG;
+            ev.value = state ? INPUT_EVENT_WAKUP_MODE_ON : INPUT_EVENT_WAKUP_MODE_OFF;
+            write(fd, &ev, sizeof(ev));
+            close(fd);
+        }
+    }
 }

power/power-feature.h

@@ -15,3 +15,8 @@
  */
 
 #define LOG_TAG "libpower_feature.davinci"
+
+#define TAP_TO_WAKE_EVENT_NODE "/dev/input/event2"
+
+#define INPUT_EVENT_WAKUP_MODE_OFF 4
+#define INPUT_EVENT_WAKUP_MODE_ON 5