1 files changed, 25 insertions, 2 deletions

diff --git a/keyboard/hhkb/matrix.c b/keyboard/hhkb/matrix.c
index b0af4baa5..fb9699794 100644
--- a/keyboard/hhkb/matrix.c
+++ b/keyboard/hhkb/matrix.c
@@ -27,8 +27,15 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "timer.h"
 #include "matrix.h"
 #include "hhkb_avr.h"
+#include <avr/wdt.h>
+#include "suspend.h"
+#include "lufa.h"
 
 
+// matrix power saving
+#define MATRIX_POWER_SAVE       10000
+static uint32_t matrix_last_modified = 0;
+
 // matrix state buffer(1:on, 0:off)
 static matrix_row_t *matrix;
 static matrix_row_t *matrix_prev;
@@ -72,7 +79,8 @@ uint8_t matrix_scan(void)
     matrix_prev = matrix;
     matrix = tmp;
 
-    KEY_POWER_ON();
+    // power on
+    if (!KEY_POWER_STATE()) KEY_POWER_ON();
     for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
         for (uint8_t col = 0; col < MATRIX_COLS; col++) {
             KEY_SELECT(row, col);
@@ -126,8 +134,16 @@ uint8_t matrix_scan(void)
             // This takes 25us or more to make sure KEY_STATE returns to idle state.
             _delay_us(75);
         }
+        if (matrix[row] ^ matrix_prev[row]) matrix_last_modified = timer_read32();
+    }
+    // power off
+    if (KEY_POWER_STATE() &&
+            (USB_DeviceState == DEVICE_STATE_Suspended ||
+             USB_DeviceState == DEVICE_STATE_Unattached ) &&
+            timer_elapsed32(matrix_last_modified) > MATRIX_POWER_SAVE) {
+        KEY_POWER_OFF();
+        suspend_power_down();
     }
-    KEY_POWER_OFF();
     return 1;
 }
 
@@ -165,3 +181,10 @@ void matrix_print(void)
         xprintf("%02X: %08b\n", row, bitrev(matrix_get_row(row)));
     }
 }
+
+void matrix_power_up(void) {
+    KEY_POWER_ON();
+}
+void matrix_power_down(void) {
+    KEY_POWER_OFF();
+}