MTK_KPD_NUM_BITS
bitmap_fill(keypad->keymap_state, MTK_KPD_NUM_BITS);
DECLARE_BITMAP(keymap_state, MTK_KPD_NUM_BITS);
DECLARE_BITMAP(new_state, MTK_KPD_NUM_BITS);
DECLARE_BITMAP(change, MTK_KPD_NUM_BITS);
bitmap_xor(change, new_state, keypad->keymap_state, MTK_KPD_NUM_BITS);
for_each_set_bit(bit_nr, change, MTK_KPD_NUM_BITS) {
bitmap_copy(keypad->keymap_state, new_state, MTK_KPD_NUM_BITS);