pmic8xxx_kp_read_matrix
rc = pmic8xxx_kp_read_matrix(kp, new_state, NULL);
rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);
rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);
rc = pmic8xxx_kp_read_matrix(kp, new_state, old_state);