voyager_twiddle_bits
void voyager_twiddle_bits(void *, int, uint32_t, uint32_t);
voyager_twiddle_bits(cookie, SM502_GPIO_DATA0, m_and, m_or)
voyager_twiddle_bits(cookie, SM502_GPIO0_CONTROL, m_and, m_or)
voyager_twiddle_bits(cookie, SM502_GPIO_DIR0, m_and, m_or)
voyager_twiddle_bits(cookie, SM502_POWER_MODE0_GATE, m_and, m_or)