LINE_INPUT_MUTE
l = ce4231_read(sc, CS_LEFT_LINE_CONTROL) & ~LINE_INPUT_MUTE;
r = ce4231_read(sc, CS_RIGHT_LINE_CONTROL) & ~LINE_INPUT_MUTE;
l |= LINE_INPUT_MUTE;
r |= LINE_INPUT_MUTE;
LINE_INPUT_MUTE) ? 1 : 0;