cx_swrite
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, (old & ~0x3f) | v);
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, vol);
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, volume);