Turning an external amplifier on or off when audio is played

[Amr Bekhit]

Hello,

I'm working with an embedded system that uses the SGTL5000 to play audio.
We have an amplifier connected to the DAC output, which we can turn off
using a GPIO pin. I'd like to automatically enable the amplifier before
playing a sound and disable it after playback has completed. Are there any
hooks that would allow me to do that in userspace? If not, is there
something in kernel-space that would allow me to accomplish this?

Thanks,

Amr