Codec/sound card input channels do not work simultaneously

Hi. I am a new Linux user that works on an embedded system (not a PC). I have codec/sound card that has 2 input channels and 2 output channels. And yes, I need all of them working at the same time. Here’s the issue: When I run a code, only one input is actually working.
Can I change settings on ALSA regarding how many inputs are working? Is 1 input a default set?

Please follow the link below,
A sound card (also known as an audio card ) is an internal [expansion card] that provides input and output of [audio signals] to and from a [computer]under control of [computer programs]The term sound card is also applied to external audio interfaces used for [professional audio]