Say Y or M if you want to add support for SoC audio device
connected to a handset and a speakerphone found on Amstrad E3 (Delta)
videophone.

Note that in order to get those devices fully supported, you have to
build the kernel with standard serial port driver included and
configured for at least 4 ports. Then, from userspace, you must load
a line discipline #19 on the modem (ttyS3) serial line. The simplest
way to achieve this is to install util-linux-ng and use the included
ldattach utility. This can be started automatically from udev,
a simple rule like this one should do the trick (it does for me):
ACTION=="add", KERNEL=="controlC0", \
RUN+="/usr/sbin/ldattach 19 /dev/ttyS3"

source code:

sound/soc//ti/