I would suggest the following approach (not tested):

1 - get a list of all running processes

List of system processes is not available through Android SDK API, so we would use Runtime.exec(...) to execute OS command and to capture its output into string variable. We would use /system/bin/ps (but we could have used /proc and then do some proc output parsing)

String cmd = "/system/bin/ps"; // alternative cmd would be "/proc" but then we would need to loop through proc subdirectories, etc
// run cmd and read its output into string
java.util.Scanner s = new java.util.Scanner(Runtime.getRuntime().exec(cmd).getInputStream()).useDelimiter("\\A");
String cmdRes = s.hasNext() ? s.next() : "";

2 - loop through the list trying to find known TEE client drivers

• parse String cmdRes into list of process names
• loop through the list of names and try to identify known TEE client driver names