What is the best way to verify the TPM is available, that is, that it hasn’t died?  I have a requirement to send an alert if the TPM stops working.  We have snmp processes that run every five seconds, so I figure I can, say, check for something in /sys/class/tpm/tpm0 and as long as I get an expected response, I’ll report that everything is fine.  But what exactly should I look for?  Is the simple presence of /sys/class/tpm/tpm0 sufficient, because it means the kernel thinks the TPM is there?  If I cat /sys/class/tpm/tpm0/dev I get the major and minor numbers; I could look at those, or just test for the presence of the dev file on the premise that if the TPM failed that file would disappear.  Is that a good test?  Suggestions?

Peter