I found the PMIC docs and I could get the information I want from it.
But it is I2C and owned by the kernel and I can not seem to communicate with the PMIC while the kernel driver is loaded, which does not surprise me.
I noted from other posts that there is a patch to the tps65217.c driver that generates KEY_POWER hits on various changes that the PMIC detects.
Unfortunately the current tps65217.c source (5.1-rc3) has significantly different interrupt handling, and patching it to incorporate the KEY_POWER functionality without breaking the other things that have been changed is on the edge of my abilities.
Is there someone that understand threaded and nested interrupt handling in Linux that can guide me in patching the current tps65217.c driver to include the Key generation without blowing it up ?