smb347: issues with IRQSTAT_D

Hello,

after wiring smb347-charge into our DTS, I noticed issues with Safety Timer Expiration[1]. This functionality was added with commit 1502cfe19bac2f8490e4167f2b7cb50b9759b273. I suppose that it worked originally for Ramakrishna.
I did also notice, that SMB345 patch omits functionality with IF.
Since it fails for me even on SMB347 I guess there could be possible that:

- this funtionality is available only on some specific chips?
- something must be configured (in HW or SW) differently to use it?
- it wasn't working from begining (since I didn't found any user of smb347 in tree).

I work with gathered patches [2] and preparing them for upstream. Testing is done on Nexus 7 2012, tilapia (grouper-nakasi3g). Charging and discharging is reported by driver correctly.

Any ideas welcome!
Thank you
David

[1] "smb347 2-006a: reading IRQSTAT_D failed"
[2] https://github.com/okias/linux/commits/smb3xx-charger