Battery Monitor Widget reports estimated mA consumption. All other data are available (%, mV and temperature).
Just added a FAQ here about this question. Don't hesitate to post comments on it.
I don't think the battery doesn't have a probe... But I think it doesn't provide the data at all, hence no kernels even custom can report it.
I've had a S1 and S2, and also O2X, none of which had the mA being reported. Tried many ROMs on the O2X (even CM7) didn't help at all.
I still want to investigate whether there's a way to get to the data using battery driver and direct access to its registers. When I got free time!
My wife has a SGS2, but she's away until the 14th, so I'll get on it as soon as she returns with the phone :)
Thanks for the info! Note that even though I suspect most phone should be capable of reporting mA current, most manufacturers will not build the driver to read those registers and often do not provide a sysfs interface.
Nevertheless if you want to investigate on your phone if the data is readily available, you can search through the /sys/class folder hierarchy for a MAX17047 or MAX17042 folder references.
There is usually a folder named after the device which contains files providing an interface to the actual device registers. If you find one, look open those files (even they're 0-bytes size) they provide direct data output.
If none can be found, this will require some native code to be written, as it was done (i suspect) with the 'Battery Calibrator' app for the Nexus S. Unfortunately I didn't find much information about this yet, but this could prove very useful in providing supports for real mA with more phones!
Let me know if you find anything useful, I can build a test APK if so.
Interestingly the app already support that file: /sys/class/power_supply/max17042-0/current_now
But it's not available on the Galaxy S or S2... Meaning it was removed or not implemented by Samsung.
Support can only be achieved through native code or getting a custom kernel supporting it! So I'll study the links you provided and start looking for ways to read device registers directly.