On Tue, Nov 16, 2021 at 1:28 PM Matti Vaittinen
[off-list ref] wrote:

Add generic 'simple gauge' helper for performing iterative SOC estimation
and coulomb counter correction for devices with a (drifting) coulomb
counter. This should allow few charger/fuel-gauge drivers to use generic
loop instead of implementing their own.

Charger/fuel-gauge drivers can register 'simple-gauge' which does
periodically poll the driver and:
 - get battery state
 - adjust coulomb counter value (to fix drifting caused for example by ADC
   offset) if:
     - Battery is relaxed and OCV<=>SOC table is given
     - Battery is full charged
 - get battery age (cycles) from driver
 - get battery temperature
 - do battery capacity correction
     - by battery temperature
     - by battery age
     - by computed Vbat/OCV difference at low-battery condition if
       low-limit is set and OCV table given
     - by IC specific low-battery correction if provided
 - compute current State Of Charge (SOC)
 - do periodical calibration if IC supports that. (Many ICs do calibration
   of CC by shorting the ADC pins and getting the offset).
 - provide the user-space a consistent interface for getting/setting the
   battery-cycle information for ICs which can't store the battery aging
   information. Uses POWER_SUPPLY_PROP_CYCLE_COUNT for this.

The simple gauge provides the last computed SOC as
POWER_SUPPLY_PROP_CAPACITY to power_supply_class when requested.

Things that should/could be added but are missing from this commit:
 - Support starting calibration in HW when entering to suspend. This
   is useful for ICs supporting delayed calibration to mitigate CC error
   during suspend - and to make periodical wake-up less critical.
 - periodical wake-up for performing SOC estimation computation (RTC
   integration)

Signed-off-by: Matti Vaittinen <redacted>

This is the right ambition, I haven't looked close at it but the way
you use it seem to be what you need, so:
Acked-by: Linus Walleij <redacted>
(and the rest of the patches to the Rohm chips)

Yours,
Linus Walleij