Re: [PATCH 2/2] power: supply: qcom_battmgr: expose CHARGE_NOW on SM8350-class firmware

[Konrad Dybcio]

On 8/29/26 7:45 AM, Jan-Michael Brummer wrote:
> The SM8350-class firmware does not implement a dedicated 'charge now'
> property. It does however report BATT_CHG_COUNTER, and on this class of
> firmware that value is the remaining charge in uAh rather than a
> monotonic counter. Measured on a Fairphone 5 with charge_full at
> 4116000 uAh:
> 
>   BATT_CHG_COUNTER   reported capacity   counter / charge_full
>   2434614            59%                 59.1%
>   3525354            85%                 85.6%
> 
> Map POWER_SUPPLY_PROP_CHARGE_NOW onto the same firmware property and
> store the value in status.capacity, which the CHARGE_NOW/ENERGY_NOW case
> of qcom_battmgr_bat_get_property() already reads.
> 
> Together with the preceding patch this gives userspace both the full
> charge and the current charge. UPower now derives an energy level and
> runtime estimates in both directions:
> 
>     state:               discharging      state:               charging
>     energy:              14.4347 Wh       energy:              15.6003 Wh
>     energy-full:         16.8807 Wh       energy-full:         18.1505 Wh
>     energy-rate:         3.39313 W        energy-rate:         7.3492 W
>     time to empty:       4.3 hours        time to full:        20.8 minutes
> 
> Signed-off-by: Jan-Michael Brummer <jan.brummer@xxxxxxxxx>
> ---

Ok this makes more sense now. We should still gate the other property though.

[...]

> @@ -1442,7 +1445,10 @@ static void qcom_battmgr_sm8350_callback(struct qcom_battmgr *battmgr,
>  			battmgr->info.technology = le32_to_cpu(resp->intval.value);
>  			break;
>  		case BATT_CHG_COUNTER:
> -			battmgr->info.charge_count = le32_to_cpu(resp->intval.value);
> +			val = le32_to_cpu(resp->intval.value);
> +			battmgr->info.charge_count = val;
> +			/* the firmware reports the remaining charge here */
> +			battmgr->status.capacity = val;

Let me try and find whether we can rely on this - on newer targets
many properties are more or less just front-ends for vendor
plumbing (because there's a ton of different chargers etc.)

Konrad