[PATCH 3/3] power: supply: max17042: add handler for energy_now property

From: Amit Sunil Dhamne via B4 Relay

Date: Fri May 15 2026 - 01:54:20 EST


From: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>

Add handler to report power_supply_prop_energy_now so that users can get
current SoC in uWH. Additionally, add helper functions to get avg_vcell
and repcap values in uv and uah units respectively to avoid code
duplication.

Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
---
drivers/power/supply/max17042_battery.c | 60 ++++++++++++++++++++++++++-------
1 file changed, 47 insertions(+), 13 deletions(-)

diff --git a/drivers/power/supply/max17042_battery.c b/drivers/power/supply/max17042_battery.c
index 167fb3fb3732..e16eb6985b70 100644
--- a/drivers/power/supply/max17042_battery.c
+++ b/drivers/power/supply/max17042_battery.c
@@ -81,6 +81,7 @@ static enum power_supply_property max17042_battery_props[] = {
POWER_SUPPLY_PROP_CHARGE_NOW,
POWER_SUPPLY_PROP_CHARGE_COUNTER,
POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+ POWER_SUPPLY_PROP_ENERGY_NOW,
POWER_SUPPLY_PROP_TEMP,
POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
@@ -95,6 +96,36 @@ static enum power_supply_property max17042_battery_props[] = {
POWER_SUPPLY_PROP_CURRENT_AVG,
};

+static int max17042_get_repcap_uah(struct max17042_chip *chip, u64 *rep_cap)
+{
+ u32 data;
+ int ret;
+
+ ret = regmap_read(chip->regmap, MAX17042_RepCap, &data);
+ if (ret < 0)
+ return ret;
+
+ *rep_cap = data * 5000000ll;
+ *rep_cap *= chip->task_period;
+ do_div(*rep_cap, MAX17042_DEFAULT_TASK_PERIOD);
+ do_div(*rep_cap, chip->pdata->r_sns);
+
+ return 0;
+}
+
+static int max17042_get_avgvcell_uv(struct max17042_chip *chip, u32 *vcell)
+{
+ int ret;
+
+ ret = regmap_read(chip->regmap, MAX17042_AvgVCELL, vcell);
+ if (ret < 0)
+ return ret;
+
+ *vcell = (*vcell * 625) / 8;
+
+ return 0;
+}
+
static int max17042_get_temperature(struct max17042_chip *chip, int *temp)
{
int ret;
@@ -180,14 +211,12 @@ static int max17042_get_battery_health(struct max17042_chip *chip, int *health)
int temp, vavg, vbatt, ret;
u32 val;

- ret = regmap_read(chip->regmap, MAX17042_AvgVCELL, &val);
+ ret = max17042_get_avgvcell_uv(chip, &val);
if (ret < 0)
goto health_error;

- /* bits [0-3] unused */
- vavg = val * 625 / 8;
/* Convert to millivolts */
- vavg /= 1000;
+ vavg = val / 1000;

ret = regmap_read(chip->regmap, MAX17042_VCELL, &val);
if (ret < 0)
@@ -304,11 +333,10 @@ static int max17042_get_property(struct power_supply *psy,
val->intval = data * 625 / 8;
break;
case POWER_SUPPLY_PROP_VOLTAGE_AVG:
- ret = regmap_read(map, MAX17042_AvgVCELL, &data);
+ ret = max17042_get_avgvcell_uv(chip, &data);
if (ret < 0)
return ret;
-
- val->intval = data * 625 / 8;
+ val->intval = data;
break;
case POWER_SUPPLY_PROP_VOLTAGE_OCV:
ret = regmap_read(map, MAX17042_OCVInternal, &data);
@@ -350,14 +378,9 @@ static int max17042_get_property(struct power_supply *psy,
val->intval = data64;
break;
case POWER_SUPPLY_PROP_CHARGE_NOW:
- ret = regmap_read(map, MAX17042_RepCap, &data);
+ ret = max17042_get_repcap_uah(chip, &data64);
if (ret < 0)
return ret;
-
- data64 = data * 5000000ll;
- data64 *= chip->task_period;
- do_div(data64, MAX17042_DEFAULT_TASK_PERIOD);
- do_div(data64, chip->pdata->r_sns);
val->intval = data64;
break;
case POWER_SUPPLY_PROP_CHARGE_COUNTER:
@@ -370,6 +393,17 @@ static int max17042_get_property(struct power_supply *psy,
data64 = div_s64(data64, MAX17042_DEFAULT_TASK_PERIOD);
val->intval = div_s64(data64, chip->pdata->r_sns);
break;
+ case POWER_SUPPLY_PROP_ENERGY_NOW:
+ ret = max17042_get_repcap_uah(chip, &data64);
+ if (ret < 0)
+ return ret;
+
+ ret = max17042_get_avgvcell_uv(chip, &data);
+ if (ret < 0)
+ return ret;
+
+ val->intval = data64 * data / 1000000;
+ break;
case POWER_SUPPLY_PROP_TEMP:
ret = max17042_get_temperature(chip, &val->intval);
if (ret < 0)

--
2.54.0.563.g4f69b47b94-goog