power: supply: bq25890: Reduce reported CONSTANT_CHARGE_CURRENT_MAX for low temperatures

Take into account possible current reduction due to low-temperature when
reading POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX. As described in
the datasheet in cool (0-20° Celcius) conditions the current limit is
decreased to 20% or 50% of ICHG field value depended on JEITA_ISET field.

Also add NTC_FAULT field value to the debug message in
bq25890_get_chip_state().

Changed by Hans de Goede:
- Fix reading F_CHG_FAULT instead of F_NTC_FIELD for state->ntc_fault
- Only read JEITA_ISET field if necessary
- Tweak commit message a bit
Signed-off-by: Yauhen Kharuzhy <jekhor@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Co-developed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/bq25890_charger.c

@@ -94,6 +94,7 @@ struct bq25890_state {
 	u8 vsys_status;
 	u8 boost_fault;
 	u8 bat_fault;
+	u8 ntc_fault;
 };
 
 struct bq25890_device {
@@ -407,6 +408,14 @@ enum bq25890_chrg_fault {
 	CHRG_FAULT_TIMER_EXPIRED,
 };
 
+enum bq25890_ntc_fault {
+	NTC_FAULT_NORMAL = 0,
+	NTC_FAULT_WARM = 2,
+	NTC_FAULT_COOL = 3,
+	NTC_FAULT_COLD = 5,
+	NTC_FAULT_HOT = 6,
+};
+
 static bool bq25890_is_adc_property(enum power_supply_property psp)
 {
 	switch (psp) {
@@ -499,6 +508,18 @@ static int bq25890_power_supply_get_property(struct power_supply *psy,
 
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
 		val->intval = bq25890_find_val(bq->init_data.ichg, TBL_ICHG);
+
+		/* When temperature is too low, charge current is decreased */
+		if (bq->state.ntc_fault == NTC_FAULT_COOL) {
+			ret = bq25890_field_read(bq, F_JEITA_ISET);
+			if (ret < 0)
+				return ret;
+
+			if (ret)
+				val->intval /= 5;
+			else
+				val->intval /= 2;
+		}
 		break;
 
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
@@ -583,7 +604,8 @@ static int bq25890_get_chip_state(struct bq25890_device *bq,
 		{F_VSYS_STAT,	&state->vsys_status},
 		{F_BOOST_FAULT, &state->boost_fault},
 		{F_BAT_FAULT,	&state->bat_fault},
-		{F_CHG_FAULT,	&state->chrg_fault}
+		{F_CHG_FAULT,	&state->chrg_fault},
+		{F_NTC_FAULT,	&state->ntc_fault}
 	};
 
 	for (i = 0; i < ARRAY_SIZE(state_fields); i++) {
@@ -594,9 +616,10 @@ static int bq25890_get_chip_state(struct bq25890_device *bq,
 		*state_fields[i].data = ret;
 	}
 
-	dev_dbg(bq->dev, "S:CHG/PG/VSYS=%d/%d/%d, F:CHG/BOOST/BAT=%d/%d/%d\n",
+	dev_dbg(bq->dev, "S:CHG/PG/VSYS=%d/%d/%d, F:CHG/BOOST/BAT/NTC=%d/%d/%d/%d\n",
 		state->chrg_status, state->online, state->vsys_status,
-		state->chrg_fault, state->boost_fault, state->bat_fault);
+		state->chrg_fault, state->boost_fault, state->bat_fault,
+		state->ntc_fault);
 
 	return 0;
 }