power: max17042_battery: add HEALTH and TEMP_* properties support

This patch adds the support for following battery properties
to max17042 fuel gauge driver.

POWER_SUPPLY_PROP_TEMP_ALERT_MIN
POWER_SUPPLY_PROP_TEMP_ALERT_MAX
POWER_SUPPLY_PROP_TEMP_MIN
POWER_SUPPLY_PROP_TEMP_MAX
POWER_SUPPLY_PROP_HEALTH

Signed-off-by: Ramakrishna Pallala <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/max17042_battery.c

···
 #define dP_ACC_100	0x1900
 #define dP_ACC_200	0x3200
 
+#define MAX17042_VMAX_TOLERANCE		50 /* 50 mV */
+
 struct max17042_chip {
 	struct i2c_client *client;
 	struct regmap *regmap;
···
 	POWER_SUPPLY_PROP_CHARGE_FULL,
 	POWER_SUPPLY_PROP_CHARGE_COUNTER,
 	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
+	POWER_SUPPLY_PROP_TEMP_MIN,
+	POWER_SUPPLY_PROP_TEMP_MAX,
+	POWER_SUPPLY_PROP_HEALTH,
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 	POWER_SUPPLY_PROP_CURRENT_AVG,
 };
+
+static int max17042_get_temperature(struct max17042_chip *chip, int *temp)
+{
+	int ret;
+	u32 data;
+	struct regmap *map = chip->regmap;
+
+	ret = regmap_read(map, MAX17042_TEMP, &data);
+	if (ret < 0)
+		return ret;
+
+	*temp = data;
+	/* The value is signed. */
+	if (*temp & 0x8000) {
+		*temp = (0x7fff & ~*temp) + 1;
+		*temp *= -1;
+	}
+
+	/* The value is converted into deci-centigrade scale */
+	/* Units of LSB = 1 / 256 degree Celsius */
+	*temp = *temp * 10 / 256;
+	return 0;
+}
+
+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);
+	if (ret < 0)
+		goto health_error;
+
+	/* bits [0-3] unused */
+	vavg = val * 625 / 8;
+	/* Convert to millivolts */
+	vavg /= 1000;
+
+	ret = regmap_read(chip->regmap, MAX17042_VCELL, &val);
+	if (ret < 0)
+		goto health_error;
+
+	/* bits [0-3] unused */
+	vbatt = val * 625 / 8;
+	/* Convert to millivolts */
+	vbatt /= 1000;
+
+	if (vavg < chip->pdata->vmin) {
+		*health = POWER_SUPPLY_HEALTH_DEAD;
+		goto out;
+	}
+
+	if (vbatt > chip->pdata->vmax + MAX17042_VMAX_TOLERANCE) {
+		*health = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		goto out;
+	}
+
+	ret = max17042_get_temperature(chip, &temp);
+	if (ret < 0)
+		goto health_error;
+
+	if (temp <= chip->pdata->temp_min) {
+		*health = POWER_SUPPLY_HEALTH_COLD;
+		goto out;
+	}
+
+	if (temp >= chip->pdata->temp_max) {
+		*health = POWER_SUPPLY_HEALTH_OVERHEAT;
+		goto out;
+	}
+
+	*health = POWER_SUPPLY_HEALTH_GOOD;
+
+out:
+	return 0;
+
+health_error:
+	return ret;
+}
 
 static int max17042_get_property(struct power_supply *psy,
 			    enum power_supply_property psp,
···
 		val->intval = data * 1000 / 2;
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
-		ret = regmap_read(map, MAX17042_TEMP, &data);
+		ret = max17042_get_temperature(chip, &val->intval);
 		if (ret < 0)
 			return ret;
-
-		val->intval = data;
-		/* The value is signed. */
-		if (val->intval & 0x8000) {
-			val->intval = (0x7fff & ~val->intval) + 1;
-			val->intval *= -1;
-		}
-		/* The value is converted into deci-centigrade scale */
-		/* Units of LSB = 1 / 256 degree Celsius */
-		val->intval = val->intval * 10 / 256;
+		break;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		ret = regmap_read(map, MAX17042_TALRT_Th, &data);
+		if (ret < 0)
+			return ret;
+		/* LSB is Alert Minimum. In deci-centigrade */
+		val->intval = (data & 0xff) * 10;
+		break;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		ret = regmap_read(map, MAX17042_TALRT_Th, &data);
+		if (ret < 0)
+			return ret;
+		/* MSB is Alert Maximum. In deci-centigrade */
+		val->intval = (data >> 8) * 10;
+		break;
+	case POWER_SUPPLY_PROP_TEMP_MIN:
+		val->intval = chip->pdata->temp_min;
+		break;
+	case POWER_SUPPLY_PROP_TEMP_MAX:
+		val->intval = chip->pdata->temp_max;
+		break;
+	case POWER_SUPPLY_PROP_HEALTH:
+		ret = max17042_get_battery_health(chip, &val->intval);
+		if (ret < 0)
+			return ret;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
 		if (chip->pdata->enable_current_sense) {
···
 		return -EINVAL;
 	}
 	return 0;
+}
+
+static int max17042_set_property(struct power_supply *psy,
+			    enum power_supply_property psp,
+			    const union power_supply_propval *val)
+{
+	struct max17042_chip *chip = power_supply_get_drvdata(psy);
+	struct regmap *map = chip->regmap;
+	int ret = 0;
+	u32 data;
+	int8_t temp;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		ret = regmap_read(map, MAX17042_TALRT_Th, &data);
+		if (ret < 0)
+			return ret;
+
+		/* Input in deci-centigrade, convert to centigrade */
+		temp = val->intval / 10;
+		/* force min < max */
+		if (temp >= (int8_t)(data >> 8))
+			temp = (int8_t)(data >> 8) - 1;
+		/* Write both MAX and MIN ALERT */
+		data = (data & 0xff00) + temp;
+		ret = regmap_write(map, MAX17042_TALRT_Th, data);
+		break;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		ret = regmap_read(map, MAX17042_TALRT_Th, &data);
+		if (ret < 0)
+			return ret;
+
+		/* Input in Deci-Centigrade, convert to centigrade */
+		temp = val->intval / 10;
+		/* force max > min */
+		if (temp <= (int8_t)(data & 0xff))
+			temp = (int8_t)(data & 0xff) + 1;
+		/* Write both MAX and MIN ALERT */
+		data = (data & 0xff) + (temp << 8);
+		ret = regmap_write(map, MAX17042_TALRT_Th, data);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int max17042_property_is_writeable(struct power_supply *psy,
+		enum power_supply_property psp)
+{
+	int ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		ret = 1;
+		break;
+	default:
+		ret = 0;
+	}
+
+	return ret;
 }
 
 static int max17042_write_verify_reg(struct regmap *map, u8 reg, u32 value)
···
 	.name		= "max170xx_battery",
 	.type		= POWER_SUPPLY_TYPE_BATTERY,
 	.get_property	= max17042_get_property,
+	.set_property	= max17042_set_property,
+	.property_is_writeable	= max17042_property_is_writeable,
 	.properties	= max17042_battery_props,
 	.num_properties	= ARRAY_SIZE(max17042_battery_props),
 };
···
 	.name		= "max170xx_battery",
 	.type		= POWER_SUPPLY_TYPE_BATTERY,
 	.get_property	= max17042_get_property,
+	.set_property	= max17042_set_property,
+	.property_is_writeable	= max17042_property_is_writeable,
 	.properties	= max17042_battery_props,
 	.num_properties	= ARRAY_SIZE(max17042_battery_props) - 2,
 };

include/linux/power/max17042_battery.h

···
 	 * the datasheet although it can be changed by board designers.
 	 */
 	unsigned int r_sns;
+	int         vmin;	/* in millivolts */
+	int         vmax;	/* in millivolts */
+	int         temp_min;	/* in tenths of degree Celsius */
+	int         temp_max;	/* in tenths of degree Celsius */
 };
 
 #endif /* __MAX17042_BATTERY_H_ */