power: supply: act8945a_charger: Add capacity level property

Add the power supply capacity level property, it corresponds to
POWER_SUPPLY_CAPACITY_LEVEL_*.

It also utilizes the precision voltage detector function module
to catch the low battery voltage.
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/supply/act8945a_charger.c

@@ -18,6 +18,7 @@
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/regmap.h>
+#include <linux/gpio/consumer.h>
 
 static const char *act8945a_charger_model = "ACT8945A";
 static const char *act8945a_charger_manufacturer = "Active-semi";
@@ -83,6 +84,7 @@ struct act8945a_charger {
 	struct work_struct work;
 
 	bool init_done;
+	struct gpio_desc *lbo_gpio;
 };
 
 static int act8945a_get_charger_state(struct regmap *regmap, int *val)
@@ -208,11 +210,67 @@ static int act8945a_get_battery_health(struct regmap *regmap, int *val)
 	return 0;
 }
 
+static int act8945a_get_capacity_level(struct act8945a_charger *charger,
+				       struct regmap *regmap, int *val)
+{
+	int ret;
+	unsigned int status, state, config;
+	int lbo_level = gpiod_get_value(charger->lbo_gpio);
+
+	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(regmap, ACT8945A_APCH_CFG, &config);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
+	if (ret < 0)
+		return ret;
+
+	state &= APCH_STATE_CSTATE;
+	state >>= APCH_STATE_CSTATE_SHIFT;
+
+	switch (state) {
+	case APCH_STATE_CSTATE_PRE:
+		*val = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
+		break;
+	case APCH_STATE_CSTATE_FAST:
+		if (lbo_level)
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_HIGH;
+		else
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
+		break;
+	case APCH_STATE_CSTATE_EOC:
+		if (status & APCH_STATUS_CHGDAT)
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
+		else
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
+		break;
+	case APCH_STATE_CSTATE_DISABLED:
+	default:
+		if (config & APCH_CFG_SUSCHG) {
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
+		} else {
+			*val = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
+			if (!(status & APCH_STATUS_INDAT)) {
+				if (!lbo_level)
+					*val = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
+			}
+		}
+		break;
+	}
+
+	return 0;
+}
+
 static enum power_supply_property act8945a_charger_props[] = {
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_CHARGE_TYPE,
 	POWER_SUPPLY_PROP_TECHNOLOGY,
 	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_MANUFACTURER
 };
@@ -238,6 +296,10 @@ static int act8945a_charger_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_HEALTH:
 		ret = act8945a_get_battery_health(regmap, &val->intval);
 		break;
+	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
+		ret = act8945a_get_capacity_level(charger,
+						  regmap, &val->intval);
+		break;
 	case POWER_SUPPLY_PROP_MODEL_NAME:
 		val->strval = act8945a_charger_model;
 		break;
@@ -335,7 +397,7 @@ static int act8945a_charger_config(struct device *dev,
 	u32 pre_time_out;
 	u32 input_voltage_threshold;
 	int chglev_pin;
-	int ret;
+	int err, ret;
 
 	unsigned int tmp;
 	unsigned int value = 0;
@@ -354,6 +416,21 @@ static int act8945a_charger_config(struct device *dev,
 		dev_info(dev, "have been suspended\n");
 	}
 
+	charger->lbo_gpio = devm_gpiod_get_optional(dev, "active-semi,lbo",
+						    GPIOD_IN);
+	if (IS_ERR(charger->lbo_gpio)) {
+		err = PTR_ERR(charger->lbo_gpio);
+		dev_err(dev, "unable to claim gpio \"lbo\": %d\n", err);
+		return err;
+	}
+
+	ret = devm_request_irq(dev, gpiod_to_irq(charger->lbo_gpio),
+			       act8945a_status_changed,
+			       (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
+			       "act8945a_lbo_detect", charger);
+	if (ret)
+		dev_info(dev, "failed to request gpio \"lbo\" IRQ\n");
+
 	chglev_pin = of_get_named_gpio_flags(np,
 				"active-semi,chglev-gpios", 0, &flags);