power: supply: rn5t618: Add input current limit

Adds properties for setting the maximum current to USB, ADP and Battery
supplies. USB and ADP limits are reset to OTP values upon replugging.
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/rn5t618_power.c

@@ -44,6 +44,20 @@
 
 #define FG_ENABLE 1
 
+/*
+ * Formula seems accurate for battery current, but for USB current around 70mA
+ * per step was seen on Kobo Clara HD but all sources show the same formula
+ * also fur USB current. To avoid accidentially unwanted high currents we stick
+ * to that formula
+ */
+#define TO_CUR_REG(x) ((x) / 100000 - 1)
+#define FROM_CUR_REG(x) ((((x) & 0x1f) + 1) * 100000)
+#define CHG_MIN_CUR 100000
+#define CHG_MAX_CUR 1800000
+#define ADP_MAX_CUR 2500000
+#define USB_MAX_CUR 1400000
+
+
 struct rn5t618_power_info {
 	struct rn5t618 *rn5t618;
 	struct platform_device *pdev;
@@ -61,12 +75,16 @@ static enum power_supply_usb_type rn5t618_usb_types[] = {
 };
 
 static enum power_supply_property rn5t618_usb_props[] = {
+	/* input current limit is not very accurate */
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_USB_TYPE,
 	POWER_SUPPLY_PROP_ONLINE,
 };
 
 static enum power_supply_property rn5t618_adp_props[] = {
+	/* input current limit is not very accurate */
+	POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
 	POWER_SUPPLY_PROP_STATUS,
 	POWER_SUPPLY_PROP_ONLINE,
 };
@@ -82,6 +100,7 @@ static enum power_supply_property rn5t618_battery_props[] = {
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
 	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT,
 	POWER_SUPPLY_PROP_CHARGE_FULL,
 	POWER_SUPPLY_PROP_CHARGE_NOW,
 };
@@ -271,6 +290,36 @@ static int rn5t618_battery_ttf(struct rn5t618_power_info *info,
 	return 0;
 }
 
+static int rn5t618_battery_set_current_limit(struct rn5t618_power_info *info,
+				const union power_supply_propval *val)
+{
+	if (val->intval < CHG_MIN_CUR)
+		return -EINVAL;
+
+	if (val->intval >= CHG_MAX_CUR)
+		return -EINVAL;
+
+	return regmap_update_bits(info->rn5t618->regmap,
+				  RN5T618_CHGISET,
+				  0x1F, TO_CUR_REG(val->intval));
+}
+
+static int rn5t618_battery_get_current_limit(struct rn5t618_power_info *info,
+					     union power_supply_propval *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGISET,
+			  &regval);
+	if (ret < 0)
+		return ret;
+
+	val->intval = FROM_CUR_REG(regval);
+
+	return 0;
+}
+
 static int rn5t618_battery_charge_full(struct rn5t618_power_info *info,
 				       union power_supply_propval *val)
 {
@@ -336,6 +385,9 @@ static int rn5t618_battery_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_TECHNOLOGY:
 		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 		break;
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		ret = rn5t618_battery_get_current_limit(info, val);
+		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL:
 		ret = rn5t618_battery_charge_full(info, val);
 		break;
@@ -349,12 +401,38 @@ static int rn5t618_battery_get_property(struct power_supply *psy,
 	return ret;
 }
 
+static int rn5t618_battery_set_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					const union power_supply_propval *val)
+{
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		return rn5t618_battery_set_current_limit(info, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rn5t618_battery_property_is_writeable(struct power_supply *psy,
+						enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int rn5t618_adp_get_property(struct power_supply *psy,
 				    enum power_supply_property psp,
 				    union power_supply_propval *val)
 {
 	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
 	unsigned int chgstate;
+	unsigned int regval;
 	bool online;
 	int ret;
 
@@ -377,6 +455,14 @@ static int rn5t618_adp_get_property(struct power_supply *psy,
 		if (val->intval != POWER_SUPPLY_STATUS_CHARGING)
 			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 
+		break;
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		ret = regmap_read(info->rn5t618->regmap,
+				  RN5T618_REGISET1, &regval);
+		if (ret < 0)
+			return ret;
+
+		val->intval = FROM_CUR_REG(regval);
 		break;
 	default:
 		return -EINVAL;
@@ -385,6 +471,45 @@ static int rn5t618_adp_get_property(struct power_supply *psy,
 	return 0;
 }
 
+static int rn5t618_adp_set_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    const union power_supply_propval *val)
+{
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+	int ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		if (val->intval > ADP_MAX_CUR)
+			return -EINVAL;
+
+		if (val->intval < CHG_MIN_CUR)
+			return -EINVAL;
+
+		ret = regmap_write(info->rn5t618->regmap, RN5T618_REGISET1,
+				   TO_CUR_REG(val->intval));
+		if (ret < 0)
+			return ret;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rn5t618_adp_property_is_writeable(struct power_supply *psy,
+					     enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int rc5t619_usb_get_type(struct rn5t618_power_info *info,
 				union power_supply_propval *val)
 {
@@ -418,6 +543,7 @@ static int rn5t618_usb_get_property(struct power_supply *psy,
 {
 	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
 	unsigned int chgstate;
+	unsigned int regval;
 	bool online;
 	int ret;
 
@@ -446,6 +572,23 @@ static int rn5t618_usb_get_property(struct power_supply *psy,
 			return -ENODATA;
 
 		return rc5t619_usb_get_type(info, val);
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		ret = regmap_read(info->rn5t618->regmap, RN5T618_CHGCTL1,
+				  &regval);
+		if (ret < 0)
+			return ret;
+
+		val->intval = 0;
+		if (regval & 2) {
+			ret = regmap_read(info->rn5t618->regmap,
+					  RN5T618_REGISET2,
+					  &regval);
+			if (ret < 0)
+				return ret;
+
+			val->intval = FROM_CUR_REG(regval);
+		}
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -453,12 +596,53 @@ static int rn5t618_usb_get_property(struct power_supply *psy,
 	return 0;
 }
 
+static int rn5t618_usb_set_property(struct power_supply *psy,
+				    enum power_supply_property psp,
+				    const union power_supply_propval *val)
+{
+	struct rn5t618_power_info *info = power_supply_get_drvdata(psy);
+	int ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		if (val->intval > USB_MAX_CUR)
+			return -EINVAL;
+
+		if (val->intval < CHG_MIN_CUR)
+			return -EINVAL;
+
+		ret = regmap_write(info->rn5t618->regmap, RN5T618_REGISET2,
+				   0xE0 | TO_CUR_REG(val->intval));
+		if (ret < 0)
+			return ret;
+
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int rn5t618_usb_property_is_writeable(struct power_supply *psy,
+					     enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static const struct power_supply_desc rn5t618_battery_desc = {
 	.name                   = "rn5t618-battery",
 	.type                   = POWER_SUPPLY_TYPE_BATTERY,
 	.properties             = rn5t618_battery_props,
 	.num_properties         = ARRAY_SIZE(rn5t618_battery_props),
 	.get_property           = rn5t618_battery_get_property,
+	.set_property           = rn5t618_battery_set_property,
+	.property_is_writeable  = rn5t618_battery_property_is_writeable,
 };
 
 static const struct power_supply_desc rn5t618_adp_desc = {
@@ -467,6 +651,8 @@ static const struct power_supply_desc rn5t618_adp_desc = {
 	.properties             = rn5t618_adp_props,
 	.num_properties         = ARRAY_SIZE(rn5t618_adp_props),
 	.get_property           = rn5t618_adp_get_property,
+	.set_property           = rn5t618_adp_set_property,
+	.property_is_writeable  = rn5t618_adp_property_is_writeable,
 };
 
 static const struct power_supply_desc rn5t618_usb_desc = {
@@ -477,6 +663,8 @@ static const struct power_supply_desc rn5t618_usb_desc = {
 	.properties             = rn5t618_usb_props,
 	.num_properties         = ARRAY_SIZE(rn5t618_usb_props),
 	.get_property           = rn5t618_usb_get_property,
+	.set_property           = rn5t618_usb_set_property,
+	.property_is_writeable  = rn5t618_usb_property_is_writeable,
 };
 
 static irqreturn_t rn5t618_charger_irq(int irq, void *data)