power: supply: axp20x_usb_power: set min voltage and max current from sysfs

AXP20X and AXP22X PMICs allow setting the min voltage and max current of
VBUS power supply. This adds entries in sysfs to allow to do so.
Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/supply/axp20x_usb_power.c

@@ -31,6 +31,8 @@
 #define AXP20X_USB_STATUS_VBUS_VALID	BIT(2)
 
 #define AXP20X_VBUS_VHOLD_uV(b)		(4000000 + (((b) >> 3) & 7) * 100000)
+#define AXP20X_VBUS_VHOLD_MASK		GENMASK(5, 3)
+#define AXP20X_VBUS_VHOLD_OFFSET	3
 #define AXP20X_VBUS_CLIMIT_MASK		3
 #define AXP20X_VBUC_CLIMIT_900mA	0
 #define AXP20X_VBUC_CLIMIT_500mA	1
@@ -155,6 +157,81 @@ static int axp20x_usb_power_get_property(struct power_supply *psy,
 	return 0;
 }
 
+static int axp20x_usb_power_set_voltage_min(struct axp20x_usb_power *power,
+					    int intval)
+{
+	int val;
+
+	switch (intval) {
+	case 4000000:
+	case 4100000:
+	case 4200000:
+	case 4300000:
+	case 4400000:
+	case 4500000:
+	case 4600000:
+	case 4700000:
+		val = (intval - 4000000) / 100000;
+		return regmap_update_bits(power->regmap,
+					  AXP20X_VBUS_IPSOUT_MGMT,
+					  AXP20X_VBUS_VHOLD_MASK,
+					  val << AXP20X_VBUS_VHOLD_OFFSET);
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int axp20x_usb_power_set_current_max(struct axp20x_usb_power *power,
+					    int intval)
+{
+	int val;
+
+	switch (intval) {
+	case 100000:
+		if (power->axp20x_id == AXP221_ID)
+			return -EINVAL;
+	case 500000:
+	case 900000:
+		val = (900000 - intval) / 400000;
+		return regmap_update_bits(power->regmap,
+					  AXP20X_VBUS_IPSOUT_MGMT,
+					  AXP20X_VBUS_CLIMIT_MASK, val);
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int axp20x_usb_power_set_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 const union power_supply_propval *val)
+{
+	struct axp20x_usb_power *power = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+		return axp20x_usb_power_set_voltage_min(power, val->intval);
+
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		return axp20x_usb_power_set_current_max(power, val->intval);
+
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+static int axp20x_usb_power_prop_writeable(struct power_supply *psy,
+					   enum power_supply_property psp)
+{
+	return psp == POWER_SUPPLY_PROP_VOLTAGE_MIN ||
+	       psp == POWER_SUPPLY_PROP_CURRENT_MAX;
+}
+
 static enum power_supply_property axp20x_usb_power_properties[] = {
 	POWER_SUPPLY_PROP_HEALTH,
 	POWER_SUPPLY_PROP_PRESENT,
@@ -178,7 +255,9 @@ static const struct power_supply_desc axp20x_usb_power_desc = {
 	.type = POWER_SUPPLY_TYPE_USB,
 	.properties = axp20x_usb_power_properties,
 	.num_properties = ARRAY_SIZE(axp20x_usb_power_properties),
+	.property_is_writeable = axp20x_usb_power_prop_writeable,
 	.get_property = axp20x_usb_power_get_property,
+	.set_property = axp20x_usb_power_set_property,
 };
 
 static const struct power_supply_desc axp22x_usb_power_desc = {
@@ -186,7 +265,9 @@ static const struct power_supply_desc axp22x_usb_power_desc = {
 	.type = POWER_SUPPLY_TYPE_USB,
 	.properties = axp22x_usb_power_properties,
 	.num_properties = ARRAY_SIZE(axp22x_usb_power_properties),
+	.property_is_writeable = axp20x_usb_power_prop_writeable,
 	.get_property = axp20x_usb_power_get_property,
+	.set_property = axp20x_usb_power_set_property,
 };
 
 static int axp20x_usb_power_probe(struct platform_device *pdev)