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 <redacted>
---
 drivers/power/supply/axp20x_usb_power.c | 72 +++++++++++++++++++++++++++++++++
 include/linux/mfd/axp20x.h              |  3 ++
 2 files changed, 75 insertions(+)

diff --git a/drivers/power/supply/axp20x_usb_power.c b/drivers/power/supply/axp20x_usb_power.c
index b19754e..638cb52 100644
--- a/drivers/power/supply/axp20x_usb_power.c
+++ b/drivers/power/supply/axp20x_usb_power.c

@@ -155,6 +155,74 @@ static int axp20x_usb_power_get_property(struct power_supply *psy,
        return 0;
 }

+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);
+       int ret, val1;
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+               switch (val->intval) {
+               case 4000000:
+               case 4100000:
+               case 4200000:
+               case 4300000:
+               case 4400000:
+               case 4500000:
+               case 4600000:
+               case 4700000:
+                       val1 = (val->intval - 4000000) / 100000;
+                       ret = regmap_update_bits(power->regmap,
+                                                AXP20X_VBUS_IPSOUT_MGMT,
+                                                AXP20X_VBUS_VHOLD_MASK,
+                                                val1 << 3);

+                       if (ret)
+                               return ret;
+
+                       return 0;
+               default:
+                       return -EINVAL;
+               }
+
+               return 0;
+
+       case POWER_SUPPLY_PROP_CURRENT_MAX:
+               switch (val->intval) {
+               case 100000:
+                       if (power->axp20x_id == AXP221_ID)
+                               return -EINVAL;
+               case 500000:
+               case 900000:
+                       val1 = (900000 - val->intval) / 400000;
+                       ret = regmap_update_bits(power->regmap,
+                                                AXP20X_VBUS_IPSOUT_MGMT,
+                                                AXP20X_VBUS_CLIMIT_MASK, val1);
+                       if (ret)
+                               return ret;
+
+                       return 0;
+               default:
+                       return -EINVAL;
+               }
+
+               return 0;
+
+       default:
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+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 +246,9 @@ 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 +256,9 @@ 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 const struct of_device_id axp20x_usb_power_match[] = {

diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
index fec597f..8883595 100644
--- a/include/linux/mfd/axp20x.h
+++ b/include/linux/mfd/axp20x.h

@@ -56,6 +56,9 @@ enum {
 #define AXP20X_LDO24_V_OUT             0x28
 #define AXP20X_LDO3_V_OUT              0x29
 #define AXP20X_VBUS_IPSOUT_MGMT                0x30
+
+#define AXP20X_VBUS_VHOLD_MASK         GENMASK(5, 3)
+