[PATCH v3] power: supply: axp20x_battery: implement writeable status to enable/disable battery charging

[Hermann Lauer]

Allow disabling and reenabling battery charging of an axp209 PMIC through a
writable status property. With the current driver code charging is always on.

This works on the axp209 of Banana {Pi M1+,Pro} and should work on all AXP chips.

Signed-off-by: Hermann.Lauer@xxxxxxxxxxxxxxxxx
---
v2: add fallthrough and improve commit message (thanks to Maxime and ChenYu)
v3: fix fallthrough usage

Thanks to ChenYu for the idea and greetings
  Hermann

 drivers/power/supply/axp20x_battery.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/axp20x_battery.c b/drivers/power/supply/axp20x_battery.c
--- a/drivers/power/supply/axp20x_battery.c
+++ b/drivers/power/supply/axp20x_battery.c
@@ -40,6 +40,7 @@
 #define AXP209_FG_PERCENT		GENMASK(6, 0)
 #define AXP22X_FG_VALID			BIT(7)
 
+#define AXP20X_CHRG_CTRL1_ENABLE	BIT(7)
 #define AXP20X_CHRG_CTRL1_TGT_VOLT	GENMASK(6, 5)
 #define AXP20X_CHRG_CTRL1_TGT_4_1V	(0 << 5)
 #define AXP20X_CHRG_CTRL1_TGT_4_15V	(1 << 5)
@@ -468,7 +469,18 @@
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
 		return axp20x_set_max_constant_charge_current(axp20x_batt,
 							      val->intval);
+	case POWER_SUPPLY_PROP_STATUS:
+		switch (val->intval) {
+		case POWER_SUPPLY_STATUS_CHARGING:
+			return regmap_update_bits(axp20x_batt->regmap, AXP20X_CHRG_CTRL1,
+				AXP20X_CHRG_CTRL1_ENABLE, AXP20X_CHRG_CTRL1_ENABLE);
 
+		case POWER_SUPPLY_STATUS_DISCHARGING:
+		case POWER_SUPPLY_STATUS_NOT_CHARGING:
+			return regmap_update_bits(axp20x_batt->regmap, AXP20X_CHRG_CTRL1,
+				AXP20X_CHRG_CTRL1_ENABLE, 0);
+		}
+		fallthrough;
 	default:
 		return -EINVAL;
 	}
@@ -491,7 +503,8 @@
 static int axp20x_battery_prop_writeable(struct power_supply *psy,
 					 enum power_supply_property psp)
 {
-	return psp == POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN ||
+	return psp == POWER_SUPPLY_PROP_STATUS ||
+	       psp == POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN ||
 	       psp == POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN ||
 	       psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT ||
 	       psp == POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;