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Date:   Wed, 21 Apr 2021 11:03:54 +0200
From:   Hermann.Lauer@uni-heidelberg.de
To:     sre@kernel.org, wens@csie.org
Cc:     linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH] axp209 PMIC: setting constant_charge_current to 0
 disables battery charging
Message-ID: <20210421090354.GF19953@lemon.iwr.uni-heidelberg.de>
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User-Agent: Mutt/1.10.1 (2018-07-13)
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Dear Maintainers,

this proposed patch allows setting constant_charge_current to 0 on axp209
PMIC to disable charging. constant_charge_current_max with a value of 0 makes
no sense and should still report the maximum allowed value, so the getter code
is unrolled for the POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT case.

This works on the axp209 of Banana{Pi M1,Pi M1+,Pro}. I have no access to
the other chips the driver deals with.

Thanks for comments and greetings
  Hermann

Signed-off-by: Hermann.Lauer@uni-heidelberg.de
---
 patches/axp209-charge-current0.patchl | 18 ++++++++++--------
 1 files changed, 10 insertions(+), 8 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)
@@ -249,11 +250,18 @@
 		break;
 
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
-		ret = axp20x_get_constant_charge_current(axp20x_batt,
-							 &val->intval);
+		ret = regmap_read(axp20x_batt->regmap, AXP20X_CHRG_CTRL1, &val->intval);
 		if (ret)
 			return ret;
-		break;
+
+		if (val->intval & AXP20X_CHRG_CTRL1_ENABLE) {
+			val->intval &= AXP20X_CHRG_CTRL1_TGT_CURR;
+			val->intval = val->intval * axp20x_batt->data->ccc_scale +
+					axp20x_batt->data->ccc_offset;
+		} else
+			val->intval = 0;
+
+		return 0;
 
 	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
 		val->intval = axp20x_batt->max_ccc;
@@ -392,6 +400,10 @@
 static int axp20x_set_constant_charge_current(struct axp20x_batt_ps *axp_batt,
 					      int charge_current)
 {
+	if (charge_current == 0)
+		return regmap_update_bits(axp_batt->regmap, AXP20X_CHRG_CTRL1,
+				  AXP20X_CHRG_CTRL1_ENABLE, 0);
+
 	if (charge_current > axp_batt->max_ccc)
 		return -EINVAL;
 
@@ -402,7 +414,8 @@
 		return -EINVAL;
 
 	return regmap_update_bits(axp_batt->regmap, AXP20X_CHRG_CTRL1,
-				  AXP20X_CHRG_CTRL1_TGT_CURR, charge_current);
+				  AXP20X_CHRG_CTRL1_TGT_CURR | AXP20X_CHRG_CTRL1_ENABLE,
+				  charge_current | AXP20X_CHRG_CTRL1_ENABLE);
 }
 
 static int axp20x_set_max_constant_charge_current(struct axp20x_batt_ps *axp,