[PATCH v2 5/5] power: supply: axp20x_usb_power: set input current limit in probe

[Aren Moynihan <aren@peacevolution.org>]

axp803 sets the current limit to 3A by default if it doesn't detect a
battery. The datasheet says that register 0x2D bit 6 is used to indicate
first power on status. According to it, if that bit is 0 and the battery
is not detected, it will set the input current limit to 3A, however
setting that bit to 1 doesn't to prevent the pmic from setting the
current limit to 3A.

Waiting for USB BC detection doesn't work either, because (as far as I
can tell) USB BC detection isn't performed when there isn't a battery
detected.

Fixes: c279adafe6ab ("power: supply: axp20x_usb_power: add support for AXP813")

Signed-off-by: Aren Moynihan <aren@peacevolution.org>
---
I'm not sure if the pmic simply ignores the first power on field, or if
it needs to be set in a specific way / at a specific time. I tried
setting it in arm-trusted-firmware, and the pmic still set the input
current limit to 3A.

The datasheet for axp813 says it has the same first power on bit, but I
don't have hardware to test if it behaves the same way. This driver uses
the same platform data for axp803 and axp813.

(no changes since v1)

 drivers/power/supply/axp20x_usb_power.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/power/supply/axp20x_usb_power.c b/drivers/power/supply/axp20x_usb_power.c
index dae7e5cfc54e..751b9f02d36f 100644
--- a/drivers/power/supply/axp20x_usb_power.c
+++ b/drivers/power/supply/axp20x_usb_power.c
@@ -51,6 +51,7 @@ struct axp_data {
 	unsigned int			num_irq_names;
 	const int			*curr_lim_table;
 	int				curr_lim_table_size;
+	int				force_curr_lim;
 	struct reg_field		curr_lim_fld;
 	struct reg_field		vbus_valid_bit;
 	struct reg_field		vbus_mon_bit;
@@ -545,6 +546,7 @@ static const struct axp_data axp813_data = {
 	.curr_lim_table = axp813_usb_curr_lim_table,
 	.curr_lim_table_size = ARRAY_SIZE(axp813_usb_curr_lim_table),
 	.curr_lim_fld	= REG_FIELD(AXP22X_CHRG_CTRL3, 4, 7),
+	.force_curr_lim = 500000,
 	.usb_bc_en_bit	= REG_FIELD(AXP288_BC_GLOBAL, 0, 0),
 	.usb_bc_det_fld = REG_FIELD(AXP288_BC_DET_STAT, 5, 7),
 	.vbus_disable_bit = REG_FIELD(AXP20X_VBUS_IPSOUT_MGMT, 7, 7),
@@ -726,6 +728,17 @@ static int axp20x_usb_power_probe(struct platform_device *pdev)
 			return ret;
 	}
 
+	if (power->axp_data->force_curr_lim) {
+		/*
+		 * Some chips set the input current limit to 3A when there is no
+		 * battery connected. Normally the default is 500mA.
+		 */
+		ret = axp20x_usb_power_set_input_current_limit(power,
+				power->axp_data->force_curr_lim);
+		if (ret)
+			return ret;
+	}
+
 	if (power->usb_bc_en_bit) {
 		/* Enable USB Battery Charging specification detection */
 		ret = regmap_field_write(power->usb_bc_en_bit, 1);
-- 
2.43.0