power: supply: axp20x_usb_power: add input-current-limit-microamp

Allow users to specify a maximum input current for the device. Some
devices allow up to 3.25A of input current (such as the AXP717), which
may be too much for some implementations.
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240821215456.962564-7-macroalpha82@gmail.comSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/supply/axp20x_usb_power.c

@@ -80,6 +80,7 @@ struct axp20x_usb_power {
 	struct iio_channel *vbus_v;
 	struct iio_channel *vbus_i;
 	struct delayed_work vbus_detect;
+	int max_input_cur;
 	unsigned int old_status;
 	unsigned int online;
 	unsigned int num_irqs;
@@ -323,6 +324,13 @@ static int axp20x_usb_power_set_input_current_limit(struct axp20x_usb_power *pow
 	if (intval == -1)
 		return -EINVAL;
 
+	if (power->max_input_cur && (intval > power->max_input_cur)) {
+		dev_warn(power->dev,
+			 "reqested current %d clamped to max current %d\n",
+			 intval, power->max_input_cur);
+		intval = power->max_input_cur;
+	}
+
 	/*
 	 * BC1.2 detection can cause a race condition if we try to set a current
 	 * limit while it's in progress. When it finishes it will overwrite the
@@ -661,6 +669,18 @@ static int axp20x_regmap_field_alloc_optional(struct device *dev,
 	return 0;
 }
 
+/* Optionally allow users to specify a maximum charging current. */
+static void axp20x_usb_power_parse_dt(struct device *dev,
+				      struct axp20x_usb_power *power)
+{
+	int ret;
+
+	ret = device_property_read_u32(dev, "input-current-limit-microamp",
+				       &power->max_input_cur);
+	if (ret)
+		dev_dbg(dev, "%s() no input-current-limit specified\n", __func__);
+}
+
 static int axp20x_usb_power_probe(struct platform_device *pdev)
 {
 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
@@ -697,6 +717,8 @@ static int axp20x_usb_power_probe(struct platform_device *pdev)
 	if (IS_ERR(power->curr_lim_fld))
 		return PTR_ERR(power->curr_lim_fld);
 
+	axp20x_usb_power_parse_dt(&pdev->dev, power);
+
 	ret = axp20x_regmap_field_alloc_optional(&pdev->dev, power->regmap,
 						 axp_data->vbus_valid_bit,
 						 &power->vbus_valid_bit);