Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 238 insertions, 0 deletions

diff --git a/drivers/power/supply/lego_ev3_battery.c b/drivers/power/supply/lego_ev3_battery.c
new file mode 100644
index 000000000..1ae371090
--- /dev/null
+++ b/drivers/power/supply/lego_ev3_battery.c
@@ -0,0 +1,238 @@
+/*
+ * Battery driver for LEGO MINDSTORMS EV3
+ *
+ * Copyright (C) 2017 David Lechner <david@lechnology.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+
+struct lego_ev3_battery {
+	struct iio_channel *iio_v;
+	struct iio_channel *iio_i;
+	struct gpio_desc *rechargeable_gpio;
+	struct power_supply *psy;
+	int technology;
+	int v_max;
+	int v_min;
+};
+
+static int lego_ev3_battery_get_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 union power_supply_propval *val)
+{
+	struct lego_ev3_battery *batt = power_supply_get_drvdata(psy);
+	int ret, val2;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = batt->technology;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		/* battery voltage is iio channel * 2 + Vce of transistor */
+		ret = iio_read_channel_processed(batt->iio_v, &val->intval);
+		if (ret)
+			return ret;
+
+		val->intval *= 2000;
+		val->intval += 50000;
+
+		/* plus adjust for shunt resistor drop */
+		ret = iio_read_channel_processed(batt->iio_i, &val2);
+		if (ret)
+			return ret;
+
+		val2 *= 1000;
+		val2 /= 15;
+		val->intval += val2;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		val->intval = batt->v_max;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		val->intval = batt->v_min;
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		/* battery current is iio channel / 15 / 0.05 ohms */
+		ret = iio_read_channel_processed(batt->iio_i, &val->intval);
+		if (ret)
+			return ret;
+
+		val->intval *= 20000;
+		val->intval /= 15;
+		break;
+	case POWER_SUPPLY_PROP_SCOPE:
+		val->intval = POWER_SUPPLY_SCOPE_SYSTEM;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int lego_ev3_battery_set_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 const union power_supply_propval *val)
+{
+	struct lego_ev3_battery *batt = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		/*
+		 * Only allow changing technology from Unknown to NiMH. Li-ion
+		 * batteries are automatically detected and should not be
+		 * overridden. Rechargeable AA batteries, on the other hand,
+		 * cannot be automatically detected, and so must be manually
+		 * specified. This should only be set once during system init,
+		 * so there is no mechanism to go back to Unknown.
+		 */
+		if (batt->technology != POWER_SUPPLY_TECHNOLOGY_UNKNOWN)
+			return -EINVAL;
+		switch (val->intval) {
+		case POWER_SUPPLY_TECHNOLOGY_NiMH:
+			batt->technology = POWER_SUPPLY_TECHNOLOGY_NiMH;
+			batt->v_max = 7800000;
+			batt->v_min = 5400000;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int lego_ev3_battery_property_is_writeable(struct power_supply *psy,
+						  enum power_supply_property psp)
+{
+	struct lego_ev3_battery *batt = power_supply_get_drvdata(psy);
+
+	return psp == POWER_SUPPLY_PROP_TECHNOLOGY &&
+		batt->technology == POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
+}
+
+static enum power_supply_property lego_ev3_battery_props[] = {
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_SCOPE,
+};
+
+static const struct power_supply_desc lego_ev3_battery_desc = {
+	.name			= "lego-ev3-battery",
+	.type			= POWER_SUPPLY_TYPE_BATTERY,
+	.properties		= lego_ev3_battery_props,
+	.num_properties		= ARRAY_SIZE(lego_ev3_battery_props),
+	.get_property		= lego_ev3_battery_get_property,
+	.set_property		= lego_ev3_battery_set_property,
+	.property_is_writeable	= lego_ev3_battery_property_is_writeable,
+};
+
+static int lego_ev3_battery_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct lego_ev3_battery *batt;
+	struct power_supply_config psy_cfg = {};
+	int err;
+
+	batt = devm_kzalloc(dev, sizeof(*batt), GFP_KERNEL);
+	if (!batt)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, batt);
+
+	batt->iio_v = devm_iio_channel_get(dev, "voltage");
+	err = PTR_ERR_OR_ZERO(batt->iio_v);
+	if (err) {
+		if (err != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get voltage iio channel\n");
+		return err;
+	}
+
+	batt->iio_i = devm_iio_channel_get(dev, "current");
+	err = PTR_ERR_OR_ZERO(batt->iio_i);
+	if (err) {
+		if (err != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get current iio channel\n");
+		return err;
+	}
+
+	batt->rechargeable_gpio = devm_gpiod_get(dev, "rechargeable", GPIOD_IN);
+	err = PTR_ERR_OR_ZERO(batt->rechargeable_gpio);
+	if (err) {
+		if (err != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get rechargeable gpio\n");
+		return err;
+	}
+
+	/*
+	 * The rechargeable battery indication switch cannot be changed without
+	 * removing the battery, so we only need to read it once.
+	 */
+	if (gpiod_get_value(batt->rechargeable_gpio)) {
+		/* 2-cell Li-ion, 7.4V nominal */
+		batt->technology = POWER_SUPPLY_TECHNOLOGY_LION;
+		batt->v_max = 84000000;
+		batt->v_min = 60000000;
+	} else {
+		/* 6x AA Alkaline, 9V nominal */
+		batt->technology = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
+		batt->v_max = 90000000;
+		batt->v_min = 48000000;
+	}
+
+	psy_cfg.of_node = pdev->dev.of_node;
+	psy_cfg.drv_data = batt;
+
+	batt->psy = devm_power_supply_register(dev, &lego_ev3_battery_desc,
+					       &psy_cfg);
+	err = PTR_ERR_OR_ZERO(batt->psy);
+	if (err) {
+		dev_err(dev, "failed to register power supply\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id of_lego_ev3_battery_match[] = {
+	{ .compatible = "lego,ev3-battery", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, of_lego_ev3_battery_match);
+
+static struct platform_driver lego_ev3_battery_driver = {
+	.driver	= {
+		.name		= "lego-ev3-battery",
+		.of_match_table = of_lego_ev3_battery_match,
+	},
+	.probe	= lego_ev3_battery_probe,
+};
+module_platform_driver(lego_ev3_battery_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Lechner <david@lechnology.com>");
+MODULE_DESCRIPTION("LEGO MINDSTORMS EV3 Battery Driver");