1 files changed, 400 insertions, 0 deletions
diff --git a/drivers/power/supply/gpio-charger.c b/drivers/power/supply/gpio-charger.c
new file mode 100644
index 000000000..68212b397
--- /dev/null
+++ b/drivers/power/supply/gpio-charger.c
@@ -0,0 +1,400 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  Driver for chargers which report their online status through a GPIO pin
+ */
+
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/gpio/consumer.h>
+
+#include <linux/power/gpio-charger.h>
+
+struct gpio_mapping {
+	u32 limit_ua;
+	u32 gpiodata;
+} __packed;
+
+struct gpio_charger {
+	struct device *dev;
+	unsigned int irq;
+	unsigned int charge_status_irq;
+	bool wakeup_enabled;
+
+	struct power_supply *charger;
+	struct power_supply_desc charger_desc;
+	struct gpio_desc *gpiod;
+	struct gpio_desc *charge_status;
+
+	struct gpio_descs *current_limit_gpios;
+	struct gpio_mapping *current_limit_map;
+	u32 current_limit_map_size;
+	u32 charge_current_limit;
+};
+
+static irqreturn_t gpio_charger_irq(int irq, void *devid)
+{
+	struct power_supply *charger = devid;
+
+	power_supply_changed(charger);
+
+	return IRQ_HANDLED;
+}
+
+static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
+{
+	return power_supply_get_drvdata(psy);
+}
+
+static int set_charge_current_limit(struct gpio_charger *gpio_charger, int val)
+{
+	struct gpio_mapping mapping;
+	int ndescs = gpio_charger->current_limit_gpios->ndescs;
+	struct gpio_desc **gpios = gpio_charger->current_limit_gpios->desc;
+	int i;
+
+	if (!gpio_charger->current_limit_map_size)
+		return -EINVAL;
+
+	for (i = 0; i < gpio_charger->current_limit_map_size; i++) {
+		if (gpio_charger->current_limit_map[i].limit_ua <= val)
+			break;
+	}
+	mapping = gpio_charger->current_limit_map[i];
+
+	for (i = 0; i < ndescs; i++) {
+		bool val = (mapping.gpiodata >> i) & 1;
+		gpiod_set_value_cansleep(gpios[ndescs-i-1], val);
+	}
+
+	gpio_charger->charge_current_limit = mapping.limit_ua;
+
+	dev_dbg(gpio_charger->dev, "set charge current limit to %d (requested: %d)\n",
+		gpio_charger->charge_current_limit, val);
+
+	return 0;
+}
+
+static int gpio_charger_get_property(struct power_supply *psy,
+		enum power_supply_property psp, union power_supply_propval *val)
+{
+	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = gpiod_get_value_cansleep(gpio_charger->gpiod);
+		break;
+	case POWER_SUPPLY_PROP_STATUS:
+		if (gpiod_get_value_cansleep(gpio_charger->charge_status))
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		else
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		break;
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		val->intval = gpio_charger->charge_current_limit;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int gpio_charger_set_property(struct power_supply *psy,
+	enum power_supply_property psp, const union power_supply_propval *val)
+{
+	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		return set_charge_current_limit(gpio_charger, val->intval);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int gpio_charger_property_is_writeable(struct power_supply *psy,
+					      enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		return 1;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static enum power_supply_type gpio_charger_get_type(struct device *dev)
+{
+	const char *chargetype;
+
+	if (!device_property_read_string(dev, "charger-type", &chargetype)) {
+		if (!strcmp("unknown", chargetype))
+			return POWER_SUPPLY_TYPE_UNKNOWN;
+		if (!strcmp("battery", chargetype))
+			return POWER_SUPPLY_TYPE_BATTERY;
+		if (!strcmp("ups", chargetype))
+			return POWER_SUPPLY_TYPE_UPS;
+		if (!strcmp("mains", chargetype))
+			return POWER_SUPPLY_TYPE_MAINS;
+		if (!strcmp("usb-sdp", chargetype))
+			return POWER_SUPPLY_TYPE_USB;
+		if (!strcmp("usb-dcp", chargetype))
+			return POWER_SUPPLY_TYPE_USB;
+		if (!strcmp("usb-cdp", chargetype))
+			return POWER_SUPPLY_TYPE_USB;
+		if (!strcmp("usb-aca", chargetype))
+			return POWER_SUPPLY_TYPE_USB;
+	}
+	dev_warn(dev, "unknown charger type %s\n", chargetype);
+
+	return POWER_SUPPLY_TYPE_UNKNOWN;
+}
+
+static int gpio_charger_get_irq(struct device *dev, void *dev_id,
+				struct gpio_desc *gpio)
+{
+	int ret, irq = gpiod_to_irq(gpio);
+
+	if (irq > 0) {
+		ret = devm_request_any_context_irq(dev, irq, gpio_charger_irq,
+						   IRQF_TRIGGER_RISING |
+						   IRQF_TRIGGER_FALLING,
+						   dev_name(dev),
+						   dev_id);
+		if (ret < 0) {
+			dev_warn(dev, "Failed to request irq: %d\n", ret);
+			irq = 0;
+		}
+	}
+
+	return irq;
+}
+
+static int init_charge_current_limit(struct device *dev,
+				    struct gpio_charger *gpio_charger)
+{
+	int i, len;
+	u32 cur_limit = U32_MAX;
+
+	gpio_charger->current_limit_gpios = devm_gpiod_get_array_optional(dev,
+		"charge-current-limit", GPIOD_OUT_LOW);
+	if (IS_ERR(gpio_charger->current_limit_gpios)) {
+		dev_err(dev, "error getting current-limit GPIOs\n");
+		return PTR_ERR(gpio_charger->current_limit_gpios);
+	}
+
+	if (!gpio_charger->current_limit_gpios)
+		return 0;
+
+	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
+		NULL, 0);
+	if (len < 0)
+		return len;
+
+	if (len == 0 || len % 2) {
+		dev_err(dev, "invalid charge-current-limit-mapping length\n");
+		return -EINVAL;
+	}
+
+	gpio_charger->current_limit_map = devm_kmalloc_array(dev,
+		len / 2, sizeof(*gpio_charger->current_limit_map), GFP_KERNEL);
+	if (!gpio_charger->current_limit_map)
+		return -ENOMEM;
+
+	gpio_charger->current_limit_map_size = len / 2;
+
+	len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
+		(u32*) gpio_charger->current_limit_map, len);
+	if (len < 0)
+		return len;
+
+	for (i=0; i < gpio_charger->current_limit_map_size; i++) {
+		if (gpio_charger->current_limit_map[i].limit_ua > cur_limit) {
+			dev_err(dev, "charge-current-limit-mapping not sorted by current in descending order\n");
+			return -EINVAL;
+		}
+
+		cur_limit = gpio_charger->current_limit_map[i].limit_ua;
+	}
+
+	/* default to smallest current limitation for safety reasons */
+	len = gpio_charger->current_limit_map_size - 1;
+	set_charge_current_limit(gpio_charger,
+		gpio_charger->current_limit_map[len].limit_ua);
+
+	return 0;
+}
+
+/*
+ * The entries will be overwritten by driver's probe routine depending
+ * on the available features. This list ensures, that the array is big
+ * enough for all optional features.
+ */
+static enum power_supply_property gpio_charger_properties[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
+};
+
+static int gpio_charger_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct gpio_charger_platform_data *pdata = dev->platform_data;
+	struct power_supply_config psy_cfg = {};
+	struct gpio_charger *gpio_charger;
+	struct power_supply_desc *charger_desc;
+	struct gpio_desc *charge_status;
+	int charge_status_irq;
+	int ret;
+	int num_props = 0;
+
+	if (!pdata && !dev->of_node) {
+		dev_err(dev, "No platform data\n");
+		return -ENOENT;
+	}
+
+	gpio_charger = devm_kzalloc(dev, sizeof(*gpio_charger), GFP_KERNEL);
+	if (!gpio_charger)
+		return -ENOMEM;
+	gpio_charger->dev = dev;
+
+	/*
+	 * This will fetch a GPIO descriptor from device tree, ACPI or
+	 * boardfile descriptor tables. It's good to try this first.
+	 */
+	gpio_charger->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
+	if (IS_ERR(gpio_charger->gpiod)) {
+		/* Just try again if this happens */
+		return dev_err_probe(dev, PTR_ERR(gpio_charger->gpiod),
+				     "error getting GPIO descriptor\n");
+	}
+
+	if (gpio_charger->gpiod) {
+		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_ONLINE;
+		num_props++;
+	}
+
+	charge_status = devm_gpiod_get_optional(dev, "charge-status", GPIOD_IN);
+	if (IS_ERR(charge_status))
+		return PTR_ERR(charge_status);
+	if (charge_status) {
+		gpio_charger->charge_status = charge_status;
+		gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_STATUS;
+		num_props++;
+	}
+
+	ret = init_charge_current_limit(dev, gpio_charger);
+	if (ret < 0)
+		return ret;
+	if (gpio_charger->current_limit_map) {
+		gpio_charger_properties[num_props] =
+			POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
+		num_props++;
+	}
+
+	charger_desc = &gpio_charger->charger_desc;
+	charger_desc->properties = gpio_charger_properties;
+	charger_desc->num_properties = num_props;
+	charger_desc->get_property = gpio_charger_get_property;
+	charger_desc->set_property = gpio_charger_set_property;
+	charger_desc->property_is_writeable =
+					gpio_charger_property_is_writeable;
+
+	psy_cfg.of_node = dev->of_node;
+	psy_cfg.drv_data = gpio_charger;
+
+	if (pdata) {
+		charger_desc->name = pdata->name;
+		charger_desc->type = pdata->type;
+		psy_cfg.supplied_to = pdata->supplied_to;
+		psy_cfg.num_supplicants = pdata->num_supplicants;
+	} else {
+		charger_desc->name = dev->of_node->name;
+		charger_desc->type = gpio_charger_get_type(dev);
+	}
+
+	if (!charger_desc->name)
+		charger_desc->name = pdev->name;
+
+	gpio_charger->charger = devm_power_supply_register(dev, charger_desc,
+							   &psy_cfg);
+	if (IS_ERR(gpio_charger->charger)) {
+		ret = PTR_ERR(gpio_charger->charger);
+		dev_err(dev, "Failed to register power supply: %d\n", ret);
+		return ret;
+	}
+
+	gpio_charger->irq = gpio_charger_get_irq(dev, gpio_charger->charger,
+						 gpio_charger->gpiod);
+
+	charge_status_irq = gpio_charger_get_irq(dev, gpio_charger->charger,
+						 gpio_charger->charge_status);
+	gpio_charger->charge_status_irq = charge_status_irq;
+
+	platform_set_drvdata(pdev, gpio_charger);
+
+	device_init_wakeup(dev, 1);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int gpio_charger_suspend(struct device *dev)
+{
+	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		gpio_charger->wakeup_enabled =
+			!enable_irq_wake(gpio_charger->irq);
+
+	return 0;
+}
+
+static int gpio_charger_resume(struct device *dev)
+{
+	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
+		disable_irq_wake(gpio_charger->irq);
+	power_supply_changed(gpio_charger->charger);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
+		gpio_charger_suspend, gpio_charger_resume);
+
+static const struct of_device_id gpio_charger_match[] = {
+	{ .compatible = "gpio-charger" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gpio_charger_match);
+
+static struct platform_driver gpio_charger_driver = {
+	.probe = gpio_charger_probe,
+	.driver = {
+		.name = "gpio-charger",
+		.pm = &gpio_charger_pm_ops,
+		.of_match_table = gpio_charger_match,
+	},
+};
+
+module_platform_driver(gpio_charger_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Driver for chargers only communicating via GPIO(s)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-charger");