text: /*
   *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   *  Driver for chargers which report their online status through a GPIO pin
   *
   *  This program is free software; you can redistribute it and/or modify it
   *  under  the terms of the GNU General  Public License as published by the
   *  Free Software Foundation;  either version 2 of the License, or (at your
   *  option) any later version.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  675 Mass Ave, Cambridge, MA 02139, USA.
   *
   */
  
  #include <linux/device.h>
  #include <linux/gpio.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/of_gpio.h>
  
  #include <linux/power/gpio-charger.h>
  
  struct gpio_charger {
  	const struct gpio_charger_platform_data *pdata;
  	unsigned int irq;
  	bool wakeup_enabled;
  
  	struct power_supply charger;
  };
  
  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 container_of(psy, struct gpio_charger, charger);
  }
  
  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);
  	const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = !!gpio_get_value_cansleep(pdata->gpio);
  		val->intval ^= pdata->gpio_active_low;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static enum power_supply_property gpio_charger_properties[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static
  struct gpio_charger_platform_data *gpio_charger_parse_dt(struct device *dev)
  {
  	struct device_node *np = dev->of_node;
  	struct gpio_charger_platform_data *pdata;
  	const char *chargetype;
  	enum of_gpio_flags flags;
  	int ret;
  
  	if (!np)
  		return ERR_PTR(-ENOENT);
  
  	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return ERR_PTR(-ENOMEM);
  
  	pdata->name = np->name;
  
  	pdata->gpio = of_get_gpio_flags(np, 0, &flags);
  	if (pdata->gpio < 0) {
  		if (pdata->gpio != -EPROBE_DEFER)
  			dev_err(dev, "could not get charger gpio\n");
  		return ERR_PTR(pdata->gpio);
  	}
  
  	pdata->gpio_active_low = !!(flags & OF_GPIO_ACTIVE_LOW);
  
  	pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
  	ret = of_property_read_string(np, "charger-type", &chargetype);
  	if (ret >= 0) {
  		if (!strncmp("unknown", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
  		else if (!strncmp("battery", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_BATTERY;
  		else if (!strncmp("ups", chargetype, 3))
  			pdata->type = POWER_SUPPLY_TYPE_UPS;
  		else if (!strncmp("mains", chargetype, 5))
  			pdata->type = POWER_SUPPLY_TYPE_MAINS;
  		else if (!strncmp("usb-sdp", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_USB;
  		else if (!strncmp("usb-dcp", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_USB_DCP;
  		else if (!strncmp("usb-cdp", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_USB_CDP;
  		else if (!strncmp("usb-aca", chargetype, 7))
  			pdata->type = POWER_SUPPLY_TYPE_USB_ACA;
  		else
  			dev_warn(dev, "unknown charger type %s\n", chargetype);
  	}
  
  	return pdata;
  }
  
  static int gpio_charger_probe(struct platform_device *pdev)
  {
  	const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
  	struct gpio_charger *gpio_charger;
  	struct power_supply *charger;
  	int ret;
  	int irq;
  
  	if (!pdata) {
  		pdata = gpio_charger_parse_dt(&pdev->dev);
  		if (IS_ERR(pdata)) {
  			ret = PTR_ERR(pdata);
  			if (ret != -EPROBE_DEFER)
  				dev_err(&pdev->dev, "No platform data\n");
  			return ret;
  		}
  	}
  
  	if (!gpio_is_valid(pdata->gpio)) {
  		dev_err(&pdev->dev, "Invalid gpio pin\n");
  		return -EINVAL;
  	}
  
  	gpio_charger = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger),
  					GFP_KERNEL);
  	if (!gpio_charger) {
  		dev_err(&pdev->dev, "Failed to alloc driver structure\n");
  		return -ENOMEM;
  	}
  
  	charger = &gpio_charger->charger;
  
  	charger->name = pdata->name ? pdata->name : "gpio-charger";
  	charger->type = pdata->type;
  	charger->properties = gpio_charger_properties;
  	charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
  	charger->get_property = gpio_charger_get_property;
  	charger->supplied_to = pdata->supplied_to;
  	charger->num_supplicants = pdata->num_supplicants;
  	charger->of_node = pdev->dev.of_node;
  
  	ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
  	if (ret) {
  		dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
  		goto err_free;
  	}
  	ret = gpio_direction_input(pdata->gpio);
  	if (ret) {
  		dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
  		goto err_gpio_free;
  	}
  
  	gpio_charger->pdata = pdata;
  
  	ret = power_supply_register(&pdev->dev, charger);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Failed to register power supply: %d\n",
  			ret);
  		goto err_gpio_free;
  	}
  
  	irq = gpio_to_irq(pdata->gpio);
  	if (irq > 0) {
  		ret = request_any_context_irq(irq, gpio_charger_irq,
  				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
  				dev_name(&pdev->dev), charger);
  		if (ret < 0)
  			dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
  		else
  			gpio_charger->irq = irq;
  	}
  
  	platform_set_drvdata(pdev, gpio_charger);
  
  	device_init_wakeup(&pdev->dev, 1);
  
  	return 0;
  
  err_gpio_free:
  	gpio_free(pdata->gpio);
  err_free:
  	return ret;
  }
  
  static int gpio_charger_remove(struct platform_device *pdev)
  {
  	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
  
  	if (gpio_charger->irq)
  		free_irq(gpio_charger->irq, &gpio_charger->charger);
  
  	power_supply_unregister(&gpio_charger->charger);
  
  	gpio_free(gpio_charger->pdata->gpio);
  
  	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 platform_device *pdev = to_platform_device(dev);
  	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
  
  	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,
  	.remove = gpio_charger_remove,
  	.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 which report their online status through a GPIO");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:gpio-charger");
  