/*
   * Common power driver for PDAs and phones with one or two external
   * power supplies (AC/USB) connected to main and backup batteries,
   * and optional builtin charger.
   *
   * Copyright © 2007 Anton Vorontsov <cbou@mail.ru>
   *
   * 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.
   */
  
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/err.h>
  #include <linux/interrupt.h>
  #include <linux/notifier.h>
  #include <linux/power_supply.h>
  #include <linux/pda_power.h>
  #include <linux/regulator/consumer.h>
  #include <linux/timer.h>
  #include <linux/jiffies.h>
  #include <linux/usb/otg.h>
  
  static inline unsigned int get_irq_flags(struct resource *res)
  {
  	return IRQF_SHARED | (res->flags & IRQF_TRIGGER_MASK);
  }
  
  static struct device *dev;
  static struct pda_power_pdata *pdata;
  static struct resource *ac_irq, *usb_irq;
  static struct timer_list charger_timer;
  static struct timer_list supply_timer;
  static struct timer_list polling_timer;
  static int polling;
  
  #if IS_ENABLED(CONFIG_USB_PHY)
  static struct usb_phy *transceiver;
  static struct notifier_block otg_nb;
  #endif
  
  static struct regulator *ac_draw;
  
  enum {
  	PDA_PSY_OFFLINE = 0,
  	PDA_PSY_ONLINE = 1,
  	PDA_PSY_TO_CHANGE,
  };
  static int new_ac_status = -1;
  static int new_usb_status = -1;
  static int ac_status = -1;
  static int usb_status = -1;
  
  static int pda_power_get_property(struct power_supply *psy,
  				  enum power_supply_property psp,
  				  union power_supply_propval *val)
  {
  	switch (psp) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		if (psy->type == POWER_SUPPLY_TYPE_MAINS)
  			val->intval = pdata->is_ac_online ?
  				      pdata->is_ac_online() : 0;
  		else
  			val->intval = pdata->is_usb_online ?
  				      pdata->is_usb_online() : 0;
  		break;
  	default:
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static enum power_supply_property pda_power_props[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static char *pda_power_supplied_to[] = {
  	"main-battery",
  	"backup-battery",
  };
  
  static struct power_supply pda_psy_ac = {
  	.name = "ac",
  	.type = POWER_SUPPLY_TYPE_MAINS,
  	.supplied_to = pda_power_supplied_to,
  	.num_supplicants = ARRAY_SIZE(pda_power_supplied_to),
  	.properties = pda_power_props,
  	.num_properties = ARRAY_SIZE(pda_power_props),
  	.get_property = pda_power_get_property,
  };
  
  static struct power_supply pda_psy_usb = {
  	.name = "usb",
  	.type = POWER_SUPPLY_TYPE_USB,
  	.supplied_to = pda_power_supplied_to,
  	.num_supplicants = ARRAY_SIZE(pda_power_supplied_to),
  	.properties = pda_power_props,
  	.num_properties = ARRAY_SIZE(pda_power_props),
  	.get_property = pda_power_get_property,
  };
  
  static void update_status(void)
  {
  	if (pdata->is_ac_online)
  		new_ac_status = !!pdata->is_ac_online();
  
  	if (pdata->is_usb_online)
  		new_usb_status = !!pdata->is_usb_online();
  }
  
  static void update_charger(void)
  {
  	static int regulator_enabled;
  	int max_uA = pdata->ac_max_uA;
  
  	if (pdata->set_charge) {
  		if (new_ac_status > 0) {
  			dev_dbg(dev, "charger on (AC)
  ");
  			pdata->set_charge(PDA_POWER_CHARGE_AC);
  		} else if (new_usb_status > 0) {
  			dev_dbg(dev, "charger on (USB)
  ");
  			pdata->set_charge(PDA_POWER_CHARGE_USB);
  		} else {
  			dev_dbg(dev, "charger off
  ");
  			pdata->set_charge(0);
  		}
  	} else if (ac_draw) {
  		if (new_ac_status > 0) {
  			regulator_set_current_limit(ac_draw, max_uA, max_uA);
  			if (!regulator_enabled) {
  				dev_dbg(dev, "charger on (AC)
  ");
  				WARN_ON(regulator_enable(ac_draw));
  				regulator_enabled = 1;
  			}
  		} else {
  			if (regulator_enabled) {
  				dev_dbg(dev, "charger off
  ");
  				WARN_ON(regulator_disable(ac_draw));
  				regulator_enabled = 0;
  			}
  		}
  	}
  }
  
  static void supply_timer_func(unsigned long unused)
  {
  	if (ac_status == PDA_PSY_TO_CHANGE) {
  		ac_status = new_ac_status;
  		power_supply_changed(&pda_psy_ac);
  	}
  
  	if (usb_status == PDA_PSY_TO_CHANGE) {
  		usb_status = new_usb_status;
  		power_supply_changed(&pda_psy_usb);
  	}
  }
  
  static void psy_changed(void)
  {
  	update_charger();
  
  	/*
  	 * Okay, charger set. Now wait a bit before notifying supplicants,
  	 * charge power should stabilize.
  	 */
  	mod_timer(&supply_timer,
  		  jiffies + msecs_to_jiffies(pdata->wait_for_charger));
  }
  
  static void charger_timer_func(unsigned long unused)
  {
  	update_status();
  	psy_changed();
  }
  
  static irqreturn_t power_changed_isr(int irq, void *power_supply)
  {
  	if (power_supply == &pda_psy_ac)
  		ac_status = PDA_PSY_TO_CHANGE;
  	else if (power_supply == &pda_psy_usb)
  		usb_status = PDA_PSY_TO_CHANGE;
  	else
  		return IRQ_NONE;
  
  	/*
  	 * Wait a bit before reading ac/usb line status and setting charger,
  	 * because ac/usb status readings may lag from irq.
  	 */
  	mod_timer(&charger_timer,
  		  jiffies + msecs_to_jiffies(pdata->wait_for_status));
  
  	return IRQ_HANDLED;
  }
  
  static void polling_timer_func(unsigned long unused)
  {
  	int changed = 0;
  
  	dev_dbg(dev, "polling...
  ");
  
  	update_status();
  
  	if (!ac_irq && new_ac_status != ac_status) {
  		ac_status = PDA_PSY_TO_CHANGE;
  		changed = 1;
  	}
  
  	if (!usb_irq && new_usb_status != usb_status) {
  		usb_status = PDA_PSY_TO_CHANGE;
  		changed = 1;
  	}
  
  	if (changed)
  		psy_changed();
  
  	mod_timer(&polling_timer,
  		  jiffies + msecs_to_jiffies(pdata->polling_interval));
  }
  
  #if IS_ENABLED(CONFIG_USB_PHY)
  static int otg_is_usb_online(void)
  {
  	return (transceiver->last_event == USB_EVENT_VBUS ||
  		transceiver->last_event == USB_EVENT_ENUMERATED);
  }
  
  static int otg_is_ac_online(void)
  {
  	return (transceiver->last_event == USB_EVENT_CHARGER);
  }
  
  static int otg_handle_notification(struct notifier_block *nb,
  		unsigned long event, void *unused)
  {
  	switch (event) {
  	case USB_EVENT_CHARGER:
  		ac_status = PDA_PSY_TO_CHANGE;
  		break;
  	case USB_EVENT_VBUS:
  	case USB_EVENT_ENUMERATED:
  		usb_status = PDA_PSY_TO_CHANGE;
  		break;
  	case USB_EVENT_NONE:
  		ac_status = PDA_PSY_TO_CHANGE;
  		usb_status = PDA_PSY_TO_CHANGE;
  		break;
  	default:
  		return NOTIFY_OK;
  	}
  
  	/*
  	 * Wait a bit before reading ac/usb line status and setting charger,
  	 * because ac/usb status readings may lag from irq.
  	 */
  	mod_timer(&charger_timer,
  		  jiffies + msecs_to_jiffies(pdata->wait_for_status));
  
  	return NOTIFY_OK;
  }
  #endif
  
  static int pda_power_probe(struct platform_device *pdev)
  {
  	int ret = 0;
  
  	dev = &pdev->dev;
  
  	if (pdev->id != -1) {
  		dev_err(dev, "it's meaningless to register several "
  			"pda_powers; use id = -1
  ");
  		ret = -EINVAL;
  		goto wrongid;
  	}
  
  	pdata = pdev->dev.platform_data;
  
  	if (pdata->init) {
  		ret = pdata->init(dev);
  		if (ret < 0)
  			goto init_failed;
  	}
  
  	ac_draw = regulator_get(dev, "ac_draw");
  	if (IS_ERR(ac_draw)) {
  		dev_dbg(dev, "couldn't get ac_draw regulator
  ");
  		ac_draw = NULL;
  	}
  
  	update_status();
  	update_charger();
  
  	if (!pdata->wait_for_status)
  		pdata->wait_for_status = 500;
  
  	if (!pdata->wait_for_charger)
  		pdata->wait_for_charger = 500;
  
  	if (!pdata->polling_interval)
  		pdata->polling_interval = 2000;
  
  	if (!pdata->ac_max_uA)
  		pdata->ac_max_uA = 500000;
  
  	setup_timer(&charger_timer, charger_timer_func, 0);
  	setup_timer(&supply_timer, supply_timer_func, 0);
  
  	ac_irq = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "ac");
  	usb_irq = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "usb");
  
  	if (pdata->supplied_to) {
  		pda_psy_ac.supplied_to = pdata->supplied_to;
  		pda_psy_ac.num_supplicants = pdata->num_supplicants;
  		pda_psy_usb.supplied_to = pdata->supplied_to;
  		pda_psy_usb.num_supplicants = pdata->num_supplicants;
  	}
  
  #if IS_ENABLED(CONFIG_USB_PHY)
  	transceiver = usb_get_phy(USB_PHY_TYPE_USB2);
  	if (!IS_ERR_OR_NULL(transceiver)) {
  		if (!pdata->is_usb_online)
  			pdata->is_usb_online = otg_is_usb_online;
  		if (!pdata->is_ac_online)
  			pdata->is_ac_online = otg_is_ac_online;
  	}
  #endif
  
  	if (pdata->is_ac_online) {
  		ret = power_supply_register(&pdev->dev, &pda_psy_ac);
  		if (ret) {
  			dev_err(dev, "failed to register %s power supply
  ",
  				pda_psy_ac.name);
  			goto ac_supply_failed;
  		}
  
  		if (ac_irq) {
  			ret = request_irq(ac_irq->start, power_changed_isr,
  					  get_irq_flags(ac_irq), ac_irq->name,
  					  &pda_psy_ac);
  			if (ret) {
  				dev_err(dev, "request ac irq failed
  ");
  				goto ac_irq_failed;
  			}
  		} else {
  			polling = 1;
  		}
  	}
  
  	if (pdata->is_usb_online) {
  		ret = power_supply_register(&pdev->dev, &pda_psy_usb);
  		if (ret) {
  			dev_err(dev, "failed to register %s power supply
  ",
  				pda_psy_usb.name);
  			goto usb_supply_failed;
  		}
  
  		if (usb_irq) {
  			ret = request_irq(usb_irq->start, power_changed_isr,
  					  get_irq_flags(usb_irq),
  					  usb_irq->name, &pda_psy_usb);
  			if (ret) {
  				dev_err(dev, "request usb irq failed
  ");
  				goto usb_irq_failed;
  			}
  		} else {
  			polling = 1;
  		}
  	}
  
  #if IS_ENABLED(CONFIG_USB_PHY)
  	if (!IS_ERR_OR_NULL(transceiver) && pdata->use_otg_notifier) {
  		otg_nb.notifier_call = otg_handle_notification;
  		ret = usb_register_notifier(transceiver, &otg_nb);
  		if (ret) {
  			dev_err(dev, "failure to register otg notifier
  ");
  			goto otg_reg_notifier_failed;
  		}
  		polling = 0;
  	}
  #endif
  
  	if (polling) {
  		dev_dbg(dev, "will poll for status
  ");
  		setup_timer(&polling_timer, polling_timer_func, 0);
  		mod_timer(&polling_timer,
  			  jiffies + msecs_to_jiffies(pdata->polling_interval));
  	}
  
  	if (ac_irq || usb_irq)
  		device_init_wakeup(&pdev->dev, 1);
  
  	return 0;
  
  #if IS_ENABLED(CONFIG_USB_PHY)
  otg_reg_notifier_failed:
  	if (pdata->is_usb_online && usb_irq)
  		free_irq(usb_irq->start, &pda_psy_usb);
  #endif
  usb_irq_failed:
  	if (pdata->is_usb_online)
  		power_supply_unregister(&pda_psy_usb);
  usb_supply_failed:
  	if (pdata->is_ac_online && ac_irq)
  		free_irq(ac_irq->start, &pda_psy_ac);
  #if IS_ENABLED(CONFIG_USB_PHY)
  	if (!IS_ERR_OR_NULL(transceiver))
  		usb_put_phy(transceiver);
  #endif
  ac_irq_failed:
  	if (pdata->is_ac_online)
  		power_supply_unregister(&pda_psy_ac);
  ac_supply_failed:
  	if (ac_draw) {
  		regulator_put(ac_draw);
  		ac_draw = NULL;
  	}
  	if (pdata->exit)
  		pdata->exit(dev);
  init_failed:
  wrongid:
  	return ret;
  }
  
  static int pda_power_remove(struct platform_device *pdev)
  {
  	if (pdata->is_usb_online && usb_irq)
  		free_irq(usb_irq->start, &pda_psy_usb);
  	if (pdata->is_ac_online && ac_irq)
  		free_irq(ac_irq->start, &pda_psy_ac);
  
  	if (polling)
  		del_timer_sync(&polling_timer);
  	del_timer_sync(&charger_timer);
  	del_timer_sync(&supply_timer);
  
  	if (pdata->is_usb_online)
  		power_supply_unregister(&pda_psy_usb);
  	if (pdata->is_ac_online)
  		power_supply_unregister(&pda_psy_ac);
  #if IS_ENABLED(CONFIG_USB_PHY)
  	if (!IS_ERR_OR_NULL(transceiver))
  		usb_put_phy(transceiver);
  #endif
  	if (ac_draw) {
  		regulator_put(ac_draw);
  		ac_draw = NULL;
  	}
  	if (pdata->exit)
  		pdata->exit(dev);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int ac_wakeup_enabled;
  static int usb_wakeup_enabled;
  
  static int pda_power_suspend(struct platform_device *pdev, pm_message_t state)
  {
  	if (pdata->suspend) {
  		int ret = pdata->suspend(state);
  
  		if (ret)
  			return ret;
  	}
  
  	if (device_may_wakeup(&pdev->dev)) {
  		if (ac_irq)
  			ac_wakeup_enabled = !enable_irq_wake(ac_irq->start);
  		if (usb_irq)
  			usb_wakeup_enabled = !enable_irq_wake(usb_irq->start);
  	}
  
  	return 0;
  }
  
  static int pda_power_resume(struct platform_device *pdev)
  {
  	if (device_may_wakeup(&pdev->dev)) {
  		if (usb_irq && usb_wakeup_enabled)
  			disable_irq_wake(usb_irq->start);
  		if (ac_irq && ac_wakeup_enabled)
  			disable_irq_wake(ac_irq->start);
  	}
  
  	if (pdata->resume)
  		return pdata->resume();
  
  	return 0;
  }
  #else
  #define pda_power_suspend NULL
  #define pda_power_resume NULL
  #endif /* CONFIG_PM */
  
  static struct platform_driver pda_power_pdrv = {
  	.driver = {
  		.name = "pda-power",
  	},
  	.probe = pda_power_probe,
  	.remove = pda_power_remove,
  	.suspend = pda_power_suspend,
  	.resume = pda_power_resume,
  };
  
  module_platform_driver(pda_power_pdrv);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Anton Vorontsov <cbou@mail.ru>");
  MODULE_ALIAS("platform:pda-power");