/*
   * Battery charger driver for TI's tps65217
   *
   * Copyright (c) 2015, Collabora Ltd.
  
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
  
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
  
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  /*
   * Battery charger driver for TI's tps65217
   */
  #include <linux/kernel.h>
  #include <linux/kthread.h>
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/power_supply.h>
  
  #include <linux/mfd/core.h>
  #include <linux/mfd/tps65217.h>
  
  #define POLL_INTERVAL		(HZ * 2)
  
  struct tps65217_charger {
  	struct tps65217 *tps;
  	struct device *dev;
  	struct power_supply *ac;
  
  	int	ac_online;
  	int	prev_ac_online;
  
  	struct task_struct	*poll_task;

  
  	int	irq;

  };
  
  static enum power_supply_property tps65217_ac_props[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static int tps65217_config_charger(struct tps65217_charger *charger)
  {
  	int ret;
  
  	dev_dbg(charger->dev, "%s
  ", __func__);
  
  	/*
  	 * tps65217 rev. G, p. 31 (see p. 32 for NTC schematic)
  	 *
  	 * The device can be configured to support a 100k NTC (B = 3960) by
  	 * setting the the NTC_TYPE bit in register CHGCONFIG1 to 1. However it
  	 * is not recommended to do so. In sleep mode, the charger continues
  	 * charging the battery, but all register values are reset to default
  	 * values. Therefore, the charger would get the wrong temperature
  	 * information. If 100k NTC setting is required, please contact the
  	 * factory.
  	 *
  	 * ATTENTION, conflicting information, from p. 46
  	 *
  	 * NTC TYPE (for battery temperature measurement)
  	 *   0 – 100k (curve 1, B = 3960)
  	 *   1 – 10k  (curve 2, B = 3480) (default on reset)
  	 *
  	 */
  	ret = tps65217_clear_bits(charger->tps, TPS65217_REG_CHGCONFIG1,
  				  TPS65217_CHGCONFIG1_NTC_TYPE,
  				  TPS65217_PROTECT_NONE);
  	if (ret) {
  		dev_err(charger->dev,
  			"failed to set 100k NTC setting: %d
  ", ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int tps65217_enable_charging(struct tps65217_charger *charger)
  {
  	int ret;
  
  	/* charger already enabled */
  	if (charger->ac_online)
  		return 0;
  
  	dev_dbg(charger->dev, "%s: enable charging
  ", __func__);
  	ret = tps65217_set_bits(charger->tps, TPS65217_REG_CHGCONFIG1,
  				TPS65217_CHGCONFIG1_CHG_EN,
  				TPS65217_CHGCONFIG1_CHG_EN,
  				TPS65217_PROTECT_NONE);
  	if (ret) {
  		dev_err(charger->dev,
  			"%s: Error in writing CHG_EN in reg 0x%x: %d
  ",
  			__func__, TPS65217_REG_CHGCONFIG1, ret);
  		return ret;
  	}
  
  	charger->ac_online = 1;
  
  	return 0;
  }
  
  static int tps65217_ac_get_property(struct power_supply *psy,
  			enum power_supply_property psp,
  			union power_supply_propval *val)
  {
  	struct tps65217_charger *charger = power_supply_get_drvdata(psy);
  
  	if (psp == POWER_SUPPLY_PROP_ONLINE) {
  		val->intval = charger->ac_online;
  		return 0;
  	}
  	return -EINVAL;
  }
  
  static irqreturn_t tps65217_charger_irq(int irq, void *dev)
  {
  	int ret, val;
  	struct tps65217_charger *charger = dev;
  
  	charger->prev_ac_online = charger->ac_online;
  
  	ret = tps65217_reg_read(charger->tps, TPS65217_REG_STATUS, &val);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s: Error in reading reg 0x%x
  ",
  			__func__, TPS65217_REG_STATUS);
  		return IRQ_HANDLED;
  	}
  
  	dev_dbg(charger->dev, "%s: 0x%x
  ", __func__, val);
  
  	/* check for AC status bit */
  	if (val & TPS65217_STATUS_ACPWR) {
  		ret = tps65217_enable_charging(charger);
  		if (ret) {
  			dev_err(charger->dev,
  				"failed to enable charger: %d
  ", ret);
  			return IRQ_HANDLED;
  		}
  	} else {
  		charger->ac_online = 0;
  	}
  
  	if (charger->prev_ac_online != charger->ac_online)
  		power_supply_changed(charger->ac);
  
  	ret = tps65217_reg_read(charger->tps, TPS65217_REG_CHGCONFIG0, &val);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s: Error in reading reg 0x%x
  ",
  			__func__, TPS65217_REG_CHGCONFIG0);
  		return IRQ_HANDLED;
  	}
  
  	if (val & TPS65217_CHGCONFIG0_ACTIVE)
  		dev_dbg(charger->dev, "%s: charger is charging
  ", __func__);
  	else
  		dev_dbg(charger->dev,
  			"%s: charger is NOT charging
  ", __func__);
  
  	return IRQ_HANDLED;
  }
  
  static int tps65217_charger_poll_task(void *data)
  {
  	set_freezable();
  
  	while (!kthread_should_stop()) {
  		schedule_timeout_interruptible(POLL_INTERVAL);
  		try_to_freeze();
  		tps65217_charger_irq(-1, data);
  	}
  	return 0;
  }
  
  static const struct power_supply_desc tps65217_charger_desc = {
  	.name			= "tps65217-ac",
  	.type			= POWER_SUPPLY_TYPE_MAINS,
  	.get_property		= tps65217_ac_get_property,
  	.properties		= tps65217_ac_props,
  	.num_properties		= ARRAY_SIZE(tps65217_ac_props),
  };
  
  static int tps65217_charger_probe(struct platform_device *pdev)
  {
  	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
  	struct tps65217_charger *charger;

  	struct power_supply_config cfg = {};

  	int irq;

  	int ret;
  
  	dev_dbg(&pdev->dev, "%s
  ", __func__);
  
  	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
  	if (!charger)
  		return -ENOMEM;

  	platform_set_drvdata(pdev, charger);

  	charger->tps = tps;
  	charger->dev = &pdev->dev;

  	cfg.of_node = pdev->dev.of_node;
  	cfg.drv_data = charger;

  	charger->ac = devm_power_supply_register(&pdev->dev,
  						 &tps65217_charger_desc,

  						 &cfg);

  	if (IS_ERR(charger->ac)) {
  		dev_err(&pdev->dev, "failed: power supply register
  ");
  		return PTR_ERR(charger->ac);
  	}

  	irq = platform_get_irq_byname(pdev, "AC");
  	if (irq < 0)
  		irq = -ENXIO;
  	charger->irq = irq;

  	ret = tps65217_config_charger(charger);
  	if (ret < 0) {
  		dev_err(charger->dev, "charger config failed, err %d
  ", ret);
  		return ret;
  	}

  	if (irq != -ENXIO) {
  		ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
  						tps65217_charger_irq,
  						0, "tps65217-charger",
  						charger);
  		if (ret) {
  			dev_err(charger->dev,
  				"Unable to register irq %d err %d
  ", irq,
  				ret);
  			return ret;
  		}
  
  		/* Check current state */
  		tps65217_charger_irq(irq, charger);
  	} else {
  		charger->poll_task = kthread_run(tps65217_charger_poll_task,
  						charger, "ktps65217charger");
  		if (IS_ERR(charger->poll_task)) {
  			ret = PTR_ERR(charger->poll_task);
  			dev_err(charger->dev,
  				"Unable to run kthread err %d
  ", ret);
  			return ret;
  		}

  	}
  
  	return 0;
  }
  
  static int tps65217_charger_remove(struct platform_device *pdev)
  {
  	struct tps65217_charger *charger = platform_get_drvdata(pdev);

  	if (charger->irq == -ENXIO)
  		kthread_stop(charger->poll_task);

  
  	return 0;
  }
  
  static const struct of_device_id tps65217_charger_match_table[] = {
  	{ .compatible = "ti,tps65217-charger", },
  	{ /* sentinel */ }
  };
  MODULE_DEVICE_TABLE(of, tps65217_charger_match_table);
  
  static struct platform_driver tps65217_charger_driver = {
  	.probe	= tps65217_charger_probe,
  	.remove = tps65217_charger_remove,
  	.driver	= {
  		.name	= "tps65217-charger",
  		.of_match_table = of_match_ptr(tps65217_charger_match_table),
  	},
  
  };
  module_platform_driver(tps65217_charger_driver);
  
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Enric Balletbo Serra <enric.balletbo@collabora.com>");
  MODULE_DESCRIPTION("TPS65217 battery charger driver");