/*
   * Battery charger driver for TI's tps65090
   *
   * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
  
   * 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/>.
   */

  #include <linux/delay.h>

  #include <linux/err.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/of_device.h>

  #include <linux/platform_device.h>
  #include <linux/power_supply.h>

  #include <linux/slab.h>

  #include <linux/mfd/tps65090.h>
  
  #define TPS65090_REG_INTR_STS	0x00

  #define TPS65090_REG_INTR_MASK	0x02

  #define TPS65090_REG_CG_CTRL0	0x04
  #define TPS65090_REG_CG_CTRL1	0x05
  #define TPS65090_REG_CG_CTRL2	0x06
  #define TPS65090_REG_CG_CTRL3	0x07
  #define TPS65090_REG_CG_CTRL4	0x08
  #define TPS65090_REG_CG_CTRL5	0x09
  #define TPS65090_REG_CG_STATUS1	0x0a
  #define TPS65090_REG_CG_STATUS2	0x0b
  
  #define TPS65090_CHARGER_ENABLE	BIT(0)
  #define TPS65090_VACG		BIT(1)
  #define TPS65090_NOITERM	BIT(5)
  
  struct tps65090_charger {
  	struct	device	*dev;
  	int	ac_online;
  	int	prev_ac_online;
  	int	irq;
  	struct power_supply	ac;
  	struct tps65090_platform_data *pdata;
  };
  
  static enum power_supply_property tps65090_ac_props[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static int tps65090_low_chrg_current(struct tps65090_charger *charger)
  {
  	int ret;
  
  	ret = tps65090_write(charger->dev->parent, TPS65090_REG_CG_CTRL5,
  			TPS65090_NOITERM);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): error reading in register 0x%x
  ",
  			__func__, TPS65090_REG_CG_CTRL5);
  		return ret;
  	}
  	return 0;
  }

  static int tps65090_enable_charging(struct tps65090_charger *charger)

  {
  	int ret;
  	uint8_t ctrl0 = 0;
  
  	ret = tps65090_read(charger->dev->parent, TPS65090_REG_CG_CTRL0,
  			    &ctrl0);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): error reading in register 0x%x
  ",
  				__func__, TPS65090_REG_CG_CTRL0);
  		return ret;
  	}
  
  	ret = tps65090_write(charger->dev->parent, TPS65090_REG_CG_CTRL0,
  				(ctrl0 | TPS65090_CHARGER_ENABLE));
  	if (ret < 0) {

  		dev_err(charger->dev, "%s(): error writing in register 0x%x
  ",

  				__func__, TPS65090_REG_CG_CTRL0);
  		return ret;
  	}
  	return 0;
  }
  
  static int tps65090_config_charger(struct tps65090_charger *charger)
  {

  	uint8_t intrmask = 0;

  	int ret;
  
  	if (charger->pdata->enable_low_current_chrg) {
  		ret = tps65090_low_chrg_current(charger);
  		if (ret < 0) {
  			dev_err(charger->dev,
  				"error configuring low charge current
  ");
  			return ret;
  		}
  	}

  	/* Enable the VACG interrupt for AC power detect */
  	ret = tps65090_read(charger->dev->parent, TPS65090_REG_INTR_MASK,
  			    &intrmask);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): error reading in register 0x%x
  ",
  			__func__, TPS65090_REG_INTR_MASK);
  		return ret;
  	}
  
  	ret = tps65090_write(charger->dev->parent, TPS65090_REG_INTR_MASK,
  			     (intrmask | TPS65090_VACG));
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): error writing in register 0x%x
  ",
  			__func__, TPS65090_REG_CG_CTRL0);
  		return ret;
  	}

  	return 0;
  }
  
  static int tps65090_ac_get_property(struct power_supply *psy,
  			enum power_supply_property psp,
  			union power_supply_propval *val)
  {
  	struct tps65090_charger *charger = container_of(psy,
  					struct tps65090_charger, ac);
  
  	if (psp == POWER_SUPPLY_PROP_ONLINE) {
  		val->intval = charger->ac_online;
  		charger->prev_ac_online = charger->ac_online;
  		return 0;
  	}
  	return -EINVAL;
  }
  
  static irqreturn_t tps65090_charger_isr(int irq, void *dev_id)
  {
  	struct tps65090_charger *charger = dev_id;
  	int ret;
  	uint8_t status1 = 0;
  	uint8_t intrsts = 0;
  
  	ret = tps65090_read(charger->dev->parent, TPS65090_REG_CG_STATUS1,
  			    &status1);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): Error in reading reg 0x%x
  ",
  				__func__, TPS65090_REG_CG_STATUS1);
  		return IRQ_HANDLED;
  	}
  	msleep(75);
  	ret = tps65090_read(charger->dev->parent, TPS65090_REG_INTR_STS,
  			    &intrsts);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): Error in reading reg 0x%x
  ",
  				__func__, TPS65090_REG_INTR_STS);
  		return IRQ_HANDLED;
  	}
  
  	if (intrsts & TPS65090_VACG) {

  		ret = tps65090_enable_charging(charger);

  		if (ret < 0)
  			return IRQ_HANDLED;
  		charger->ac_online = 1;
  	} else {
  		charger->ac_online = 0;
  	}

  	/* Clear interrupts. */
  	ret = tps65090_write(charger->dev->parent, TPS65090_REG_INTR_STS, 0x00);
  	if (ret < 0) {
  		dev_err(charger->dev, "%s(): Error in writing reg 0x%x
  ",
  				__func__, TPS65090_REG_INTR_STS);
  	}

  	if (charger->prev_ac_online != charger->ac_online)
  		power_supply_changed(&charger->ac);
  
  	return IRQ_HANDLED;
  }

  static struct tps65090_platform_data *
  		tps65090_parse_dt_charger_data(struct platform_device *pdev)
  {
  	struct tps65090_platform_data *pdata;

  	struct device_node *np = pdev->dev.of_node;

  	unsigned int prop;
  
  	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata) {
  		dev_err(&pdev->dev, "Memory alloc for tps65090_pdata failed
  ");
  		return NULL;
  	}
  
  	prop = of_property_read_bool(np, "ti,enable-low-current-chrg");
  	pdata->enable_low_current_chrg = prop;
  
  	pdata->irq_base = -1;
  
  	return pdata;
  
  }

  
  static int tps65090_charger_probe(struct platform_device *pdev)
  {

  	struct tps65090_charger *cdata;
  	struct tps65090_platform_data *pdata;
  	uint8_t status1 = 0;
  	int ret;
  	int irq;
  
  	pdata = dev_get_platdata(pdev->dev.parent);

  	if (IS_ENABLED(CONFIG_OF) && !pdata && pdev->dev.of_node)

  		pdata = tps65090_parse_dt_charger_data(pdev);
  
  	if (!pdata) {
  		dev_err(&pdev->dev, "%s():no platform data available
  ",
  				__func__);
  		return -ENODEV;
  	}
  
  	cdata = devm_kzalloc(&pdev->dev, sizeof(*cdata), GFP_KERNEL);
  	if (!cdata) {
  		dev_err(&pdev->dev, "failed to allocate memory status
  ");
  		return -ENOMEM;
  	}

  	platform_set_drvdata(pdev, cdata);

  
  	cdata->dev			= &pdev->dev;
  	cdata->pdata			= pdata;
  
  	cdata->ac.name			= "tps65090-ac";
  	cdata->ac.type			= POWER_SUPPLY_TYPE_MAINS;
  	cdata->ac.get_property		= tps65090_ac_get_property;
  	cdata->ac.properties		= tps65090_ac_props;
  	cdata->ac.num_properties	= ARRAY_SIZE(tps65090_ac_props);
  	cdata->ac.supplied_to		= pdata->supplied_to;
  	cdata->ac.num_supplicants	= pdata->num_supplicants;

  	cdata->ac.of_node		= pdev->dev.of_node;

  
  	ret = power_supply_register(&pdev->dev, &cdata->ac);
  	if (ret) {
  		dev_err(&pdev->dev, "failed: power supply register
  ");
  		return ret;
  	}
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq <= 0) {
  		dev_warn(&pdev->dev, "Unable to get charger irq = %d
  ", irq);
  		ret = irq;
  		goto fail_unregister_supply;
  	}
  
  	cdata->irq = irq;
  
  	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
  		tps65090_charger_isr, 0, "tps65090-charger", cdata);
  	if (ret) {
  		dev_err(cdata->dev, "Unable to register irq %d err %d
  ", irq,
  			ret);

  		goto fail_unregister_supply;

  	}
  
  	ret = tps65090_config_charger(cdata);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "charger config failed, err %d
  ", ret);

  		goto fail_unregister_supply;

  	}
  
  	/* Check for charger presence */
  	ret = tps65090_read(cdata->dev->parent, TPS65090_REG_CG_STATUS1,
  			&status1);
  	if (ret < 0) {
  		dev_err(cdata->dev, "%s(): Error in reading reg 0x%x", __func__,
  			TPS65090_REG_CG_STATUS1);

  		goto fail_unregister_supply;

  	}
  
  	if (status1 != 0) {

  		ret = tps65090_enable_charging(cdata);

  		if (ret < 0) {
  			dev_err(cdata->dev, "error enabling charger
  ");

  			goto fail_unregister_supply;

  		}
  		cdata->ac_online = 1;
  		power_supply_changed(&cdata->ac);
  	}
  
  	return 0;

  fail_unregister_supply:
  	power_supply_unregister(&cdata->ac);
  
  	return ret;
  }
  
  static int tps65090_charger_remove(struct platform_device *pdev)
  {

  	struct tps65090_charger *cdata = platform_get_drvdata(pdev);

  	power_supply_unregister(&cdata->ac);
  
  	return 0;
  }

  static struct of_device_id of_tps65090_charger_match[] = {
  	{ .compatible = "ti,tps65090-charger", },
  	{ /* end */ }
  };

  static struct platform_driver tps65090_charger_driver = {
  	.driver	= {
  		.name	= "tps65090-charger",

  		.of_match_table = of_tps65090_charger_match,

  		.owner	= THIS_MODULE,
  	},
  	.probe	= tps65090_charger_probe,
  	.remove = tps65090_charger_remove,
  };
  module_platform_driver(tps65090_charger_driver);
  
  MODULE_LICENSE("GPL v2");
  MODULE_AUTHOR("Syed Rafiuddin <srafiuddin@nvidia.com>");
  MODULE_DESCRIPTION("tps65090 battery charger driver");