/*
   * max14577.c - Regulator driver for the Maxim 14577
   *
   * Copyright (C) 2013 Samsung Electronics
   * Krzysztof Kozlowski <k.kozlowski@samsung.com>
   *
   * 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.
   *
   * This program is distributed in the hope that 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.
   */
  
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/mfd/max14577.h>
  #include <linux/mfd/max14577-private.h>
  #include <linux/regulator/of_regulator.h>
  
  struct max14577_regulator {
  	struct device *dev;
  	struct max14577 *max14577;
  	struct regulator_dev **regulators;
  };
  
  static int max14577_reg_is_enabled(struct regulator_dev *rdev)
  {
  	int rid = rdev_get_id(rdev);
  	struct regmap *rmap = rdev->regmap;
  	u8 reg_data;
  
  	switch (rid) {
  	case MAX14577_CHARGER:
  		max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
  		if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0)
  			return 0;
  		max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
  		if ((reg_data & STATUS3_CGMBC_MASK) == 0)
  			return 0;
  		/* MBCHOSTEN and CGMBC are on */
  		return 1;
  	default:
  		return -EINVAL;
  	}
  }
  
  static int max14577_reg_get_current_limit(struct regulator_dev *rdev)
  {
  	u8 reg_data;
  	struct regmap *rmap = rdev->regmap;
  
  	if (rdev_get_id(rdev) != MAX14577_CHARGER)
  		return -EINVAL;
  
  	max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL4, &reg_data);
  
  	if ((reg_data & CHGCTRL4_MBCICHWRCL_MASK) == 0)
  		return MAX14577_REGULATOR_CURRENT_LIMIT_MIN;
  
  	reg_data = ((reg_data & CHGCTRL4_MBCICHWRCH_MASK) >>
  			CHGCTRL4_MBCICHWRCH_SHIFT);
  	return MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START +
  		reg_data * MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP;
  }
  
  static int max14577_reg_set_current_limit(struct regulator_dev *rdev,
  		int min_uA, int max_uA)
  {
  	int i, current_bits = 0xf;
  	u8 reg_data;
  
  	if (rdev_get_id(rdev) != MAX14577_CHARGER)
  		return -EINVAL;
  
  	if (min_uA > MAX14577_REGULATOR_CURRENT_LIMIT_MAX ||
  			max_uA < MAX14577_REGULATOR_CURRENT_LIMIT_MIN)
  		return -EINVAL;
  
  	if (max_uA < MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START) {
  		/* Less than 200 mA, so set 90mA (turn only Low Bit off) */
  		u8 reg_data = 0x0 << CHGCTRL4_MBCICHWRCL_SHIFT;
  		return max14577_update_reg(rdev->regmap,
  				MAX14577_CHG_REG_CHG_CTRL4,
  				CHGCTRL4_MBCICHWRCL_MASK, reg_data);
  	}
  
  	/* max_uA is in range: <LIMIT_HIGH_START, inifinite>, so search for
  	 * valid current starting from LIMIT_MAX. */
  	for (i = MAX14577_REGULATOR_CURRENT_LIMIT_MAX;
  			i >= MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START;
  			i -= MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP) {
  		if (i <= max_uA)
  			break;
  		current_bits--;
  	}
  	BUG_ON(current_bits < 0); /* Cannot happen */
  	/* Turn Low Bit on (use range 200mA-950 mA) */
  	reg_data = 0x1 << CHGCTRL4_MBCICHWRCL_SHIFT;
  	/* and set proper High Bits */
  	reg_data |= current_bits << CHGCTRL4_MBCICHWRCH_SHIFT;
  
  	return max14577_update_reg(rdev->regmap, MAX14577_CHG_REG_CHG_CTRL4,
  			CHGCTRL4_MBCICHWRCL_MASK | CHGCTRL4_MBCICHWRCH_MASK,
  			reg_data);
  }
  
  static struct regulator_ops max14577_safeout_ops = {
  	.is_enabled		= regulator_is_enabled_regmap,
  	.enable			= regulator_enable_regmap,
  	.disable		= regulator_disable_regmap,
  	.list_voltage		= regulator_list_voltage_linear,
  };
  
  static struct regulator_ops max14577_charger_ops = {
  	.is_enabled		= max14577_reg_is_enabled,
  	.enable			= regulator_enable_regmap,
  	.disable		= regulator_disable_regmap,
  	.get_current_limit	= max14577_reg_get_current_limit,
  	.set_current_limit	= max14577_reg_set_current_limit,
  };
  
  static const struct regulator_desc supported_regulators[] = {
  	[MAX14577_SAFEOUT] = {
  		.name		= "SAFEOUT",
  		.id		= MAX14577_SAFEOUT,
  		.ops		= &max14577_safeout_ops,
  		.type		= REGULATOR_VOLTAGE,
  		.owner		= THIS_MODULE,
  		.n_voltages	= 1,
  		.min_uV		= MAX14577_REGULATOR_SAFEOUT_VOLTAGE,
  		.enable_reg	= MAX14577_REG_CONTROL2,
  		.enable_mask	= CTRL2_SFOUTORD_MASK,
  	},
  	[MAX14577_CHARGER] = {
  		.name		= "CHARGER",
  		.id		= MAX14577_CHARGER,
  		.ops		= &max14577_charger_ops,
  		.type		= REGULATOR_CURRENT,
  		.owner		= THIS_MODULE,
  		.enable_reg	= MAX14577_CHG_REG_CHG_CTRL2,
  		.enable_mask	= CHGCTRL2_MBCHOSTEN_MASK,
  	},
  };
  
  #ifdef CONFIG_OF
  static struct of_regulator_match max14577_regulator_matches[] = {
  	{ .name	= "SAFEOUT", },
  	{ .name = "CHARGER", },
  };
  
  static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev)
  {
  	int ret;
  	struct device_node *np;
  
  	np = of_get_child_by_name(pdev->dev.parent->of_node, "regulators");
  	if (!np) {
  		dev_err(&pdev->dev, "Failed to get child OF node for regulators
  ");
  		return -EINVAL;
  	}
  
  	ret = of_regulator_match(&pdev->dev, np, max14577_regulator_matches,
  			MAX14577_REG_MAX);
  	if (ret < 0)
  		dev_err(&pdev->dev, "Error parsing regulator init data: %d
  ", ret);
  	else
  		ret = 0;
  
  	of_node_put(np);
  
  	return ret;
  }
  
  static inline struct regulator_init_data *match_init_data(int index)
  {
  	return max14577_regulator_matches[index].init_data;
  }
  
  static inline struct device_node *match_of_node(int index)
  {
  	return max14577_regulator_matches[index].of_node;
  }
  #else /* CONFIG_OF */
  static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev)
  {
  	return 0;
  }
  static inline struct regulator_init_data *match_init_data(int index)
  {
  	return NULL;
  }
  
  static inline struct device_node *match_of_node(int index)
  {
  	return NULL;
  }
  #endif /* CONFIG_OF */
  
  
  static int max14577_regulator_probe(struct platform_device *pdev)
  {
  	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
  	struct max14577_platform_data *pdata = dev_get_platdata(max14577->dev);
  	int i, ret;
  	struct regulator_config config = {};
  
  	ret = max14577_regulator_dt_parse_pdata(pdev);
  	if (ret)
  		return ret;
  
  	config.dev = &pdev->dev;
  	config.regmap = max14577->regmap;
  
  	for (i = 0; i < ARRAY_SIZE(supported_regulators); i++) {
  		struct regulator_dev *regulator;
  		/*
  		 * Index of supported_regulators[] is also the id and must
  		 * match index of pdata->regulators[].
  		 */
  		if (pdata && pdata->regulators) {
  			config.init_data = pdata->regulators[i].initdata;
  			config.of_node = pdata->regulators[i].of_node;
  		} else {
  			config.init_data = match_init_data(i);
  			config.of_node = match_of_node(i);
  		}
  
  		regulator = devm_regulator_register(&pdev->dev,
  				&supported_regulators[i], &config);
  		if (IS_ERR(regulator)) {
  			ret = PTR_ERR(regulator);
  			dev_err(&pdev->dev,
  					"Regulator init failed for ID %d with error: %d
  ",
  					i, ret);
  			return ret;
  		}
  	}
  
  	return ret;
  }
  
  static struct platform_driver max14577_regulator_driver = {
  	.driver = {
  		   .owner = THIS_MODULE,
  		   .name = "max14577-regulator",
  		   },
  	.probe	= max14577_regulator_probe,
  };
  
  static int __init max14577_regulator_init(void)
  {
  	BUILD_BUG_ON(MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START +
  			MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP * 0xf !=
  			MAX14577_REGULATOR_CURRENT_LIMIT_MAX);
  	BUILD_BUG_ON(ARRAY_SIZE(supported_regulators) != MAX14577_REG_MAX);
  
  	return platform_driver_register(&max14577_regulator_driver);
  }
  subsys_initcall(max14577_regulator_init);
  
  static void __exit max14577_regulator_exit(void)
  {
  	platform_driver_unregister(&max14577_regulator_driver);
  }
  module_exit(max14577_regulator_exit);
  
  MODULE_AUTHOR("Krzysztof Kozlowski <k.kozlowski@samsung.com>");
  MODULE_DESCRIPTION("MAXIM 14577 regulator driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:max14577-regulator");