/*
   * tps62360.c -- TI tps62360
   *
   * Driver for processor core supply tps62360, tps62361B, tps62362 and tps62363.
   *
   * Copyright (c) 2012, NVIDIA Corporation.
   *
   * Author: Laxman Dewangan <ldewangan@nvidia.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 version 2.
   *
   * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
   * whether express or implied; 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, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   * 02111-1307, USA
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/of_gpio.h>
  #include <linux/regulator/of_regulator.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/machine.h>
  #include <linux/regulator/tps62360.h>
  #include <linux/gpio.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <linux/regmap.h>
  
  /* Register definitions */
  #define REG_VSET0		0
  #define REG_VSET1		1
  #define REG_VSET2		2
  #define REG_VSET3		3
  #define REG_CONTROL		4
  #define REG_TEMP		5
  #define REG_RAMPCTRL		6
  #define REG_CHIPID		8
  
  #define FORCE_PWM_ENABLE	BIT(7)
  
  enum chips {TPS62360, TPS62361, TPS62362, TPS62363};
  
  #define TPS62360_BASE_VOLTAGE	770000
  #define TPS62360_N_VOLTAGES	64
  
  #define TPS62361_BASE_VOLTAGE	500000
  #define TPS62361_N_VOLTAGES	128
  
  /* tps 62360 chip information */
  struct tps62360_chip {
  	struct device *dev;
  	struct regulator_desc desc;
  	struct regulator_dev *rdev;
  	struct regmap *regmap;
  	int vsel0_gpio;
  	int vsel1_gpio;
  	u8 voltage_reg_mask;
  	bool en_internal_pulldn;
  	bool en_discharge;
  	bool valid_gpios;
  	int lru_index[4];
  	int curr_vset_vsel[4];
  	int curr_vset_id;
  };
  
  /*
   * find_voltage_set_register: Find new voltage configuration register
   * (VSET) id.
   * The finding of the new VSET register will be based on the LRU mechanism.
   * Each VSET register will have different voltage configured . This
   * Function will look if any of the VSET register have requested voltage set
   * or not.
   *     - If it is already there then it will make that register as most
   *       recently used and return as found so that caller need not to set
   *       the VSET register but need to set the proper gpios to select this
   *       VSET register.
   *     - If requested voltage is not found then it will use the least
   *       recently mechanism to get new VSET register for new configuration
   *       and will return not_found so that caller need to set new VSET
   *       register and then gpios (both).
   */
  static bool find_voltage_set_register(struct tps62360_chip *tps,
  		int req_vsel, int *vset_reg_id)
  {
  	int i;
  	bool found = false;
  	int new_vset_reg = tps->lru_index[3];
  	int found_index = 3;
  
  	for (i = 0; i < 4; ++i) {
  		if (tps->curr_vset_vsel[tps->lru_index[i]] == req_vsel) {
  			new_vset_reg = tps->lru_index[i];
  			found_index = i;
  			found = true;
  			goto update_lru_index;
  		}
  	}
  
  update_lru_index:
  	for (i = found_index; i > 0; i--)
  		tps->lru_index[i] = tps->lru_index[i - 1];
  
  	tps->lru_index[0] = new_vset_reg;
  	*vset_reg_id = new_vset_reg;
  	return found;
  }
  
  static int tps62360_dcdc_get_voltage_sel(struct regulator_dev *dev)
  {
  	struct tps62360_chip *tps = rdev_get_drvdata(dev);
  	int vsel;
  	unsigned int data;
  	int ret;
  
  	ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
  	if (ret < 0) {
  		dev_err(tps->dev, "%s(): register %d read failed with err %d
  ",
  			__func__, REG_VSET0 + tps->curr_vset_id, ret);
  		return ret;
  	}
  	vsel = (int)data & tps->voltage_reg_mask;
  	return vsel;
  }
  
  static int tps62360_dcdc_set_voltage_sel(struct regulator_dev *dev,
  					 unsigned selector)
  {
  	struct tps62360_chip *tps = rdev_get_drvdata(dev);
  	int ret;
  	bool found = false;
  	int new_vset_id = tps->curr_vset_id;
  
  	/*
  	 * If gpios are available to select the VSET register then least
  	 * recently used register for new configuration.
  	 */
  	if (tps->valid_gpios)
  		found = find_voltage_set_register(tps, selector, &new_vset_id);
  
  	if (!found) {
  		ret = regmap_update_bits(tps->regmap, REG_VSET0 + new_vset_id,
  				tps->voltage_reg_mask, selector);
  		if (ret < 0) {
  			dev_err(tps->dev,
  				"%s(): register %d update failed with err %d
  ",
  				 __func__, REG_VSET0 + new_vset_id, ret);
  			return ret;
  		}
  		tps->curr_vset_id = new_vset_id;
  		tps->curr_vset_vsel[new_vset_id] = selector;
  	}
  
  	/* Select proper VSET register vio gpios */
  	if (tps->valid_gpios) {
  		gpio_set_value_cansleep(tps->vsel0_gpio, new_vset_id & 0x1);
  		gpio_set_value_cansleep(tps->vsel1_gpio,
  					(new_vset_id >> 1) & 0x1);
  	}
  	return 0;
  }
  
  static int tps62360_set_mode(struct regulator_dev *rdev, unsigned int mode)
  {
  	struct tps62360_chip *tps = rdev_get_drvdata(rdev);
  	int i;
  	int val;
  	int ret;
  
  	/* Enable force PWM mode in FAST mode only. */
  	switch (mode) {
  	case REGULATOR_MODE_FAST:
  		val = FORCE_PWM_ENABLE;
  		break;
  
  	case REGULATOR_MODE_NORMAL:
  		val = 0;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	if (!tps->valid_gpios) {
  		ret = regmap_update_bits(tps->regmap,
  			REG_VSET0 + tps->curr_vset_id, FORCE_PWM_ENABLE, val);
  		if (ret < 0)
  			dev_err(tps->dev,
  				"%s(): register %d update failed with err %d
  ",
  				__func__, REG_VSET0 + tps->curr_vset_id, ret);
  		return ret;
  	}
  
  	/* If gpios are valid then all register set need to be control */
  	for (i = 0; i < 4; ++i) {
  		ret = regmap_update_bits(tps->regmap,
  					REG_VSET0 + i, FORCE_PWM_ENABLE, val);
  		if (ret < 0) {
  			dev_err(tps->dev,
  				"%s(): register %d update failed with err %d
  ",
  				__func__, REG_VSET0 + i, ret);
  			return ret;
  		}
  	}
  	return ret;
  }
  
  static unsigned int tps62360_get_mode(struct regulator_dev *rdev)
  {
  	struct tps62360_chip *tps = rdev_get_drvdata(rdev);
  	unsigned int data;
  	int ret;
  
  	ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
  	if (ret < 0) {
  		dev_err(tps->dev, "%s(): register %d read failed with err %d
  ",
  			__func__, REG_VSET0 + tps->curr_vset_id, ret);
  		return ret;
  	}
  	return (data & FORCE_PWM_ENABLE) ?
  				REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
  }
  
  static struct regulator_ops tps62360_dcdc_ops = {
  	.get_voltage_sel	= tps62360_dcdc_get_voltage_sel,
  	.set_voltage_sel	= tps62360_dcdc_set_voltage_sel,
  	.list_voltage		= regulator_list_voltage_linear,
  	.map_voltage		= regulator_map_voltage_linear,
  	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
  	.set_mode		= tps62360_set_mode,
  	.get_mode		= tps62360_get_mode,
  };
  
  static int tps62360_init_dcdc(struct tps62360_chip *tps,
  		struct tps62360_regulator_platform_data *pdata)
  {
  	int ret;
  	unsigned int ramp_ctrl;
  
  	/* Initialize internal pull up/down control */
  	if (tps->en_internal_pulldn)
  		ret = regmap_write(tps->regmap, REG_CONTROL, 0xE0);
  	else
  		ret = regmap_write(tps->regmap, REG_CONTROL, 0x0);
  	if (ret < 0) {
  		dev_err(tps->dev,
  			"%s(): register %d write failed with err %d
  ",
  			__func__, REG_CONTROL, ret);
  		return ret;
  	}
  
  	/* Reset output discharge path to reduce power consumption */
  	ret = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), 0);
  	if (ret < 0) {
  		dev_err(tps->dev,
  			"%s(): register %d update failed with err %d
  ",
  			__func__, REG_RAMPCTRL, ret);
  		return ret;
  	}
  
  	/* Get ramp value from ramp control register */
  	ret = regmap_read(tps->regmap, REG_RAMPCTRL, &ramp_ctrl);
  	if (ret < 0) {
  		dev_err(tps->dev,
  			"%s(): register %d read failed with err %d
  ",
  			__func__, REG_RAMPCTRL, ret);
  		return ret;
  	}
  	ramp_ctrl = (ramp_ctrl >> 5) & 0x7;
  
  	/* ramp mV/us = 32/(2^ramp_ctrl) */
  	tps->desc.ramp_delay = DIV_ROUND_UP(32000, BIT(ramp_ctrl));
  	return ret;
  }
  
  static const struct regmap_config tps62360_regmap_config = {
  	.reg_bits		= 8,
  	.val_bits		= 8,
  	.max_register		= REG_CHIPID,
  	.cache_type		= REGCACHE_RBTREE,
  };
  
  static struct tps62360_regulator_platform_data *
  	of_get_tps62360_platform_data(struct device *dev,
  				      const struct regulator_desc *desc)
  {
  	struct tps62360_regulator_platform_data *pdata;
  	struct device_node *np = dev->of_node;
  
  	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return NULL;
  
  	pdata->reg_init_data = of_get_regulator_init_data(dev, dev->of_node,
  							  desc);
  	if (!pdata->reg_init_data) {
  		dev_err(dev, "Not able to get OF regulator init data
  ");
  		return NULL;
  	}
  
  	pdata->vsel0_gpio = of_get_named_gpio(np, "vsel0-gpio", 0);
  	pdata->vsel1_gpio = of_get_named_gpio(np, "vsel1-gpio", 0);
  
  	if (of_find_property(np, "ti,vsel0-state-high", NULL))
  		pdata->vsel0_def_state = 1;
  
  	if (of_find_property(np, "ti,vsel1-state-high", NULL))
  		pdata->vsel1_def_state = 1;
  
  	if (of_find_property(np, "ti,enable-pull-down", NULL))
  		pdata->en_internal_pulldn = true;
  
  	if (of_find_property(np, "ti,enable-vout-discharge", NULL))
  		pdata->en_discharge = true;
  
  	return pdata;
  }
  
  #if defined(CONFIG_OF)
  static const struct of_device_id tps62360_of_match[] = {
  	 { .compatible = "ti,tps62360", .data = (void *)TPS62360},
  	 { .compatible = "ti,tps62361", .data = (void *)TPS62361},
  	 { .compatible = "ti,tps62362", .data = (void *)TPS62362},
  	 { .compatible = "ti,tps62363", .data = (void *)TPS62363},
  	{},
  };
  MODULE_DEVICE_TABLE(of, tps62360_of_match);
  #endif
  
  static int tps62360_probe(struct i2c_client *client,
  				     const struct i2c_device_id *id)
  {
  	struct regulator_config config = { };
  	struct tps62360_regulator_platform_data *pdata;
  	struct regulator_dev *rdev;
  	struct tps62360_chip *tps;
  	int ret;
  	int i;
  	int chip_id;
  
  	pdata = dev_get_platdata(&client->dev);
  
  	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
  	if (!tps)
  		return -ENOMEM;
  
  	tps->desc.name = client->name;
  	tps->desc.id = 0;
  	tps->desc.ops = &tps62360_dcdc_ops;
  	tps->desc.type = REGULATOR_VOLTAGE;
  	tps->desc.owner = THIS_MODULE;
  	tps->desc.uV_step = 10000;
  
  	if (client->dev.of_node) {
  		const struct of_device_id *match;
  		match = of_match_device(of_match_ptr(tps62360_of_match),
  				&client->dev);
  		if (!match) {
  			dev_err(&client->dev, "Error: No device match found
  ");
  			return -ENODEV;
  		}
  		chip_id = (int)(long)match->data;
  		if (!pdata)
  			pdata = of_get_tps62360_platform_data(&client->dev,
  							      &tps->desc);
  	} else if (id) {
  		chip_id = id->driver_data;
  	} else {
  		dev_err(&client->dev, "No device tree match or id table match found
  ");
  		return -ENODEV;
  	}
  
  	if (!pdata) {
  		dev_err(&client->dev, "%s(): Platform data not found
  ",
  						__func__);
  		return -EIO;
  	}
  
  	tps->en_discharge = pdata->en_discharge;
  	tps->en_internal_pulldn = pdata->en_internal_pulldn;
  	tps->vsel0_gpio = pdata->vsel0_gpio;
  	tps->vsel1_gpio = pdata->vsel1_gpio;
  	tps->dev = &client->dev;
  
  	switch (chip_id) {
  	case TPS62360:
  	case TPS62362:
  		tps->desc.min_uV = TPS62360_BASE_VOLTAGE;
  		tps->voltage_reg_mask = 0x3F;
  		tps->desc.n_voltages = TPS62360_N_VOLTAGES;
  		break;
  	case TPS62361:
  	case TPS62363:
  		tps->desc.min_uV = TPS62361_BASE_VOLTAGE;
  		tps->voltage_reg_mask = 0x7F;
  		tps->desc.n_voltages = TPS62361_N_VOLTAGES;
  		break;
  	default:
  		return -ENODEV;
  	}
  
  	tps->regmap = devm_regmap_init_i2c(client, &tps62360_regmap_config);
  	if (IS_ERR(tps->regmap)) {
  		ret = PTR_ERR(tps->regmap);
  		dev_err(&client->dev,
  			"%s(): regmap allocation failed with err %d
  ",
  			__func__, ret);
  		return ret;
  	}
  	i2c_set_clientdata(client, tps);
  
  	tps->curr_vset_id = (pdata->vsel1_def_state & 1) * 2 +
  				(pdata->vsel0_def_state & 1);
  	tps->lru_index[0] = tps->curr_vset_id;
  	tps->valid_gpios = false;
  
  	if (gpio_is_valid(tps->vsel0_gpio) && gpio_is_valid(tps->vsel1_gpio)) {
  		int gpio_flags;
  		gpio_flags = (pdata->vsel0_def_state) ?
  				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
  		ret = devm_gpio_request_one(&client->dev, tps->vsel0_gpio,
  				gpio_flags, "tps62360-vsel0");
  		if (ret) {
  			dev_err(&client->dev,
  				"%s(): Could not obtain vsel0 GPIO %d: %d
  ",
  				__func__, tps->vsel0_gpio, ret);
  			return ret;
  		}
  
  		gpio_flags = (pdata->vsel1_def_state) ?
  				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
  		ret = devm_gpio_request_one(&client->dev, tps->vsel1_gpio,
  				gpio_flags, "tps62360-vsel1");
  		if (ret) {
  			dev_err(&client->dev,
  				"%s(): Could not obtain vsel1 GPIO %d: %d
  ",
  				__func__, tps->vsel1_gpio, ret);
  			return ret;
  		}
  		tps->valid_gpios = true;
  
  		/*
  		 * Initialize the lru index with vset_reg id
  		 * The index 0 will be most recently used and
  		 * set with the tps->curr_vset_id */
  		for (i = 0; i < 4; ++i)
  			tps->lru_index[i] = i;
  		tps->lru_index[0] = tps->curr_vset_id;
  		tps->lru_index[tps->curr_vset_id] = 0;
  	}
  
  	ret = tps62360_init_dcdc(tps, pdata);
  	if (ret < 0) {
  		dev_err(tps->dev, "%s(): Init failed with err = %d
  ",
  				__func__, ret);
  		return ret;
  	}
  
  	config.dev = &client->dev;
  	config.init_data = pdata->reg_init_data;
  	config.driver_data = tps;
  	config.of_node = client->dev.of_node;
  
  	/* Register the regulators */
  	rdev = devm_regulator_register(&client->dev, &tps->desc, &config);
  	if (IS_ERR(rdev)) {
  		dev_err(tps->dev,
  			"%s(): regulator register failed with err %s
  ",
  			__func__, id->name);
  		return PTR_ERR(rdev);
  	}
  
  	tps->rdev = rdev;
  	return 0;
  }
  
  static void tps62360_shutdown(struct i2c_client *client)
  {
  	struct tps62360_chip *tps = i2c_get_clientdata(client);
  	int st;
  
  	if (!tps->en_discharge)
  		return;
  
  	/* Configure the output discharge path */
  	st = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), BIT(2));
  	if (st < 0)
  		dev_err(tps->dev,
  			"%s(): register %d update failed with err %d
  ",
  			__func__, REG_RAMPCTRL, st);
  }
  
  static const struct i2c_device_id tps62360_id[] = {
  	{.name = "tps62360", .driver_data = TPS62360},
  	{.name = "tps62361", .driver_data = TPS62361},
  	{.name = "tps62362", .driver_data = TPS62362},
  	{.name = "tps62363", .driver_data = TPS62363},
  	{},
  };
  
  MODULE_DEVICE_TABLE(i2c, tps62360_id);
  
  static struct i2c_driver tps62360_i2c_driver = {
  	.driver = {
  		.name = "tps62360",
  		.of_match_table = of_match_ptr(tps62360_of_match),
  	},
  	.probe = tps62360_probe,
  	.shutdown = tps62360_shutdown,
  	.id_table = tps62360_id,
  };
  
  static int __init tps62360_init(void)
  {
  	return i2c_add_driver(&tps62360_i2c_driver);
  }
  subsys_initcall(tps62360_init);
  
  static void __exit tps62360_cleanup(void)
  {
  	i2c_del_driver(&tps62360_i2c_driver);
  }
  module_exit(tps62360_cleanup);
  
  MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  MODULE_DESCRIPTION("TPS6236x voltage regulator driver");
  MODULE_LICENSE("GPL v2");