/*
   * tps51632-regulator.c -- TI TPS51632
   *
   * Regulator driver for TPS51632 3-2-1 Phase D-Cap Step Down Driverless
   * Controller with serial VID control and DVFS.
   *
   * 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/err.h>
  #include <linux/i2c.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/of.h>
  #include <linux/of_device.h>

  #include <linux/platform_device.h>
  #include <linux/regmap.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/machine.h>

  #include <linux/regulator/of_regulator.h>

  #include <linux/regulator/tps51632-regulator.h>
  #include <linux/slab.h>
  
  /* Register definitions */
  #define TPS51632_VOLTAGE_SELECT_REG		0x0
  #define TPS51632_VOLTAGE_BASE_REG		0x1
  #define TPS51632_OFFSET_REG			0x2
  #define TPS51632_IMON_REG			0x3
  #define TPS51632_VMAX_REG			0x4
  #define TPS51632_DVFS_CONTROL_REG		0x5
  #define TPS51632_POWER_STATE_REG		0x6
  #define TPS51632_SLEW_REGS			0x7
  #define TPS51632_FAULT_REG			0x14
  
  #define TPS51632_MAX_REG			0x15
  
  #define TPS51632_VOUT_MASK			0x7F
  #define TPS51632_VOUT_OFFSET_MASK		0x1F
  #define TPS51632_VMAX_MASK			0x7F
  #define TPS51632_VMAX_LOCK			0x80
  
  /* TPS51632_DVFS_CONTROL_REG */
  #define TPS51632_DVFS_PWMEN			0x1
  #define TPS51632_DVFS_STEP_20			0x2
  #define TPS51632_DVFS_VMAX_PG			0x4
  #define TPS51632_DVFS_PWMRST			0x8
  #define TPS51632_DVFS_OCA_EN			0x10
  #define TPS51632_DVFS_FCCM			0x20
  
  /* TPS51632_POWER_STATE_REG */
  #define TPS51632_POWER_STATE_MASK		0x03
  #define TPS51632_POWER_STATE_MULTI_PHASE_CCM	0x0
  #define TPS51632_POWER_STATE_SINGLE_PHASE_CCM	0x1
  #define TPS51632_POWER_STATE_SINGLE_PHASE_DCM	0x2

  #define TPS51632_MIN_VOLTAGE			500000
  #define TPS51632_MAX_VOLTAGE			1520000
  #define TPS51632_VOLTAGE_STEP_10mV		10000
  #define TPS51632_VOLTAGE_STEP_20mV		20000

  #define TPS51632_MAX_VSEL			0x7F
  #define TPS51632_MIN_VSEL			0x19
  #define TPS51632_DEFAULT_RAMP_DELAY		6000
  #define TPS51632_VOLT_VSEL(uV)					\

  		(DIV_ROUND_UP(uV - TPS51632_MIN_VOLTAGE,	\
  			TPS51632_VOLTAGE_STEP_10mV) +		\

  			TPS51632_MIN_VSEL)
  
  /* TPS51632 chip information */
  struct tps51632_chip {
  	struct device *dev;
  	struct regulator_desc desc;
  	struct regulator_dev *rdev;
  	struct regmap *regmap;

  };

  static int tps51632_dcdc_set_ramp_delay(struct regulator_dev *rdev,
  		int ramp_delay)
  {
  	struct tps51632_chip *tps = rdev_get_drvdata(rdev);
  	int bit = ramp_delay/6000;
  	int ret;
  
  	if (bit)
  		bit--;
  	ret = regmap_write(tps->regmap, TPS51632_SLEW_REGS, BIT(bit));
  	if (ret < 0)
  		dev_err(tps->dev, "SLEW reg write failed, err %d
  ", ret);
  	return ret;
  }
  
  static struct regulator_ops tps51632_dcdc_ops = {

  	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
  	.set_voltage_sel	= regulator_set_voltage_sel_regmap,

  	.list_voltage		= regulator_list_voltage_linear,
  	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
  	.set_ramp_delay		= tps51632_dcdc_set_ramp_delay,
  };

  static int tps51632_init_dcdc(struct tps51632_chip *tps,

  		struct tps51632_regulator_platform_data *pdata)
  {
  	int ret;
  	uint8_t	control = 0;
  	int vsel;
  
  	if (!pdata->enable_pwm_dvfs)
  		goto skip_pwm_config;
  
  	control |= TPS51632_DVFS_PWMEN;

  	vsel = TPS51632_VOLT_VSEL(pdata->base_voltage_uV);
  	ret = regmap_write(tps->regmap, TPS51632_VOLTAGE_BASE_REG, vsel);
  	if (ret < 0) {
  		dev_err(tps->dev, "BASE reg write failed, err %d
  ", ret);
  		return ret;
  	}
  
  	if (pdata->dvfs_step_20mV)
  		control |= TPS51632_DVFS_STEP_20;
  
  	if (pdata->max_voltage_uV) {
  		unsigned int vmax;
  		/**
  		 * TPS51632 hw behavior: VMAX register can be write only
  		 * once as it get locked after first write. The lock get
  		 * reset only when device is power-reset.
  		 * Write register only when lock bit is not enabled.
  		 */
  		ret = regmap_read(tps->regmap, TPS51632_VMAX_REG, &vmax);
  		if (ret < 0) {
  			dev_err(tps->dev, "VMAX read failed, err %d
  ", ret);
  			return ret;
  		}
  		if (!(vmax & TPS51632_VMAX_LOCK)) {
  			vsel = TPS51632_VOLT_VSEL(pdata->max_voltage_uV);
  			ret = regmap_write(tps->regmap, TPS51632_VMAX_REG,
  					vsel);
  			if (ret < 0) {
  				dev_err(tps->dev,
  					"VMAX write failed, err %d
  ", ret);
  				return ret;
  			}
  		}
  	}
  
  skip_pwm_config:
  	ret = regmap_write(tps->regmap, TPS51632_DVFS_CONTROL_REG, control);
  	if (ret < 0)
  		dev_err(tps->dev, "DVFS reg write failed, err %d
  ", ret);
  	return ret;
  }

  static bool is_volatile_reg(struct device *dev, unsigned int reg)

  {

  	switch (reg) {
  	case TPS51632_OFFSET_REG:
  	case TPS51632_FAULT_REG:
  	case TPS51632_IMON_REG:
  		return true;
  	default:

  		return false;

  	}
  }
  
  static bool is_read_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case 0x08 ... 0x0F:
  		return false;
  	default:
  		return true;
  	}
  }
  
  static bool is_write_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case TPS51632_VOLTAGE_SELECT_REG:
  	case TPS51632_VOLTAGE_BASE_REG:
  	case TPS51632_VMAX_REG:
  	case TPS51632_DVFS_CONTROL_REG:
  	case TPS51632_POWER_STATE_REG:
  	case TPS51632_SLEW_REGS:
  		return true;
  	default:
  		return false;
  	}

  }
  
  static const struct regmap_config tps51632_regmap_config = {
  	.reg_bits		= 8,
  	.val_bits		= 8,

  	.writeable_reg		= is_write_reg,
  	.readable_reg		= is_read_reg,
  	.volatile_reg		= is_volatile_reg,

  	.max_register		= TPS51632_MAX_REG - 1,
  	.cache_type		= REGCACHE_RBTREE,
  };

  #if defined(CONFIG_OF)
  static const struct of_device_id tps51632_of_match[] = {
  	{ .compatible = "ti,tps51632",},
  	{},
  };
  MODULE_DEVICE_TABLE(of, tps51632_of_match);
  
  static struct tps51632_regulator_platform_data *
  	of_get_tps51632_platform_data(struct device *dev)
  {
  	struct tps51632_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);
  	if (!pdata->reg_init_data) {
  		dev_err(dev, "Not able to get OF regulator init data
  ");
  		return NULL;
  	}
  
  	pdata->enable_pwm_dvfs =
  			of_property_read_bool(np, "ti,enable-pwm-dvfs");
  	pdata->dvfs_step_20mV = of_property_read_bool(np, "ti,dvfs-step-20mV");
  
  	pdata->base_voltage_uV = pdata->reg_init_data->constraints.min_uV ? :

  					TPS51632_MIN_VOLTAGE;

  	pdata->max_voltage_uV = pdata->reg_init_data->constraints.max_uV ? :

  					TPS51632_MAX_VOLTAGE;

  	return pdata;
  }
  #else
  static struct tps51632_regulator_platform_data *
  	of_get_tps51632_platform_data(struct device *dev)
  {
  	return NULL;
  }
  #endif

  static int tps51632_probe(struct i2c_client *client,

  				const struct i2c_device_id *id)
  {
  	struct tps51632_regulator_platform_data *pdata;
  	struct regulator_dev *rdev;
  	struct tps51632_chip *tps;
  	int ret;
  	struct regulator_config config = { };

  	if (client->dev.of_node) {
  		const struct of_device_id *match;
  		match = of_match_device(of_match_ptr(tps51632_of_match),
  				&client->dev);
  		if (!match) {
  			dev_err(&client->dev, "Error: No device match found
  ");
  			return -ENODEV;
  		}
  	}

  	pdata = dev_get_platdata(&client->dev);

  	if (!pdata && client->dev.of_node)
  		pdata = of_get_tps51632_platform_data(&client->dev);

  	if (!pdata) {
  		dev_err(&client->dev, "No Platform data
  ");
  		return -EINVAL;
  	}

  	if (pdata->enable_pwm_dvfs) {

  		if ((pdata->base_voltage_uV < TPS51632_MIN_VOLTAGE) ||
  		    (pdata->base_voltage_uV > TPS51632_MAX_VOLTAGE)) {

  			dev_err(&client->dev, "Invalid base_voltage_uV setting
  ");
  			return -EINVAL;
  		}
  
  		if ((pdata->max_voltage_uV) &&

  		    ((pdata->max_voltage_uV < TPS51632_MIN_VOLTAGE) ||
  		     (pdata->max_voltage_uV > TPS51632_MAX_VOLTAGE))) {

  			dev_err(&client->dev, "Invalid max_voltage_uV setting
  ");
  			return -EINVAL;
  		}
  	}

  	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);

  	if (!tps)

  		return -ENOMEM;

  
  	tps->dev = &client->dev;

  	tps->desc.name = client->name;

  	tps->desc.id = 0;
  	tps->desc.ramp_delay = TPS51632_DEFAULT_RAMP_DELAY;

  	tps->desc.min_uV = TPS51632_MIN_VOLTAGE;
  	tps->desc.uV_step = TPS51632_VOLTAGE_STEP_10mV;

  	tps->desc.linear_min_sel = TPS51632_MIN_VSEL;
  	tps->desc.n_voltages = TPS51632_MAX_VSEL + 1;

  	tps->desc.ops = &tps51632_dcdc_ops;
  	tps->desc.type = REGULATOR_VOLTAGE;
  	tps->desc.owner = THIS_MODULE;

  	if (pdata->enable_pwm_dvfs)
  		tps->desc.vsel_reg = TPS51632_VOLTAGE_BASE_REG;
  	else
  		tps->desc.vsel_reg = TPS51632_VOLTAGE_SELECT_REG;
  	tps->desc.vsel_mask = TPS51632_VOUT_MASK;

  	tps->regmap = devm_regmap_init_i2c(client, &tps51632_regmap_config);
  	if (IS_ERR(tps->regmap)) {
  		ret = PTR_ERR(tps->regmap);
  		dev_err(&client->dev, "regmap init failed, err %d
  ", ret);
  		return ret;
  	}
  	i2c_set_clientdata(client, tps);
  
  	ret = tps51632_init_dcdc(tps, pdata);
  	if (ret < 0) {
  		dev_err(tps->dev, "Init failed, err = %d
  ", ret);
  		return ret;
  	}
  
  	/* Register the regulators */
  	config.dev = &client->dev;
  	config.init_data = pdata->reg_init_data;
  	config.driver_data = tps;
  	config.regmap = tps->regmap;
  	config.of_node = client->dev.of_node;

  	rdev = devm_regulator_register(&client->dev, &tps->desc, &config);

  	if (IS_ERR(rdev)) {
  		dev_err(tps->dev, "regulator register failed
  ");
  		return PTR_ERR(rdev);
  	}
  
  	tps->rdev = rdev;
  	return 0;
  }

  static const struct i2c_device_id tps51632_id[] = {
  	{.name = "tps51632",},
  	{},
  };
  
  MODULE_DEVICE_TABLE(i2c, tps51632_id);
  
  static struct i2c_driver tps51632_i2c_driver = {
  	.driver = {
  		.name = "tps51632",
  		.owner = THIS_MODULE,

  		.of_match_table = of_match_ptr(tps51632_of_match),

  	},
  	.probe = tps51632_probe,

  	.id_table = tps51632_id,
  };
  
  static int __init tps51632_init(void)
  {
  	return i2c_add_driver(&tps51632_i2c_driver);
  }
  subsys_initcall(tps51632_init);
  
  static void __exit tps51632_cleanup(void)
  {
  	i2c_del_driver(&tps51632_i2c_driver);
  }
  module_exit(tps51632_cleanup);
  
  MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  MODULE_DESCRIPTION("TPS51632 voltage regulator driver");
  MODULE_LICENSE("GPL v2");