/*
   * TI LP8788 MFD - buck regulator driver
   *
   * Copyright 2012 Texas Instruments
   *
   * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/mfd/lp8788.h>
  #include <linux/gpio.h>
  
  /* register address */
  #define LP8788_EN_BUCK			0x0C
  #define LP8788_BUCK_DVS_SEL		0x1D
  #define LP8788_BUCK1_VOUT0		0x1E
  #define LP8788_BUCK1_VOUT1		0x1F
  #define LP8788_BUCK1_VOUT2		0x20
  #define LP8788_BUCK1_VOUT3		0x21
  #define LP8788_BUCK2_VOUT0		0x22
  #define LP8788_BUCK2_VOUT1		0x23
  #define LP8788_BUCK2_VOUT2		0x24
  #define LP8788_BUCK2_VOUT3		0x25
  #define LP8788_BUCK3_VOUT		0x26
  #define LP8788_BUCK4_VOUT		0x27
  #define LP8788_BUCK1_TIMESTEP		0x28
  #define LP8788_BUCK_PWM			0x2D
  
  /* mask/shift bits */
  #define LP8788_EN_BUCK1_M		BIT(0)	/* Addr 0Ch */
  #define LP8788_EN_BUCK2_M		BIT(1)
  #define LP8788_EN_BUCK3_M		BIT(2)
  #define LP8788_EN_BUCK4_M		BIT(3)
  #define LP8788_BUCK1_DVS_SEL_M		0x04	/* Addr 1Dh */
  #define LP8788_BUCK1_DVS_M		0x03
  #define LP8788_BUCK1_DVS_S		0
  #define LP8788_BUCK2_DVS_SEL_M		0x40
  #define LP8788_BUCK2_DVS_M		0x30
  #define LP8788_BUCK2_DVS_S		4
  #define LP8788_BUCK1_DVS_I2C		BIT(2)
  #define LP8788_BUCK2_DVS_I2C		BIT(6)
  #define LP8788_BUCK1_DVS_PIN		(0 << 2)
  #define LP8788_BUCK2_DVS_PIN		(0 << 6)
  #define LP8788_VOUT_M			0x1F	/* Addr 1Eh ~ 27h */
  #define LP8788_STARTUP_TIME_M		0xF8	/* Addr 28h ~ 2Bh */
  #define LP8788_STARTUP_TIME_S		3
  #define LP8788_FPWM_BUCK1_M		BIT(0)	/* Addr 2Dh */
  #define LP8788_FPWM_BUCK1_S		0
  #define LP8788_FPWM_BUCK2_M		BIT(1)
  #define LP8788_FPWM_BUCK2_S		1
  #define LP8788_FPWM_BUCK3_M		BIT(2)
  #define LP8788_FPWM_BUCK3_S		2
  #define LP8788_FPWM_BUCK4_M		BIT(3)
  #define LP8788_FPWM_BUCK4_S		3
  
  #define INVALID_ADDR			0xFF
  #define LP8788_FORCE_PWM		1
  #define LP8788_AUTO_PWM			0
  #define PIN_LOW				0
  #define PIN_HIGH			1
  #define ENABLE_TIME_USEC		32
  
  #define BUCK_FPWM_MASK(x)		(1 << (x))
  #define BUCK_FPWM_SHIFT(x)		(x)
  
  enum lp8788_dvs_state {
  	DVS_LOW  = GPIOF_OUT_INIT_LOW,
  	DVS_HIGH = GPIOF_OUT_INIT_HIGH,
  };
  
  enum lp8788_dvs_mode {
  	REGISTER,
  	EXTPIN,
  };
  
  enum lp8788_buck_id {
  	BUCK1,
  	BUCK2,
  	BUCK3,
  	BUCK4,
  };
  
  struct lp8788_buck {
  	struct lp8788 *lp;
  	struct regulator_dev *regulator;
  	void *dvs;
  };
  
  /* BUCK 1 ~ 4 voltage table */
  static const int lp8788_buck_vtbl[] = {
  	 500000,  800000,  850000,  900000,  950000, 1000000, 1050000, 1100000,
  	1150000, 1200000, 1250000, 1300000, 1350000, 1400000, 1450000, 1500000,
  	1550000, 1600000, 1650000, 1700000, 1750000, 1800000, 1850000, 1900000,
  	1950000, 2000000,
  };
  
  static void lp8788_buck1_set_dvs(struct lp8788_buck *buck)
  {
  	struct lp8788_buck1_dvs *dvs = (struct lp8788_buck1_dvs *)buck->dvs;
  	enum lp8788_dvs_state pinstate;
  
  	if (!dvs)
  		return;
  
  	pinstate = dvs->vsel == DVS_SEL_V0 ? DVS_LOW : DVS_HIGH;
  	if (gpio_is_valid(dvs->gpio))
  		gpio_set_value(dvs->gpio, pinstate);
  }
  
  static void lp8788_buck2_set_dvs(struct lp8788_buck *buck)
  {
  	struct lp8788_buck2_dvs *dvs = (struct lp8788_buck2_dvs *)buck->dvs;
  	enum lp8788_dvs_state pin1, pin2;
  
  	if (!dvs)
  		return;
  
  	switch (dvs->vsel) {
  	case DVS_SEL_V0:
  		pin1 = DVS_LOW;
  		pin2 = DVS_LOW;
  		break;
  	case DVS_SEL_V1:
  		pin1 = DVS_HIGH;
  		pin2 = DVS_LOW;
  		break;
  	case DVS_SEL_V2:
  		pin1 = DVS_LOW;
  		pin2 = DVS_HIGH;
  		break;
  	case DVS_SEL_V3:
  		pin1 = DVS_HIGH;
  		pin2 = DVS_HIGH;
  		break;
  	default:
  		return;
  	}
  
  	if (gpio_is_valid(dvs->gpio[0]))
  		gpio_set_value(dvs->gpio[0], pin1);
  
  	if (gpio_is_valid(dvs->gpio[1]))
  		gpio_set_value(dvs->gpio[1], pin2);
  }
  
  static void lp8788_set_dvs(struct lp8788_buck *buck, enum lp8788_buck_id id)
  {
  	switch (id) {
  	case BUCK1:
  		lp8788_buck1_set_dvs(buck);
  		break;
  	case BUCK2:
  		lp8788_buck2_set_dvs(buck);
  		break;
  	default:
  		break;
  	}
  }
  
  static enum lp8788_dvs_mode
  lp8788_get_buck_dvs_ctrl_mode(struct lp8788_buck *buck, enum lp8788_buck_id id)
  {
  	u8 val, mask;
  
  	switch (id) {
  	case BUCK1:
  		mask = LP8788_BUCK1_DVS_SEL_M;
  		break;
  	case BUCK2:
  		mask = LP8788_BUCK2_DVS_SEL_M;
  		break;
  	default:
  		return REGISTER;
  	}
  
  	lp8788_read_byte(buck->lp, LP8788_BUCK_DVS_SEL, &val);
  
  	return val & mask ? REGISTER : EXTPIN;
  }
  
  static bool lp8788_is_valid_buck_addr(u8 addr)
  {
  	switch (addr) {
  	case LP8788_BUCK1_VOUT0:
  	case LP8788_BUCK1_VOUT1:
  	case LP8788_BUCK1_VOUT2:
  	case LP8788_BUCK1_VOUT3:
  	case LP8788_BUCK2_VOUT0:
  	case LP8788_BUCK2_VOUT1:
  	case LP8788_BUCK2_VOUT2:
  	case LP8788_BUCK2_VOUT3:
  		return true;
  	default:
  		return false;
  	}
  }
  
  static u8 lp8788_select_buck_vout_addr(struct lp8788_buck *buck,
  					enum lp8788_buck_id id)
  {
  	enum lp8788_dvs_mode mode = lp8788_get_buck_dvs_ctrl_mode(buck, id);
  	struct lp8788_buck1_dvs *b1_dvs;
  	struct lp8788_buck2_dvs *b2_dvs;
  	u8 val, idx, addr;
  	int pin1, pin2;
  
  	switch (id) {
  	case BUCK1:
  		if (mode == EXTPIN) {
  			b1_dvs = (struct lp8788_buck1_dvs *)buck->dvs;
  			if (!b1_dvs)
  				goto err;
  
  			idx = gpio_get_value(b1_dvs->gpio) ? 1 : 0;
  		} else {
  			lp8788_read_byte(buck->lp, LP8788_BUCK_DVS_SEL, &val);
  			idx = (val & LP8788_BUCK1_DVS_M) >> LP8788_BUCK1_DVS_S;
  		}
  		addr = LP8788_BUCK1_VOUT0 + idx;
  		break;
  	case BUCK2:
  		if (mode == EXTPIN) {
  			b2_dvs = (struct lp8788_buck2_dvs *)buck->dvs;
  			if (!b2_dvs)
  				goto err;
  
  			pin1 = gpio_get_value(b2_dvs->gpio[0]);
  			pin2 = gpio_get_value(b2_dvs->gpio[1]);
  
  			if (pin1 == PIN_LOW && pin2 == PIN_LOW)
  				idx = 0;
  			else if (pin1 == PIN_LOW && pin2 == PIN_HIGH)
  				idx = 2;
  			else if (pin1 == PIN_HIGH && pin2 == PIN_LOW)
  				idx = 1;
  			else
  				idx = 3;
  		} else {
  			lp8788_read_byte(buck->lp, LP8788_BUCK_DVS_SEL, &val);
  			idx = (val & LP8788_BUCK2_DVS_M) >> LP8788_BUCK2_DVS_S;
  		}
  		addr = LP8788_BUCK2_VOUT0 + idx;
  		break;
  	default:
  		goto err;
  	}
  
  	return addr;
  err:
  	return INVALID_ADDR;
  }
  
  static int lp8788_buck12_set_voltage_sel(struct regulator_dev *rdev,
  					unsigned selector)
  {
  	struct lp8788_buck *buck = rdev_get_drvdata(rdev);
  	enum lp8788_buck_id id = rdev_get_id(rdev);
  	u8 addr;
  
  	if (buck->dvs)
  		lp8788_set_dvs(buck, id);
  
  	addr = lp8788_select_buck_vout_addr(buck, id);
  	if (!lp8788_is_valid_buck_addr(addr))
  		return -EINVAL;
  
  	return lp8788_update_bits(buck->lp, addr, LP8788_VOUT_M, selector);
  }
  
  static int lp8788_buck12_get_voltage_sel(struct regulator_dev *rdev)
  {
  	struct lp8788_buck *buck = rdev_get_drvdata(rdev);
  	enum lp8788_buck_id id = rdev_get_id(rdev);
  	int ret;
  	u8 val, addr;
  
  	addr = lp8788_select_buck_vout_addr(buck, id);
  	if (!lp8788_is_valid_buck_addr(addr))
  		return -EINVAL;
  
  	ret = lp8788_read_byte(buck->lp, addr, &val);
  	if (ret)
  		return ret;
  
  	return val & LP8788_VOUT_M;
  }
  
  static int lp8788_buck_enable_time(struct regulator_dev *rdev)
  {
  	struct lp8788_buck *buck = rdev_get_drvdata(rdev);
  	enum lp8788_buck_id id = rdev_get_id(rdev);
  	u8 val, addr = LP8788_BUCK1_TIMESTEP + id;
  
  	if (lp8788_read_byte(buck->lp, addr, &val))
  		return -EINVAL;
  
  	val = (val & LP8788_STARTUP_TIME_M) >> LP8788_STARTUP_TIME_S;
  
  	return ENABLE_TIME_USEC * val;
  }
  
  static int lp8788_buck_set_mode(struct regulator_dev *rdev, unsigned int mode)
  {
  	struct lp8788_buck *buck = rdev_get_drvdata(rdev);
  	enum lp8788_buck_id id = rdev_get_id(rdev);
  	u8 mask, val;
  
  	mask = BUCK_FPWM_MASK(id);
  	switch (mode) {
  	case REGULATOR_MODE_FAST:
  		val = LP8788_FORCE_PWM << BUCK_FPWM_SHIFT(id);
  		break;
  	case REGULATOR_MODE_NORMAL:
  		val = LP8788_AUTO_PWM << BUCK_FPWM_SHIFT(id);
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return lp8788_update_bits(buck->lp, LP8788_BUCK_PWM, mask, val);
  }
  
  static unsigned int lp8788_buck_get_mode(struct regulator_dev *rdev)
  {
  	struct lp8788_buck *buck = rdev_get_drvdata(rdev);
  	enum lp8788_buck_id id = rdev_get_id(rdev);
  	u8 val;
  	int ret;
  
  	ret = lp8788_read_byte(buck->lp, LP8788_BUCK_PWM, &val);
  	if (ret)
  		return ret;
  
  	return val & BUCK_FPWM_MASK(id) ?
  				REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
  }
  
  static struct regulator_ops lp8788_buck12_ops = {
  	.list_voltage = regulator_list_voltage_table,
  	.map_voltage = regulator_map_voltage_ascend,
  	.set_voltage_sel = lp8788_buck12_set_voltage_sel,
  	.get_voltage_sel = lp8788_buck12_get_voltage_sel,
  	.enable = regulator_enable_regmap,
  	.disable = regulator_disable_regmap,
  	.is_enabled = regulator_is_enabled_regmap,
  	.enable_time = lp8788_buck_enable_time,
  	.set_mode = lp8788_buck_set_mode,
  	.get_mode = lp8788_buck_get_mode,
  };
  
  static struct regulator_ops lp8788_buck34_ops = {
  	.list_voltage = regulator_list_voltage_table,
  	.map_voltage = regulator_map_voltage_ascend,
  	.set_voltage_sel = regulator_set_voltage_sel_regmap,
  	.get_voltage_sel = regulator_get_voltage_sel_regmap,
  	.enable = regulator_enable_regmap,
  	.disable = regulator_disable_regmap,
  	.is_enabled = regulator_is_enabled_regmap,
  	.enable_time = lp8788_buck_enable_time,
  	.set_mode = lp8788_buck_set_mode,
  	.get_mode = lp8788_buck_get_mode,
  };
  
  static struct regulator_desc lp8788_buck_desc[] = {
  	{
  		.name = "buck1",
  		.id = BUCK1,
  		.ops = &lp8788_buck12_ops,
  		.n_voltages = ARRAY_SIZE(lp8788_buck_vtbl),
  		.volt_table = lp8788_buck_vtbl,
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  		.enable_reg = LP8788_EN_BUCK,
  		.enable_mask = LP8788_EN_BUCK1_M,
  	},
  	{
  		.name = "buck2",
  		.id = BUCK2,
  		.ops = &lp8788_buck12_ops,
  		.n_voltages = ARRAY_SIZE(lp8788_buck_vtbl),
  		.volt_table = lp8788_buck_vtbl,
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  		.enable_reg = LP8788_EN_BUCK,
  		.enable_mask = LP8788_EN_BUCK2_M,
  	},
  	{
  		.name = "buck3",
  		.id = BUCK3,
  		.ops = &lp8788_buck34_ops,
  		.n_voltages = ARRAY_SIZE(lp8788_buck_vtbl),
  		.volt_table = lp8788_buck_vtbl,
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  		.vsel_reg = LP8788_BUCK3_VOUT,
  		.vsel_mask = LP8788_VOUT_M,
  		.enable_reg = LP8788_EN_BUCK,
  		.enable_mask = LP8788_EN_BUCK3_M,
  	},
  	{
  		.name = "buck4",
  		.id = BUCK4,
  		.ops = &lp8788_buck34_ops,
  		.n_voltages = ARRAY_SIZE(lp8788_buck_vtbl),
  		.volt_table = lp8788_buck_vtbl,
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  		.vsel_reg = LP8788_BUCK4_VOUT,
  		.vsel_mask = LP8788_VOUT_M,
  		.enable_reg = LP8788_EN_BUCK,
  		.enable_mask = LP8788_EN_BUCK4_M,
  	},
  };
  
  static int lp8788_dvs_gpio_request(struct platform_device *pdev,
  				struct lp8788_buck *buck,
  				enum lp8788_buck_id id)
  {
  	struct lp8788_platform_data *pdata = buck->lp->pdata;
  	char *b1_name = "LP8788_B1_DVS";
  	char *b2_name[] = { "LP8788_B2_DVS1", "LP8788_B2_DVS2" };
  	int i, gpio, ret;
  
  	switch (id) {
  	case BUCK1:
  		gpio = pdata->buck1_dvs->gpio;
  		ret = devm_gpio_request_one(&pdev->dev, gpio, DVS_LOW,
  					    b1_name);
  		if (ret)
  			return ret;
  
  		buck->dvs = pdata->buck1_dvs;
  		break;
  	case BUCK2:
  		for (i = 0; i < LP8788_NUM_BUCK2_DVS; i++) {
  			gpio = pdata->buck2_dvs->gpio[i];
  			ret = devm_gpio_request_one(&pdev->dev, gpio,
  						    DVS_LOW, b2_name[i]);
  			if (ret)
  				return ret;
  		}
  		buck->dvs = pdata->buck2_dvs;
  		break;
  	default:
  		break;
  	}
  
  	return 0;
  }
  
  static int lp8788_init_dvs(struct platform_device *pdev,
  			struct lp8788_buck *buck, enum lp8788_buck_id id)
  {
  	struct lp8788_platform_data *pdata = buck->lp->pdata;
  	u8 mask[] = { LP8788_BUCK1_DVS_SEL_M, LP8788_BUCK2_DVS_SEL_M };
  	u8 val[]  = { LP8788_BUCK1_DVS_PIN, LP8788_BUCK2_DVS_PIN };
  	u8 default_dvs_mode[] = { LP8788_BUCK1_DVS_I2C, LP8788_BUCK2_DVS_I2C };
  
  	/* no dvs for buck3, 4 */
  	if (id > BUCK2)
  		return 0;
  
  	/* no dvs platform data, then dvs will be selected by I2C registers */
  	if (!pdata)
  		goto set_default_dvs_mode;
  
  	if ((id == BUCK1 && !pdata->buck1_dvs) ||
  		(id == BUCK2 && !pdata->buck2_dvs))
  		goto set_default_dvs_mode;
  
  	if (lp8788_dvs_gpio_request(pdev, buck, id))
  		goto set_default_dvs_mode;
  
  	return lp8788_update_bits(buck->lp, LP8788_BUCK_DVS_SEL, mask[id],
  				val[id]);
  
  set_default_dvs_mode:
  	return lp8788_update_bits(buck->lp, LP8788_BUCK_DVS_SEL, mask[id],
  				  default_dvs_mode[id]);
  }
  
  static int lp8788_buck_probe(struct platform_device *pdev)
  {
  	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
  	int id = pdev->id;
  	struct lp8788_buck *buck;
  	struct regulator_config cfg = { };
  	struct regulator_dev *rdev;
  	int ret;
  
  	if (id >= LP8788_NUM_BUCKS)
  		return -EINVAL;
  
  	buck = devm_kzalloc(&pdev->dev, sizeof(struct lp8788_buck), GFP_KERNEL);
  	if (!buck)
  		return -ENOMEM;
  
  	buck->lp = lp;
  
  	ret = lp8788_init_dvs(pdev, buck, id);
  	if (ret)
  		return ret;
  
  	cfg.dev = pdev->dev.parent;
  	cfg.init_data = lp->pdata ? lp->pdata->buck_data[id] : NULL;
  	cfg.driver_data = buck;
  	cfg.regmap = lp->regmap;
  
  	rdev = devm_regulator_register(&pdev->dev, &lp8788_buck_desc[id], &cfg);
  	if (IS_ERR(rdev)) {
  		ret = PTR_ERR(rdev);
  		dev_err(&pdev->dev, "BUCK%d regulator register err = %d
  ",
  				id + 1, ret);
  		return ret;
  	}
  
  	buck->regulator = rdev;
  	platform_set_drvdata(pdev, buck);
  
  	return 0;
  }
  
  static struct platform_driver lp8788_buck_driver = {
  	.probe = lp8788_buck_probe,
  	.driver = {
  		.name = LP8788_DEV_BUCK,
  		.owner = THIS_MODULE,
  	},
  };
  
  static int __init lp8788_buck_init(void)
  {
  	return platform_driver_register(&lp8788_buck_driver);
  }
  subsys_initcall(lp8788_buck_init);
  
  static void __exit lp8788_buck_exit(void)
  {
  	platform_driver_unregister(&lp8788_buck_driver);
  }
  module_exit(lp8788_buck_exit);
  
  MODULE_DESCRIPTION("TI LP8788 BUCK Driver");
  MODULE_AUTHOR("Milo Kim");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:lp8788-buck");