/*
 * 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 const u8 buck1_vout_addr[] = {
	LP8788_BUCK1_VOUT0, LP8788_BUCK1_VOUT1,
	LP8788_BUCK1_VOUT2, LP8788_BUCK1_VOUT3,
};

static const u8 buck2_vout_addr[] = {
	LP8788_BUCK2_VOUT0, LP8788_BUCK2_VOUT1,
	LP8788_BUCK2_VOUT2, LP8788_BUCK2_VOUT3,
};

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 = buck1_vout_addr[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 = buck2_vout_addr[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,
	.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,
	.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 _gpio_request(struct lp8788_buck *buck, int gpio, char *name)
{
	struct device *dev = buck->lp->dev;

	if (!gpio_is_valid(gpio)) {
		dev_err(dev, "invalid gpio: %d\n", gpio);
		return -EINVAL;
	}

	return devm_gpio_request_one(dev, gpio, DVS_LOW, name);
}

static int lp8788_dvs_gpio_request(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 = _gpio_request(buck, gpio, 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 = _gpio_request(buck, gpio, b2_name[i]);
			if (ret)
				return ret;
		}
		buck->dvs = pdata->buck2_dvs;
		break;
	default:
		break;
	}

	return 0;
}

static int lp8788_init_dvs(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 == BUCK3 || id == BUCK4)
		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(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 __devinit 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;

	buck = devm_kzalloc(lp->dev, sizeof(struct lp8788_buck), GFP_KERNEL);
	if (!buck)
		return -ENOMEM;

	buck->lp = lp;

	ret = lp8788_init_dvs(buck, id);
	if (ret)
		return ret;

	cfg.dev = lp->dev;
	cfg.init_data = lp->pdata ? lp->pdata->buck_data[id] : NULL;
	cfg.driver_data = buck;
	cfg.regmap = lp->regmap;

	rdev = regulator_register(&lp8788_buck_desc[id], &cfg);
	if (IS_ERR(rdev)) {
		ret = PTR_ERR(rdev);
		dev_err(lp->dev, "BUCK%d regulator register err = %d\n",
				id + 1, ret);
		return ret;
	}

	buck->regulator = rdev;
	platform_set_drvdata(pdev, buck);

	return 0;
}

static int __devexit lp8788_buck_remove(struct platform_device *pdev)
{
	struct lp8788_buck *buck = platform_get_drvdata(pdev);

	platform_set_drvdata(pdev, NULL);
	regulator_unregister(buck->regulator);

	return 0;
}

static struct platform_driver lp8788_buck_driver = {
	.probe = lp8788_buck_probe,
	.remove = __devexit_p(lp8788_buck_remove),
	.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");