/*
 * AS3711 PMIC regulator driver, using DCDC Step Down and LDO supplies
 *
 * Copyright (C) 2012 Renesas Electronics Corporation
 * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License as
 * published by the Free Software Foundation
 */

#include <linux/err.h>
#include <linux/init.h>
#include <linux/mfd/as3711.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/slab.h>

struct as3711_regulator_info {
	struct regulator_desc	desc;
	unsigned int		max_uV;
};

struct as3711_regulator {
	struct as3711_regulator_info *reg_info;
	struct regulator_dev *rdev;
};

static int as3711_list_voltage_sd(struct regulator_dev *rdev,
				  unsigned int selector)
{
	if (selector >= rdev->desc->n_voltages)
		return -EINVAL;

	if (!selector)
		return 0;
	if (selector < 0x41)
		return 600000 + selector * 12500;
	if (selector < 0x71)
		return 1400000 + (selector - 0x40) * 25000;
	return 2600000 + (selector - 0x70) * 50000;
}

static int as3711_list_voltage_aldo(struct regulator_dev *rdev,
				    unsigned int selector)
{
	if (selector >= rdev->desc->n_voltages)
		return -EINVAL;

	if (selector < 0x10)
		return 1200000 + selector * 50000;
	return 1800000 + (selector - 0x10) * 100000;
}

static int as3711_list_voltage_dldo(struct regulator_dev *rdev,
				    unsigned int selector)
{
	if (selector >= rdev->desc->n_voltages ||
	    (selector > 0x10 && selector < 0x20))
		return -EINVAL;

	if (selector < 0x11)
		return 900000 + selector * 50000;
	return 1750000 + (selector - 0x20) * 50000;
}

static int as3711_bound_check(struct regulator_dev *rdev,
			      int *min_uV, int *max_uV)
{
	struct as3711_regulator *reg = rdev_get_drvdata(rdev);
	struct as3711_regulator_info *info = reg->reg_info;

	dev_dbg(&rdev->dev, "%s(), %d, %d, %d\n", __func__,
		*min_uV, rdev->desc->min_uV, info->max_uV);

	if (*max_uV < *min_uV ||
	    *min_uV > info->max_uV || rdev->desc->min_uV > *max_uV)
		return -EINVAL;

	if (rdev->desc->n_voltages == 1)
		return 0;

	if (*max_uV > info->max_uV)
		*max_uV = info->max_uV;

	if (*min_uV < rdev->desc->min_uV)
		*min_uV = rdev->desc->min_uV;

	return *min_uV;
}

static int as3711_sel_check(int min, int max, int bottom, int step)
{
	int sel, voltage;

	/* Round up min, when dividing: keeps us within the range */
	sel = DIV_ROUND_UP(min - bottom, step);
	voltage = sel * step + bottom;
	pr_debug("%s(): select %d..%d in %d+N*%d: %d\n", __func__,
	       min, max, bottom, step, sel);
	if (voltage > max)
		return -EINVAL;

	return sel;
}

static int as3711_map_voltage_sd(struct regulator_dev *rdev,
				 int min_uV, int max_uV)
{
	int ret;

	ret = as3711_bound_check(rdev, &min_uV, &max_uV);
	if (ret <= 0)
		return ret;

	if (min_uV <= 1400000)
		return as3711_sel_check(min_uV, max_uV, 600000, 12500);

	if (min_uV <= 2600000)
		return as3711_sel_check(min_uV, max_uV, 1400000, 25000) + 0x40;

	return as3711_sel_check(min_uV, max_uV, 2600000, 50000) + 0x70;
}

/*
 * The regulator API supports 4 modes of operataion: FAST, NORMAL, IDLE and
 * STANDBY. We map them in the following way to AS3711 SD1-4 DCDC modes:
 * FAST:	sdX_fast=1
 * NORMAL:	low_noise=1
 * IDLE:	low_noise=0
 */

static int as3711_set_mode_sd(struct regulator_dev *rdev, unsigned int mode)
{
	unsigned int fast_bit = rdev->desc->enable_mask,
		low_noise_bit = fast_bit << 4;
	u8 val;

	switch (mode) {
	case REGULATOR_MODE_FAST:
		val = fast_bit | low_noise_bit;
		break;
	case REGULATOR_MODE_NORMAL:
		val = low_noise_bit;
		break;
	case REGULATOR_MODE_IDLE:
		val = 0;
		break;
	default:
		return -EINVAL;
	}

	return regmap_update_bits(rdev->regmap, AS3711_SD_CONTROL_1,
				  low_noise_bit | fast_bit, val);
}

static unsigned int as3711_get_mode_sd(struct regulator_dev *rdev)
{
	unsigned int fast_bit = rdev->desc->enable_mask,
		low_noise_bit = fast_bit << 4, mask = fast_bit | low_noise_bit;
	unsigned int val;
	int ret = regmap_read(rdev->regmap, AS3711_SD_CONTROL_1, &val);

	if (ret < 0)
		return ret;

	if ((val & mask) == mask)
		return REGULATOR_MODE_FAST;

	if ((val & mask) == low_noise_bit)
		return REGULATOR_MODE_NORMAL;

	if (!(val & mask))
		return REGULATOR_MODE_IDLE;

	return -EINVAL;
}

static int as3711_map_voltage_aldo(struct regulator_dev *rdev,
				  int min_uV, int max_uV)
{
	int ret;

	ret = as3711_bound_check(rdev, &min_uV, &max_uV);
	if (ret <= 0)
		return ret;

	if (min_uV <= 1800000)
		return as3711_sel_check(min_uV, max_uV, 1200000, 50000);

	return as3711_sel_check(min_uV, max_uV, 1800000, 100000) + 0x10;
}

static int as3711_map_voltage_dldo(struct regulator_dev *rdev,
				  int min_uV, int max_uV)
{
	int ret;

	ret = as3711_bound_check(rdev, &min_uV, &max_uV);
	if (ret <= 0)
		return ret;

	if (min_uV <= 1700000)
		return as3711_sel_check(min_uV, max_uV, 900000, 50000);

	return as3711_sel_check(min_uV, max_uV, 1750000, 50000) + 0x20;
}

static struct regulator_ops as3711_sd_ops = {
	.is_enabled		= regulator_is_enabled_regmap,
	.enable			= regulator_enable_regmap,
	.disable		= regulator_disable_regmap,
	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
	.list_voltage		= as3711_list_voltage_sd,
	.map_voltage		= as3711_map_voltage_sd,
	.get_mode		= as3711_get_mode_sd,
	.set_mode		= as3711_set_mode_sd,
};

static struct regulator_ops as3711_aldo_ops = {
	.is_enabled		= regulator_is_enabled_regmap,
	.enable			= regulator_enable_regmap,
	.disable		= regulator_disable_regmap,
	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
	.list_voltage		= as3711_list_voltage_aldo,
	.map_voltage		= as3711_map_voltage_aldo,
};

static struct regulator_ops as3711_dldo_ops = {
	.is_enabled		= regulator_is_enabled_regmap,
	.enable			= regulator_enable_regmap,
	.disable		= regulator_disable_regmap,
	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
	.list_voltage		= as3711_list_voltage_dldo,
	.map_voltage		= as3711_map_voltage_dldo,
};

#define AS3711_REG(_id, _en_reg, _en_bit, _vmask, _vshift, _min_uV, _max_uV, _sfx)	\
	[AS3711_REGULATOR_ ## _id] = {							\
	.desc = {									\
		.name = "as3711-regulator-" # _id,					\
		.id = AS3711_REGULATOR_ ## _id,						\
		.n_voltages = (_vmask + 1),						\
		.ops = &as3711_ ## _sfx ## _ops,					\
		.type = REGULATOR_VOLTAGE,						\
		.owner = THIS_MODULE,							\
		.vsel_reg = AS3711_ ## _id ## _VOLTAGE,					\
		.vsel_mask = _vmask << _vshift,						\
		.enable_reg = AS3711_ ## _en_reg,					\
		.enable_mask = BIT(_en_bit),						\
		.min_uV	= _min_uV,							\
	},										\
	.max_uV = _max_uV,								\
}

static struct as3711_regulator_info as3711_reg_info[] = {
	AS3711_REG(SD_1, SD_CONTROL, 0, 0x7f, 0, 612500, 3350000, sd),
	AS3711_REG(SD_2, SD_CONTROL, 1, 0x7f, 0, 612500, 3350000, sd),
	AS3711_REG(SD_3, SD_CONTROL, 2, 0x7f, 0, 612500, 3350000, sd),
	AS3711_REG(SD_4, SD_CONTROL, 3, 0x7f, 0, 612500, 3350000, sd),
	AS3711_REG(LDO_1, LDO_1_VOLTAGE, 7, 0x1f, 0, 1200000, 3300000, aldo),
	AS3711_REG(LDO_2, LDO_2_VOLTAGE, 7, 0x1f, 0, 1200000, 3300000, aldo),
	AS3711_REG(LDO_3, LDO_3_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	AS3711_REG(LDO_4, LDO_4_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	AS3711_REG(LDO_5, LDO_5_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	AS3711_REG(LDO_6, LDO_6_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	AS3711_REG(LDO_7, LDO_7_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	AS3711_REG(LDO_8, LDO_8_VOLTAGE, 7, 0x3f, 0, 900000, 3300000, dldo),
	/* StepUp output voltage depends on supplying regulator */
};

#define AS3711_REGULATOR_NUM ARRAY_SIZE(as3711_reg_info)

static int as3711_regulator_probe(struct platform_device *pdev)
{
	struct as3711_regulator_pdata *pdata = dev_get_platdata(&pdev->dev);
	struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
	struct regulator_init_data *reg_data;
	struct regulator_config config = {.dev = &pdev->dev,};
	struct as3711_regulator *reg = NULL;
	struct as3711_regulator *regs;
	struct regulator_dev *rdev;
	struct as3711_regulator_info *ri;
	int ret;
	int id;

	if (!pdata)
		dev_dbg(&pdev->dev, "No platform data...\n");

	regs = devm_kzalloc(&pdev->dev, AS3711_REGULATOR_NUM *
			sizeof(struct as3711_regulator), GFP_KERNEL);
	if (!regs) {
		dev_err(&pdev->dev, "Memory allocation failed exiting..\n");
		return -ENOMEM;
	}

	for (id = 0, ri = as3711_reg_info; id < AS3711_REGULATOR_NUM; ++id, ri++) {
		reg_data = pdata ? pdata->init_data[id] : NULL;

		/* No need to register if there is no regulator data */
		if (!ri->desc.name)
			continue;

		reg = &regs[id];
		reg->reg_info = ri;

		config.init_data = reg_data;
		config.driver_data = reg;
		config.regmap = as3711->regmap;

		rdev = regulator_register(&ri->desc, &config);
		if (IS_ERR(rdev)) {
			dev_err(&pdev->dev, "Failed to register regulator %s\n",
				ri->desc.name);
			ret = PTR_ERR(rdev);
			goto eregreg;
		}
		reg->rdev = rdev;
	}
	platform_set_drvdata(pdev, regs);
	return 0;

eregreg:
	while (--id >= 0)
		regulator_unregister(regs[id].rdev);

	return ret;
}

static int as3711_regulator_remove(struct platform_device *pdev)
{
	struct as3711_regulator *regs = platform_get_drvdata(pdev);
	int id;

	for (id = 0; id < AS3711_REGULATOR_NUM; ++id)
		regulator_unregister(regs[id].rdev);
	return 0;
}

static struct platform_driver as3711_regulator_driver = {
	.driver	= {
		.name	= "as3711-regulator",
		.owner	= THIS_MODULE,
	},
	.probe		= as3711_regulator_probe,
	.remove		= as3711_regulator_remove,
};

static int __init as3711_regulator_init(void)
{
	return platform_driver_register(&as3711_regulator_driver);
}
subsys_initcall(as3711_regulator_init);

static void __exit as3711_regulator_exit(void)
{
	platform_driver_unregister(&as3711_regulator_driver);
}
module_exit(as3711_regulator_exit);

MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
MODULE_DESCRIPTION("AS3711 regulator driver");
MODULE_ALIAS("platform:as3711-regulator");
MODULE_LICENSE("GPL v2");