/*
 * linux/drivers/regulator/aat2870-regulator.c
 *
 * Copyright (c) 2011, NVIDIA Corporation.
 * Author: Jin Park <jinyoungp@nvidia.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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; 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., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/mfd/aat2870.h>

struct aat2870_regulator {
	struct platform_device *pdev;
	struct regulator_desc desc;

	const int *voltages; /* uV */

	int min_uV;
	int max_uV;

	u8 enable_addr;
	u8 enable_shift;
	u8 enable_mask;

	u8 voltage_addr;
	u8 voltage_shift;
	u8 voltage_mask;
};

static int aat2870_ldo_list_voltage(struct regulator_dev *rdev,
				    unsigned selector)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);

	return ri->voltages[selector];
}

static int aat2870_ldo_set_voltage_sel(struct regulator_dev *rdev,
				       unsigned selector)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
	struct aat2870_data *aat2870 = dev_get_drvdata(ri->pdev->dev.parent);

	return aat2870->update(aat2870, ri->voltage_addr, ri->voltage_mask,
			(selector << ri->voltage_shift) & ri->voltage_mask);
}

static int aat2870_ldo_get_voltage_sel(struct regulator_dev *rdev)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
	struct aat2870_data *aat2870 = dev_get_drvdata(ri->pdev->dev.parent);
	u8 val;
	int ret;

	ret = aat2870->read(aat2870, ri->voltage_addr, &val);
	if (ret)
		return ret;

	return (val & ri->voltage_mask) >> ri->voltage_shift;
}

static int aat2870_ldo_enable(struct regulator_dev *rdev)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
	struct aat2870_data *aat2870 = dev_get_drvdata(ri->pdev->dev.parent);

	return aat2870->update(aat2870, ri->enable_addr, ri->enable_mask,
			       ri->enable_mask);
}

static int aat2870_ldo_disable(struct regulator_dev *rdev)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
	struct aat2870_data *aat2870 = dev_get_drvdata(ri->pdev->dev.parent);

	return aat2870->update(aat2870, ri->enable_addr, ri->enable_mask, 0);
}

static int aat2870_ldo_is_enabled(struct regulator_dev *rdev)
{
	struct aat2870_regulator *ri = rdev_get_drvdata(rdev);
	struct aat2870_data *aat2870 = dev_get_drvdata(ri->pdev->dev.parent);
	u8 val;
	int ret;

	ret = aat2870->read(aat2870, ri->enable_addr, &val);
	if (ret)
		return ret;

	return val & ri->enable_mask ? 1 : 0;
}

static struct regulator_ops aat2870_ldo_ops = {
	.list_voltage = aat2870_ldo_list_voltage,
	.set_voltage_sel = aat2870_ldo_set_voltage_sel,
	.get_voltage_sel = aat2870_ldo_get_voltage_sel,
	.enable = aat2870_ldo_enable,
	.disable = aat2870_ldo_disable,
	.is_enabled = aat2870_ldo_is_enabled,
};

static const int aat2870_ldo_voltages[] = {
	1200000, 1300000, 1500000, 1600000,
	1800000, 2000000, 2200000, 2500000,
	2600000, 2700000, 2800000, 2900000,
	3000000, 3100000, 3200000, 3300000,
};

#define AAT2870_LDO(ids)				\
	{						\
		.desc = {				\
			.name = #ids,			\
			.id = AAT2870_ID_##ids,		\
			.n_voltages = ARRAY_SIZE(aat2870_ldo_voltages),	\
			.ops = &aat2870_ldo_ops,	\
			.type = REGULATOR_VOLTAGE,	\
			.owner = THIS_MODULE,		\
		},					\
		.voltages = aat2870_ldo_voltages,	\
		.min_uV = 1200000,			\
		.max_uV = 3300000,			\
	}

static struct aat2870_regulator aat2870_regulators[] = {
	AAT2870_LDO(LDOA),
	AAT2870_LDO(LDOB),
	AAT2870_LDO(LDOC),
	AAT2870_LDO(LDOD),
};

static struct aat2870_regulator *aat2870_get_regulator(int id)
{
	struct aat2870_regulator *ri = NULL;
	int i;

	for (i = 0; i < ARRAY_SIZE(aat2870_regulators); i++) {
		ri = &aat2870_regulators[i];
		if (ri->desc.id == id)
			break;
	}

	if (i == ARRAY_SIZE(aat2870_regulators))
		return NULL;

	ri->enable_addr = AAT2870_LDO_EN;
	ri->enable_shift = id - AAT2870_ID_LDOA;
	ri->enable_mask = 0x1 << ri->enable_shift;

	ri->voltage_addr = (id - AAT2870_ID_LDOA) / 2 ?
			   AAT2870_LDO_CD : AAT2870_LDO_AB;
	ri->voltage_shift = (id - AAT2870_ID_LDOA) % 2 ? 0 : 4;
	ri->voltage_mask = 0xF << ri->voltage_shift;

	return ri;
}

static int aat2870_regulator_probe(struct platform_device *pdev)
{
	struct aat2870_regulator *ri;
	struct regulator_dev *rdev;

	ri = aat2870_get_regulator(pdev->id);
	if (!ri) {
		dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
		return -EINVAL;
	}
	ri->pdev = pdev;

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

	return 0;
}

static int __devexit aat2870_regulator_remove(struct platform_device *pdev)
{
	struct regulator_dev *rdev = platform_get_drvdata(pdev);

	regulator_unregister(rdev);
	return 0;
}

static struct platform_driver aat2870_regulator_driver = {
	.driver = {
		.name	= "aat2870-regulator",
		.owner	= THIS_MODULE,
	},
	.probe	= aat2870_regulator_probe,
	.remove	= __devexit_p(aat2870_regulator_remove),
};

static int __init aat2870_regulator_init(void)
{
	return platform_driver_register(&aat2870_regulator_driver);
}
subsys_initcall(aat2870_regulator_init);

static void __exit aat2870_regulator_exit(void)
{
	platform_driver_unregister(&aat2870_regulator_driver);
}
module_exit(aat2870_regulator_exit);

MODULE_DESCRIPTION("AnalogicTech AAT2870 Regulator");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");