/*
* Voltage and current regulation for AD5398 and AD5821
*
* Copyright 2010 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#define AD5398_CURRENT_EN_MASK 0x8000
struct ad5398_chip_info {
struct i2c_client *client;
int min_uA;
int max_uA;
unsigned int current_level;
unsigned int current_mask;
unsigned int current_offset;
struct regulator_dev *rdev;
};
static int ad5398_calc_current(struct ad5398_chip_info *chip,
unsigned selector)
{
unsigned range_uA = chip->max_uA - chip->min_uA;
return chip->min_uA + (selector * range_uA / chip->current_level);
}
static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
{
unsigned short val;
int ret;
ret = i2c_master_recv(client, (char *)&val, 2);
if (ret < 0) {
dev_err(&client->dev, "I2C read error\n");
return ret;
}
*data = be16_to_cpu(val);
return ret;
}
static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
{
unsigned short val;
int ret;
val = cpu_to_be16(data);
ret = i2c_master_send(client, (char *)&val, 2);
if (ret < 0)
dev_err(&client->dev, "I2C write error\n");
return ret;
}
static int ad5398_get_current_limit(struct regulator_dev *rdev)
{
struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
struct i2c_client *client = chip->client;
unsigned short data;
int ret;
ret = ad5398_read_reg(client, &data);
if (ret < 0)
return ret;
ret = (data & chip->current_mask) >> chip->current_offset;
return ad5398_calc_current(chip, ret);
}
static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
{
struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
struct i2c_client *client = chip->client;
unsigned range_uA = chip->max_uA - chip->min_uA;
unsigned selector;
unsigned short data;
int ret;
if (min_uA < chip->min_uA)
min_uA = chip->min_uA;
if (max_uA > chip->max_uA)
max_uA = chip->max_uA;
if (min_uA > chip->max_uA || max_uA < chip->min_uA)
return -EINVAL;
selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
range_uA);
if (ad5398_calc_current(chip, selector) > max_uA)
return -EINVAL;
dev_dbg(&client->dev, "changing current %duA\n",
ad5398_calc_current(chip, selector));
/* read chip enable bit */
ret = ad5398_read_reg(client, &data);
if (ret < 0)
return ret;
/* prepare register data */
selector = (selector << chip->current_offset) & chip->current_mask;
data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
/* write the new current value back as well as enable bit */
ret = ad5398_write_reg(client, data);
return ret;
}
static int ad5398_is_enabled(struct regulator_dev *rdev)
{
struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
struct i2c_client *client = chip->client;
unsigned short data;
int ret;
ret = ad5398_read_reg(client, &data);
if (ret < 0)
return ret;
if (data & AD5398_CURRENT_EN_MASK)
return 1;
else
return 0;
}
static int ad5398_enable(struct regulator_dev *rdev)
{
struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
struct i2c_client *client = chip->client;
unsigned short data;
int ret;
ret = ad5398_read_reg(client, &data);
if (ret < 0)
return ret;
if (data & AD5398_CURRENT_EN_MASK)
return 0;
data |= AD5398_CURRENT_EN_MASK;
ret = ad5398_write_reg(client, data);
return ret;
}
static int ad5398_disable(struct regulator_dev *rdev)
{
struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
struct i2c_client *client = chip->client;
unsigned short data;
int ret;
ret = ad5398_read_reg(client, &data);
if (ret < 0)
return ret;
if (!(data & AD5398_CURRENT_EN_MASK))
return 0;
data &= ~AD5398_CURRENT_EN_MASK;
ret = ad5398_write_reg(client, data);
return ret;
}
static struct regulator_ops ad5398_ops = {
.get_current_limit = ad5398_get_current_limit,
.set_current_limit = ad5398_set_current_limit,
.enable = ad5398_enable,
.disable = ad5398_disable,
.is_enabled = ad5398_is_enabled,
};
static const struct regulator_desc ad5398_reg = {
.name = "isink",
.id = 0,
.ops = &ad5398_ops,
.type = REGULATOR_CURRENT,
.owner = THIS_MODULE,
};
struct ad5398_current_data_format {
int current_bits;
int current_offset;
int min_uA;
int max_uA;
};
static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
static const struct i2c_device_id ad5398_id[] = {
{ "ad5398", (kernel_ulong_t)&df_10_4_120 },
{ "ad5821", (kernel_ulong_t)&df_10_4_120 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ad5398_id);
static int ad5398_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
struct regulator_config config = { };
struct ad5398_chip_info *chip;
const struct ad5398_current_data_format *df =
(struct ad5398_current_data_format *)id->driver_data;
if (!init_data)
return -EINVAL;
chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
config.dev = &client->dev;
config.init_data = init_data;
config.driver_data = chip;
chip->client = client;
chip->min_uA = df->min_uA;
chip->max_uA = df->max_uA;
chip->current_level = 1 << df->current_bits;
chip->current_offset = df->current_offset;
chip->current_mask = (chip->current_level - 1) << chip->current_offset;
chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
&config);
if (IS_ERR(chip->rdev)) {
dev_err(&client->dev, "failed to register %s %s\n",
id->name, ad5398_reg.name);
return PTR_ERR(chip->rdev);
}
i2c_set_clientdata(client, chip);
dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
return 0;
}
static struct i2c_driver ad5398_driver = {
.probe = ad5398_probe,
.driver = {
.name = "ad5398",
},
.id_table = ad5398_id,
};
static int __init ad5398_init(void)
{
return i2c_add_driver(&ad5398_driver);
}
subsys_initcall(ad5398_init);
static void __exit ad5398_exit(void)
{
i2c_del_driver(&ad5398_driver);
}
module_exit(ad5398_exit);
MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
MODULE_AUTHOR("Sonic Zhang");
MODULE_LICENSE("GPL");
MODULE_ALIAS("i2c:ad5398-regulator");
