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linux/drivers/regulator/max1586.c
Philipp Zabel b110a8fb24 regulator/max1586: support increased V3 voltage range 
The V3 regulator can be configured with an external resistor
connected to the feedback pin (R24 in the data sheet) to
increase the voltage range.

For example, hx4700 has R24 = 3.32 kOhm to achieve a maximum
V3 voltage of 1.55 V which is needed for 624 MHz CPU frequency.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-06-15 11:18:26 +01:00

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/*
* max1586.c -- Voltage and current regulation for the Maxim 1586
*
* Copyright (C) 2008 Robert Jarzmik
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/max1586.h>
#define MAX1586_V3_MAX_VSEL 31
#define MAX1586_V6_MAX_VSEL 3
#define MAX1586_V3_MIN_UV 700000
#define MAX1586_V3_MAX_UV 1475000
#define MAX1586_V6_MIN_UV 0
#define MAX1586_V6_MAX_UV 3000000
#define I2C_V3_SELECT (0 << 5)
#define I2C_V6_SELECT (1 << 5)
struct max1586_data {
struct i2c_client *client;
/* min/max V3 voltage */
int min_uV;
int max_uV;
struct regulator_dev *rdev[0];
};
/*
* V3 voltage
* On I2C bus, sending a "x" byte to the max1586 means :
* set V3 to 0.700V + (x & 0x1f) * 0.025V
* This voltage can be increased by external resistors
* R24 and R25=100kOhm as described in the data sheet.
* The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
*/
static int max1586_v3_calc_voltage(struct max1586_data *max1586,
unsigned selector)
{
unsigned range_uV = max1586->max_uV - max1586->min_uV;
return max1586->min_uV + (selector * range_uV / MAX1586_V3_MAX_VSEL);
}
static int max1586_v3_set(struct regulator_dev *rdev, int min_uV, int max_uV)
{
struct max1586_data *max1586 = rdev_get_drvdata(rdev);
struct i2c_client *client = max1586->client;
unsigned range_uV = max1586->max_uV - max1586->min_uV;
unsigned selector;
u8 v3_prog;
if (min_uV > max1586->max_uV || max_uV < max1586->min_uV)
return -EINVAL;
if (min_uV < max1586->min_uV)
min_uV = max1586->min_uV;
selector = ((min_uV - max1586->min_uV) * MAX1586_V3_MAX_VSEL +
range_uV - 1) / range_uV;
if (max1586_v3_calc_voltage(max1586, selector) > max_uV)
return -EINVAL;
dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
max1586_v3_calc_voltage(max1586, selector) / 1000);
v3_prog = I2C_V3_SELECT | (u8) selector;
return i2c_smbus_write_byte(client, v3_prog);
}
static int max1586_v3_list(struct regulator_dev *rdev, unsigned selector)
{
struct max1586_data *max1586 = rdev_get_drvdata(rdev);
if (selector > MAX1586_V3_MAX_VSEL)
return -EINVAL;
return max1586_v3_calc_voltage(max1586, selector);
}
/*
* V6 voltage
* On I2C bus, sending a "x" byte to the max1586 means :
* set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
* As regulator framework doesn't accept voltages to be 0V, we use 1uV.
*/
static int max1586_v6_calc_voltage(unsigned selector)
{
static int voltages_uv[] = { 1, 1800000, 2500000, 3000000 };
return voltages_uv[selector];
}
static int max1586_v6_set(struct regulator_dev *rdev, int min_uV, int max_uV)
{
struct i2c_client *client = rdev_get_drvdata(rdev);
unsigned selector;
u8 v6_prog;
if (min_uV < MAX1586_V6_MIN_UV || min_uV > MAX1586_V6_MAX_UV)
return -EINVAL;
if (max_uV < MAX1586_V6_MIN_UV || max_uV > MAX1586_V6_MAX_UV)
return -EINVAL;
if (min_uV >= 3000000)
selector = 3;
if (min_uV < 3000000)
selector = 2;
if (min_uV < 2500000)
selector = 1;
if (min_uV < 1800000)
selector = 0;
if (max1586_v6_calc_voltage(selector) > max_uV)
return -EINVAL;
dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
max1586_v6_calc_voltage(selector) / 1000);
v6_prog = I2C_V6_SELECT | (u8) selector;
return i2c_smbus_write_byte(client, v6_prog);
}
static int max1586_v6_list(struct regulator_dev *rdev, unsigned selector)
{
if (selector > MAX1586_V6_MAX_VSEL)
return -EINVAL;
return max1586_v6_calc_voltage(selector);
}
/*
* The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
* the set up value.
*/
static struct regulator_ops max1586_v3_ops = {
.set_voltage = max1586_v3_set,
.list_voltage = max1586_v3_list,
};
static struct regulator_ops max1586_v6_ops = {
.set_voltage = max1586_v6_set,
.list_voltage = max1586_v6_list,
};
static struct regulator_desc max1586_reg[] = {
{
.name = "Output_V3",
.id = MAX1586_V3,
.ops = &max1586_v3_ops,
.type = REGULATOR_VOLTAGE,
.n_voltages = MAX1586_V3_MAX_VSEL + 1,
.owner = THIS_MODULE,
},
{
.name = "Output_V6",
.id = MAX1586_V6,
.ops = &max1586_v6_ops,
.type = REGULATOR_VOLTAGE,
.n_voltages = MAX1586_V6_MAX_VSEL + 1,
.owner = THIS_MODULE,
},
};
static int max1586_pmic_probe(struct i2c_client *client,
const struct i2c_device_id *i2c_id)
{
struct regulator_dev **rdev;
struct max1586_platform_data *pdata = client->dev.platform_data;
struct max1586_data *max1586;
int i, id, ret = -ENOMEM;
max1586 = kzalloc(sizeof(struct max1586_data) +
sizeof(struct regulator_dev *) * (MAX1586_V6 + 1),
GFP_KERNEL);
if (!max1586)
goto out;
max1586->client = client;
if (!pdata->v3_gain) {
ret = -EINVAL;
goto out_unmap;
}
max1586->min_uV = MAX1586_V3_MIN_UV * pdata->v3_gain / 1000000;
max1586->max_uV = MAX1586_V3_MAX_UV * pdata->v3_gain / 1000000;
rdev = max1586->rdev;
for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
id = pdata->subdevs[i].id;
if (!pdata->subdevs[i].platform_data)
continue;
if (id < MAX1586_V3 || id > MAX1586_V6) {
dev_err(&client->dev, "invalid regulator id %d\n", id);
goto err;
}
rdev[i] = regulator_register(&max1586_reg[id], &client->dev,
pdata->subdevs[i].platform_data,
max1586);
if (IS_ERR(rdev[i])) {
ret = PTR_ERR(rdev[i]);
dev_err(&client->dev, "failed to register %s\n",
max1586_reg[id].name);
goto err;
}
}
i2c_set_clientdata(client, rdev);
dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
return 0;
err:
while (--i >= 0)
regulator_unregister(rdev[i]);
out_unmap:
kfree(max1586);
out:
return ret;
}
static int max1586_pmic_remove(struct i2c_client *client)
{
struct regulator_dev **rdev = i2c_get_clientdata(client);
int i;
for (i = 0; i <= MAX1586_V6; i++)
if (rdev[i])
regulator_unregister(rdev[i]);
kfree(rdev);
i2c_set_clientdata(client, NULL);
return 0;
}
static const struct i2c_device_id max1586_id[] = {
{ "max1586", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max1586_id);
static struct i2c_driver max1586_pmic_driver = {
.probe = max1586_pmic_probe,
.remove = max1586_pmic_remove,
.driver = {
.name = "max1586",
},
.id_table = max1586_id,
};
static int __init max1586_pmic_init(void)
{
return i2c_add_driver(&max1586_pmic_driver);
}
subsys_initcall(max1586_pmic_init);
static void __exit max1586_pmic_exit(void)
{
i2c_del_driver(&max1586_pmic_driver);
}
module_exit(max1586_pmic_exit);
/* Module information */
MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
MODULE_AUTHOR("Robert Jarzmik");
MODULE_LICENSE("GPL");
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