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linux/drivers/regulator/max8952.c
Axel Lin ec10b0e94e regulator: max8952 - fix max8952_set_voltage 
In current implementation, vid is declared as u8,
then "vid == -1" is always false, and "vid >= 0" is always true.
Thus change it to s8.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-10-28 22:40:32 +01:00

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/*
* max8952.c - Voltage and current regulation for the Maxim 8952
*
* Copyright (C) 2010 Samsung Electronics
* MyungJoo Ham <myungjoo.ham@samsung.com>
*
* 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/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/max8952.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/slab.h>
/* Registers */
enum {
MAX8952_REG_MODE0,
MAX8952_REG_MODE1,
MAX8952_REG_MODE2,
MAX8952_REG_MODE3,
MAX8952_REG_CONTROL,
MAX8952_REG_SYNC,
MAX8952_REG_RAMP,
MAX8952_REG_CHIP_ID1,
MAX8952_REG_CHIP_ID2,
};
struct max8952_data {
struct i2c_client *client;
struct device *dev;
struct mutex mutex;
struct max8952_platform_data *pdata;
struct regulator_dev *rdev;
bool vid0;
bool vid1;
bool en;
};
static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
{
int ret = i2c_smbus_read_byte_data(max8952->client, reg);
if (ret > 0)
ret &= 0xff;
return ret;
}
static int max8952_write_reg(struct max8952_data *max8952,
u8 reg, u8 value)
{
return i2c_smbus_write_byte_data(max8952->client, reg, value);
}
static int max8952_voltage(struct max8952_data *max8952, u8 mode)
{
return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000;
}
static int max8952_list_voltage(struct regulator_dev *rdev,
unsigned int selector)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
if (rdev_get_id(rdev) != 0)
return -EINVAL;
return max8952_voltage(max8952, selector);
}
static int max8952_is_enabled(struct regulator_dev *rdev)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
return max8952->en;
}
static int max8952_enable(struct regulator_dev *rdev)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
/* If not valid, assume "ALWAYS_HIGH" */
if (gpio_is_valid(max8952->pdata->gpio_en))
gpio_set_value(max8952->pdata->gpio_en, 1);
max8952->en = true;
return 0;
}
static int max8952_disable(struct regulator_dev *rdev)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
/* If not valid, assume "ALWAYS_HIGH" -> not permitted */
if (gpio_is_valid(max8952->pdata->gpio_en))
gpio_set_value(max8952->pdata->gpio_en, 0);
else
return -EPERM;
max8952->en = false;
return 0;
}
static int max8952_get_voltage(struct regulator_dev *rdev)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
u8 vid = 0;
if (max8952->vid0)
vid += 1;
if (max8952->vid1)
vid += 2;
return max8952_voltage(max8952, vid);
}
static int max8952_set_voltage(struct regulator_dev *rdev,
int min_uV, int max_uV)
{
struct max8952_data *max8952 = rdev_get_drvdata(rdev);
s8 vid = -1, i;
if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
!gpio_is_valid(max8952->pdata->gpio_vid0)) {
/* DVS not supported */
return -EPERM;
}
for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) {
int volt = max8952_voltage(max8952, i);
/* Set the voltage as low as possible within the range */
if (volt <= max_uV && volt >= min_uV)
if (vid == -1 || max8952_voltage(max8952, vid) > volt)
vid = i;
}
if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) {
max8952->vid0 = (vid % 2 == 1);
max8952->vid1 = (((vid >> 1) % 2) == 1);
gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
} else
return -EINVAL;
return 0;
}
static struct regulator_ops max8952_ops = {
.list_voltage = max8952_list_voltage,
.is_enabled = max8952_is_enabled,
.enable = max8952_enable,
.disable = max8952_disable,
.get_voltage = max8952_get_voltage,
.set_voltage = max8952_set_voltage,
.set_suspend_disable = max8952_disable,
};
static struct regulator_desc regulator = {
.name = "MAX8952_VOUT",
.id = 0,
.n_voltages = MAX8952_NUM_DVS_MODE,
.ops = &max8952_ops,
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
};
static int __devinit max8952_pmic_probe(struct i2c_client *client,
const struct i2c_device_id *i2c_id)
{
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
struct max8952_platform_data *pdata = client->dev.platform_data;
struct max8952_data *max8952;
int ret = 0, err = 0;
if (!pdata) {
dev_err(&client->dev, "Require the platform data\n");
return -EINVAL;
}
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
return -EIO;
max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL);
if (!max8952)
return -ENOMEM;
max8952->client = client;
max8952->dev = &client->dev;
max8952->pdata = pdata;
mutex_init(&max8952->mutex);
max8952->rdev = regulator_register(&regulator, max8952->dev,
&pdata->reg_data, max8952);
if (IS_ERR(max8952->rdev)) {
ret = PTR_ERR(max8952->rdev);
dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
goto err_reg;
}
max8952->en = !!(pdata->reg_data.constraints.boot_on);
max8952->vid0 = (pdata->default_mode % 2) == 1;
max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1;
if (gpio_is_valid(pdata->gpio_en)) {
if (!gpio_request(pdata->gpio_en, "MAX8952 EN"))
gpio_direction_output(pdata->gpio_en, max8952->en);
else
err = 1;
} else
err = 2;
if (err) {
dev_info(max8952->dev, "EN gpio invalid: assume that EN"
"is always High\n");
max8952->en = 1;
pdata->gpio_en = -1; /* Mark invalid */
}
err = 0;
if (gpio_is_valid(pdata->gpio_vid0) &&
gpio_is_valid(pdata->gpio_vid1)) {
if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
gpio_direction_output(pdata->gpio_vid0,
(pdata->default_mode) % 2);
else
err = 1;
if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
gpio_direction_output(pdata->gpio_vid1,
(pdata->default_mode >> 1) % 2);
else {
if (!err)
gpio_free(pdata->gpio_vid0);
err = 2;
}
} else
err = 3;
if (err) {
dev_warn(max8952->dev, "VID0/1 gpio invalid: "
"DVS not avilable.\n");
max8952->vid0 = 0;
max8952->vid1 = 0;
/* Mark invalid */
pdata->gpio_vid0 = -1;
pdata->gpio_vid1 = -1;
/* Disable Pulldown of EN only */
max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
" do not have proper controls.\n");
} else {
/*
* Disable Pulldown on EN, VID0, VID1 to reduce
* leakage current of MAX8952 assuming that MAX8952
* is turned on (EN==1). Note that without having VID0/1
* properly connected, turning pulldown off can be
* problematic. Thus, turn this off only when they are
* controllable by GPIO.
*/
max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
}
max8952_write_reg(max8952, MAX8952_REG_MODE0,
(max8952_read_reg(max8952,
MAX8952_REG_MODE0) & 0xC0) |
(pdata->dvs_mode[0] & 0x3F));
max8952_write_reg(max8952, MAX8952_REG_MODE1,
(max8952_read_reg(max8952,
MAX8952_REG_MODE1) & 0xC0) |
(pdata->dvs_mode[1] & 0x3F));
max8952_write_reg(max8952, MAX8952_REG_MODE2,
(max8952_read_reg(max8952,
MAX8952_REG_MODE2) & 0xC0) |
(pdata->dvs_mode[2] & 0x3F));
max8952_write_reg(max8952, MAX8952_REG_MODE3,
(max8952_read_reg(max8952,
MAX8952_REG_MODE3) & 0xC0) |
(pdata->dvs_mode[3] & 0x3F));
max8952_write_reg(max8952, MAX8952_REG_SYNC,
(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
((pdata->sync_freq & 0x3) << 6));
max8952_write_reg(max8952, MAX8952_REG_RAMP,
(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
((pdata->ramp_speed & 0x7) << 5));
i2c_set_clientdata(client, max8952);
return 0;
err_reg:
kfree(max8952);
return ret;
}
static int __devexit max8952_pmic_remove(struct i2c_client *client)
{
struct max8952_data *max8952 = i2c_get_clientdata(client);
struct max8952_platform_data *pdata = max8952->pdata;
struct regulator_dev *rdev = max8952->rdev;
regulator_unregister(rdev);
gpio_free(pdata->gpio_vid0);
gpio_free(pdata->gpio_vid1);
gpio_free(pdata->gpio_en);
kfree(max8952);
return 0;
}
static const struct i2c_device_id max8952_ids[] = {
{ "max8952", 0 },
{ },
};
MODULE_DEVICE_TABLE(i2c, max8952_ids);
static struct i2c_driver max8952_pmic_driver = {
.probe = max8952_pmic_probe,
.remove = __devexit_p(max8952_pmic_remove),
.driver = {
.name = "max8952",
},
.id_table = max8952_ids,
};
static int __init max8952_pmic_init(void)
{
return i2c_add_driver(&max8952_pmic_driver);
}
subsys_initcall(max8952_pmic_init);
static void __exit max8952_pmic_exit(void)
{
i2c_del_driver(&max8952_pmic_driver);
}
module_exit(max8952_pmic_exit);
MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_LICENSE("GPL");
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