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linux/drivers/hwmon/tmp421.c

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/* tmp421.c
*
* Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
* Preliminary support by:
* Melvin Rook, Raymond Ng
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
* Supported models: TMP421, TMP422, TMP423
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
I2C_CLIENT_END };
enum chips { tmp421, tmp422, tmp423 };
/* The TMP421 registers */
#define TMP421_CONFIG_REG_1 0x09
#define TMP421_CONVERSION_RATE_REG 0x0B
#define TMP421_MANUFACTURER_ID_REG 0xFE
#define TMP421_DEVICE_ID_REG 0xFF
static const u8 TMP421_TEMP_MSB[4] = { 0x00, 0x01, 0x02, 0x03 };
static const u8 TMP421_TEMP_LSB[4] = { 0x10, 0x11, 0x12, 0x13 };
/* Flags */
#define TMP421_CONFIG_SHUTDOWN 0x40
#define TMP421_CONFIG_RANGE 0x04
/* Manufacturer / Device ID's */
#define TMP421_MANUFACTURER_ID 0x55
#define TMP421_DEVICE_ID 0x21
#define TMP422_DEVICE_ID 0x22
#define TMP423_DEVICE_ID 0x23
static const struct i2c_device_id tmp421_id[] = {
{ "tmp421", 2 },
{ "tmp422", 3 },
{ "tmp423", 4 },
{ }
};
MODULE_DEVICE_TABLE(i2c, tmp421_id);
struct tmp421_data {
struct device *hwmon_dev;
struct mutex update_lock;
char valid;
unsigned long last_updated;
int channels;
u8 config;
s16 temp[4];
};
static int temp_from_s16(s16 reg)
{
/* Mask out status bits */
int temp = reg & ~0xf;
return (temp * 1000 + 128) / 256;
}
static int temp_from_u16(u16 reg)
{
/* Mask out status bits */
int temp = reg & ~0xf;
/* Add offset for extended temperature range. */
temp -= 64 * 256;
return (temp * 1000 + 128) / 256;
}
static struct tmp421_data *tmp421_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct tmp421_data *data = i2c_get_clientdata(client);
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
data->config = i2c_smbus_read_byte_data(client,
TMP421_CONFIG_REG_1);
for (i = 0; i < data->channels; i++) {
data->temp[i] = i2c_smbus_read_byte_data(client,
TMP421_TEMP_MSB[i]) << 8;
data->temp[i] |= i2c_smbus_read_byte_data(client,
TMP421_TEMP_LSB[i]);
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static ssize_t show_temp_value(struct device *dev,
struct device_attribute *devattr, char *buf)
{
int index = to_sensor_dev_attr(devattr)->index;
struct tmp421_data *data = tmp421_update_device(dev);
int temp;
mutex_lock(&data->update_lock);
if (data->config & TMP421_CONFIG_RANGE)
temp = temp_from_u16(data->temp[index]);
else
temp = temp_from_s16(data->temp[index]);
mutex_unlock(&data->update_lock);
return sprintf(buf, "%d\n", temp);
}
static ssize_t show_fault(struct device *dev,
struct device_attribute *devattr, char *buf)
{
int index = to_sensor_dev_attr(devattr)->index;
struct tmp421_data *data = tmp421_update_device(dev);
/*
* The OPEN bit signals a fault. This is bit 0 of the temperature
* register (low byte).
*/
if (data->temp[index] & 0x01)
return sprintf(buf, "1\n");
else
return sprintf(buf, "0\n");
}
static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
int n)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct tmp421_data *data = dev_get_drvdata(dev);
struct device_attribute *devattr;
unsigned int index;
devattr = container_of(a, struct device_attribute, attr);
index = to_sensor_dev_attr(devattr)->index;
if (index < data->channels)
return a->mode;
return 0;
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
static struct attribute *tmp421_attr[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp2_input.dev_attr.attr,
&sensor_dev_attr_temp2_fault.dev_attr.attr,
&sensor_dev_attr_temp3_input.dev_attr.attr,
&sensor_dev_attr_temp3_fault.dev_attr.attr,
&sensor_dev_attr_temp4_input.dev_attr.attr,
&sensor_dev_attr_temp4_fault.dev_attr.attr,
NULL
};
static const struct attribute_group tmp421_group = {
.attrs = tmp421_attr,
.is_visible = tmp421_is_visible,
};
static int tmp421_init_client(struct i2c_client *client)
{
int config, config_orig;
/* Set the conversion rate to 2 Hz */
i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
/* Start conversions (disable shutdown if necessary) */
config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
if (config < 0) {
dev_err(&client->dev, "Could not read configuration"
" register (%d)\n", config);
return -ENODEV;
}
config_orig = config;
config &= ~TMP421_CONFIG_SHUTDOWN;
if (config != config_orig) {
dev_info(&client->dev, "Enable monitoring chip\n");
i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
}
return 0;
}
static int tmp421_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
enum chips kind;
struct i2c_adapter *adapter = client->adapter;
const char *names[] = { "TMP421", "TMP422", "TMP423" };
u8 reg;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
if (reg != TMP421_MANUFACTURER_ID)
return -ENODEV;
reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
switch (reg) {
case TMP421_DEVICE_ID:
kind = tmp421;
break;
case TMP422_DEVICE_ID:
kind = tmp422;
break;
case TMP423_DEVICE_ID:
kind = tmp423;
break;
default:
return -ENODEV;
}
strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
names[kind], client->addr);
return 0;
}
static int tmp421_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct tmp421_data *data;
int err;
data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
data->channels = id->driver_data;
err = tmp421_init_client(client);
if (err)
goto exit_free;
err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
if (err)
goto exit_free;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
data->hwmon_dev = NULL;
goto exit_remove;
}
return 0;
exit_remove:
sysfs_remove_group(&client->dev.kobj, &tmp421_group);
exit_free:
kfree(data);
return err;
}
static int tmp421_remove(struct i2c_client *client)
{
struct tmp421_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &tmp421_group);
kfree(data);
return 0;
}
static struct i2c_driver tmp421_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "tmp421",
},
.probe = tmp421_probe,
.remove = tmp421_remove,
.id_table = tmp421_id,
.detect = tmp421_detect,
.address_list = normal_i2c,
};
static int __init tmp421_init(void)
{
return i2c_add_driver(&tmp421_driver);
}
static void __exit tmp421_exit(void)
{
i2c_del_driver(&tmp421_driver);
}
MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
" driver");
MODULE_LICENSE("GPL");
module_init(tmp421_init);
module_exit(tmp421_exit);
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