/*
lm75.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
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.
*/
#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 "lm75.h"
/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* Insmod parameters */
I2C_CLIENT_INSMOD_1(lm75);
/* Many LM75 constants specified below */
/* The LM75 registers */
#define LM75_REG_CONF 0x01
static const u8 LM75_REG_TEMP[3] = {
0x00, /* input */
0x03, /* max */
0x02, /* hyst */
};
/* Each client has this additional data */
struct lm75_data {
struct i2c_client client;
struct device *hwmon_dev;
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
u16 temp[3]; /* Register values,
0 = input
1 = max
2 = hyst */
};
static int lm75_attach_adapter(struct i2c_adapter *adapter);
static int lm75_detect(struct i2c_adapter *adapter, int address, int kind);
static void lm75_init_client(struct i2c_client *client);
static int lm75_detach_client(struct i2c_client *client);
static int lm75_read_value(struct i2c_client *client, u8 reg);
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
static struct lm75_data *lm75_update_device(struct device *dev);
/* This is the driver that will be inserted */
static struct i2c_driver lm75_driver = {
.driver = {
.name = "lm75",
},
.attach_adapter = lm75_attach_adapter,
.detach_client = lm75_detach_client,
};
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = lm75_update_device(dev);
return sprintf(buf, "%d\n",
LM75_TEMP_FROM_REG(data->temp[attr->index]));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
int nr = attr->index;
long temp = simple_strtol(buf, NULL, 10);
mutex_lock(&data->update_lock);
data->temp[nr] = LM75_TEMP_TO_REG(temp);
lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static int lm75_attach_adapter(struct i2c_adapter *adapter)
{
if (!(adapter->class & I2C_CLASS_HWMON))
return 0;
return i2c_probe(adapter, &addr_data, lm75_detect);
}
static struct attribute *lm75_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
NULL
};
static const struct attribute_group lm75_group = {
.attrs = lm75_attributes,
};
/* This function is called by i2c_probe */
static int lm75_detect(struct i2c_adapter *adapter, int address, int kind)
{
int i;
struct i2c_client *new_client;
struct lm75_data *data;
int err = 0;
const char *name = "";
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
goto exit;
/* OK. For now, we presume we have a valid client. We now create the
client structure, even though we cannot fill it completely yet.
But it allows us to access lm75_{read,write}_value. */
if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) {
err = -ENOMEM;
goto exit;
}
new_client = &data->client;
i2c_set_clientdata(new_client, data);
new_client->addr = address;
new_client->adapter = adapter;
new_client->driver = &lm75_driver;
new_client->flags = 0;
/* Now, we do the remaining detection. There is no identification-
dedicated register so we have to rely on several tricks:
unused bits, registers cycling over 8-address boundaries,
addresses 0x04-0x07 returning the last read value.
The cycling+unused addresses combination is not tested,
since it would significantly slow the detection down and would
hardly add any value. */
if (kind < 0) {
int cur, conf, hyst, os;
/* Unused addresses */
cur = i2c_smbus_read_word_data(new_client, 0);
conf = i2c_smbus_read_byte_data(new_client, 1);
hyst = i2c_smbus_read_word_data(new_client, 2);
if (i2c_smbus_read_word_data(new_client, 4) != hyst
|| i2c_smbus_read_word_data(new_client, 5) != hyst
|| i2c_smbus_read_word_data(new_client, 6) != hyst
|| i2c_smbus_read_word_data(new_client, 7) != hyst)
goto exit_free;
os = i2c_smbus_read_word_data(new_client, 3);
if (i2c_smbus_read_word_data(new_client, 4) != os
|| i2c_smbus_read_word_data(new_client, 5) != os
|| i2c_smbus_read_word_data(new_client, 6) != os
|| i2c_smbus_read_word_data(new_client, 7) != os)
goto exit_free;
/* Unused bits */
if (conf & 0xe0)
goto exit_free;
/* Addresses cycling */
for (i = 8; i < 0xff; i += 8)
if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
|| i2c_smbus_read_word_data(new_client, i + 2) != hyst
|| i2c_smbus_read_word_data(new_client, i + 3) != os)
goto exit_free;
}
/* Determine the chip type - only one kind supported! */
if (kind <= 0)
kind = lm75;
if (kind == lm75) {
name = "lm75";
}
/* Fill in the remaining client fields and put it into the global list */
strlcpy(new_client->name, name, I2C_NAME_SIZE);
data->valid = 0;
mutex_init(&data->update_lock);
/* Tell the I2C layer a new client has arrived */
if ((err = i2c_attach_client(new_client)))
goto exit_free;
/* Initialize the LM75 chip */
lm75_init_client(new_client);
/* Register sysfs hooks */
if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group)))
goto exit_detach;
data->hwmon_dev = hwmon_device_register(&new_client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
goto exit_remove;
}
return 0;
exit_remove:
sysfs_remove_group(&new_client->dev.kobj, &lm75_group);
exit_detach:
i2c_detach_client(new_client);
exit_free:
kfree(data);
exit:
return err;
}
static int lm75_detach_client(struct i2c_client *client)
{
struct lm75_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm75_group);
i2c_detach_client(client);
kfree(data);
return 0;
}
/* All registers are word-sized, except for the configuration register.
LM75 uses a high-byte first convention, which is exactly opposite to
the usual practice. */
static int lm75_read_value(struct i2c_client *client, u8 reg)
{
if (reg == LM75_REG_CONF)
return i2c_smbus_read_byte_data(client, reg);
else
return swab16(i2c_smbus_read_word_data(client, reg));
}
/* All registers are word-sized, except for the configuration register.
LM75 uses a high-byte first convention, which is exactly opposite to
the usual practice. */
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
{
if (reg == LM75_REG_CONF)
return i2c_smbus_write_byte_data(client, reg, value);
else
return i2c_smbus_write_word_data(client, reg, swab16(value));
}
static void lm75_init_client(struct i2c_client *client)
{
int reg;
/* Enable if in shutdown mode */
reg = lm75_read_value(client, LM75_REG_CONF);
if (reg >= 0 && (reg & 0x01))
lm75_write_value(client, LM75_REG_CONF, reg & 0xfe);
}
static struct lm75_data *lm75_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
int i;
dev_dbg(&client->dev, "Starting lm75 update\n");
for (i = 0; i < ARRAY_SIZE(data->temp); i++)
data->temp[i] = lm75_read_value(client,
LM75_REG_TEMP[i]);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static int __init sensors_lm75_init(void)
{
return i2c_add_driver(&lm75_driver);
}
static void __exit sensors_lm75_exit(void)
{
i2c_del_driver(&lm75_driver);
}
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");
module_init(sensors_lm75_init);
module_exit(sensors_lm75_exit);
