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linux-sg2042/drivers/hwmon/lm77.c

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/*
lm77.c - Part of lm_sensors, Linux kernel modules for hardware
monitoring
Copyright (c) 2004 Andras BALI <drewie@freemail.hu>
Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77
is a temperature sensor and thermal window comparator with 0.5 deg
resolution made by National Semiconductor. Complete datasheet can be
obtained at their site:
http://www.national.com/pf/LM/LM77.html
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>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
I2C_CLIENT_END };
/* The LM77 registers */
#define LM77_REG_TEMP 0x00
#define LM77_REG_CONF 0x01
#define LM77_REG_TEMP_HYST 0x02
#define LM77_REG_TEMP_CRIT 0x03
#define LM77_REG_TEMP_MIN 0x04
#define LM77_REG_TEMP_MAX 0x05
/* Each client has this additional data */
struct lm77_data {
struct device *hwmon_dev;
struct mutex update_lock;
char valid;
unsigned long last_updated; /* In jiffies */
int temp_input; /* Temperatures */
int temp_crit;
int temp_min;
int temp_max;
int temp_hyst;
u8 alarms;
};
static int lm77_probe(struct i2c_client *client,
const struct i2c_device_id *id);
static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
static void lm77_init_client(struct i2c_client *client);
static int lm77_remove(struct i2c_client *client);
static u16 lm77_read_value(struct i2c_client *client, u8 reg);
static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
static struct lm77_data *lm77_update_device(struct device *dev);
static const struct i2c_device_id lm77_id[] = {
{ "lm77", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, lm77_id);
/* This is the driver that will be inserted */
static struct i2c_driver lm77_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm77",
},
.probe = lm77_probe,
.remove = lm77_remove,
.id_table = lm77_id,
.detect = lm77_detect,
.address_list = normal_i2c,
};
/* straight from the datasheet */
#define LM77_TEMP_MIN (-55000)
#define LM77_TEMP_MAX 125000
/* In the temperature registers, the low 3 bits are not part of the
temperature values; they are the status bits. */
static inline s16 LM77_TEMP_TO_REG(int temp)
{
int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
return (ntemp / 500) * 8;
}
static inline int LM77_TEMP_FROM_REG(s16 reg)
{
return (reg / 8) * 500;
}
/* sysfs stuff */
/* read routines for temperature limits */
#define show(value) \
static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \
{ \
struct lm77_data *data = lm77_update_device(dev); \
return sprintf(buf, "%d\n", data->value); \
}
show(temp_input);
show(temp_crit);
show(temp_min);
show(temp_max);
/* read routines for hysteresis values */
static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
struct lm77_data *data = lm77_update_device(dev);
return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst);
}
static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
struct lm77_data *data = lm77_update_device(dev);
return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst);
}
static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf)
{
struct lm77_data *data = lm77_update_device(dev);
return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst);
}
/* write routines */
#define set(value, reg) \
static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \
{ \
struct i2c_client *client = to_i2c_client(dev); \
struct lm77_data *data = i2c_get_clientdata(client); \
long val = simple_strtol(buf, NULL, 10); \
\
mutex_lock(&data->update_lock); \
data->value = val; \
lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \
mutex_unlock(&data->update_lock); \
return count; \
}
set(temp_min, LM77_REG_TEMP_MIN);
set(temp_max, LM77_REG_TEMP_MAX);
/* hysteresis is stored as a relative value on the chip, so it has to be
converted first */
static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm77_data *data = i2c_get_clientdata(client);
unsigned long val = simple_strtoul(buf, NULL, 10);
mutex_lock(&data->update_lock);
data->temp_hyst = data->temp_crit - val;
lm77_write_value(client, LM77_REG_TEMP_HYST,
LM77_TEMP_TO_REG(data->temp_hyst));
mutex_unlock(&data->update_lock);
return count;
}
/* preserve hysteresis when setting T_crit */
static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm77_data *data = i2c_get_clientdata(client);
long val = simple_strtoul(buf, NULL, 10);
int oldcrithyst;
mutex_lock(&data->update_lock);
oldcrithyst = data->temp_crit - data->temp_hyst;
data->temp_crit = val;
data->temp_hyst = data->temp_crit - oldcrithyst;
lm77_write_value(client, LM77_REG_TEMP_CRIT,
LM77_TEMP_TO_REG(data->temp_crit));
lm77_write_value(client, LM77_REG_TEMP_HYST,
LM77_TEMP_TO_REG(data->temp_hyst));
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct lm77_data *data = lm77_update_device(dev);
return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}
static DEVICE_ATTR(temp1_input, S_IRUGO,
show_temp_input, NULL);
static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
show_temp_crit, set_temp_crit);
static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
show_temp_min, set_temp_min);
static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_temp_max, set_temp_max);
static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
show_temp_crit_hyst, set_temp_crit_hyst);
static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
show_temp_min_hyst, NULL);
static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
show_temp_max_hyst, NULL);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
static struct attribute *lm77_attributes[] = {
&dev_attr_temp1_input.attr,
&dev_attr_temp1_crit.attr,
&dev_attr_temp1_min.attr,
&dev_attr_temp1_max.attr,
&dev_attr_temp1_crit_hyst.attr,
&dev_attr_temp1_min_hyst.attr,
&dev_attr_temp1_max_hyst.attr,
&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
NULL
};
static const struct attribute_group lm77_group = {
.attrs = lm77_attributes,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm77_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
int i, cur, conf, hyst, crit, min, max;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
/* Here comes the remaining detection. Since the LM77 has no
register dedicated to identification, we have to rely on the
following tricks:
1. the high 4 bits represent the sign and thus they should
always be the same
2. the high 3 bits are unused in the configuration register
3. addresses 0x06 and 0x07 return the last read value
4. registers cycling over 8-address boundaries
Word-sized registers are high-byte first. */
/* addresses cycling */
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);
crit = i2c_smbus_read_word_data(new_client, 3);
min = i2c_smbus_read_word_data(new_client, 4);
max = i2c_smbus_read_word_data(new_client, 5);
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) != crit
|| i2c_smbus_read_word_data(new_client, i + 4) != min
|| i2c_smbus_read_word_data(new_client, i + 5) != max)
return -ENODEV;
}
/* sign bits */
if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0)
|| ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0)
|| ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0)
|| ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0)
|| ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0))
return -ENODEV;
/* unused bits */
if (conf & 0xe0)
return -ENODEV;
/* 0x06 and 0x07 return the last read value */
cur = i2c_smbus_read_word_data(new_client, 0);
if (i2c_smbus_read_word_data(new_client, 6) != cur
|| i2c_smbus_read_word_data(new_client, 7) != cur)
return -ENODEV;
hyst = i2c_smbus_read_word_data(new_client, 2);
if (i2c_smbus_read_word_data(new_client, 6) != hyst
|| i2c_smbus_read_word_data(new_client, 7) != hyst)
return -ENODEV;
min = i2c_smbus_read_word_data(new_client, 4);
if (i2c_smbus_read_word_data(new_client, 6) != min
|| i2c_smbus_read_word_data(new_client, 7) != min)
return -ENODEV;
strlcpy(info->type, "lm77", I2C_NAME_SIZE);
return 0;
}
static int lm77_probe(struct i2c_client *new_client,
const struct i2c_device_id *id)
{
struct lm77_data *data;
int err;
data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(new_client, data);
data->valid = 0;
mutex_init(&data->update_lock);
/* Initialize the LM77 chip */
lm77_init_client(new_client);
/* Register sysfs hooks */
if ((err = sysfs_create_group(&new_client->dev.kobj, &lm77_group)))
goto exit_free;
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, &lm77_group);
exit_free:
kfree(data);
exit:
return err;
}
static int lm77_remove(struct i2c_client *client)
{
struct lm77_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm77_group);
kfree(data);
return 0;
}
/* All registers are word-sized, except for the configuration register.
The LM77 uses the high-byte first convention. */
static u16 lm77_read_value(struct i2c_client *client, u8 reg)
{
if (reg == LM77_REG_CONF)
return i2c_smbus_read_byte_data(client, reg);
else
return swab16(i2c_smbus_read_word_data(client, reg));
}
static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value)
{
if (reg == LM77_REG_CONF)
return i2c_smbus_write_byte_data(client, reg, value);
else
return i2c_smbus_write_word_data(client, reg, swab16(value));
}
static void lm77_init_client(struct i2c_client *client)
{
/* Initialize the LM77 chip - turn off shutdown mode */
int conf = lm77_read_value(client, LM77_REG_CONF);
if (conf & 1)
lm77_write_value(client, LM77_REG_CONF, conf & 0xfe);
}
static struct lm77_data *lm77_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm77_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
dev_dbg(&client->dev, "Starting lm77 update\n");
data->temp_input =
LM77_TEMP_FROM_REG(lm77_read_value(client,
LM77_REG_TEMP));
data->temp_hyst =
LM77_TEMP_FROM_REG(lm77_read_value(client,
LM77_REG_TEMP_HYST));
data->temp_crit =
LM77_TEMP_FROM_REG(lm77_read_value(client,
LM77_REG_TEMP_CRIT));
data->temp_min =
LM77_TEMP_FROM_REG(lm77_read_value(client,
LM77_REG_TEMP_MIN));
data->temp_max =
LM77_TEMP_FROM_REG(lm77_read_value(client,
LM77_REG_TEMP_MAX));
data->alarms =
lm77_read_value(client, LM77_REG_TEMP) & 0x0007;
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static int __init sensors_lm77_init(void)
{
return i2c_add_driver(&lm77_driver);
}
static void __exit sensors_lm77_exit(void)
{
i2c_del_driver(&lm77_driver);
}
MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
MODULE_DESCRIPTION("LM77 driver");
MODULE_LICENSE("GPL");
module_init(sensors_lm77_init);
module_exit(sensors_lm77_exit);
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