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|
/*
* lm92 - Hardware monitoring driver
* Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
*
* Based on the lm90 driver, with some ideas taken from the lm_sensors
* lm92 driver as well.
*
* The LM92 is a sensor chip made by National Semiconductor. It reports
* its own temperature with a 0.0625 deg resolution and a 0.33 deg
* accuracy. Complete datasheet can be obtained from National's website
* at:
* http://www.national.com/pf/LM/LM92.html
*
* This driver also supports the MAX6635 sensor chip made by Maxim.
* This chip is compatible with the LM92, but has a lesser accuracy
* (1.0 deg). Complete datasheet can be obtained from Maxim's website
* at:
* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
*
* Since the LM92 was the first chipset supported by this driver, most
* comments will refer to this chipset, but are actually general and
* concern all supported chipsets, unless mentioned otherwise.
*
* Support could easily be added for the National Semiconductor LM76
* and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
* with the LM92.
*
* 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/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
/*
* The LM92 and MAX6635 have 2 two-state pins for address selection,
* resulting in 4 possible addresses.
*/
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
I2C_CLIENT_END };
/* The LM92 registers */
#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
/*
* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
* left-justified in 16-bit registers. No rounding is done, with such
* a resolution it's just not worth it. Note that the MAX6635 doesn't
* make use of the 4 lower bits for limits (i.e. effective resolution
* for limits is 1 degree Celsius).
*/
static inline int TEMP_FROM_REG(s16 reg)
{
return reg / 8 * 625 / 10;
}
static inline s16 TEMP_TO_REG(int val)
{
if (val <= -60000)
return -60000 * 10 / 625 * 8;
if (val >= 160000)
return 160000 * 10 / 625 * 8;
return val * 10 / 625 * 8;
}
/* Alarm flags are stored in the 3 LSB of the temperature register */
static inline u8 ALARMS_FROM_REG(s16 reg)
{
return reg & 0x0007;
}
/* Driver data (common to all clients) */
static struct i2c_driver lm92_driver;
/* Client data (each client gets its own) */
struct lm92_data {
struct device *hwmon_dev;
struct mutex update_lock;
char valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* registers values */
s16 temp1_input, temp1_crit, temp1_min, temp1_max, temp1_hyst;
};
/*
* Sysfs attributes and callback functions
*/
static struct lm92_data *lm92_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm92_data *data = i2c_get_clientdata(client);
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ)
|| !data->valid) {
dev_dbg(&client->dev, "Updating lm92 data\n");
data->temp1_input = i2c_smbus_read_word_swapped(client,
LM92_REG_TEMP);
data->temp1_hyst = i2c_smbus_read_word_swapped(client,
LM92_REG_TEMP_HYST);
data->temp1_crit = i2c_smbus_read_word_swapped(client,
LM92_REG_TEMP_CRIT);
data->temp1_min = i2c_smbus_read_word_swapped(client,
LM92_REG_TEMP_LOW);
data->temp1_max = i2c_smbus_read_word_swapped(client,
LM92_REG_TEMP_HIGH);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
#define show_temp(value) \
static ssize_t show_##value(struct device *dev, struct device_attribute *attr, \
char *buf) \
{ \
struct lm92_data *data = lm92_update_device(dev); \
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->value)); \
}
show_temp(temp1_input);
show_temp(temp1_crit);
show_temp(temp1_min);
show_temp(temp1_max);
#define set_temp(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 lm92_data *data = i2c_get_clientdata(client); \
long val; \
int err = kstrtol(buf, 10, &val); \
if (err) \
return err; \
\
mutex_lock(&data->update_lock); \
data->value = TEMP_TO_REG(val); \
i2c_smbus_write_word_swapped(client, reg, data->value); \
mutex_unlock(&data->update_lock); \
return count; \
}
set_temp(temp1_crit, LM92_REG_TEMP_CRIT);
set_temp(temp1_min, LM92_REG_TEMP_LOW);
set_temp(temp1_max, LM92_REG_TEMP_HIGH);
static ssize_t show_temp1_crit_hyst(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_crit)
- TEMP_FROM_REG(data->temp1_hyst));
}
static ssize_t show_temp1_max_hyst(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_max)
- TEMP_FROM_REG(data->temp1_hyst));
}
static ssize_t show_temp1_min_hyst(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp1_min)
+ TEMP_FROM_REG(data->temp1_hyst));
}
static ssize_t set_temp1_crit_hyst(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm92_data *data = i2c_get_clientdata(client);
long val;
int err;
err = kstrtol(buf, 10, &val);
if (err)
return err;
mutex_lock(&data->update_lock);
data->temp1_hyst = TEMP_FROM_REG(data->temp1_crit) - val;
i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
TEMP_TO_REG(data->temp1_hyst));
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp1_input));
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", (data->temp1_input >> bitnr) & 1);
}
static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp1_input, NULL);
static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp1_crit,
set_temp1_crit);
static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp1_crit_hyst,
set_temp1_crit_hyst);
static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp1_min,
set_temp1_min);
static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp1_min_hyst, NULL);
static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp1_max,
set_temp1_max);
static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp1_max_hyst, NULL);
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, 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);
/*
* Detection and registration
*/
static void lm92_init_client(struct i2c_client *client)
{
u8 config;
/* Start the conversions if needed */
config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
if (config & 0x01)
i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
config & 0xFE);
}
/*
* The MAX6635 has no identification register, so we have to use tricks
* to identify it reliably. This is somewhat slow.
* Note that we do NOT rely on the 2 MSB of the configuration register
* always reading 0, as suggested by the datasheet, because it was once
* reported not to be true.
*/
static int max6635_check(struct i2c_client *client)
{
u16 temp_low, temp_high, temp_hyst, temp_crit;
u8 conf;
int i;
/*
* No manufacturer ID register, so a read from this address will
*
|