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linux/drivers/hwmon/lm92.c

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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.
*/
#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;
}
enum temp_index {
t_input,
t_crit,
t_min,
t_max,
t_hyst,
t_num_regs
};
static const u8 regs[t_num_regs] = {
[t_input] = LM92_REG_TEMP,
[t_crit] = LM92_REG_TEMP_CRIT,
[t_min] = LM92_REG_TEMP_LOW,
[t_max] = LM92_REG_TEMP_HIGH,
[t_hyst] = LM92_REG_TEMP_HYST,
};
/* Client data (each client gets its own) */
struct lm92_data {
struct i2c_client *client;
struct mutex update_lock;
char valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* registers values */
s16 temp[t_num_regs]; /* index with enum temp_index */
};
/*
* Sysfs attributes and callback functions
*/
static struct lm92_data *lm92_update_device(struct device *dev)
{
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ)
|| !data->valid) {
dev_dbg(&client->dev, "Updating lm92 data\n");
for (i = 0; i < t_num_regs; i++) {
data->temp[i] =
i2c_smbus_read_word_swapped(client, regs[i]);
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int nr = attr->index;
long val;
int err;
err = kstrtol(buf, 10, &val);
if (err)
return err;
mutex_lock(&data->update_lock);
data->temp[nr] = TEMP_TO_REG(val);
i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_temp_hyst(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
- TEMP_FROM_REG(data->temp[t_hyst]));
}
static ssize_t show_temp_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->temp[t_min])
+ TEMP_FROM_REG(data->temp[t_hyst]));
}
static ssize_t set_temp_hyst(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
long val;
int err;
err = kstrtol(buf, 10, &val);
if (err)
return err;
mutex_lock(&data->update_lock);
data->temp[t_hyst] = TEMP_FROM_REG(data->temp[attr->index]) - val;
i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
TEMP_TO_REG(data->temp[t_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->temp[t_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->temp[t_input] >> bitnr) & 1);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_crit);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
set_temp_hyst, t_crit);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_min);
static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, show_temp_min_hyst, NULL);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_max);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
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
* always return the last read value.
*/
temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
return 0;
temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
return 0;
/* Limits are stored as integer values (signed, 9-bit). */
if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
return 0;
temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
return 0;
/*
* Registers addresses were found to cycle over 16-byte boundaries.
* We don't test all registers with all offsets so as to save some
* reads and time, but this should still be sufficient to dismiss
* non-MAX6635 chips.
*/
conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
for (i = 16; i < 96; i *= 2) {
if (temp_hyst != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_HYST + i - 16)
|| temp_crit != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_CRIT + i)
|| temp_low != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_LOW + i + 16)
|| temp_high != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_HIGH + i + 32)
|| conf != i2c_smbus_read_byte_data(client,
LM92_REG_CONFIG + i))
return 0;
}
return 1;
}
static struct attribute *lm92_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_crit.dev_attr.attr,
&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&dev_attr_temp1_min_hyst.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
&dev_attr_alarms.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
};
ATTRIBUTE_GROUPS(lm92);
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm92_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
u8 config;
u16 man_id;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
if ((config & 0xe0) == 0x00 && man_id == 0x0180)
pr_info("lm92: Found National Semiconductor LM92 chip\n");
else if (max6635_check(new_client))
pr_info("lm92: Found Maxim MAX6635 chip\n");
else
return -ENODEV;
strlcpy(info->type, "lm92", I2C_NAME_SIZE);
return 0;
}
static int lm92_probe(struct i2c_client *new_client,
const struct i2c_device_id *id)
{
struct device *hwmon_dev;
struct lm92_data *data;
data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = new_client;
mutex_init(&data->update_lock);
/* Initialize the chipset */
lm92_init_client(new_client);
hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
new_client->name,
data, lm92_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
/*
* Module and driver stuff
*/
static const struct i2c_device_id lm92_id[] = {
{ "lm92", 0 },
/* max6635 could be added here */
{ }
};
MODULE_DEVICE_TABLE(i2c, lm92_id);
static struct i2c_driver lm92_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm92",
},
.probe = lm92_probe,
.id_table = lm92_id,
.detect = lm92_detect,
.address_list = normal_i2c,
};
module_i2c_driver(lm92_driver);
MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("LM92/MAX6635 driver");
MODULE_LICENSE("GPL");
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