diff options
Diffstat (limited to 'drivers/hwmon/lm92.c')
| -rw-r--r-- | drivers/hwmon/lm92.c | 449 |
1 files changed, 449 insertions, 0 deletions
diff --git a/drivers/hwmon/lm92.c b/drivers/hwmon/lm92.c new file mode 100644 index 00000000..fdc691a4 --- /dev/null +++ b/drivers/hwmon/lm92.c @@ -0,0 +1,449 @@ +/* + * lm92 - Hardware monitoring driver + * Copyright (C) 2005-2008 Jean Delvare <khali@linux-fr.org> + * + * 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> + +/* + * 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 + * 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_attributes[] = { + &dev_attr_temp1_input.attr, + &dev_attr_temp1_crit.attr, + &dev_attr_temp1_crit_hyst.attr, + &dev_attr_temp1_min.attr, + &dev_attr_temp1_min_hyst.attr, + &dev_attr_temp1_max.attr, + &dev_attr_temp1_max_hyst.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 +}; + +static const struct attribute_group lm92_group = { + .attrs = lm92_attributes, +}; + +/* 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 lm92_data *data; + int err; + + data = kzalloc(sizeof(struct lm92_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 chipset */ + lm92_init_client(new_client); + + /* Register sysfs hooks */ + err = sysfs_create_group(&new_client->dev.kobj, &lm92_group); + if (err) + 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, &lm92_group); +exit_free: + kfree(data); +exit: + return err; +} + +static int lm92_remove(struct i2c_client *client) +{ + struct lm92_data *data = i2c_get_clientdata(client); + + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&client->dev.kobj, &lm92_group); + + kfree(data); + return 0; +} + + +/* + * 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, + .remove = lm92_remove, + .id_table = lm92_id, + .detect = lm92_detect, + .address_list = normal_i2c, +}; + +module_i2c_driver(lm92_driver); + +MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); +MODULE_DESCRIPTION("LM92/MAX6635 driver"); +MODULE_LICENSE("GPL"); |