/* * 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 = simple_strtol(buf, NULL, 10); \ \ 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 = simple_strtol(buf, NULL, 10); 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 */ if ((err = sysfs_create_group(&new_client->dev.kobj, &lm92_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, &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, }; static int __init sensors_lm92_init(void) { return i2c_add_driver(&lm92_driver); } static void __exit sensors_lm92_exit(void) { i2c_del_driver(&lm92_driver); } MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); MODULE_DESCRIPTION("LM92/MAX6635 driver"); MODULE_LICENSE("GPL"); module_init(sensors_lm92_init); module_exit(sensors_lm92_exit);