/* 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);