/* * 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(long val) { val = clamp_val(val, -60000, 160000); 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 temp1_min_hyst_show(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; val = clamp_val(val, -120000, 220000); mutex_lock(&data->update_lock); data->temp[t_hyst] = TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val); i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST, data->temp[t_hyst]); mutex_unlock(&data->update_lock); return count; } static ssize_t alarms_show(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_RO(temp1_min_hyst); 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_RO(alarms); 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");