/* * 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. */ #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 enum temp_index { t_input = 0, t_crit, t_min, t_max, t_hyst, t_num_temp }; static const u8 temp_regs[t_num_temp] = { [t_input] = LM77_REG_TEMP, [t_min] = LM77_REG_TEMP_MIN, [t_max] = LM77_REG_TEMP_MAX, [t_crit] = LM77_REG_TEMP_CRIT, [t_hyst] = LM77_REG_TEMP_HYST, }; /* Each client has this additional data */ struct lm77_data { struct i2c_client *client; struct mutex update_lock; char valid; unsigned long last_updated; /* In jiffies */ int temp[t_num_temp]; /* index using temp_index */ u8 alarms; }; /* 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 = clamp_val(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); return (ntemp / 500) * 8; } static inline int LM77_TEMP_FROM_REG(s16 reg) { return (reg / 8) * 500; } /* * 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 i2c_smbus_read_word_swapped(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_swapped(client, reg, value); } static struct lm77_data *lm77_update_device(struct device *dev) { struct lm77_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 + HZ / 2) || !data->valid) { dev_dbg(&client->dev, "Starting lm77 update\n"); for (i = 0; i < t_num_temp; i++) { data->temp[i] = LM77_TEMP_FROM_REG(lm77_read_value(client, temp_regs[i])); } data->alarms = lm77_read_value(client, LM77_REG_TEMP) & 0x0007; data->last_updated = jiffies; data->valid = 1; } mutex_unlock(&data->update_lock); return data; } /* sysfs stuff */ 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 lm77_data *data = lm77_update_device(dev); return sprintf(buf, "%d\n", data->temp[attr->index]); } 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 lm77_data *data = lm77_update_device(dev); int nr = attr->index; int temp; temp = nr == t_min ? data->temp[nr] + data->temp[t_hyst] : data->temp[nr] - data->temp[t_hyst]; return sprintf(buf, "%d\n", temp); } 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 lm77_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] = val; lm77_write_value(client, temp_regs[nr], LM77_TEMP_TO_REG(val)); mutex_unlock(&data->update_lock); return count; } /* * hysteresis is stored as a relative value on the chip, so it has to be * converted first. */ static ssize_t set_temp_hyst(struct device *dev, struct device_attribute *devattr, const char *buf, size_t count) { struct lm77_data *data = dev_get_drvdata(dev); struct i2c_client *client = data->client; unsigned long val; int err; err = kstrtoul(buf, 10, &val); if (err) return err; mutex_lock(&data->update_lock); data->temp[t_hyst] = data->temp[t_crit] - val; lm77_write_value(client, LM77_REG_TEMP_HYST, LM77_TEMP_TO_REG(data->temp[t_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 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_min, S_IWUSR | S_IRUGO, show_temp, set_temp, t_min); static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, t_max); 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_hyst, S_IRUGO, show_temp_hyst, NULL, t_min); static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max); 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_attrs[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_temp1_crit.dev_attr.attr, &sensor_dev_attr_temp1_min.dev_attr.attr, &sensor_dev_attr_temp1_max.dev_attr.attr, &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr, &sensor_dev_attr_temp1_min_hyst.dev_attr.attr, &sensor_dev_attr_temp1_max_hyst.dev_attr.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(lm77); /* Return 0 if detection is successful, -ENODEV otherwise */ static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) { struct i2c_adapter *adapter = 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(client, 0); conf = i2c_smbus_read_byte_data(client, 1); hyst = i2c_smbus_read_word_data(client, 2); crit = i2c_smbus_read_word_data(client, 3); min = i2c_smbus_read_word_data(client, 4); max = i2c_smbus_read_word_data(client, 5); for (i = 8; i <= 0xff; i += 8) { if (i2c_smbus_read_byte_data(client, i + 1) != conf || i2c_smbus_read_word_data(client, i + 2) != hyst || i2c_smbus_read_word_data(client, i + 3) != crit || i2c_smbus_read_word_data(client, i + 4) != min || i2c_smbus_read_word_data(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(client, 0); if (i2c_smbus_read_word_data(client, 6) != cur || i2c_smbus_read_word_data(client, 7) != cur) return -ENODEV; hyst = i2c_smbus_read_word_data(client, 2); if (i2c_smbus_read_word_data(client, 6) != hyst || i2c_smbus_read_word_data(client, 7) != hyst) return -ENODEV; min = i2c_smbus_read_word_data(client, 4); if (i2c_smbus_read_word_data(client, 6) != min || i2c_smbus_read_word_data(client, 7) != min) return -ENODEV; strlcpy(info->type, "lm77", I2C_NAME_SIZE); return 0; } 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 int lm77_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct device *hwmon_dev; struct lm77_data *data; data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL); if (!data) return -ENOMEM; data->client = client; mutex_init(&data->update_lock); /* Initialize the LM77 chip */ lm77_init_client(client); hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, data, lm77_groups); return PTR_ERR_OR_ZERO(hwmon_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, .id_table = lm77_id, .detect = lm77_detect, .address_list = normal_i2c, }; module_i2c_driver(lm77_driver); MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); MODULE_DESCRIPTION("LM77 driver"); MODULE_LICENSE("GPL");