/* * lm75.c - Part of lm_sensors, Linux kernel modules for hardware * monitoring * Copyright (c) 1998, 1999 Frodo Looijaard * * 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 #include #include #include #include #include #include #include #include #include "lm75.h" /* * This driver handles the LM75 and compatible digital temperature sensors. */ enum lm75_type { /* keep sorted in alphabetical order */ adt75, ds1775, ds75, lm75, lm75a, max6625, max6626, mcp980x, stds75, tcn75, tmp100, tmp101, tmp105, tmp175, tmp275, tmp75, }; /* Addresses scanned */ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; /* The LM75 registers */ #define LM75_REG_CONF 0x01 static const u8 LM75_REG_TEMP[3] = { 0x00, /* input */ 0x03, /* max */ 0x02, /* hyst */ }; /* Each client has this additional data */ struct lm75_data { struct device *hwmon_dev; struct mutex update_lock; u8 orig_conf; char valid; /* !=0 if registers are valid */ unsigned long last_updated; /* In jiffies */ u16 temp[3]; /* Register values, 0 = input 1 = max 2 = hyst */ }; static int lm75_read_value(struct i2c_client *client, u8 reg); static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); static struct lm75_data *lm75_update_device(struct device *dev); /*-----------------------------------------------------------------------*/ /* sysfs attributes for hwmon */ static ssize_t show_temp(struct device *dev, struct device_attribute *da, char *buf) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); struct lm75_data *data = lm75_update_device(dev); if (IS_ERR(data)) return PTR_ERR(data); return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->temp[attr->index])); } static ssize_t set_temp(struct device *dev, struct device_attribute *da, const char *buf, size_t count) { struct sensor_device_attribute *attr = to_sensor_dev_attr(da); struct i2c_client *client = to_i2c_client(dev); struct lm75_data *data = i2c_get_clientdata(client); int nr = attr->index; long temp; int error; error = kstrtol(buf, 10, &temp); if (error) return error; mutex_lock(&data->update_lock); data->temp[nr] = LM75_TEMP_TO_REG(temp); lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]); mutex_unlock(&data->update_lock); return count; } static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 1); static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp, set_temp, 2); static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0); static struct attribute *lm75_attributes[] = { &sensor_dev_attr_temp1_input.dev_attr.attr, &sensor_dev_attr_temp1_max.dev_attr.attr, &sensor_dev_attr_temp1_max_hyst.dev_attr.attr, NULL }; static const struct attribute_group lm75_group = { .attrs = lm75_attributes, }; /*-----------------------------------------------------------------------*/ /* device probe and removal */ static int lm75_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct lm75_data *data; int status; u8 set_mask, clr_mask; int new; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) return -EIO; data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL); if (!data) return -ENOMEM; i2c_set_clientdata(client, data); mutex_init(&data->update_lock); /* Set to LM75 resolution (9 bits, 1/2 degree C) and range. * Then tweak to be more precise when appropriate. */ set_mask = 0; clr_mask = (1 << 0) /* continuous conversions */ | (1 << 6) | (1 << 5); /* 9-bit mode */ /* configure as specified */ status = lm75_read_value(client, LM75_REG_CONF); if (status < 0) { dev_dbg(&client->dev, "Can't read config? %d\n", status); goto exit_free; } data->orig_conf = status; new = status & ~clr_mask; new |= set_mask; if (status != new) lm75_write_value(client, LM75_REG_CONF, new); dev_dbg(&client->dev, "Config %02x\n", new); /* Register sysfs hooks */ status = sysfs_create_group(&client->dev.kobj, &lm75_group); if (status) goto exit_free; data->hwmon_dev = hwmon_device_register(&client->dev); if (IS_ERR(data->hwmon_dev)) { status = PTR_ERR(data->hwmon_dev); goto exit_remove; } dev_info(&client->dev, "%s: sensor '%s'\n", dev_name(data->hwmon_dev), client->name); return 0; exit_remove: sysfs_remove_group(&client->dev.kobj, &lm75_group); exit_free: kfree(data); return status; } static int lm75_remove(struct i2c_client *client) { struct lm75_data *data = i2c_get_clientdata(client); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&client->dev.kobj, &lm75_group); lm75_write_value(client, LM75_REG_CONF, data->orig_conf); kfree(data); return 0; } static const struct i2c_device_id lm75_ids[] = { { "adt75", adt75, }, { "ds1775", ds1775, }, { "ds75", ds75, }, { "lm75", lm75, }, { "lm75a", lm75a, }, { "max6625", max6625, }, { "max6626", max6626, }, { "mcp980x", mcp980x, }, { "stds75", stds75, }, { "tcn75", tcn75, }, { "tmp100", tmp100, }, { "tmp101", tmp101, }, { "tmp105", tmp105, }, { "tmp175", tmp175, }, { "tmp275", tmp275, }, { "tmp75", tmp75, }, { /* LIST END */ } }; MODULE_DEVICE_TABLE(i2c, lm75_ids); #define LM75A_ID 0xA1 /* Return 0 if detection is successful, -ENODEV otherwise */ static int lm75_detect(struct i2c_client *new_client, struct i2c_board_info *info) { struct i2c_adapter *adapter = new_client->adapter; int i; int conf, hyst, os; bool is_lm75a = 0; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) return -ENODEV; /* * Now, we do the remaining detection. There is no identification- * dedicated register so we have to rely on several tricks: * unused bits, registers cycling over 8-address boundaries, * addresses 0x04-0x07 returning the last read value. * The cycling+unused addresses combination is not tested, * since it would significantly slow the detection down and would * hardly add any value. * * The National Semiconductor LM75A is different than earlier * LM75s. It has an ID byte of 0xaX (where X is the chip * revision, with 1 being the only revision in existence) in * register 7, and unused registers return 0xff rather than the * last read value. * * Note that this function only detects the original National * Semiconductor LM75 and the LM75A. Clones from other vendors * aren't detected, on purpose, because they are typically never * found on PC hardware. They are found on embedded designs where * they can be instantiated explicitly so detection is not needed. * The absence of identification registers on all these clones * would make their exhaustive detection very difficult and weak, * and odds are that the driver would bind to unsupported devices. */ /* Unused bits */ conf = i2c_smbus_read_byte_data(new_client, 1); if (conf & 0xe0) return -ENODEV; /* First check for LM75A */ if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) { /* LM75A returns 0xff on unused registers so just to be sure we check for that too. */ if (i2c_smbus_read_byte_data(new_client, 4) != 0xff || i2c_smbus_read_byte_data(new_client, 5) != 0xff || i2c_smbus_read_byte_data(new_client, 6) != 0xff) return -ENODEV; is_lm75a = 1; hyst = i2c_smbus_read_byte_data(new_client, 2); os = i2c_smbus_read_byte_data(new_client, 3); } else { /* Traditional style LM75 detection */ /* Unused addresses */ hyst = i2c_smbus_read_byte_data(new_client, 2); if (i2c_smbus_read_byte_data(new_client, 4) != hyst || i2c_smbus_read_byte_data(new_client, 5) != hyst || i2c_smbus_read_byte_data(new_client, 6) != hyst || i2c_smbus_read_byte_data(new_client, 7) != hyst) return -ENODEV; os = i2c_smbus_read_byte_data(new_client, 3); if (i2c_smbus_read_byte_data(new_client, 4) != os || i2c_smbus_read_byte_data(new_client, 5) != os || i2c_smbus_read_byte_data(new_client, 6) != os || i2c_smbus_read_byte_data(new_client, 7) != os) return -ENODEV; } /* Addresses cycling */ for (i = 8; i <= 248; i += 40) { if (i2c_smbus_read_byte_data(new_client, i + 1) != conf || i2c_smbus_read_byte_data(new_client, i + 2) != hyst || i2c_smbus_read_byte_data(new_client, i + 3) != os) return -ENODEV; if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7) != LM75A_ID) return -ENODEV; } strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE); return 0; } #ifdef CONFIG_PM static int lm75_suspend(struct device *dev) { int status; struct i2c_client *client = to_i2c_client(dev); status = lm75_read_value(client, LM75_REG_CONF); if (status < 0) { dev_dbg(&client->dev, "Can't read config? %d\n", status); return status; } status = status | LM75_SHUTDOWN; lm75_write_value(client, LM75_REG_CONF, status); return 0; } static int lm75_resume(struct device *dev) { int status; struct i2c_client *client = to_i2c_client(dev); status = lm75_read_value(client, LM75_REG_CONF); if (status < 0) { dev_dbg(&client->dev, "Can't read config? %d\n", status); return status; } status = status & ~LM75_SHUTDOWN; lm75_write_value(client, LM75_REG_CONF, status); return 0; } static const struct dev_pm_ops lm75_dev_pm_ops = { .suspend = lm75_suspend, .resume = lm75_resume, }; #define LM75_DEV_PM_OPS (&lm75_dev_pm_ops) #else #define LM75_DEV_PM_OPS NULL #endif /* CONFIG_PM */ static struct i2c_driver lm75_driver = { .class = I2C_CLASS_HWMON, .driver = { .name = "lm75", .pm = LM75_DEV_PM_OPS, }, .probe = lm75_probe, .remove = lm75_remove, .id_table = lm75_ids, .detect = lm75_detect, .address_list = normal_i2c, }; /*-----------------------------------------------------------------------*/ /* register access */ /* * All registers are word-sized, except for the configuration register. * LM75 uses a high-byte first convention, which is exactly opposite to * the SMBus standard. */ static int lm75_read_value(struct i2c_client *client, u8 reg) { if (reg == LM75_REG_CONF) return i2c_smbus_read_byte_data(client, reg); else return i2c_smbus_read_word_swapped(client, reg); } static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) { if (reg == LM75_REG_CONF) return i2c_smbus_write_byte_data(client, reg, value); else return i2c_smbus_write_word_swapped(client, reg, value); } static struct lm75_data *lm75_update_device(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); struct lm75_data *data = i2c_get_clientdata(client); struct lm75_data *ret = data; mutex_lock(&data->update_lock); if (time_after(jiffies, data->last_updated + HZ + HZ / 2) || !data->valid) { int i; dev_dbg(&client->dev, "Starting lm75 update\n"); for (i = 0; i < ARRAY_SIZE(data->temp); i++) { int status; status = lm75_read_value(client, LM75_REG_TEMP[i]); if (unlikely(status < 0)) { dev_dbg(dev, "LM75: Failed to read value: reg %d, error %d\n", LM75_REG_TEMP[i], status); ret = ERR_PTR(status); data->valid = 0; goto abort; } data->temp[i] = status; } data->last_updated = jiffies; data->valid = 1; } abort: mutex_unlock(&data->update_lock); return ret; } /*-----------------------------------------------------------------------*/ /* module glue */ static int __init sensors_lm75_init(void) { return i2c_add_driver(&lm75_driver); } static void __exit sensors_lm75_exit(void) { i2c_del_driver(&lm75_driver); } MODULE_AUTHOR("Frodo Looijaard "); MODULE_DESCRIPTION("LM75 driver"); MODULE_LICENSE("GPL"); module_init(sensors_lm75_init); module_exit(sensors_lm75_exit);