/* lm75.c - Part of lm_sensors, Linux kernel modules for hardware monitoring Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> 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> #include "lm75.h" /* Addresses to scan */ static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; /* Insmod parameters */ I2C_CLIENT_INSMOD_1(lm75); /* Many LM75 constants specified below */ /* 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 i2c_client client; struct device *hwmon_dev; struct mutex update_lock; char valid; /* !=0 if following fields are valid */ unsigned long last_updated; /* In jiffies */ u16 temp[3]; /* Register values, 0 = input 1 = max 2 = hyst */ }; static int lm75_attach_adapter(struct i2c_adapter *adapter); static int lm75_detect(struct i2c_adapter *adapter, int address, int kind); static void lm75_init_client(struct i2c_client *client); static int lm75_detach_client(struct i2c_client *client); 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); /* This is the driver that will be inserted */ static struct i2c_driver lm75_driver = { .driver = { .name = "lm75", }, .attach_adapter = lm75_attach_adapter, .detach_client = lm75_detach_client, }; 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); 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 = simple_strtol(buf, NULL, 10); 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 int lm75_attach_adapter(struct i2c_adapter *adapter) { if (!(adapter->class & I2C_CLASS_HWMON)) return 0; return i2c_probe(adapter, &addr_data, lm75_detect); } 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, }; /* This function is called by i2c_probe */ static int lm75_detect(struct i2c_adapter *adapter, int address, int kind) { int i; struct i2c_client *new_client; struct lm75_data *data; int err = 0; const char *name = ""; if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA)) goto exit; /* OK. For now, we presume we have a valid client. We now create the client structure, even though we cannot fill it completely yet. But it allows us to access lm75_{read,write}_value. */ if (!(data = kzalloc(sizeof(struct lm75_data), GFP_KERNEL))) { err = -ENOMEM; goto exit; } new_client = &data->client; i2c_set_clientdata(new_client, data); new_client->addr = address; new_client->adapter = adapter; new_client->driver = &lm75_driver; new_client->flags = 0; /* 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. */ if (kind < 0) { int cur, conf, hyst, os; /* Unused addresses */ 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); if (i2c_smbus_read_word_data(new_client, 4) != hyst || i2c_smbus_read_word_data(new_client, 5) != hyst || i2c_smbus_read_word_data(new_client, 6) != hyst || i2c_smbus_read_word_data(new_client, 7) != hyst) goto exit_free; os = i2c_smbus_read_word_data(new_client, 3); if (i2c_smbus_read_word_data(new_client, 4) != os || i2c_smbus_read_word_data(new_client, 5) != os || i2c_smbus_read_word_data(new_client, 6) != os || i2c_smbus_read_word_data(new_client, 7) != os) goto exit_free; /* Unused bits */ if (conf & 0xe0) goto exit_free; /* Addresses cycling */ 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) != os) goto exit_free; } /* Determine the chip type - only one kind supported! */ if (kind <= 0) kind = lm75; if (kind == lm75) { name = "lm75"; } /* Fill in the remaining client fields and put it into the global list */ strlcpy(new_client->name, name, I2C_NAME_SIZE); data->valid = 0; mutex_init(&data->update_lock); /* Tell the I2C layer a new client has arrived */ if ((err = i2c_attach_client(new_client))) goto exit_free; /* Initialize the LM75 chip */ lm75_init_client(new_client); /* Register sysfs hooks */ if ((err = sysfs_create_group(&new_client->dev.kobj, &lm75_group))) goto exit_detach; 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, &lm75_group); exit_detach: i2c_detach_client(new_client); exit_free: kfree(data); exit: return err; } static int lm75_detach_client(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); i2c_detach_client(client); kfree(data); return 0; } /* All registers are word-sized, except for the configuration register. LM75 uses a high-byte first convention, which is exactly opposite to the usual practice. */ 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 swab16(i2c_smbus_read_word_data(client, reg)); } /* All registers are word-sized, except for the configuration register. LM75 uses a high-byte first convention, which is exactly opposite to the usual practice. */ 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_data(client, reg, swab16(value)); } static void lm75_init_client(struct i2c_client *client) { int reg; /* Enable if in shutdown mode */ reg = lm75_read_value(client, LM75_REG_CONF); if (reg >= 0 && (reg & 0x01)) lm75_write_value(client, LM75_REG_CONF, reg & 0xfe); } 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); 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++) data->temp[i] = lm75_read_value(client, LM75_REG_TEMP[i]); data->last_updated = jiffies; data->valid = 1; } mutex_unlock(&data->update_lock); return data; } 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 <frodol@dds.nl>"); MODULE_DESCRIPTION("LM75 driver"); MODULE_LICENSE("GPL"); module_init(sensors_lm75_init); module_exit(sensors_lm75_exit);