diff options
Diffstat (limited to 'drivers/i2c/chips/lm75.c')
| -rw-r--r-- | drivers/i2c/chips/lm75.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/i2c/chips/lm75.c b/drivers/i2c/chips/lm75.c new file mode 100644 index 000000000000..0e86cc893981 --- /dev/null +++ b/drivers/i2c/chips/lm75.c @@ -0,0 +1,297 @@ +/* + 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/config.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/jiffies.h> +#include <linux/i2c.h> +#include <linux/i2c-sensor.h> +#include "lm75.h" + + +/* Addresses to scan */ +static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, + 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; +static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; + +/* Insmod parameters */ +SENSORS_INSMOD_1(lm75); + +/* Many LM75 constants specified below */ + +/* The LM75 registers */ +#define LM75_REG_TEMP 0x00 +#define LM75_REG_CONF 0x01 +#define LM75_REG_TEMP_HYST 0x02 +#define LM75_REG_TEMP_OS 0x03 + +/* Each client has this additional data */ +struct lm75_data { + struct i2c_client client; + struct semaphore update_lock; + char valid; /* !=0 if following fields are valid */ + unsigned long last_updated; /* In jiffies */ + u16 temp_input; /* Register values */ + u16 temp_max; + u16 temp_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 = { + .owner = THIS_MODULE, + .name = "lm75", + .id = I2C_DRIVERID_LM75, + .flags = I2C_DF_NOTIFY, + .attach_adapter = lm75_attach_adapter, + .detach_client = lm75_detach_client, +}; + +#define show(value) \ +static ssize_t show_##value(struct device *dev, char *buf) \ +{ \ + struct lm75_data *data = lm75_update_device(dev); \ + return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value)); \ +} +show(temp_max); +show(temp_hyst); +show(temp_input); + +#define set(value, reg) \ +static ssize_t set_##value(struct device *dev, const char *buf, size_t count) \ +{ \ + struct i2c_client *client = to_i2c_client(dev); \ + struct lm75_data *data = i2c_get_clientdata(client); \ + int temp = simple_strtoul(buf, NULL, 10); \ + \ + down(&data->update_lock); \ + data->value = LM75_TEMP_TO_REG(temp); \ + lm75_write_value(client, reg, data->value); \ + up(&data->update_lock); \ + return count; \ +} +set(temp_max, LM75_REG_TEMP_OS); +set(temp_hyst, LM75_REG_TEMP_HYST); + +static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max); +static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst); +static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL); + +static int lm75_attach_adapter(struct i2c_adapter *adapter) +{ + if (!(adapter->class & I2C_CLASS_HWMON)) + return 0; + return i2c_detect(adapter, &addr_data, lm75_detect); +} + +/* This function is called by i2c_detect */ +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 = ""; + + /* Make sure we aren't probing the ISA bus!! This is just a safety check + at this moment; i2c_detect really won't call us. */ +#ifdef DEBUG + if (i2c_is_isa_adapter(adapter)) { + dev_dbg(&adapter->dev, + "lm75_detect called for an ISA bus adapter?!?\n"); + goto exit; + } +#endif + + 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 = kmalloc(sizeof(struct lm75_data), GFP_KERNEL))) { + err = -ENOMEM; + goto exit; + } + memset(data, 0, sizeof(struct lm75_data)); + + 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; + init_MUTEX(&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 */ + device_create_file(&new_client->dev, &dev_attr_temp1_max); + device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); + device_create_file(&new_client->dev, &dev_attr_temp1_input); + + return 0; + +exit_free: + kfree(data); +exit: + return err; +} + +static int lm75_detach_client(struct i2c_client *client) +{ + i2c_detach_client(client); + kfree(i2c_get_clientdata(client)); + 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) +{ + /* Initialize the LM75 chip */ + lm75_write_value(client, LM75_REG_CONF, 0); +} + +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); + + down(&data->update_lock); + + if (time_after(jiffies, data->last_updated + HZ + HZ / 2) + || !data->valid) { + dev_dbg(&client->dev, "Starting lm75 update\n"); + + data->temp_input = lm75_read_value(client, LM75_REG_TEMP); + data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS); + data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST); + data->last_updated = jiffies; + data->valid = 1; + } + + up(&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); |