/* 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. */ /* #define DEBUG 1 */ #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/i2c.h> #include <linux/i2c-sensor.h> /* Addresses to scan */ static unsigned short normal_i2c[] = { I2C_CLIENT_END }; static unsigned short normal_i2c_range[] = { 0x48, 0x4f, I2C_CLIENT_END }; static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; static unsigned int normal_isa_range[] = { 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 /* Conversions. Rounding and limit checking is only done on the TO_REG variants. Note that you should be a bit careful with which arguments these macros are called: arguments may be evaluated more than once. Fixing this is just not worth it. */ #define TEMP_FROM_REG(val) ((((val & 0x7fff) >> 7) * 5) | ((val & 0x8000)?-256:0)) #define TEMP_TO_REG(val) (SENSORS_LIMIT((val<0?(0x200+((val)/5))<<7:(((val) + 2) / 5) << 7),0,0xffff)) /* Initial values */ #define LM75_INIT_TEMP_OS 600 #define LM75_INIT_TEMP_HYST 500 /* Each client has this additional data */ struct lm75_data { 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 void lm75_update_client(struct i2c_client *client); /* 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, }; static int lm75_id = 0; #define show(value) \ static ssize_t show_##value(struct device *dev, char *buf) \ { \ struct i2c_client *client = to_i2c_client(dev); \ struct lm75_data *data = i2c_get_clientdata(client); \ int temp; \ \ lm75_update_client(client); \ temp = TEMP_FROM_REG(data->value); \ return sprintf(buf, "%d\n", temp * 100); \ } 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) / 100; \ \ data->value = TEMP_TO_REG(temp); \ lm75_write_value(client, reg, data->value); \ return count; \ } set(temp_max, LM75_REG_TEMP_OS); set(temp_hyst, LM75_REG_TEMP_HYST); static DEVICE_ATTR(temp_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max); static DEVICE_ATTR(temp_min, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst); static DEVICE_ATTR(temp_input, S_IRUGO, show_temp_input, NULL); static int lm75_attach_adapter(struct i2c_adapter *adapter) { if (!(adapter->class & I2C_ADAP_CLASS_SMBUS)) 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, cur, conf, hyst, os; 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 (!(new_client = kmalloc(sizeof(struct i2c_client) + sizeof(struct lm75_data), GFP_KERNEL))) { err = -ENOMEM; goto exit; } memset(new_client, 0x00, sizeof(struct i2c_client) + sizeof(struct lm75_data)); data = (struct lm75_data *) (new_client + 1); 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. It is lousy. */ if (kind < 0) { 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); os = i2c_smbus_read_word_data(new_client, 3); for (i = 0; i <= 0x1f; i++) if ((i2c_smbus_read_byte_data(new_client, i * 8 + 1) != conf) || (i2c_smbus_read_word_data(new_client, i * 8 + 2) != hyst) || (i2c_smbus_read_word_data(new_client, i * 8 + 3) != os)) goto exit_free; } /* Determine the chip type - only one kind supported! */ if (kind <= 0) kind = lm75; if (kind == lm75) { name = "lm75"; } else { dev_dbg(&adapter->dev, "Internal error: unknown kind (%d)?!?", kind); goto exit_free; } /* Fill in the remaining client fields and put it into the global list */ strlcpy(new_client->name, name, I2C_NAME_SIZE); new_client->id = lm75_id++; 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; device_create_file(&new_client->dev, &dev_attr_temp_max); device_create_file(&new_client->dev, &dev_attr_temp_min); device_create_file(&new_client->dev, &dev_attr_temp_input); lm75_init_client(new_client); return 0; exit_free: kfree(new_client); exit: return err; } static int lm75_detach_client(struct i2c_client *client) { i2c_detach_client(client); kfree(client); return 0; } static u16 swap_bytes(u16 val) { return (val >> 8) | (val << 8); } /* 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 swap_bytes(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, swap_bytes(value)); } static void lm75_init_client(struct i2c_client *client) { /* Initialize the LM75 chip */ lm75_write_value(client, LM75_REG_TEMP_OS, TEMP_TO_REG(LM75_INIT_TEMP_OS)); lm75_write_value(client, LM75_REG_TEMP_HYST, TEMP_TO_REG(LM75_INIT_TEMP_HYST)); lm75_write_value(client, LM75_REG_CONF, 0); } static void lm75_update_client(struct i2c_client *client) { struct lm75_data *data = i2c_get_clientdata(client); down(&data->update_lock); if ((jiffies - data->last_updated > HZ + HZ / 2) || (jiffies < data->last_updated) || !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); } 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);