1 /* 2 lm75.c - Part of lm_sensors, Linux kernel modules for hardware 3 monitoring 4 Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl> 5 6 This program is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2 of the License, or 9 (at your option) any later version. 10 11 This program is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; if not, write to the Free Software 18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/slab.h> 24 #include <linux/jiffies.h> 25 #include <linux/i2c.h> 26 #include <linux/i2c-sensor.h> 27 #include "lm75.h" 28 29 30 /* Addresses to scan */ 31 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c, 32 0x4d, 0x4e, 0x4f, I2C_CLIENT_END }; 33 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; 34 35 /* Insmod parameters */ 36 SENSORS_INSMOD_1(lm75); 37 38 /* Many LM75 constants specified below */ 39 40 /* The LM75 registers */ 41 #define LM75_REG_TEMP 0x00 42 #define LM75_REG_CONF 0x01 43 #define LM75_REG_TEMP_HYST 0x02 44 #define LM75_REG_TEMP_OS 0x03 45 46 /* Each client has this additional data */ 47 struct lm75_data { 48 struct i2c_client client; 49 struct semaphore update_lock; 50 char valid; /* !=0 if following fields are valid */ 51 unsigned long last_updated; /* In jiffies */ 52 u16 temp_input; /* Register values */ 53 u16 temp_max; 54 u16 temp_hyst; 55 }; 56 57 static int lm75_attach_adapter(struct i2c_adapter *adapter); 58 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind); 59 static void lm75_init_client(struct i2c_client *client); 60 static int lm75_detach_client(struct i2c_client *client); 61 static int lm75_read_value(struct i2c_client *client, u8 reg); 62 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value); 63 static struct lm75_data *lm75_update_device(struct device *dev); 64 65 66 /* This is the driver that will be inserted */ 67 static struct i2c_driver lm75_driver = { 68 .owner = THIS_MODULE, 69 .name = "lm75", 70 .id = I2C_DRIVERID_LM75, 71 .flags = I2C_DF_NOTIFY, 72 .attach_adapter = lm75_attach_adapter, 73 .detach_client = lm75_detach_client, 74 }; 75 76 #define show(value) \ 77 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 78 { \ 79 struct lm75_data *data = lm75_update_device(dev); \ 80 return sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(data->value)); \ 81 } 82 show(temp_max); 83 show(temp_hyst); 84 show(temp_input); 85 86 #define set(value, reg) \ 87 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 88 { \ 89 struct i2c_client *client = to_i2c_client(dev); \ 90 struct lm75_data *data = i2c_get_clientdata(client); \ 91 int temp = simple_strtoul(buf, NULL, 10); \ 92 \ 93 down(&data->update_lock); \ 94 data->value = LM75_TEMP_TO_REG(temp); \ 95 lm75_write_value(client, reg, data->value); \ 96 up(&data->update_lock); \ 97 return count; \ 98 } 99 set(temp_max, LM75_REG_TEMP_OS); 100 set(temp_hyst, LM75_REG_TEMP_HYST); 101 102 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max, set_temp_max); 103 static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hyst, set_temp_hyst); 104 static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL); 105 106 static int lm75_attach_adapter(struct i2c_adapter *adapter) 107 { 108 if (!(adapter->class & I2C_CLASS_HWMON)) 109 return 0; 110 return i2c_detect(adapter, &addr_data, lm75_detect); 111 } 112 113 /* This function is called by i2c_detect */ 114 static int lm75_detect(struct i2c_adapter *adapter, int address, int kind) 115 { 116 int i; 117 struct i2c_client *new_client; 118 struct lm75_data *data; 119 int err = 0; 120 const char *name = ""; 121 122 /* Make sure we aren't probing the ISA bus!! This is just a safety check 123 at this moment; i2c_detect really won't call us. */ 124 #ifdef DEBUG 125 if (i2c_is_isa_adapter(adapter)) { 126 dev_dbg(&adapter->dev, 127 "lm75_detect called for an ISA bus adapter?!?\n"); 128 goto exit; 129 } 130 #endif 131 132 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 133 I2C_FUNC_SMBUS_WORD_DATA)) 134 goto exit; 135 136 /* OK. For now, we presume we have a valid client. We now create the 137 client structure, even though we cannot fill it completely yet. 138 But it allows us to access lm75_{read,write}_value. */ 139 if (!(data = kmalloc(sizeof(struct lm75_data), GFP_KERNEL))) { 140 err = -ENOMEM; 141 goto exit; 142 } 143 memset(data, 0, sizeof(struct lm75_data)); 144 145 new_client = &data->client; 146 i2c_set_clientdata(new_client, data); 147 new_client->addr = address; 148 new_client->adapter = adapter; 149 new_client->driver = &lm75_driver; 150 new_client->flags = 0; 151 152 /* Now, we do the remaining detection. There is no identification- 153 dedicated register so we have to rely on several tricks: 154 unused bits, registers cycling over 8-address boundaries, 155 addresses 0x04-0x07 returning the last read value. 156 The cycling+unused addresses combination is not tested, 157 since it would significantly slow the detection down and would 158 hardly add any value. */ 159 if (kind < 0) { 160 int cur, conf, hyst, os; 161 162 /* Unused addresses */ 163 cur = i2c_smbus_read_word_data(new_client, 0); 164 conf = i2c_smbus_read_byte_data(new_client, 1); 165 hyst = i2c_smbus_read_word_data(new_client, 2); 166 if (i2c_smbus_read_word_data(new_client, 4) != hyst 167 || i2c_smbus_read_word_data(new_client, 5) != hyst 168 || i2c_smbus_read_word_data(new_client, 6) != hyst 169 || i2c_smbus_read_word_data(new_client, 7) != hyst) 170 goto exit_free; 171 os = i2c_smbus_read_word_data(new_client, 3); 172 if (i2c_smbus_read_word_data(new_client, 4) != os 173 || i2c_smbus_read_word_data(new_client, 5) != os 174 || i2c_smbus_read_word_data(new_client, 6) != os 175 || i2c_smbus_read_word_data(new_client, 7) != os) 176 goto exit_free; 177 178 /* Unused bits */ 179 if (conf & 0xe0) 180 goto exit_free; 181 182 /* Addresses cycling */ 183 for (i = 8; i < 0xff; i += 8) 184 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 185 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 186 || i2c_smbus_read_word_data(new_client, i + 3) != os) 187 goto exit_free; 188 } 189 190 /* Determine the chip type - only one kind supported! */ 191 if (kind <= 0) 192 kind = lm75; 193 194 if (kind == lm75) { 195 name = "lm75"; 196 } 197 198 /* Fill in the remaining client fields and put it into the global list */ 199 strlcpy(new_client->name, name, I2C_NAME_SIZE); 200 data->valid = 0; 201 init_MUTEX(&data->update_lock); 202 203 /* Tell the I2C layer a new client has arrived */ 204 if ((err = i2c_attach_client(new_client))) 205 goto exit_free; 206 207 /* Initialize the LM75 chip */ 208 lm75_init_client(new_client); 209 210 /* Register sysfs hooks */ 211 device_create_file(&new_client->dev, &dev_attr_temp1_max); 212 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 213 device_create_file(&new_client->dev, &dev_attr_temp1_input); 214 215 return 0; 216 217 exit_free: 218 kfree(data); 219 exit: 220 return err; 221 } 222 223 static int lm75_detach_client(struct i2c_client *client) 224 { 225 i2c_detach_client(client); 226 kfree(i2c_get_clientdata(client)); 227 return 0; 228 } 229 230 /* All registers are word-sized, except for the configuration register. 231 LM75 uses a high-byte first convention, which is exactly opposite to 232 the usual practice. */ 233 static int lm75_read_value(struct i2c_client *client, u8 reg) 234 { 235 if (reg == LM75_REG_CONF) 236 return i2c_smbus_read_byte_data(client, reg); 237 else 238 return swab16(i2c_smbus_read_word_data(client, reg)); 239 } 240 241 /* All registers are word-sized, except for the configuration register. 242 LM75 uses a high-byte first convention, which is exactly opposite to 243 the usual practice. */ 244 static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value) 245 { 246 if (reg == LM75_REG_CONF) 247 return i2c_smbus_write_byte_data(client, reg, value); 248 else 249 return i2c_smbus_write_word_data(client, reg, swab16(value)); 250 } 251 252 static void lm75_init_client(struct i2c_client *client) 253 { 254 /* Initialize the LM75 chip */ 255 lm75_write_value(client, LM75_REG_CONF, 0); 256 } 257 258 static struct lm75_data *lm75_update_device(struct device *dev) 259 { 260 struct i2c_client *client = to_i2c_client(dev); 261 struct lm75_data *data = i2c_get_clientdata(client); 262 263 down(&data->update_lock); 264 265 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 266 || !data->valid) { 267 dev_dbg(&client->dev, "Starting lm75 update\n"); 268 269 data->temp_input = lm75_read_value(client, LM75_REG_TEMP); 270 data->temp_max = lm75_read_value(client, LM75_REG_TEMP_OS); 271 data->temp_hyst = lm75_read_value(client, LM75_REG_TEMP_HYST); 272 data->last_updated = jiffies; 273 data->valid = 1; 274 } 275 276 up(&data->update_lock); 277 278 return data; 279 } 280 281 static int __init sensors_lm75_init(void) 282 { 283 return i2c_add_driver(&lm75_driver); 284 } 285 286 static void __exit sensors_lm75_exit(void) 287 { 288 i2c_del_driver(&lm75_driver); 289 } 290 291 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>"); 292 MODULE_DESCRIPTION("LM75 driver"); 293 MODULE_LICENSE("GPL"); 294 295 module_init(sensors_lm75_init); 296 module_exit(sensors_lm75_exit); 297