1 /* 2 lm77.c - Part of lm_sensors, Linux kernel modules for hardware 3 monitoring 4 5 Copyright (c) 2004 Andras BALI <drewie@freemail.hu> 6 7 Heavily based on lm75.c by Frodo Looijaard <frodol@dds.nl>. The LM77 8 is a temperature sensor and thermal window comparator with 0.5 deg 9 resolution made by National Semiconductor. Complete datasheet can be 10 obtained at their site: 11 http://www.national.com/pf/LM/LM77.html 12 13 This program is free software; you can redistribute it and/or modify 14 it under the terms of the GNU General Public License as published by 15 the Free Software Foundation; either version 2 of the License, or 16 (at your option) any later version. 17 18 This program is distributed in the hope that it will be useful, 19 but WITHOUT ANY WARRANTY; without even the implied warranty of 20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 GNU General Public License for more details. 22 23 You should have received a copy of the GNU General Public License 24 along with this program; if not, write to the Free Software 25 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 26 */ 27 28 #include <linux/module.h> 29 #include <linux/init.h> 30 #include <linux/slab.h> 31 #include <linux/jiffies.h> 32 #include <linux/i2c.h> 33 #include <linux/i2c-sensor.h> 34 35 36 /* Addresses to scan */ 37 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END }; 38 static unsigned int normal_isa[] = { I2C_CLIENT_ISA_END }; 39 40 /* Insmod parameters */ 41 SENSORS_INSMOD_1(lm77); 42 43 /* The LM77 registers */ 44 #define LM77_REG_TEMP 0x00 45 #define LM77_REG_CONF 0x01 46 #define LM77_REG_TEMP_HYST 0x02 47 #define LM77_REG_TEMP_CRIT 0x03 48 #define LM77_REG_TEMP_MIN 0x04 49 #define LM77_REG_TEMP_MAX 0x05 50 51 /* Each client has this additional data */ 52 struct lm77_data { 53 struct i2c_client client; 54 struct semaphore update_lock; 55 char valid; 56 unsigned long last_updated; /* In jiffies */ 57 int temp_input; /* Temperatures */ 58 int temp_crit; 59 int temp_min; 60 int temp_max; 61 int temp_hyst; 62 u8 alarms; 63 }; 64 65 static int lm77_attach_adapter(struct i2c_adapter *adapter); 66 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind); 67 static void lm77_init_client(struct i2c_client *client); 68 static int lm77_detach_client(struct i2c_client *client); 69 static u16 lm77_read_value(struct i2c_client *client, u8 reg); 70 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value); 71 72 static struct lm77_data *lm77_update_device(struct device *dev); 73 74 75 /* This is the driver that will be inserted */ 76 static struct i2c_driver lm77_driver = { 77 .owner = THIS_MODULE, 78 .name = "lm77", 79 .flags = I2C_DF_NOTIFY, 80 .attach_adapter = lm77_attach_adapter, 81 .detach_client = lm77_detach_client, 82 }; 83 84 /* straight from the datasheet */ 85 #define LM77_TEMP_MIN (-55000) 86 #define LM77_TEMP_MAX 125000 87 88 /* In the temperature registers, the low 3 bits are not part of the 89 temperature values; they are the status bits. */ 90 static inline u16 LM77_TEMP_TO_REG(int temp) 91 { 92 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 93 return (u16)((ntemp / 500) * 8); 94 } 95 96 static inline int LM77_TEMP_FROM_REG(u16 reg) 97 { 98 return ((int)reg / 8) * 500; 99 } 100 101 /* sysfs stuff */ 102 103 /* read routines for temperature limits */ 104 #define show(value) \ 105 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 106 { \ 107 struct lm77_data *data = lm77_update_device(dev); \ 108 return sprintf(buf, "%d\n", data->value); \ 109 } 110 111 show(temp_input); 112 show(temp_crit); 113 show(temp_min); 114 show(temp_max); 115 show(alarms); 116 117 /* read routines for hysteresis values */ 118 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 119 { 120 struct lm77_data *data = lm77_update_device(dev); 121 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 122 } 123 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 124 { 125 struct lm77_data *data = lm77_update_device(dev); 126 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 127 } 128 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 129 { 130 struct lm77_data *data = lm77_update_device(dev); 131 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 132 } 133 134 /* write routines */ 135 #define set(value, reg) \ 136 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 137 { \ 138 struct i2c_client *client = to_i2c_client(dev); \ 139 struct lm77_data *data = i2c_get_clientdata(client); \ 140 long val = simple_strtoul(buf, NULL, 10); \ 141 \ 142 down(&data->update_lock); \ 143 data->value = val; \ 144 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 145 up(&data->update_lock); \ 146 return count; \ 147 } 148 149 set(temp_min, LM77_REG_TEMP_MIN); 150 set(temp_max, LM77_REG_TEMP_MAX); 151 152 /* hysteresis is stored as a relative value on the chip, so it has to be 153 converted first */ 154 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 155 { 156 struct i2c_client *client = to_i2c_client(dev); 157 struct lm77_data *data = i2c_get_clientdata(client); 158 unsigned long val = simple_strtoul(buf, NULL, 10); 159 160 down(&data->update_lock); 161 data->temp_hyst = data->temp_crit - val; 162 lm77_write_value(client, LM77_REG_TEMP_HYST, 163 LM77_TEMP_TO_REG(data->temp_hyst)); 164 up(&data->update_lock); 165 return count; 166 } 167 168 /* preserve hysteresis when setting T_crit */ 169 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 170 { 171 struct i2c_client *client = to_i2c_client(dev); 172 struct lm77_data *data = i2c_get_clientdata(client); 173 long val = simple_strtoul(buf, NULL, 10); 174 int oldcrithyst; 175 176 down(&data->update_lock); 177 oldcrithyst = data->temp_crit - data->temp_hyst; 178 data->temp_crit = val; 179 data->temp_hyst = data->temp_crit - oldcrithyst; 180 lm77_write_value(client, LM77_REG_TEMP_CRIT, 181 LM77_TEMP_TO_REG(data->temp_crit)); 182 lm77_write_value(client, LM77_REG_TEMP_HYST, 183 LM77_TEMP_TO_REG(data->temp_hyst)); 184 up(&data->update_lock); 185 return count; 186 } 187 188 static DEVICE_ATTR(temp1_input, S_IRUGO, 189 show_temp_input, NULL); 190 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 191 show_temp_crit, set_temp_crit); 192 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 193 show_temp_min, set_temp_min); 194 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 195 show_temp_max, set_temp_max); 196 197 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 198 show_temp_crit_hyst, set_temp_crit_hyst); 199 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 200 show_temp_min_hyst, NULL); 201 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 202 show_temp_max_hyst, NULL); 203 204 static DEVICE_ATTR(alarms, S_IRUGO, 205 show_alarms, NULL); 206 207 static int lm77_attach_adapter(struct i2c_adapter *adapter) 208 { 209 if (!(adapter->class & I2C_CLASS_HWMON)) 210 return 0; 211 return i2c_detect(adapter, &addr_data, lm77_detect); 212 } 213 214 /* This function is called by i2c_detect */ 215 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind) 216 { 217 struct i2c_client *new_client; 218 struct lm77_data *data; 219 int err = 0; 220 const char *name = ""; 221 222 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 223 I2C_FUNC_SMBUS_WORD_DATA)) 224 goto exit; 225 226 /* OK. For now, we presume we have a valid client. We now create the 227 client structure, even though we cannot fill it completely yet. 228 But it allows us to access lm77_{read,write}_value. */ 229 if (!(data = kmalloc(sizeof(struct lm77_data), GFP_KERNEL))) { 230 err = -ENOMEM; 231 goto exit; 232 } 233 memset(data, 0, sizeof(struct lm77_data)); 234 235 new_client = &data->client; 236 i2c_set_clientdata(new_client, data); 237 new_client->addr = address; 238 new_client->adapter = adapter; 239 new_client->driver = &lm77_driver; 240 new_client->flags = 0; 241 242 /* Here comes the remaining detection. Since the LM77 has no 243 register dedicated to identification, we have to rely on the 244 following tricks: 245 246 1. the high 4 bits represent the sign and thus they should 247 always be the same 248 2. the high 3 bits are unused in the configuration register 249 3. addresses 0x06 and 0x07 return the last read value 250 4. registers cycling over 8-address boundaries 251 252 Word-sized registers are high-byte first. */ 253 if (kind < 0) { 254 int i, cur, conf, hyst, crit, min, max; 255 256 /* addresses cycling */ 257 cur = i2c_smbus_read_word_data(new_client, 0); 258 conf = i2c_smbus_read_byte_data(new_client, 1); 259 hyst = i2c_smbus_read_word_data(new_client, 2); 260 crit = i2c_smbus_read_word_data(new_client, 3); 261 min = i2c_smbus_read_word_data(new_client, 4); 262 max = i2c_smbus_read_word_data(new_client, 5); 263 for (i = 8; i <= 0xff; i += 8) 264 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 265 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 266 || i2c_smbus_read_word_data(new_client, i + 3) != crit 267 || i2c_smbus_read_word_data(new_client, i + 4) != min 268 || i2c_smbus_read_word_data(new_client, i + 5) != max) 269 goto exit_free; 270 271 /* sign bits */ 272 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 273 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 274 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 275 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 276 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 277 goto exit_free; 278 279 /* unused bits */ 280 if (conf & 0xe0) 281 goto exit_free; 282 283 /* 0x06 and 0x07 return the last read value */ 284 cur = i2c_smbus_read_word_data(new_client, 0); 285 if (i2c_smbus_read_word_data(new_client, 6) != cur 286 || i2c_smbus_read_word_data(new_client, 7) != cur) 287 goto exit_free; 288 hyst = i2c_smbus_read_word_data(new_client, 2); 289 if (i2c_smbus_read_word_data(new_client, 6) != hyst 290 || i2c_smbus_read_word_data(new_client, 7) != hyst) 291 goto exit_free; 292 min = i2c_smbus_read_word_data(new_client, 4); 293 if (i2c_smbus_read_word_data(new_client, 6) != min 294 || i2c_smbus_read_word_data(new_client, 7) != min) 295 goto exit_free; 296 297 } 298 299 /* Determine the chip type - only one kind supported! */ 300 if (kind <= 0) 301 kind = lm77; 302 303 if (kind == lm77) { 304 name = "lm77"; 305 } 306 307 /* Fill in the remaining client fields and put it into the global list */ 308 strlcpy(new_client->name, name, I2C_NAME_SIZE); 309 data->valid = 0; 310 init_MUTEX(&data->update_lock); 311 312 /* Tell the I2C layer a new client has arrived */ 313 if ((err = i2c_attach_client(new_client))) 314 goto exit_free; 315 316 /* Initialize the LM77 chip */ 317 lm77_init_client(new_client); 318 319 /* Register sysfs hooks */ 320 device_create_file(&new_client->dev, &dev_attr_temp1_input); 321 device_create_file(&new_client->dev, &dev_attr_temp1_crit); 322 device_create_file(&new_client->dev, &dev_attr_temp1_min); 323 device_create_file(&new_client->dev, &dev_attr_temp1_max); 324 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst); 325 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst); 326 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 327 device_create_file(&new_client->dev, &dev_attr_alarms); 328 return 0; 329 330 exit_free: 331 kfree(data); 332 exit: 333 return err; 334 } 335 336 static int lm77_detach_client(struct i2c_client *client) 337 { 338 i2c_detach_client(client); 339 kfree(i2c_get_clientdata(client)); 340 return 0; 341 } 342 343 /* All registers are word-sized, except for the configuration register. 344 The LM77 uses the high-byte first convention. */ 345 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 346 { 347 if (reg == LM77_REG_CONF) 348 return i2c_smbus_read_byte_data(client, reg); 349 else 350 return swab16(i2c_smbus_read_word_data(client, reg)); 351 } 352 353 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 354 { 355 if (reg == LM77_REG_CONF) 356 return i2c_smbus_write_byte_data(client, reg, value); 357 else 358 return i2c_smbus_write_word_data(client, reg, swab16(value)); 359 } 360 361 static void lm77_init_client(struct i2c_client *client) 362 { 363 /* Initialize the LM77 chip - turn off shutdown mode */ 364 int conf = lm77_read_value(client, LM77_REG_CONF); 365 if (conf & 1) 366 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 367 } 368 369 static struct lm77_data *lm77_update_device(struct device *dev) 370 { 371 struct i2c_client *client = to_i2c_client(dev); 372 struct lm77_data *data = i2c_get_clientdata(client); 373 374 down(&data->update_lock); 375 376 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 377 || !data->valid) { 378 dev_dbg(&client->dev, "Starting lm77 update\n"); 379 data->temp_input = 380 LM77_TEMP_FROM_REG(lm77_read_value(client, 381 LM77_REG_TEMP)); 382 data->temp_hyst = 383 LM77_TEMP_FROM_REG(lm77_read_value(client, 384 LM77_REG_TEMP_HYST)); 385 data->temp_crit = 386 LM77_TEMP_FROM_REG(lm77_read_value(client, 387 LM77_REG_TEMP_CRIT)); 388 data->temp_min = 389 LM77_TEMP_FROM_REG(lm77_read_value(client, 390 LM77_REG_TEMP_MIN)); 391 data->temp_max = 392 LM77_TEMP_FROM_REG(lm77_read_value(client, 393 LM77_REG_TEMP_MAX)); 394 data->alarms = 395 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 396 data->last_updated = jiffies; 397 data->valid = 1; 398 } 399 400 up(&data->update_lock); 401 402 return data; 403 } 404 405 static int __init sensors_lm77_init(void) 406 { 407 return i2c_add_driver(&lm77_driver); 408 } 409 410 static void __exit sensors_lm77_exit(void) 411 { 412 i2c_del_driver(&lm77_driver); 413 } 414 415 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 416 MODULE_DESCRIPTION("LM77 driver"); 417 MODULE_LICENSE("GPL"); 418 419 module_init(sensors_lm77_init); 420 module_exit(sensors_lm77_exit); 421