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/hwmon.h> 34 #include <linux/err.h> 35 36 /* Addresses to scan */ 37 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END }; 38 39 /* Insmod parameters */ 40 I2C_CLIENT_INSMOD_1(lm77); 41 42 /* The LM77 registers */ 43 #define LM77_REG_TEMP 0x00 44 #define LM77_REG_CONF 0x01 45 #define LM77_REG_TEMP_HYST 0x02 46 #define LM77_REG_TEMP_CRIT 0x03 47 #define LM77_REG_TEMP_MIN 0x04 48 #define LM77_REG_TEMP_MAX 0x05 49 50 /* Each client has this additional data */ 51 struct lm77_data { 52 struct i2c_client client; 53 struct class_device *class_dev; 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_probe(adapter, &addr_data, lm77_detect); 212 } 213 214 /* This function is called by i2c_probe */ 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 = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) { 230 err = -ENOMEM; 231 goto exit; 232 } 233 234 new_client = &data->client; 235 i2c_set_clientdata(new_client, data); 236 new_client->addr = address; 237 new_client->adapter = adapter; 238 new_client->driver = &lm77_driver; 239 new_client->flags = 0; 240 241 /* Here comes the remaining detection. Since the LM77 has no 242 register dedicated to identification, we have to rely on the 243 following tricks: 244 245 1. the high 4 bits represent the sign and thus they should 246 always be the same 247 2. the high 3 bits are unused in the configuration register 248 3. addresses 0x06 and 0x07 return the last read value 249 4. registers cycling over 8-address boundaries 250 251 Word-sized registers are high-byte first. */ 252 if (kind < 0) { 253 int i, cur, conf, hyst, crit, min, max; 254 255 /* addresses cycling */ 256 cur = i2c_smbus_read_word_data(new_client, 0); 257 conf = i2c_smbus_read_byte_data(new_client, 1); 258 hyst = i2c_smbus_read_word_data(new_client, 2); 259 crit = i2c_smbus_read_word_data(new_client, 3); 260 min = i2c_smbus_read_word_data(new_client, 4); 261 max = i2c_smbus_read_word_data(new_client, 5); 262 for (i = 8; i <= 0xff; i += 8) 263 if (i2c_smbus_read_byte_data(new_client, i + 1) != conf 264 || i2c_smbus_read_word_data(new_client, i + 2) != hyst 265 || i2c_smbus_read_word_data(new_client, i + 3) != crit 266 || i2c_smbus_read_word_data(new_client, i + 4) != min 267 || i2c_smbus_read_word_data(new_client, i + 5) != max) 268 goto exit_free; 269 270 /* sign bits */ 271 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 272 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 273 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 274 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 275 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 276 goto exit_free; 277 278 /* unused bits */ 279 if (conf & 0xe0) 280 goto exit_free; 281 282 /* 0x06 and 0x07 return the last read value */ 283 cur = i2c_smbus_read_word_data(new_client, 0); 284 if (i2c_smbus_read_word_data(new_client, 6) != cur 285 || i2c_smbus_read_word_data(new_client, 7) != cur) 286 goto exit_free; 287 hyst = i2c_smbus_read_word_data(new_client, 2); 288 if (i2c_smbus_read_word_data(new_client, 6) != hyst 289 || i2c_smbus_read_word_data(new_client, 7) != hyst) 290 goto exit_free; 291 min = i2c_smbus_read_word_data(new_client, 4); 292 if (i2c_smbus_read_word_data(new_client, 6) != min 293 || i2c_smbus_read_word_data(new_client, 7) != min) 294 goto exit_free; 295 296 } 297 298 /* Determine the chip type - only one kind supported! */ 299 if (kind <= 0) 300 kind = lm77; 301 302 if (kind == lm77) { 303 name = "lm77"; 304 } 305 306 /* Fill in the remaining client fields and put it into the global list */ 307 strlcpy(new_client->name, name, I2C_NAME_SIZE); 308 data->valid = 0; 309 init_MUTEX(&data->update_lock); 310 311 /* Tell the I2C layer a new client has arrived */ 312 if ((err = i2c_attach_client(new_client))) 313 goto exit_free; 314 315 /* Initialize the LM77 chip */ 316 lm77_init_client(new_client); 317 318 /* Register sysfs hooks */ 319 data->class_dev = hwmon_device_register(&new_client->dev); 320 if (IS_ERR(data->class_dev)) { 321 err = PTR_ERR(data->class_dev); 322 goto exit_detach; 323 } 324 325 device_create_file(&new_client->dev, &dev_attr_temp1_input); 326 device_create_file(&new_client->dev, &dev_attr_temp1_crit); 327 device_create_file(&new_client->dev, &dev_attr_temp1_min); 328 device_create_file(&new_client->dev, &dev_attr_temp1_max); 329 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst); 330 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst); 331 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 332 device_create_file(&new_client->dev, &dev_attr_alarms); 333 return 0; 334 335 exit_detach: 336 i2c_detach_client(new_client); 337 exit_free: 338 kfree(data); 339 exit: 340 return err; 341 } 342 343 static int lm77_detach_client(struct i2c_client *client) 344 { 345 struct lm77_data *data = i2c_get_clientdata(client); 346 hwmon_device_unregister(data->class_dev); 347 i2c_detach_client(client); 348 kfree(data); 349 return 0; 350 } 351 352 /* All registers are word-sized, except for the configuration register. 353 The LM77 uses the high-byte first convention. */ 354 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 355 { 356 if (reg == LM77_REG_CONF) 357 return i2c_smbus_read_byte_data(client, reg); 358 else 359 return swab16(i2c_smbus_read_word_data(client, reg)); 360 } 361 362 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 363 { 364 if (reg == LM77_REG_CONF) 365 return i2c_smbus_write_byte_data(client, reg, value); 366 else 367 return i2c_smbus_write_word_data(client, reg, swab16(value)); 368 } 369 370 static void lm77_init_client(struct i2c_client *client) 371 { 372 /* Initialize the LM77 chip - turn off shutdown mode */ 373 int conf = lm77_read_value(client, LM77_REG_CONF); 374 if (conf & 1) 375 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 376 } 377 378 static struct lm77_data *lm77_update_device(struct device *dev) 379 { 380 struct i2c_client *client = to_i2c_client(dev); 381 struct lm77_data *data = i2c_get_clientdata(client); 382 383 down(&data->update_lock); 384 385 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 386 || !data->valid) { 387 dev_dbg(&client->dev, "Starting lm77 update\n"); 388 data->temp_input = 389 LM77_TEMP_FROM_REG(lm77_read_value(client, 390 LM77_REG_TEMP)); 391 data->temp_hyst = 392 LM77_TEMP_FROM_REG(lm77_read_value(client, 393 LM77_REG_TEMP_HYST)); 394 data->temp_crit = 395 LM77_TEMP_FROM_REG(lm77_read_value(client, 396 LM77_REG_TEMP_CRIT)); 397 data->temp_min = 398 LM77_TEMP_FROM_REG(lm77_read_value(client, 399 LM77_REG_TEMP_MIN)); 400 data->temp_max = 401 LM77_TEMP_FROM_REG(lm77_read_value(client, 402 LM77_REG_TEMP_MAX)); 403 data->alarms = 404 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 405 data->last_updated = jiffies; 406 data->valid = 1; 407 } 408 409 up(&data->update_lock); 410 411 return data; 412 } 413 414 static int __init sensors_lm77_init(void) 415 { 416 return i2c_add_driver(&lm77_driver); 417 } 418 419 static void __exit sensors_lm77_exit(void) 420 { 421 i2c_del_driver(&lm77_driver); 422 } 423 424 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 425 MODULE_DESCRIPTION("LM77 driver"); 426 MODULE_LICENSE("GPL"); 427 428 module_init(sensors_lm77_init); 429 module_exit(sensors_lm77_exit); 430