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 #include <linux/mutex.h> 36 37 /* Addresses to scan */ 38 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, I2C_CLIENT_END }; 39 40 /* Insmod parameters */ 41 I2C_CLIENT_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 class_device *class_dev; 55 struct mutex update_lock; 56 char valid; 57 unsigned long last_updated; /* In jiffies */ 58 int temp_input; /* Temperatures */ 59 int temp_crit; 60 int temp_min; 61 int temp_max; 62 int temp_hyst; 63 u8 alarms; 64 }; 65 66 static int lm77_attach_adapter(struct i2c_adapter *adapter); 67 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind); 68 static void lm77_init_client(struct i2c_client *client); 69 static int lm77_detach_client(struct i2c_client *client); 70 static u16 lm77_read_value(struct i2c_client *client, u8 reg); 71 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value); 72 73 static struct lm77_data *lm77_update_device(struct device *dev); 74 75 76 /* This is the driver that will be inserted */ 77 static struct i2c_driver lm77_driver = { 78 .driver = { 79 .name = "lm77", 80 }, 81 .attach_adapter = lm77_attach_adapter, 82 .detach_client = lm77_detach_client, 83 }; 84 85 /* straight from the datasheet */ 86 #define LM77_TEMP_MIN (-55000) 87 #define LM77_TEMP_MAX 125000 88 89 /* In the temperature registers, the low 3 bits are not part of the 90 temperature values; they are the status bits. */ 91 static inline s16 LM77_TEMP_TO_REG(int temp) 92 { 93 int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 94 return (ntemp / 500) * 8; 95 } 96 97 static inline int LM77_TEMP_FROM_REG(s16 reg) 98 { 99 return (reg / 8) * 500; 100 } 101 102 /* sysfs stuff */ 103 104 /* read routines for temperature limits */ 105 #define show(value) \ 106 static ssize_t show_##value(struct device *dev, struct device_attribute *attr, char *buf) \ 107 { \ 108 struct lm77_data *data = lm77_update_device(dev); \ 109 return sprintf(buf, "%d\n", data->value); \ 110 } 111 112 show(temp_input); 113 show(temp_crit); 114 show(temp_min); 115 show(temp_max); 116 show(alarms); 117 118 /* read routines for hysteresis values */ 119 static ssize_t show_temp_crit_hyst(struct device *dev, struct device_attribute *attr, char *buf) 120 { 121 struct lm77_data *data = lm77_update_device(dev); 122 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 123 } 124 static ssize_t show_temp_min_hyst(struct device *dev, struct device_attribute *attr, char *buf) 125 { 126 struct lm77_data *data = lm77_update_device(dev); 127 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 128 } 129 static ssize_t show_temp_max_hyst(struct device *dev, struct device_attribute *attr, char *buf) 130 { 131 struct lm77_data *data = lm77_update_device(dev); 132 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 133 } 134 135 /* write routines */ 136 #define set(value, reg) \ 137 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) \ 138 { \ 139 struct i2c_client *client = to_i2c_client(dev); \ 140 struct lm77_data *data = i2c_get_clientdata(client); \ 141 long val = simple_strtoul(buf, NULL, 10); \ 142 \ 143 mutex_lock(&data->update_lock); \ 144 data->value = val; \ 145 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 146 mutex_unlock(&data->update_lock); \ 147 return count; \ 148 } 149 150 set(temp_min, LM77_REG_TEMP_MIN); 151 set(temp_max, LM77_REG_TEMP_MAX); 152 153 /* hysteresis is stored as a relative value on the chip, so it has to be 154 converted first */ 155 static ssize_t set_temp_crit_hyst(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 156 { 157 struct i2c_client *client = to_i2c_client(dev); 158 struct lm77_data *data = i2c_get_clientdata(client); 159 unsigned long val = simple_strtoul(buf, NULL, 10); 160 161 mutex_lock(&data->update_lock); 162 data->temp_hyst = data->temp_crit - val; 163 lm77_write_value(client, LM77_REG_TEMP_HYST, 164 LM77_TEMP_TO_REG(data->temp_hyst)); 165 mutex_unlock(&data->update_lock); 166 return count; 167 } 168 169 /* preserve hysteresis when setting T_crit */ 170 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 171 { 172 struct i2c_client *client = to_i2c_client(dev); 173 struct lm77_data *data = i2c_get_clientdata(client); 174 long val = simple_strtoul(buf, NULL, 10); 175 int oldcrithyst; 176 177 mutex_lock(&data->update_lock); 178 oldcrithyst = data->temp_crit - data->temp_hyst; 179 data->temp_crit = val; 180 data->temp_hyst = data->temp_crit - oldcrithyst; 181 lm77_write_value(client, LM77_REG_TEMP_CRIT, 182 LM77_TEMP_TO_REG(data->temp_crit)); 183 lm77_write_value(client, LM77_REG_TEMP_HYST, 184 LM77_TEMP_TO_REG(data->temp_hyst)); 185 mutex_unlock(&data->update_lock); 186 return count; 187 } 188 189 static DEVICE_ATTR(temp1_input, S_IRUGO, 190 show_temp_input, NULL); 191 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 192 show_temp_crit, set_temp_crit); 193 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 194 show_temp_min, set_temp_min); 195 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 196 show_temp_max, set_temp_max); 197 198 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 199 show_temp_crit_hyst, set_temp_crit_hyst); 200 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 201 show_temp_min_hyst, NULL); 202 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 203 show_temp_max_hyst, NULL); 204 205 static DEVICE_ATTR(alarms, S_IRUGO, 206 show_alarms, NULL); 207 208 static int lm77_attach_adapter(struct i2c_adapter *adapter) 209 { 210 if (!(adapter->class & I2C_CLASS_HWMON)) 211 return 0; 212 return i2c_probe(adapter, &addr_data, lm77_detect); 213 } 214 215 /* This function is called by i2c_probe */ 216 static int lm77_detect(struct i2c_adapter *adapter, int address, int kind) 217 { 218 struct i2c_client *new_client; 219 struct lm77_data *data; 220 int err = 0; 221 const char *name = ""; 222 223 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 224 I2C_FUNC_SMBUS_WORD_DATA)) 225 goto exit; 226 227 /* OK. For now, we presume we have a valid client. We now create the 228 client structure, even though we cannot fill it completely yet. 229 But it allows us to access lm77_{read,write}_value. */ 230 if (!(data = kzalloc(sizeof(struct lm77_data), GFP_KERNEL))) { 231 err = -ENOMEM; 232 goto exit; 233 } 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 mutex_init(&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 data->class_dev = hwmon_device_register(&new_client->dev); 321 if (IS_ERR(data->class_dev)) { 322 err = PTR_ERR(data->class_dev); 323 goto exit_detach; 324 } 325 326 device_create_file(&new_client->dev, &dev_attr_temp1_input); 327 device_create_file(&new_client->dev, &dev_attr_temp1_crit); 328 device_create_file(&new_client->dev, &dev_attr_temp1_min); 329 device_create_file(&new_client->dev, &dev_attr_temp1_max); 330 device_create_file(&new_client->dev, &dev_attr_temp1_crit_hyst); 331 device_create_file(&new_client->dev, &dev_attr_temp1_min_hyst); 332 device_create_file(&new_client->dev, &dev_attr_temp1_max_hyst); 333 device_create_file(&new_client->dev, &dev_attr_alarms); 334 return 0; 335 336 exit_detach: 337 i2c_detach_client(new_client); 338 exit_free: 339 kfree(data); 340 exit: 341 return err; 342 } 343 344 static int lm77_detach_client(struct i2c_client *client) 345 { 346 struct lm77_data *data = i2c_get_clientdata(client); 347 hwmon_device_unregister(data->class_dev); 348 i2c_detach_client(client); 349 kfree(data); 350 return 0; 351 } 352 353 /* All registers are word-sized, except for the configuration register. 354 The LM77 uses the high-byte first convention. */ 355 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 356 { 357 if (reg == LM77_REG_CONF) 358 return i2c_smbus_read_byte_data(client, reg); 359 else 360 return swab16(i2c_smbus_read_word_data(client, reg)); 361 } 362 363 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 364 { 365 if (reg == LM77_REG_CONF) 366 return i2c_smbus_write_byte_data(client, reg, value); 367 else 368 return i2c_smbus_write_word_data(client, reg, swab16(value)); 369 } 370 371 static void lm77_init_client(struct i2c_client *client) 372 { 373 /* Initialize the LM77 chip - turn off shutdown mode */ 374 int conf = lm77_read_value(client, LM77_REG_CONF); 375 if (conf & 1) 376 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 377 } 378 379 static struct lm77_data *lm77_update_device(struct device *dev) 380 { 381 struct i2c_client *client = to_i2c_client(dev); 382 struct lm77_data *data = i2c_get_clientdata(client); 383 384 mutex_lock(&data->update_lock); 385 386 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 387 || !data->valid) { 388 dev_dbg(&client->dev, "Starting lm77 update\n"); 389 data->temp_input = 390 LM77_TEMP_FROM_REG(lm77_read_value(client, 391 LM77_REG_TEMP)); 392 data->temp_hyst = 393 LM77_TEMP_FROM_REG(lm77_read_value(client, 394 LM77_REG_TEMP_HYST)); 395 data->temp_crit = 396 LM77_TEMP_FROM_REG(lm77_read_value(client, 397 LM77_REG_TEMP_CRIT)); 398 data->temp_min = 399 LM77_TEMP_FROM_REG(lm77_read_value(client, 400 LM77_REG_TEMP_MIN)); 401 data->temp_max = 402 LM77_TEMP_FROM_REG(lm77_read_value(client, 403 LM77_REG_TEMP_MAX)); 404 data->alarms = 405 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 406 data->last_updated = jiffies; 407 data->valid = 1; 408 } 409 410 mutex_unlock(&data->update_lock); 411 412 return data; 413 } 414 415 static int __init sensors_lm77_init(void) 416 { 417 return i2c_add_driver(&lm77_driver); 418 } 419 420 static void __exit sensors_lm77_exit(void) 421 { 422 i2c_del_driver(&lm77_driver); 423 } 424 425 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 426 MODULE_DESCRIPTION("LM77 driver"); 427 MODULE_LICENSE("GPL"); 428 429 module_init(sensors_lm77_init); 430 module_exit(sensors_lm77_exit); 431