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/hwmon-sysfs.h> 35 #include <linux/err.h> 36 #include <linux/mutex.h> 37 38 /* Addresses to scan */ 39 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 40 I2C_CLIENT_END }; 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 device *hwmon_dev; 53 struct mutex update_lock; 54 char valid; 55 unsigned long last_updated; /* In jiffies */ 56 int temp_input; /* Temperatures */ 57 int temp_crit; 58 int temp_min; 59 int temp_max; 60 int temp_hyst; 61 u8 alarms; 62 }; 63 64 static int lm77_probe(struct i2c_client *client, 65 const struct i2c_device_id *id); 66 static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info); 67 static void lm77_init_client(struct i2c_client *client); 68 static int lm77_remove(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 static const struct i2c_device_id lm77_id[] = { 76 { "lm77", 0 }, 77 { } 78 }; 79 MODULE_DEVICE_TABLE(i2c, lm77_id); 80 81 /* This is the driver that will be inserted */ 82 static struct i2c_driver lm77_driver = { 83 .class = I2C_CLASS_HWMON, 84 .driver = { 85 .name = "lm77", 86 }, 87 .probe = lm77_probe, 88 .remove = lm77_remove, 89 .id_table = lm77_id, 90 .detect = lm77_detect, 91 .address_list = normal_i2c, 92 }; 93 94 /* straight from the datasheet */ 95 #define LM77_TEMP_MIN (-55000) 96 #define LM77_TEMP_MAX 125000 97 98 /* 99 * In the temperature registers, the low 3 bits are not part of the 100 * temperature values; they are the status bits. 101 */ 102 static inline s16 LM77_TEMP_TO_REG(int temp) 103 { 104 int ntemp = clamp_val(temp, LM77_TEMP_MIN, LM77_TEMP_MAX); 105 return (ntemp / 500) * 8; 106 } 107 108 static inline int LM77_TEMP_FROM_REG(s16 reg) 109 { 110 return (reg / 8) * 500; 111 } 112 113 /* sysfs stuff */ 114 115 /* read routines for temperature limits */ 116 #define show(value) \ 117 static ssize_t show_##value(struct device *dev, \ 118 struct device_attribute *attr, \ 119 char *buf) \ 120 { \ 121 struct lm77_data *data = lm77_update_device(dev); \ 122 return sprintf(buf, "%d\n", data->value); \ 123 } 124 125 show(temp_input); 126 show(temp_crit); 127 show(temp_min); 128 show(temp_max); 129 130 /* read routines for hysteresis values */ 131 static ssize_t show_temp_crit_hyst(struct device *dev, 132 struct device_attribute *attr, char *buf) 133 { 134 struct lm77_data *data = lm77_update_device(dev); 135 return sprintf(buf, "%d\n", data->temp_crit - data->temp_hyst); 136 } 137 static ssize_t show_temp_min_hyst(struct device *dev, 138 struct device_attribute *attr, char *buf) 139 { 140 struct lm77_data *data = lm77_update_device(dev); 141 return sprintf(buf, "%d\n", data->temp_min + data->temp_hyst); 142 } 143 static ssize_t show_temp_max_hyst(struct device *dev, 144 struct device_attribute *attr, char *buf) 145 { 146 struct lm77_data *data = lm77_update_device(dev); 147 return sprintf(buf, "%d\n", data->temp_max - data->temp_hyst); 148 } 149 150 /* write routines */ 151 #define set(value, reg) \ 152 static ssize_t set_##value(struct device *dev, struct device_attribute *attr, \ 153 const char *buf, size_t count) \ 154 { \ 155 struct i2c_client *client = to_i2c_client(dev); \ 156 struct lm77_data *data = i2c_get_clientdata(client); \ 157 long val; \ 158 int err = kstrtol(buf, 10, &val); \ 159 if (err) \ 160 return err; \ 161 \ 162 mutex_lock(&data->update_lock); \ 163 data->value = val; \ 164 lm77_write_value(client, reg, LM77_TEMP_TO_REG(data->value)); \ 165 mutex_unlock(&data->update_lock); \ 166 return count; \ 167 } 168 169 set(temp_min, LM77_REG_TEMP_MIN); 170 set(temp_max, LM77_REG_TEMP_MAX); 171 172 /* 173 * hysteresis is stored as a relative value on the chip, so it has to be 174 * converted first 175 */ 176 static ssize_t set_temp_crit_hyst(struct device *dev, 177 struct device_attribute *attr, 178 const char *buf, size_t count) 179 { 180 struct i2c_client *client = to_i2c_client(dev); 181 struct lm77_data *data = i2c_get_clientdata(client); 182 unsigned long val; 183 int err; 184 185 err = kstrtoul(buf, 10, &val); 186 if (err) 187 return err; 188 189 mutex_lock(&data->update_lock); 190 data->temp_hyst = data->temp_crit - val; 191 lm77_write_value(client, LM77_REG_TEMP_HYST, 192 LM77_TEMP_TO_REG(data->temp_hyst)); 193 mutex_unlock(&data->update_lock); 194 return count; 195 } 196 197 /* preserve hysteresis when setting T_crit */ 198 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr, 199 const char *buf, size_t count) 200 { 201 struct i2c_client *client = to_i2c_client(dev); 202 struct lm77_data *data = i2c_get_clientdata(client); 203 int oldcrithyst; 204 unsigned long val; 205 int err; 206 207 err = kstrtoul(buf, 10, &val); 208 if (err) 209 return err; 210 211 mutex_lock(&data->update_lock); 212 oldcrithyst = data->temp_crit - data->temp_hyst; 213 data->temp_crit = val; 214 data->temp_hyst = data->temp_crit - oldcrithyst; 215 lm77_write_value(client, LM77_REG_TEMP_CRIT, 216 LM77_TEMP_TO_REG(data->temp_crit)); 217 lm77_write_value(client, LM77_REG_TEMP_HYST, 218 LM77_TEMP_TO_REG(data->temp_hyst)); 219 mutex_unlock(&data->update_lock); 220 return count; 221 } 222 223 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr, 224 char *buf) 225 { 226 int bitnr = to_sensor_dev_attr(attr)->index; 227 struct lm77_data *data = lm77_update_device(dev); 228 return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1); 229 } 230 231 static DEVICE_ATTR(temp1_input, S_IRUGO, 232 show_temp_input, NULL); 233 static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, 234 show_temp_crit, set_temp_crit); 235 static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, 236 show_temp_min, set_temp_min); 237 static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, 238 show_temp_max, set_temp_max); 239 240 static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, 241 show_temp_crit_hyst, set_temp_crit_hyst); 242 static DEVICE_ATTR(temp1_min_hyst, S_IRUGO, 243 show_temp_min_hyst, NULL); 244 static DEVICE_ATTR(temp1_max_hyst, S_IRUGO, 245 show_temp_max_hyst, NULL); 246 247 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2); 248 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0); 249 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1); 250 251 static struct attribute *lm77_attributes[] = { 252 &dev_attr_temp1_input.attr, 253 &dev_attr_temp1_crit.attr, 254 &dev_attr_temp1_min.attr, 255 &dev_attr_temp1_max.attr, 256 &dev_attr_temp1_crit_hyst.attr, 257 &dev_attr_temp1_min_hyst.attr, 258 &dev_attr_temp1_max_hyst.attr, 259 &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr, 260 &sensor_dev_attr_temp1_min_alarm.dev_attr.attr, 261 &sensor_dev_attr_temp1_max_alarm.dev_attr.attr, 262 NULL 263 }; 264 265 static const struct attribute_group lm77_group = { 266 .attrs = lm77_attributes, 267 }; 268 269 /* Return 0 if detection is successful, -ENODEV otherwise */ 270 static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info) 271 { 272 struct i2c_adapter *adapter = client->adapter; 273 int i, cur, conf, hyst, crit, min, max; 274 275 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | 276 I2C_FUNC_SMBUS_WORD_DATA)) 277 return -ENODEV; 278 279 /* 280 * Here comes the remaining detection. Since the LM77 has no 281 * register dedicated to identification, we have to rely on the 282 * following tricks: 283 * 284 * 1. the high 4 bits represent the sign and thus they should 285 * always be the same 286 * 2. the high 3 bits are unused in the configuration register 287 * 3. addresses 0x06 and 0x07 return the last read value 288 * 4. registers cycling over 8-address boundaries 289 * 290 * Word-sized registers are high-byte first. 291 */ 292 293 /* addresses cycling */ 294 cur = i2c_smbus_read_word_data(client, 0); 295 conf = i2c_smbus_read_byte_data(client, 1); 296 hyst = i2c_smbus_read_word_data(client, 2); 297 crit = i2c_smbus_read_word_data(client, 3); 298 min = i2c_smbus_read_word_data(client, 4); 299 max = i2c_smbus_read_word_data(client, 5); 300 for (i = 8; i <= 0xff; i += 8) { 301 if (i2c_smbus_read_byte_data(client, i + 1) != conf 302 || i2c_smbus_read_word_data(client, i + 2) != hyst 303 || i2c_smbus_read_word_data(client, i + 3) != crit 304 || i2c_smbus_read_word_data(client, i + 4) != min 305 || i2c_smbus_read_word_data(client, i + 5) != max) 306 return -ENODEV; 307 } 308 309 /* sign bits */ 310 if (((cur & 0x00f0) != 0xf0 && (cur & 0x00f0) != 0x0) 311 || ((hyst & 0x00f0) != 0xf0 && (hyst & 0x00f0) != 0x0) 312 || ((crit & 0x00f0) != 0xf0 && (crit & 0x00f0) != 0x0) 313 || ((min & 0x00f0) != 0xf0 && (min & 0x00f0) != 0x0) 314 || ((max & 0x00f0) != 0xf0 && (max & 0x00f0) != 0x0)) 315 return -ENODEV; 316 317 /* unused bits */ 318 if (conf & 0xe0) 319 return -ENODEV; 320 321 /* 0x06 and 0x07 return the last read value */ 322 cur = i2c_smbus_read_word_data(client, 0); 323 if (i2c_smbus_read_word_data(client, 6) != cur 324 || i2c_smbus_read_word_data(client, 7) != cur) 325 return -ENODEV; 326 hyst = i2c_smbus_read_word_data(client, 2); 327 if (i2c_smbus_read_word_data(client, 6) != hyst 328 || i2c_smbus_read_word_data(client, 7) != hyst) 329 return -ENODEV; 330 min = i2c_smbus_read_word_data(client, 4); 331 if (i2c_smbus_read_word_data(client, 6) != min 332 || i2c_smbus_read_word_data(client, 7) != min) 333 return -ENODEV; 334 335 strlcpy(info->type, "lm77", I2C_NAME_SIZE); 336 337 return 0; 338 } 339 340 static int lm77_probe(struct i2c_client *client, const struct i2c_device_id *id) 341 { 342 struct device *dev = &client->dev; 343 struct lm77_data *data; 344 int err; 345 346 data = devm_kzalloc(dev, sizeof(struct lm77_data), GFP_KERNEL); 347 if (!data) 348 return -ENOMEM; 349 350 i2c_set_clientdata(client, data); 351 data->valid = 0; 352 mutex_init(&data->update_lock); 353 354 /* Initialize the LM77 chip */ 355 lm77_init_client(client); 356 357 /* Register sysfs hooks */ 358 err = sysfs_create_group(&dev->kobj, &lm77_group); 359 if (err) 360 return err; 361 362 data->hwmon_dev = hwmon_device_register(dev); 363 if (IS_ERR(data->hwmon_dev)) { 364 err = PTR_ERR(data->hwmon_dev); 365 goto exit_remove; 366 } 367 368 return 0; 369 370 exit_remove: 371 sysfs_remove_group(&dev->kobj, &lm77_group); 372 return err; 373 } 374 375 static int lm77_remove(struct i2c_client *client) 376 { 377 struct lm77_data *data = i2c_get_clientdata(client); 378 hwmon_device_unregister(data->hwmon_dev); 379 sysfs_remove_group(&client->dev.kobj, &lm77_group); 380 return 0; 381 } 382 383 /* 384 * All registers are word-sized, except for the configuration register. 385 * The LM77 uses the high-byte first convention. 386 */ 387 static u16 lm77_read_value(struct i2c_client *client, u8 reg) 388 { 389 if (reg == LM77_REG_CONF) 390 return i2c_smbus_read_byte_data(client, reg); 391 else 392 return i2c_smbus_read_word_swapped(client, reg); 393 } 394 395 static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value) 396 { 397 if (reg == LM77_REG_CONF) 398 return i2c_smbus_write_byte_data(client, reg, value); 399 else 400 return i2c_smbus_write_word_swapped(client, reg, value); 401 } 402 403 static void lm77_init_client(struct i2c_client *client) 404 { 405 /* Initialize the LM77 chip - turn off shutdown mode */ 406 int conf = lm77_read_value(client, LM77_REG_CONF); 407 if (conf & 1) 408 lm77_write_value(client, LM77_REG_CONF, conf & 0xfe); 409 } 410 411 static struct lm77_data *lm77_update_device(struct device *dev) 412 { 413 struct i2c_client *client = to_i2c_client(dev); 414 struct lm77_data *data = i2c_get_clientdata(client); 415 416 mutex_lock(&data->update_lock); 417 418 if (time_after(jiffies, data->last_updated + HZ + HZ / 2) 419 || !data->valid) { 420 dev_dbg(&client->dev, "Starting lm77 update\n"); 421 data->temp_input = 422 LM77_TEMP_FROM_REG(lm77_read_value(client, 423 LM77_REG_TEMP)); 424 data->temp_hyst = 425 LM77_TEMP_FROM_REG(lm77_read_value(client, 426 LM77_REG_TEMP_HYST)); 427 data->temp_crit = 428 LM77_TEMP_FROM_REG(lm77_read_value(client, 429 LM77_REG_TEMP_CRIT)); 430 data->temp_min = 431 LM77_TEMP_FROM_REG(lm77_read_value(client, 432 LM77_REG_TEMP_MIN)); 433 data->temp_max = 434 LM77_TEMP_FROM_REG(lm77_read_value(client, 435 LM77_REG_TEMP_MAX)); 436 data->alarms = 437 lm77_read_value(client, LM77_REG_TEMP) & 0x0007; 438 data->last_updated = jiffies; 439 data->valid = 1; 440 } 441 442 mutex_unlock(&data->update_lock); 443 444 return data; 445 } 446 447 module_i2c_driver(lm77_driver); 448 449 MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>"); 450 MODULE_DESCRIPTION("LM77 driver"); 451 MODULE_LICENSE("GPL"); 452