drivers/hwmon/lm95245.c

   1 /*
   2  * Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
   3  *
   4  * The LM95245 is a sensor chip made by National Semiconductors.
   5  * It reports up to two temperatures (its own plus an external one).
   6  * Complete datasheet can be obtained from National's website at:
   7  *   http://www.national.com/ds.cgi/LM/LM95245.pdf
   8  *
   9  * This driver is based on lm95241.c
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/slab.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/i2c.h>
  31 #include <linux/hwmon.h>
  32 #include <linux/hwmon-sysfs.h>
  33 #include <linux/err.h>
  34 #include <linux/mutex.h>
  35 #include <linux/sysfs.h>
  36
  37 #define DEVNAME "lm95245"
  38
  39 static const unsigned short normal_i2c[] = {
  40         0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };
  41
  42 /* LM95245 registers */
  43 /* general registers */
  44 #define LM95245_REG_RW_CONFIG1          0x03
  45 #define LM95245_REG_RW_CONVERS_RATE     0x04
  46 #define LM95245_REG_W_ONE_SHOT          0x0F
  47
  48 /* diode configuration */
  49 #define LM95245_REG_RW_CONFIG2          0xBF
  50 #define LM95245_REG_RW_REMOTE_OFFH      0x11
  51 #define LM95245_REG_RW_REMOTE_OFFL      0x12
  52
  53 /* status registers */
  54 #define LM95245_REG_R_STATUS1           0x02
  55 #define LM95245_REG_R_STATUS2           0x33
  56
  57 /* limit registers */
  58 #define LM95245_REG_RW_REMOTE_OS_LIMIT          0x07
  59 #define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT     0x20
  60 #define LM95245_REG_RW_REMOTE_TCRIT_LIMIT       0x19
  61 #define LM95245_REG_RW_COMMON_HYSTERESIS        0x21
  62
  63 /* temperature signed */
  64 #define LM95245_REG_R_LOCAL_TEMPH_S     0x00
  65 #define LM95245_REG_R_LOCAL_TEMPL_S     0x30
  66 #define LM95245_REG_R_REMOTE_TEMPH_S    0x01
  67 #define LM95245_REG_R_REMOTE_TEMPL_S    0x10
  68 /* temperature unsigned */
  69 #define LM95245_REG_R_REMOTE_TEMPH_U    0x31
  70 #define LM95245_REG_R_REMOTE_TEMPL_U    0x32
  71
  72 /* id registers */
  73 #define LM95245_REG_R_MAN_ID            0xFE
  74 #define LM95245_REG_R_CHIP_ID           0xFF
  75
  76 /* LM95245 specific bitfields */
  77 #define CFG_STOP                0x40
  78 #define CFG_REMOTE_TCRIT_MASK   0x10
  79 #define CFG_REMOTE_OS_MASK      0x08
  80 #define CFG_LOCAL_TCRIT_MASK    0x04
  81 #define CFG_LOCAL_OS_MASK       0x02
  82
  83 #define CFG2_OS_A0              0x40
  84 #define CFG2_DIODE_FAULT_OS     0x20
  85 #define CFG2_DIODE_FAULT_TCRIT  0x10
  86 #define CFG2_REMOTE_TT          0x08
  87 #define CFG2_REMOTE_FILTER_DIS  0x00
  88 #define CFG2_REMOTE_FILTER_EN   0x06
  89
  90 /* conversation rate in ms */
  91 #define RATE_CR0063     0x00
  92 #define RATE_CR0364     0x01
  93 #define RATE_CR1000     0x02
  94 #define RATE_CR2500     0x03
  95
  96 #define STATUS1_DIODE_FAULT     0x04
  97 #define STATUS1_RTCRIT          0x02
  98 #define STATUS1_LOC             0x01
  99
 100 #define MANUFACTURER_ID         0x01
 101 #define DEFAULT_REVISION        0xB3
 102
 103 static const u8 lm95245_reg_address[] = {
 104         LM95245_REG_R_LOCAL_TEMPH_S,
 105         LM95245_REG_R_LOCAL_TEMPL_S,
 106         LM95245_REG_R_REMOTE_TEMPH_S,
 107         LM95245_REG_R_REMOTE_TEMPL_S,
 108         LM95245_REG_R_REMOTE_TEMPH_U,
 109         LM95245_REG_R_REMOTE_TEMPL_U,
 110         LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
 111         LM95245_REG_RW_REMOTE_TCRIT_LIMIT,
 112         LM95245_REG_RW_COMMON_HYSTERESIS,
 113         LM95245_REG_R_STATUS1,
 114 };
 115
 116 /* Client data (each client gets its own) */
 117 struct lm95245_data {
 118         struct device *hwmon_dev;
 119         struct mutex update_lock;
 120         unsigned long last_updated;     /* in jiffies */
 121         unsigned long interval; /* in msecs */
 122         bool valid;             /* zero until following fields are valid */
 123         /* registers values */
 124         u8 regs[ARRAY_SIZE(lm95245_reg_address)];
 125         u8 config1, config2;
 126 };
 127
 128 /* Conversions */
 129 static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
 130 {
 131         return val_h * 1000 + val_l * 1000 / 256;
 132 }
 133
 134 static int temp_from_reg_signed(u8 val_h, u8 val_l)
 135 {
 136         if (val_h & 0x80)
 137                 return (val_h - 0x100) * 1000;
 138         return temp_from_reg_unsigned(val_h, val_l);
 139 }
 140
 141 static struct lm95245_data *lm95245_update_device(struct device *dev)
 142 {
 143         struct i2c_client *client = to_i2c_client(dev);
 144         struct lm95245_data *data = i2c_get_clientdata(client);
 145
 146         mutex_lock(&data->update_lock);
 147
 148         if (time_after(jiffies, data->last_updated
 149                 + msecs_to_jiffies(data->interval)) || !data->valid) {
 150                 int i;
 151
 152                 dev_dbg(&client->dev, "Updating lm95245 data.\n");
 153                 for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
 154                         data->regs[i]
 155                           = i2c_smbus_read_byte_data(client,
 156                                                      lm95245_reg_address[i]);
 157                 data->last_updated = jiffies;
 158                 data->valid = 1;
 159         }
 160
 161         mutex_unlock(&data->update_lock);
 162
 163         return data;
 164 }
 165
 166 static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
 167 {
 168         int rate;
 169         unsigned long interval;
 170
 171         rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
 172
 173         switch (rate) {
 174         case RATE_CR0063:
 175                 interval = 63;
 176                 break;
 177         case RATE_CR0364:
 178                 interval = 364;
 179                 break;
 180         case RATE_CR1000:
 181                 interval = 1000;
 182                 break;
 183         case RATE_CR2500:
 184         default:
 185                 interval = 2500;
 186                 break;
 187         }
 188
 189         return interval;
 190 }
 191
 192 static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
 193                         unsigned long interval)
 194 {
 195         int rate;
 196
 197         if (interval <= 63) {
 198                 interval = 63;
 199                 rate = RATE_CR0063;
 200         } else if (interval <= 364) {
 201                 interval = 364;
 202                 rate = RATE_CR0364;
 203         } else if (interval <= 1000) {
 204                 interval = 1000;
 205                 rate = RATE_CR1000;
 206         } else {
 207                 interval = 2500;
 208                 rate = RATE_CR2500;
 209         }
 210
 211         i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
 212
 213         return interval;
 214 }
 215
 216 /* Sysfs stuff */
 217 static ssize_t show_input(struct device *dev, struct device_attribute *attr,
 218                           char *buf)
 219 {
 220         struct lm95245_data *data = lm95245_update_device(dev);
 221         int temp;
 222         int index = to_sensor_dev_attr(attr)->index;
 223
 224         /*
 225          * Index 0 (Local temp) is always signed
 226          * Index 2 (Remote temp) has both signed and unsigned data
 227          * use signed calculation for remote if signed bit is set
 228          */
 229         if (index == 0 || data->regs[index] & 0x80)
 230                 temp = temp_from_reg_signed(data->regs[index],
 231                             data->regs[index + 1]);
 232         else
 233                 temp = temp_from_reg_unsigned(data->regs[index + 2],
 234                             data->regs[index + 3]);
 235
 236         return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
 237 }
 238
 239 static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
 240                          char *buf)
 241 {
 242         struct lm95245_data *data = lm95245_update_device(dev);
 243         int index = to_sensor_dev_attr(attr)->index;
 244
 245         return snprintf(buf, PAGE_SIZE - 1, "%d\n",
 246                         data->regs[index] * 1000);
 247 }
 248
 249 static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
 250                         const char *buf, size_t count)
 251 {
 252         struct i2c_client *client = to_i2c_client(dev);
 253         struct lm95245_data *data = i2c_get_clientdata(client);
 254         int index = to_sensor_dev_attr(attr)->index;
 255         unsigned long val;
 256
 257         if (kstrtoul(buf, 10, &val) < 0)
 258                 return -EINVAL;
 259
 260         val /= 1000;
 261
 262         val = clamp_val(val, 0, (index == 6 ? 127 : 255));
 263
 264         mutex_lock(&data->update_lock);
 265
 266         data->valid = 0;
 267
 268         i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
 269
 270         mutex_unlock(&data->update_lock);
 271
 272         return count;
 273 }
 274
 275 static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
 276                         const char *buf, size_t count)
 277 {
 278         struct i2c_client *client = to_i2c_client(dev);
 279         struct lm95245_data *data = i2c_get_clientdata(client);
 280         unsigned long val;
 281
 282         if (kstrtoul(buf, 10, &val) < 0)
 283                 return -EINVAL;
 284
 285         val /= 1000;
 286
 287         val = clamp_val(val, 0, 31);
 288
 289         mutex_lock(&data->update_lock);
 290
 291         data->valid = 0;
 292
 293         /* shared crit hysteresis */
 294         i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
 295                 val);
 296
 297         mutex_unlock(&data->update_lock);
 298
 299         return count;
 300 }
 301
 302 static ssize_t show_type(struct device *dev, struct device_attribute *attr,
 303                          char *buf)
 304 {
 305         struct i2c_client *client = to_i2c_client(dev);
 306         struct lm95245_data *data = i2c_get_clientdata(client);
 307
 308         return snprintf(buf, PAGE_SIZE - 1,
 309                 data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
 310 }
 311
 312 static ssize_t set_type(struct device *dev, struct device_attribute *attr,
 313                         const char *buf, size_t count)
 314 {
 315         struct i2c_client *client = to_i2c_client(dev);
 316         struct lm95245_data *data = i2c_get_clientdata(client);
 317         unsigned long val;
 318
 319         if (kstrtoul(buf, 10, &val) < 0)
 320                 return -EINVAL;
 321         if (val != 1 && val != 2)
 322                 return -EINVAL;
 323
 324         mutex_lock(&data->update_lock);
 325
 326         if (val == 1)
 327                 data->config2 |= CFG2_REMOTE_TT;
 328         else
 329                 data->config2 &= ~CFG2_REMOTE_TT;
 330
 331         data->valid = 0;
 332
 333         i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
 334                                   data->config2);
 335
 336         mutex_unlock(&data->update_lock);
 337
 338         return count;
 339 }
 340
 341 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 342                          char *buf)
 343 {
 344         struct lm95245_data *data = lm95245_update_device(dev);
 345         int index = to_sensor_dev_attr(attr)->index;
 346
 347         return snprintf(buf, PAGE_SIZE - 1, "%d\n",
 348                         !!(data->regs[9] & index));
 349 }
 350
 351 static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
 352                              char *buf)
 353 {
 354         struct lm95245_data *data = lm95245_update_device(dev);
 355
 356         return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
 357 }
 358
 359 static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
 360                             const char *buf, size_t count)
 361 {
 362         struct i2c_client *client = to_i2c_client(dev);
 363         struct lm95245_data *data = i2c_get_clientdata(client);
 364         unsigned long val;
 365
 366         if (kstrtoul(buf, 10, &val) < 0)
 367                 return -EINVAL;
 368
 369         mutex_lock(&data->update_lock);
 370
 371         data->interval = lm95245_set_conversion_rate(client, val);
 372
 373         mutex_unlock(&data->update_lock);
 374
 375         return count;
 376 }
 377
 378 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
 379 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
 380                 set_limit, 6);
 381 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
 382                 set_crit_hyst, 8);
 383 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
 384                 STATUS1_LOC);
 385
 386 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
 387 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
 388                 set_limit, 7);
 389 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
 390                 set_crit_hyst, 8);
 391 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
 392                 STATUS1_RTCRIT);
 393 static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
 394                 set_type, 0);
 395 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
 396                 STATUS1_DIODE_FAULT);
 397
 398 static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
 399                 set_interval);
 400
 401 static struct attribute *lm95245_attributes[] = {
 402         &sensor_dev_attr_temp1_input.dev_attr.attr,
 403         &sensor_dev_attr_temp1_crit.dev_attr.attr,
 404         &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
 405         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 406         &sensor_dev_attr_temp2_input.dev_attr.attr,
 407         &sensor_dev_attr_temp2_crit.dev_attr.attr,
 408         &sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
 409         &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
 410         &sensor_dev_attr_temp2_type.dev_attr.attr,
 411         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 412         &dev_attr_update_interval.attr,
 413         NULL
 414 };
 415
 416 static const struct attribute_group lm95245_group = {
 417         .attrs = lm95245_attributes,
 418 };
 419
 420 /* Return 0 if detection is successful, -ENODEV otherwise */
 421 static int lm95245_detect(struct i2c_client *new_client,
 422                           struct i2c_board_info *info)
 423 {
 424         struct i2c_adapter *adapter = new_client->adapter;
 425
 426         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 427                 return -ENODEV;
 428
 429         if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
 430                         != MANUFACTURER_ID
 431                 || i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
 432                         != DEFAULT_REVISION)
 433                 return -ENODEV;
 434
 435         strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
 436         return 0;
 437 }
 438
 439 static void lm95245_init_client(struct i2c_client *client)
 440 {
 441         struct lm95245_data *data = i2c_get_clientdata(client);
 442
 443         data->valid = 0;
 444         data->interval = lm95245_read_conversion_rate(client);
 445
 446         data->config1 = i2c_smbus_read_byte_data(client,
 447                 LM95245_REG_RW_CONFIG1);
 448         data->config2 = i2c_smbus_read_byte_data(client,
 449                 LM95245_REG_RW_CONFIG2);
 450
 451         if (data->config1 & CFG_STOP) {
 452                 /* Clear the standby bit */
 453                 data->config1 &= ~CFG_STOP;
 454                 i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
 455                         data->config1);
 456         }
 457 }
 458
 459 static int lm95245_probe(struct i2c_client *new_client,
 460                          const struct i2c_device_id *id)
 461 {
 462         struct lm95245_data *data;
 463         int err;
 464
 465         data = devm_kzalloc(&new_client->dev, sizeof(struct lm95245_data),
 466                             GFP_KERNEL);
 467         if (!data)
 468                 return -ENOMEM;
 469
 470         i2c_set_clientdata(new_client, data);
 471         mutex_init(&data->update_lock);
 472
 473         /* Initialize the LM95245 chip */
 474         lm95245_init_client(new_client);
 475
 476         /* Register sysfs hooks */
 477         err = sysfs_create_group(&new_client->dev.kobj, &lm95245_group);
 478         if (err)
 479                 return err;
 480
 481         data->hwmon_dev = hwmon_device_register(&new_client->dev);
 482         if (IS_ERR(data->hwmon_dev)) {
 483                 err = PTR_ERR(data->hwmon_dev);
 484                 goto exit_remove_files;
 485         }
 486
 487         return 0;
 488
 489 exit_remove_files:
 490         sysfs_remove_group(&new_client->dev.kobj, &lm95245_group);
 491         return err;
 492 }
 493
 494 static int lm95245_remove(struct i2c_client *client)
 495 {
 496         struct lm95245_data *data = i2c_get_clientdata(client);
 497
 498         hwmon_device_unregister(data->hwmon_dev);
 499         sysfs_remove_group(&client->dev.kobj, &lm95245_group);
 500
 501         return 0;
 502 }
 503
 504 /* Driver data (common to all clients) */
 505 static const struct i2c_device_id lm95245_id[] = {
 506         { DEVNAME, 0 },
 507         { }
 508 };
 509 MODULE_DEVICE_TABLE(i2c, lm95245_id);
 510
 511 static struct i2c_driver lm95245_driver = {
 512         .class          = I2C_CLASS_HWMON,
 513         .driver = {
 514                 .name   = DEVNAME,
 515         },
 516         .probe          = lm95245_probe,
 517         .remove         = lm95245_remove,
 518         .id_table       = lm95245_id,
 519         .detect         = lm95245_detect,
 520         .address_list   = normal_i2c,
 521 };
 522
 523 module_i2c_driver(lm95245_driver);
 524
 525 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
 526 MODULE_DESCRIPTION("LM95245 sensor driver");
 527 MODULE_LICENSE("GPL");