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 i2c_client *client;
 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 lm95245_data *data = dev_get_drvdata(dev);
 144         struct i2c_client *client = data->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                 for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
 153                         data->regs[i]
 154                           = i2c_smbus_read_byte_data(client,
 155                                                      lm95245_reg_address[i]);
 156                 data->last_updated = jiffies;
 157                 data->valid = 1;
 158         }
 159
 160         mutex_unlock(&data->update_lock);
 161
 162         return data;
 163 }
 164
 165 static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
 166 {
 167         int rate;
 168         unsigned long interval;
 169
 170         rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
 171
 172         switch (rate) {
 173         case RATE_CR0063:
 174                 interval = 63;
 175                 break;
 176         case RATE_CR0364:
 177                 interval = 364;
 178                 break;
 179         case RATE_CR1000:
 180                 interval = 1000;
 181                 break;
 182         case RATE_CR2500:
 183         default:
 184                 interval = 2500;
 185                 break;
 186         }
 187
 188         return interval;
 189 }
 190
 191 static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
 192                         unsigned long interval)
 193 {
 194         int rate;
 195
 196         if (interval <= 63) {
 197                 interval = 63;
 198                 rate = RATE_CR0063;
 199         } else if (interval <= 364) {
 200                 interval = 364;
 201                 rate = RATE_CR0364;
 202         } else if (interval <= 1000) {
 203                 interval = 1000;
 204                 rate = RATE_CR1000;
 205         } else {
 206                 interval = 2500;
 207                 rate = RATE_CR2500;
 208         }
 209
 210         i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
 211
 212         return interval;
 213 }
 214
 215 /* Sysfs stuff */
 216 static ssize_t show_input(struct device *dev, struct device_attribute *attr,
 217                           char *buf)
 218 {
 219         struct lm95245_data *data = lm95245_update_device(dev);
 220         int temp;
 221         int index = to_sensor_dev_attr(attr)->index;
 222
 223         /*
 224          * Index 0 (Local temp) is always signed
 225          * Index 2 (Remote temp) has both signed and unsigned data
 226          * use signed calculation for remote if signed bit is set
 227          */
 228         if (index == 0 || data->regs[index] & 0x80)
 229                 temp = temp_from_reg_signed(data->regs[index],
 230                             data->regs[index + 1]);
 231         else
 232                 temp = temp_from_reg_unsigned(data->regs[index + 2],
 233                             data->regs[index + 3]);
 234
 235         return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
 236 }
 237
 238 static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
 239                          char *buf)
 240 {
 241         struct lm95245_data *data = lm95245_update_device(dev);
 242         int index = to_sensor_dev_attr(attr)->index;
 243
 244         return snprintf(buf, PAGE_SIZE - 1, "%d\n",
 245                         data->regs[index] * 1000);
 246 }
 247
 248 static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
 249                         const char *buf, size_t count)
 250 {
 251         struct lm95245_data *data = dev_get_drvdata(dev);
 252         int index = to_sensor_dev_attr(attr)->index;
 253         struct i2c_client *client = data->client;
 254         unsigned long val;
 255
 256         if (kstrtoul(buf, 10, &val) < 0)
 257                 return -EINVAL;
 258
 259         val /= 1000;
 260
 261         val = clamp_val(val, 0, (index == 6 ? 127 : 255));
 262
 263         mutex_lock(&data->update_lock);
 264
 265         data->valid = 0;
 266
 267         i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
 268
 269         mutex_unlock(&data->update_lock);
 270
 271         return count;
 272 }
 273
 274 static ssize_t show_crit_hyst(struct device *dev, struct device_attribute *attr,
 275                         char *buf)
 276 {
 277         struct lm95245_data *data = lm95245_update_device(dev);
 278         int index = to_sensor_dev_attr(attr)->index;
 279         int hyst = data->regs[index] - data->regs[8];
 280
 281         return snprintf(buf, PAGE_SIZE - 1, "%d\n", hyst * 1000);
 282 }
 283
 284 static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
 285                         const char *buf, size_t count)
 286 {
 287         struct lm95245_data *data = dev_get_drvdata(dev);
 288         int index = to_sensor_dev_attr(attr)->index;
 289         struct i2c_client *client = data->client;
 290         unsigned long val;
 291         int hyst, limit;
 292
 293         if (kstrtoul(buf, 10, &val) < 0)
 294                 return -EINVAL;
 295
 296         mutex_lock(&data->update_lock);
 297
 298         limit = i2c_smbus_read_byte_data(client, lm95245_reg_address[index]);
 299         hyst = limit - val / 1000;
 300         hyst = clamp_val(hyst, 0, 31);
 301         data->regs[8] = hyst;
 302
 303         /* shared crit hysteresis */
 304         i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
 305                 hyst);
 306
 307         mutex_unlock(&data->update_lock);
 308
 309         return count;
 310 }
 311
 312 static ssize_t show_type(struct device *dev, struct device_attribute *attr,
 313                          char *buf)
 314 {
 315         struct lm95245_data *data = dev_get_drvdata(dev);
 316
 317         return snprintf(buf, PAGE_SIZE - 1,
 318                 data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
 319 }
 320
 321 static ssize_t set_type(struct device *dev, struct device_attribute *attr,
 322                         const char *buf, size_t count)
 323 {
 324         struct lm95245_data *data = dev_get_drvdata(dev);
 325         struct i2c_client *client = data->client;
 326         unsigned long val;
 327
 328         if (kstrtoul(buf, 10, &val) < 0)
 329                 return -EINVAL;
 330         if (val != 1 && val != 2)
 331                 return -EINVAL;
 332
 333         mutex_lock(&data->update_lock);
 334
 335         if (val == 1)
 336                 data->config2 |= CFG2_REMOTE_TT;
 337         else
 338                 data->config2 &= ~CFG2_REMOTE_TT;
 339
 340         data->valid = 0;
 341
 342         i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
 343                                   data->config2);
 344
 345         mutex_unlock(&data->update_lock);
 346
 347         return count;
 348 }
 349
 350 static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
 351                          char *buf)
 352 {
 353         struct lm95245_data *data = lm95245_update_device(dev);
 354         int index = to_sensor_dev_attr(attr)->index;
 355
 356         return snprintf(buf, PAGE_SIZE - 1, "%d\n",
 357                         !!(data->regs[9] & index));
 358 }
 359
 360 static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
 361                              char *buf)
 362 {
 363         struct lm95245_data *data = lm95245_update_device(dev);
 364
 365         return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
 366 }
 367
 368 static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
 369                             const char *buf, size_t count)
 370 {
 371         struct lm95245_data *data = dev_get_drvdata(dev);
 372         struct i2c_client *client = data->client;
 373         unsigned long val;
 374
 375         if (kstrtoul(buf, 10, &val) < 0)
 376                 return -EINVAL;
 377
 378         mutex_lock(&data->update_lock);
 379
 380         data->interval = lm95245_set_conversion_rate(client, val);
 381
 382         mutex_unlock(&data->update_lock);
 383
 384         return count;
 385 }
 386
 387 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
 388 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
 389                 set_limit, 6);
 390 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
 391                 set_crit_hyst, 6);
 392 static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
 393                 STATUS1_LOC);
 394
 395 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
 396 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
 397                 set_limit, 7);
 398 static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_crit_hyst, NULL, 7);
 399 static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
 400                 STATUS1_RTCRIT);
 401 static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
 402                 set_type, 0);
 403 static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
 404                 STATUS1_DIODE_FAULT);
 405
 406 static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
 407                 set_interval);
 408
 409 static struct attribute *lm95245_attrs[] = {
 410         &sensor_dev_attr_temp1_input.dev_attr.attr,
 411         &sensor_dev_attr_temp1_crit.dev_attr.attr,
 412         &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
 413         &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
 414         &sensor_dev_attr_temp2_input.dev_attr.attr,
 415         &sensor_dev_attr_temp2_crit.dev_attr.attr,
 416         &sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
 417         &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
 418         &sensor_dev_attr_temp2_type.dev_attr.attr,
 419         &sensor_dev_attr_temp2_fault.dev_attr.attr,
 420         &dev_attr_update_interval.attr,
 421         NULL
 422 };
 423 ATTRIBUTE_GROUPS(lm95245);
 424
 425 /* Return 0 if detection is successful, -ENODEV otherwise */
 426 static int lm95245_detect(struct i2c_client *new_client,
 427                           struct i2c_board_info *info)
 428 {
 429         struct i2c_adapter *adapter = new_client->adapter;
 430
 431         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 432                 return -ENODEV;
 433
 434         if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
 435                         != MANUFACTURER_ID
 436                 || i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
 437                         != DEFAULT_REVISION)
 438                 return -ENODEV;
 439
 440         strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
 441         return 0;
 442 }
 443
 444 static void lm95245_init_client(struct i2c_client *client,
 445                                 struct lm95245_data *data)
 446 {
 447         data->interval = lm95245_read_conversion_rate(client);
 448
 449         data->config1 = i2c_smbus_read_byte_data(client,
 450                 LM95245_REG_RW_CONFIG1);
 451         data->config2 = i2c_smbus_read_byte_data(client,
 452                 LM95245_REG_RW_CONFIG2);
 453
 454         if (data->config1 & CFG_STOP) {
 455                 /* Clear the standby bit */
 456                 data->config1 &= ~CFG_STOP;
 457                 i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
 458                         data->config1);
 459         }
 460 }
 461
 462 static int lm95245_probe(struct i2c_client *client,
 463                          const struct i2c_device_id *id)
 464 {
 465         struct device *dev = &client->dev;
 466         struct lm95245_data *data;
 467         struct device *hwmon_dev;
 468
 469         data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
 470         if (!data)
 471                 return -ENOMEM;
 472
 473         data->client = client;
 474         mutex_init(&data->update_lock);
 475
 476         /* Initialize the LM95245 chip */
 477         lm95245_init_client(client, data);
 478
 479         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 480                                                            data,
 481                                                            lm95245_groups);
 482         return PTR_ERR_OR_ZERO(hwmon_dev);
 483 }
 484
 485 /* Driver data (common to all clients) */
 486 static const struct i2c_device_id lm95245_id[] = {
 487         { DEVNAME, 0 },
 488         { }
 489 };
 490 MODULE_DEVICE_TABLE(i2c, lm95245_id);
 491
 492 static struct i2c_driver lm95245_driver = {
 493         .class          = I2C_CLASS_HWMON,
 494         .driver = {
 495                 .name   = DEVNAME,
 496         },
 497         .probe          = lm95245_probe,
 498         .id_table       = lm95245_id,
 499         .detect         = lm95245_detect,
 500         .address_list   = normal_i2c,
 501 };
 502
 503 module_i2c_driver(lm95245_driver);
 504
 505 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
 506 MODULE_DESCRIPTION("LM95245 sensor driver");
 507 MODULE_LICENSE("GPL");