linux/drivers/hwmon/lm95245.c
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   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
  39static 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
 103static 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) */
 117struct 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 */
 129static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
 130{
 131        return val_h * 1000 + val_l * 1000 / 256;
 132}
 133
 134static 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
 141static 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
 166static 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
 192static 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 */
 217static 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
 239static 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
 249static 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 = SENSORS_LIMIT(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
 275static 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 = SENSORS_LIMIT(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
 302static 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
 312static 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
 341static 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
 351static 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
 359static 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
 378static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
 379static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
 380                set_limit, 6);
 381static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
 382                set_crit_hyst, 8);
 383static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
 384                STATUS1_LOC);
 385
 386static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
 387static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
 388                set_limit, 7);
 389static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_limit,
 390                set_crit_hyst, 8);
 391static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
 392                STATUS1_RTCRIT);
 393static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
 394                set_type, 0);
 395static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
 396                STATUS1_DIODE_FAULT);
 397
 398static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
 399                set_interval);
 400
 401static 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
 416static const struct attribute_group lm95245_group = {
 417        .attrs = lm95245_attributes,
 418};
 419
 420/* Return 0 if detection is successful, -ENODEV otherwise */
 421static 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
 439static 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
 459static 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 = kzalloc(sizeof(struct lm95245_data), GFP_KERNEL);
 466        if (!data) {
 467                err = -ENOMEM;
 468                goto exit;
 469        }
 470
 471        i2c_set_clientdata(new_client, data);
 472        mutex_init(&data->update_lock);
 473
 474        /* Initialize the LM95245 chip */
 475        lm95245_init_client(new_client);
 476
 477        /* Register sysfs hooks */
 478        err = sysfs_create_group(&new_client->dev.kobj, &lm95245_group);
 479        if (err)
 480                goto exit_free;
 481
 482        data->hwmon_dev = hwmon_device_register(&new_client->dev);
 483        if (IS_ERR(data->hwmon_dev)) {
 484                err = PTR_ERR(data->hwmon_dev);
 485                goto exit_remove_files;
 486        }
 487
 488        return 0;
 489
 490exit_remove_files:
 491        sysfs_remove_group(&new_client->dev.kobj, &lm95245_group);
 492exit_free:
 493        kfree(data);
 494exit:
 495        return err;
 496}
 497
 498static int lm95245_remove(struct i2c_client *client)
 499{
 500        struct lm95245_data *data = i2c_get_clientdata(client);
 501
 502        hwmon_device_unregister(data->hwmon_dev);
 503        sysfs_remove_group(&client->dev.kobj, &lm95245_group);
 504
 505        kfree(data);
 506        return 0;
 507}
 508
 509/* Driver data (common to all clients) */
 510static const struct i2c_device_id lm95245_id[] = {
 511        { DEVNAME, 0 },
 512        { }
 513};
 514MODULE_DEVICE_TABLE(i2c, lm95245_id);
 515
 516static struct i2c_driver lm95245_driver = {
 517        .class          = I2C_CLASS_HWMON,
 518        .driver = {
 519                .name   = DEVNAME,
 520        },
 521        .probe          = lm95245_probe,
 522        .remove         = lm95245_remove,
 523        .id_table       = lm95245_id,
 524        .detect         = lm95245_detect,
 525        .address_list   = normal_i2c,
 526};
 527
 528module_i2c_driver(lm95245_driver);
 529
 530MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
 531MODULE_DESCRIPTION("LM95245 sensor driver");
 532MODULE_LICENSE("GPL");
 533
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