linux/drivers/hwmon/lm77.c
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   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 */
  39static 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 */
  51struct 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
  64static int lm77_probe(struct i2c_client *client,
  65                      const struct i2c_device_id *id);
  66static int lm77_detect(struct i2c_client *client, struct i2c_board_info *info);
  67static void lm77_init_client(struct i2c_client *client);
  68static int lm77_remove(struct i2c_client *client);
  69static u16 lm77_read_value(struct i2c_client *client, u8 reg);
  70static int lm77_write_value(struct i2c_client *client, u8 reg, u16 value);
  71
  72static struct lm77_data *lm77_update_device(struct device *dev);
  73
  74
  75static const struct i2c_device_id lm77_id[] = {
  76        { "lm77", 0 },
  77        { }
  78};
  79MODULE_DEVICE_TABLE(i2c, lm77_id);
  80
  81/* This is the driver that will be inserted */
  82static 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 */
 102static inline s16 LM77_TEMP_TO_REG(int temp)
 103{
 104        int ntemp = SENSORS_LIMIT(temp, LM77_TEMP_MIN, LM77_TEMP_MAX);
 105        return (ntemp / 500) * 8;
 106}
 107
 108static 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)     \
 117static 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
 125show(temp_input);
 126show(temp_crit);
 127show(temp_min);
 128show(temp_max);
 129
 130/* read routines for hysteresis values */
 131static 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}
 137static 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}
 143static 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) \
 152static 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
 169set(temp_min, LM77_REG_TEMP_MIN);
 170set(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 */
 176static 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 */
 198static 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
 223static 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
 231static DEVICE_ATTR(temp1_input, S_IRUGO,
 232                   show_temp_input, NULL);
 233static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
 234                   show_temp_crit, set_temp_crit);
 235static DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
 236                   show_temp_min, set_temp_min);
 237static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
 238                   show_temp_max, set_temp_max);
 239
 240static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO,
 241                   show_temp_crit_hyst, set_temp_crit_hyst);
 242static DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
 243                   show_temp_min_hyst, NULL);
 244static DEVICE_ATTR(temp1_max_hyst, S_IRUGO,
 245                   show_temp_max_hyst, NULL);
 246
 247static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
 248static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
 249static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
 250
 251static 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
 265static const struct attribute_group lm77_group = {
 266        .attrs = lm77_attributes,
 267};
 268
 269/* Return 0 if detection is successful, -ENODEV otherwise */
 270static 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
 340static 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
 370exit_remove:
 371        sysfs_remove_group(&dev->kobj, &lm77_group);
 372        return err;
 373}
 374
 375static 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 */
 387static 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
 395static 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
 403static 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
 411static 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
 447module_i2c_driver(lm77_driver);
 448
 449MODULE_AUTHOR("Andras BALI <drewie@freemail.hu>");
 450MODULE_DESCRIPTION("LM77 driver");
 451MODULE_LICENSE("GPL");
 452
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