drivers/hwmon/lm77.c

   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");