drivers/hwmon/ds1621.c

   1 /*
   2  * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
   3  *            monitoring
   4  * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
   5  * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
   6  * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   7  * the help of Jean Delvare <jdelvare@suse.de>
   8  *
   9  * The DS1621 device is a digital temperature/thermometer with 9-bit
  10  * resolution, a thermal alarm output (Tout), and user-defined minimum
  11  * and maximum temperature thresholds (TH and TL).
  12  *
  13  * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
  14  * and similar in operation, with slight variations as noted in the device
  15  * datasheets (please refer to www.maximintegrated.com for specific
  16  * device information).
  17  *
  18  * Since the DS1621 was the first chipset supported by this driver,
  19  * most comments will refer to this chipset, but are actually general
  20  * and concern all supported chipsets, unless mentioned otherwise.
  21  *
  22  * This program is free software; you can redistribute it and/or modify
  23  * it under the terms of the GNU General Public License as published by
  24  * the Free Software Foundation; either version 2 of the License, or
  25  * (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with this program; if not, write to the Free Software
  34  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  35  */
  36
  37 #include <linux/module.h>
  38 #include <linux/init.h>
  39 #include <linux/slab.h>
  40 #include <linux/jiffies.h>
  41 #include <linux/i2c.h>
  42 #include <linux/hwmon.h>
  43 #include <linux/hwmon-sysfs.h>
  44 #include <linux/err.h>
  45 #include <linux/mutex.h>
  46 #include <linux/sysfs.h>
  47 #include <linux/kernel.h>
  48
  49 /* Supported devices */
  50 enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
  51
  52 /* Insmod parameters */
  53 static int polarity = -1;
  54 module_param(polarity, int, 0);
  55 MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  56
  57 /*
  58  * The Configuration/Status register
  59  *
  60  * - DS1621:
  61  *   7    6    5    4    3    2    1    0
  62  * |Done|THF |TLF |NVB | X  | X  |POL |1SHOT|
  63  *
  64  * - DS1625:
  65  *   7    6    5    4    3    2    1    0
  66  * |Done|THF |TLF |NVB | 1  | 0  |POL |1SHOT|
  67  *
  68  * - DS1631, DS1731:
  69  *   7    6    5    4    3    2    1    0
  70  * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
  71  *
  72  * - DS1721:
  73  *   7    6    5    4    3    2    1    0
  74  * |Done| X  | X  | U  | R1 | R0 |POL |1SHOT|
  75  *
  76  * Where:
  77  * - 'X' is Reserved
  78  * - 'U' is Undefined
  79  */
  80 #define DS1621_REG_CONFIG_NVB           0x10
  81 #define DS1621_REG_CONFIG_RESOL         0x0C
  82 #define DS1621_REG_CONFIG_POLARITY      0x02
  83 #define DS1621_REG_CONFIG_1SHOT         0x01
  84 #define DS1621_REG_CONFIG_DONE          0x80
  85
  86 #define DS1621_REG_CONFIG_RESOL_SHIFT   2
  87
  88 /* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
  89 static const unsigned short ds1721_convrates[] = {
  90         94,     /*  9-bits (0.5,  93.75, RES[0..1] = 0 */
  91         188,    /* 10-bits (0.25, 187.5, RES[0..1] = 1 */
  92         375,    /* 11-bits (0.125,  375, RES[0..1] = 2 */
  93         750,    /* 12-bits (0.0625, 750, RES[0..1] = 3 */
  94 };
  95
  96 #define DS1621_CONVERSION_MAX   750
  97 #define DS1625_CONVERSION_MAX   500
  98
  99 #define DS1621_TEMP_MAX 125000
 100 #define DS1621_TEMP_MIN (-55000)
 101
 102 /* The DS1621 temperature registers */
 103 static const u8 DS1621_REG_TEMP[3] = {
 104         0xAA,           /* input, word, RO */
 105         0xA2,           /* min, word, RW */
 106         0xA1,           /* max, word, RW */
 107 };
 108 #define DS1621_REG_CONF                 0xAC /* byte, RW */
 109 #define DS1621_COM_START                0xEE /* no data */
 110 #define DS1721_COM_START                0x51 /* no data */
 111 #define DS1621_COM_STOP                 0x22 /* no data */
 112
 113 /* The DS1621 configuration register */
 114 #define DS1621_ALARM_TEMP_HIGH          0x40
 115 #define DS1621_ALARM_TEMP_LOW           0x20
 116
 117 /* Conversions */
 118 #define ALARMS_FROM_REG(val) ((val) & \
 119                         (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
 120
 121 /* Each client has this additional data */
 122 struct ds1621_data {
 123         struct i2c_client *client;
 124         struct mutex update_lock;
 125         char valid;                     /* !=0 if following fields are valid */
 126         unsigned long last_updated;     /* In jiffies */
 127         enum chips kind;                /* device type */
 128
 129         u16 temp[3];                    /* Register values, word */
 130         u8 conf;                        /* Register encoding, combined */
 131         u8 zbits;                       /* Resolution encoded as number of
 132                                          * zero bits */
 133         u16 update_interval;            /* Conversion rate in milliseconds */
 134 };
 135
 136 static inline int DS1621_TEMP_FROM_REG(u16 reg)
 137 {
 138         return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
 139 }
 140
 141 /*
 142  * TEMP: 0.001C/bit (-55C to +125C)
 143  * REG:
 144  *  - 1621, 1625: 0.5C/bit, 7 zero-bits
 145  *  - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
 146  */
 147 static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
 148 {
 149         temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
 150         temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
 151         return temp;
 152 }
 153
 154 static void ds1621_init_client(struct ds1621_data *data,
 155                                struct i2c_client *client)
 156 {
 157         u8 conf, new_conf, sreg, resol;
 158
 159         new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 160         /* switch to continuous conversion mode */
 161         new_conf &= ~DS1621_REG_CONFIG_1SHOT;
 162
 163         /* setup output polarity */
 164         if (polarity == 0)
 165                 new_conf &= ~DS1621_REG_CONFIG_POLARITY;
 166         else if (polarity == 1)
 167                 new_conf |= DS1621_REG_CONFIG_POLARITY;
 168
 169         if (conf != new_conf)
 170                 i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
 171
 172         switch (data->kind) {
 173         case ds1625:
 174                 data->update_interval = DS1625_CONVERSION_MAX;
 175                 data->zbits = 7;
 176                 sreg = DS1621_COM_START;
 177                 break;
 178         case ds1631:
 179         case ds1721:
 180         case ds1731:
 181                 resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
 182                          DS1621_REG_CONFIG_RESOL_SHIFT;
 183                 data->update_interval = ds1721_convrates[resol];
 184                 data->zbits = 7 - resol;
 185                 sreg = DS1721_COM_START;
 186                 break;
 187         default:
 188                 data->update_interval = DS1621_CONVERSION_MAX;
 189                 data->zbits = 7;
 190                 sreg = DS1621_COM_START;
 191                 break;
 192         }
 193
 194         /* start conversion */
 195         i2c_smbus_write_byte(client, sreg);
 196 }
 197
 198 static struct ds1621_data *ds1621_update_client(struct device *dev)
 199 {
 200         struct ds1621_data *data = dev_get_drvdata(dev);
 201         struct i2c_client *client = data->client;
 202         u8 new_conf;
 203
 204         mutex_lock(&data->update_lock);
 205
 206         if (time_after(jiffies, data->last_updated + data->update_interval) ||
 207             !data->valid) {
 208                 int i;
 209
 210                 dev_dbg(&client->dev, "Starting ds1621 update\n");
 211
 212                 data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 213
 214                 for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 215                         data->temp[i] = i2c_smbus_read_word_swapped(client,
 216                                                          DS1621_REG_TEMP[i]);
 217
 218                 /* reset alarms if necessary */
 219                 new_conf = data->conf;
 220                 if (data->temp[0] > data->temp[1])      /* input > min */
 221                         new_conf &= ~DS1621_ALARM_TEMP_LOW;
 222                 if (data->temp[0] < data->temp[2])      /* input < max */
 223                         new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 224                 if (data->conf != new_conf)
 225                         i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
 226                                                   new_conf);
 227
 228                 data->last_updated = jiffies;
 229                 data->valid = 1;
 230         }
 231
 232         mutex_unlock(&data->update_lock);
 233
 234         return data;
 235 }
 236
 237 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 238                          char *buf)
 239 {
 240         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 241         struct ds1621_data *data = ds1621_update_client(dev);
 242         return sprintf(buf, "%d\n",
 243                        DS1621_TEMP_FROM_REG(data->temp[attr->index]));
 244 }
 245
 246 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 247                         const char *buf, size_t count)
 248 {
 249         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 250         struct ds1621_data *data = dev_get_drvdata(dev);
 251         long val;
 252         int err;
 253
 254         err = kstrtol(buf, 10, &val);
 255         if (err)
 256                 return err;
 257
 258         mutex_lock(&data->update_lock);
 259         data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
 260         i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
 261                                      data->temp[attr->index]);
 262         mutex_unlock(&data->update_lock);
 263         return count;
 264 }
 265
 266 static ssize_t alarms_show(struct device *dev, struct device_attribute *da,
 267                            char *buf)
 268 {
 269         struct ds1621_data *data = ds1621_update_client(dev);
 270         return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 271 }
 272
 273 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 274                           char *buf)
 275 {
 276         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 277         struct ds1621_data *data = ds1621_update_client(dev);
 278         return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 279 }
 280
 281 static ssize_t update_interval_show(struct device *dev,
 282                                     struct device_attribute *da, char *buf)
 283 {
 284         struct ds1621_data *data = dev_get_drvdata(dev);
 285         return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
 286 }
 287
 288 static ssize_t update_interval_store(struct device *dev,
 289                                      struct device_attribute *da,
 290                                      const char *buf, size_t count)
 291 {
 292         struct ds1621_data *data = dev_get_drvdata(dev);
 293         struct i2c_client *client = data->client;
 294         unsigned long convrate;
 295         s32 err;
 296         int resol = 0;
 297
 298         err = kstrtoul(buf, 10, &convrate);
 299         if (err)
 300                 return err;
 301
 302         /* Convert rate into resolution bits */
 303         while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
 304                convrate > ds1721_convrates[resol])
 305                 resol++;
 306
 307         mutex_lock(&data->update_lock);
 308         data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 309         data->conf &= ~DS1621_REG_CONFIG_RESOL;
 310         data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
 311         i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
 312         data->update_interval = ds1721_convrates[resol];
 313         data->zbits = 7 - resol;
 314         mutex_unlock(&data->update_lock);
 315
 316         return count;
 317 }
 318
 319 static DEVICE_ATTR_RO(alarms);
 320 static DEVICE_ATTR_RW(update_interval);
 321
 322 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 323 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 324 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 325 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 326                 DS1621_ALARM_TEMP_LOW);
 327 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 328                 DS1621_ALARM_TEMP_HIGH);
 329
 330 static struct attribute *ds1621_attributes[] = {
 331         &sensor_dev_attr_temp1_input.dev_attr.attr,
 332         &sensor_dev_attr_temp1_min.dev_attr.attr,
 333         &sensor_dev_attr_temp1_max.dev_attr.attr,
 334         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 335         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 336         &dev_attr_alarms.attr,
 337         &dev_attr_update_interval.attr,
 338         NULL
 339 };
 340
 341 static umode_t ds1621_attribute_visible(struct kobject *kobj,
 342                                         struct attribute *attr, int index)
 343 {
 344         struct device *dev = container_of(kobj, struct device, kobj);
 345         struct ds1621_data *data = dev_get_drvdata(dev);
 346
 347         if (attr == &dev_attr_update_interval.attr)
 348                 if (data->kind == ds1621 || data->kind == ds1625)
 349                         /* shhh, we're hiding update_interval */
 350                         return 0;
 351         return attr->mode;
 352 }
 353
 354 static const struct attribute_group ds1621_group = {
 355         .attrs = ds1621_attributes,
 356         .is_visible = ds1621_attribute_visible
 357 };
 358 __ATTRIBUTE_GROUPS(ds1621);
 359
 360 static int ds1621_probe(struct i2c_client *client,
 361                         const struct i2c_device_id *id)
 362 {
 363         struct ds1621_data *data;
 364         struct device *hwmon_dev;
 365
 366         data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 367                             GFP_KERNEL);
 368         if (!data)
 369                 return -ENOMEM;
 370
 371         mutex_init(&data->update_lock);
 372
 373         data->kind = id->driver_data;
 374         data->client = client;
 375
 376         /* Initialize the DS1621 chip */
 377         ds1621_init_client(data, client);
 378
 379         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 380                                                            client->name, data,
 381                                                            ds1621_groups);
 382         return PTR_ERR_OR_ZERO(hwmon_dev);
 383 }
 384
 385 static const struct i2c_device_id ds1621_id[] = {
 386         { "ds1621", ds1621 },
 387         { "ds1625", ds1625 },
 388         { "ds1631", ds1631 },
 389         { "ds1721", ds1721 },
 390         { "ds1731", ds1731 },
 391         { }
 392 };
 393 MODULE_DEVICE_TABLE(i2c, ds1621_id);
 394
 395 /* This is the driver that will be inserted */
 396 static struct i2c_driver ds1621_driver = {
 397         .class          = I2C_CLASS_HWMON,
 398         .driver = {
 399                 .name   = "ds1621",
 400         },
 401         .probe          = ds1621_probe,
 402         .id_table       = ds1621_id,
 403 };
 404
 405 module_i2c_driver(ds1621_driver);
 406
 407 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 408 MODULE_DESCRIPTION("DS1621 driver");
 409 MODULE_LICENSE("GPL");