linux/drivers/hwmon/ds1621.c
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   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 <khali@linux-fr.org>
   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 */
  50enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
  51
  52/* Insmod parameters */
  53static int polarity = -1;
  54module_param(polarity, int, 0);
  55MODULE_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} */
  89static 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 */
 103static 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 */
 122struct ds1621_data {
 123        struct device *hwmon_dev;
 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
 136static 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 */
 147static 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
 154static void ds1621_init_client(struct i2c_client *client)
 155{
 156        u8 conf, new_conf, sreg, resol;
 157        struct ds1621_data *data = i2c_get_clientdata(client);
 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
 198static struct ds1621_data *ds1621_update_client(struct device *dev)
 199{
 200        struct i2c_client *client = to_i2c_client(dev);
 201        struct ds1621_data *data = i2c_get_clientdata(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
 237static 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
 246static 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 i2c_client *client = to_i2c_client(dev);
 251        struct ds1621_data *data = i2c_get_clientdata(client);
 252        long val;
 253        int err;
 254
 255        err = kstrtol(buf, 10, &val);
 256        if (err)
 257                return err;
 258
 259        mutex_lock(&data->update_lock);
 260        data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
 261        i2c_smbus_write_word_swapped(client, DS1621_REG_TEMP[attr->index],
 262                                     data->temp[attr->index]);
 263        mutex_unlock(&data->update_lock);
 264        return count;
 265}
 266
 267static ssize_t show_alarms(struct device *dev, struct device_attribute *da,
 268                           char *buf)
 269{
 270        struct ds1621_data *data = ds1621_update_client(dev);
 271        return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 272}
 273
 274static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 275                          char *buf)
 276{
 277        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 278        struct ds1621_data *data = ds1621_update_client(dev);
 279        return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 280}
 281
 282static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
 283                          char *buf)
 284{
 285        struct i2c_client *client = to_i2c_client(dev);
 286        struct ds1621_data *data = i2c_get_clientdata(client);
 287        return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
 288}
 289
 290static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
 291                            const char *buf, size_t count)
 292{
 293        struct i2c_client *client = to_i2c_client(dev);
 294        struct ds1621_data *data = i2c_get_clientdata(client);
 295        unsigned long convrate;
 296        s32 err;
 297        int resol = 0;
 298
 299        err = kstrtoul(buf, 10, &convrate);
 300        if (err)
 301                return err;
 302
 303        /* Convert rate into resolution bits */
 304        while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
 305               convrate > ds1721_convrates[resol])
 306                resol++;
 307
 308        mutex_lock(&data->update_lock);
 309        data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 310        data->conf &= ~DS1621_REG_CONFIG_RESOL;
 311        data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
 312        i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
 313        data->update_interval = ds1721_convrates[resol];
 314        mutex_unlock(&data->update_lock);
 315
 316        return count;
 317}
 318
 319static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 320static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_convrate,
 321                   set_convrate);
 322
 323static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 324static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 325static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 326static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 327                DS1621_ALARM_TEMP_LOW);
 328static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 329                DS1621_ALARM_TEMP_HIGH);
 330
 331static struct attribute *ds1621_attributes[] = {
 332        &sensor_dev_attr_temp1_input.dev_attr.attr,
 333        &sensor_dev_attr_temp1_min.dev_attr.attr,
 334        &sensor_dev_attr_temp1_max.dev_attr.attr,
 335        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 336        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 337        &dev_attr_alarms.attr,
 338        &dev_attr_update_interval.attr,
 339        NULL
 340};
 341
 342static umode_t ds1621_attribute_visible(struct kobject *kobj,
 343                                        struct attribute *attr, int index)
 344{
 345        struct device *dev = container_of(kobj, struct device, kobj);
 346        struct i2c_client *client = to_i2c_client(dev);
 347        struct ds1621_data *data = i2c_get_clientdata(client);
 348
 349        if (attr == &dev_attr_update_interval.attr)
 350                if (data->kind == ds1621 || data->kind == ds1625)
 351                        /* shhh, we're hiding update_interval */
 352                        return 0;
 353        return attr->mode;
 354}
 355
 356static const struct attribute_group ds1621_group = {
 357        .attrs = ds1621_attributes,
 358        .is_visible = ds1621_attribute_visible
 359};
 360
 361static int ds1621_probe(struct i2c_client *client,
 362                        const struct i2c_device_id *id)
 363{
 364        struct ds1621_data *data;
 365        int err;
 366
 367        data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 368                            GFP_KERNEL);
 369        if (!data)
 370                return -ENOMEM;
 371
 372        i2c_set_clientdata(client, data);
 373        mutex_init(&data->update_lock);
 374
 375        data->kind = id->driver_data;
 376
 377        /* Initialize the DS1621 chip */
 378        ds1621_init_client(client);
 379
 380        /* Register sysfs hooks */
 381        err = sysfs_create_group(&client->dev.kobj, &ds1621_group);
 382        if (err)
 383                return err;
 384
 385        data->hwmon_dev = hwmon_device_register(&client->dev);
 386        if (IS_ERR(data->hwmon_dev)) {
 387                err = PTR_ERR(data->hwmon_dev);
 388                goto exit_remove_files;
 389        }
 390
 391        return 0;
 392
 393 exit_remove_files:
 394        sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 395        return err;
 396}
 397
 398static int ds1621_remove(struct i2c_client *client)
 399{
 400        struct ds1621_data *data = i2c_get_clientdata(client);
 401
 402        hwmon_device_unregister(data->hwmon_dev);
 403        sysfs_remove_group(&client->dev.kobj, &ds1621_group);
 404
 405        return 0;
 406}
 407
 408static const struct i2c_device_id ds1621_id[] = {
 409        { "ds1621", ds1621 },
 410        { "ds1625", ds1625 },
 411        { "ds1631", ds1631 },
 412        { "ds1721", ds1721 },
 413        { "ds1731", ds1731 },
 414        { }
 415};
 416MODULE_DEVICE_TABLE(i2c, ds1621_id);
 417
 418/* This is the driver that will be inserted */
 419static struct i2c_driver ds1621_driver = {
 420        .class          = I2C_CLASS_HWMON,
 421        .driver = {
 422                .name   = "ds1621",
 423        },
 424        .probe          = ds1621_probe,
 425        .remove         = ds1621_remove,
 426        .id_table       = ds1621_id,
 427};
 428
 429module_i2c_driver(ds1621_driver);
 430
 431MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 432MODULE_DESCRIPTION("DS1621 driver");
 433MODULE_LICENSE("GPL");
 434
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