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 <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 */
  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 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
 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 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
 198static 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
 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 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
 266static ssize_t show_alarms(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
 273static 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
 281static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
 282                          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
 288static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
 289                            const char *buf, size_t count)
 290{
 291        struct ds1621_data *data = dev_get_drvdata(dev);
 292        struct i2c_client *client = data->client;
 293        unsigned long convrate;
 294        s32 err;
 295        int resol = 0;
 296
 297        err = kstrtoul(buf, 10, &convrate);
 298        if (err)
 299                return err;
 300
 301        /* Convert rate into resolution bits */
 302        while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
 303               convrate > ds1721_convrates[resol])
 304                resol++;
 305
 306        mutex_lock(&data->update_lock);
 307        data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 308        data->conf &= ~DS1621_REG_CONFIG_RESOL;
 309        data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
 310        i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
 311        data->update_interval = ds1721_convrates[resol];
 312        mutex_unlock(&data->update_lock);
 313
 314        return count;
 315}
 316
 317static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
 318static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_convrate,
 319                   set_convrate);
 320
 321static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 322static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 323static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 324static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 325                DS1621_ALARM_TEMP_LOW);
 326static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 327                DS1621_ALARM_TEMP_HIGH);
 328
 329static struct attribute *ds1621_attributes[] = {
 330        &sensor_dev_attr_temp1_input.dev_attr.attr,
 331        &sensor_dev_attr_temp1_min.dev_attr.attr,
 332        &sensor_dev_attr_temp1_max.dev_attr.attr,
 333        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 334        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 335        &dev_attr_alarms.attr,
 336        &dev_attr_update_interval.attr,
 337        NULL
 338};
 339
 340static umode_t ds1621_attribute_visible(struct kobject *kobj,
 341                                        struct attribute *attr, int index)
 342{
 343        struct device *dev = container_of(kobj, struct device, kobj);
 344        struct ds1621_data *data = dev_get_drvdata(dev);
 345
 346        if (attr == &dev_attr_update_interval.attr)
 347                if (data->kind == ds1621 || data->kind == ds1625)
 348                        /* shhh, we're hiding update_interval */
 349                        return 0;
 350        return attr->mode;
 351}
 352
 353static const struct attribute_group ds1621_group = {
 354        .attrs = ds1621_attributes,
 355        .is_visible = ds1621_attribute_visible
 356};
 357__ATTRIBUTE_GROUPS(ds1621);
 358
 359static int ds1621_probe(struct i2c_client *client,
 360                        const struct i2c_device_id *id)
 361{
 362        struct ds1621_data *data;
 363        struct device *hwmon_dev;
 364
 365        data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 366                            GFP_KERNEL);
 367        if (!data)
 368                return -ENOMEM;
 369
 370        mutex_init(&data->update_lock);
 371
 372        data->kind = id->driver_data;
 373        data->client = client;
 374
 375        /* Initialize the DS1621 chip */
 376        ds1621_init_client(data, client);
 377
 378        hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 379                                                           client->name, data,
 380                                                           ds1621_groups);
 381        return PTR_ERR_OR_ZERO(hwmon_dev);
 382}
 383
 384static const struct i2c_device_id ds1621_id[] = {
 385        { "ds1621", ds1621 },
 386        { "ds1625", ds1625 },
 387        { "ds1631", ds1631 },
 388        { "ds1721", ds1721 },
 389        { "ds1731", ds1731 },
 390        { }
 391};
 392MODULE_DEVICE_TABLE(i2c, ds1621_id);
 393
 394/* This is the driver that will be inserted */
 395static struct i2c_driver ds1621_driver = {
 396        .class          = I2C_CLASS_HWMON,
 397        .driver = {
 398                .name   = "ds1621",
 399        },
 400        .probe          = ds1621_probe,
 401        .id_table       = ds1621_id,
 402};
 403
 404module_i2c_driver(ds1621_driver);
 405
 406MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 407MODULE_DESCRIPTION("DS1621 driver");
 408MODULE_LICENSE("GPL");
 409