LXR linux/drivers/hwmon/ds1621.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * ds1621.c - Part of lm_sensors, Linux kernel modules for hardware
   4 *            monitoring
   5 * Christian W. Zuckschwerdt  <zany@triq.net>  2000-11-23
   6 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
   7 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
   8 * the help of Jean Delvare <jdelvare@suse.de>
   9 *
  10 * The DS1621 device is a digital temperature/thermometer with 9-bit
  11 * resolution, a thermal alarm output (Tout), and user-defined minimum
  12 * and maximum temperature thresholds (TH and TL).
  13 *
  14 * The DS1625, DS1631, DS1721, and DS1731 are pin compatible with the DS1621
  15 * and similar in operation, with slight variations as noted in the device
  16 * datasheets (please refer to www.maximintegrated.com for specific
  17 * device information).
  18 *
  19 * Since the DS1621 was the first chipset supported by this driver,
  20 * most comments will refer to this chipset, but are actually general
  21 * and concern all supported chipsets, unless mentioned otherwise.
  22 */
  23
  24#include <linux/module.h>
  25#include <linux/init.h>
  26#include <linux/slab.h>
  27#include <linux/jiffies.h>
  28#include <linux/i2c.h>
  29#include <linux/hwmon.h>
  30#include <linux/hwmon-sysfs.h>
  31#include <linux/err.h>
  32#include <linux/mutex.h>
  33#include <linux/sysfs.h>
  34#include <linux/kernel.h>
  35
  36/* Supported devices */
  37enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
  38
  39/* Insmod parameters */
  40static int polarity = -1;
  41module_param(polarity, int, 0);
  42MODULE_PARM_DESC(polarity, "Output's polarity: 0 = active high, 1 = active low");
  43
  44/*
  45 * The Configuration/Status register
  46 *
  47 * - DS1621:
  48 *   7    6    5    4    3    2    1    0
  49 * |Done|THF |TLF |NVB | X  | X  |POL |1SHOT|
  50 *
  51 * - DS1625:
  52 *   7    6    5    4    3    2    1    0
  53 * |Done|THF |TLF |NVB | 1  | 0  |POL |1SHOT|
  54 *
  55 * - DS1631, DS1731:
  56 *   7    6    5    4    3    2    1    0
  57 * |Done|THF |TLF |NVB | R1 | R0 |POL |1SHOT|
  58 *
  59 * - DS1721:
  60 *   7    6    5    4    3    2    1    0
  61 * |Done| X  | X  | U  | R1 | R0 |POL |1SHOT|
  62 *
  63 * Where:
  64 * - 'X' is Reserved
  65 * - 'U' is Undefined
  66 */
  67#define DS1621_REG_CONFIG_NVB           0x10
  68#define DS1621_REG_CONFIG_RESOL         0x0C
  69#define DS1621_REG_CONFIG_POLARITY      0x02
  70#define DS1621_REG_CONFIG_1SHOT         0x01
  71#define DS1621_REG_CONFIG_DONE          0x80
  72
  73#define DS1621_REG_CONFIG_RESOL_SHIFT   2
  74
  75/* ds1721 conversion rates: {C/LSB, time(ms), resolution bit setting} */
  76static const unsigned short ds1721_convrates[] = {
  77        94,     /*  9-bits (0.5,  93.75, RES[0..1] = 0 */
  78        188,    /* 10-bits (0.25, 187.5, RES[0..1] = 1 */
  79        375,    /* 11-bits (0.125,  375, RES[0..1] = 2 */
  80        750,    /* 12-bits (0.0625, 750, RES[0..1] = 3 */
  81};
  82
  83#define DS1621_CONVERSION_MAX   750
  84#define DS1625_CONVERSION_MAX   500
  85
  86#define DS1621_TEMP_MAX 125000
  87#define DS1621_TEMP_MIN (-55000)
  88
  89/* The DS1621 temperature registers */
  90static const u8 DS1621_REG_TEMP[3] = {
  91        0xAA,           /* input, word, RO */
  92        0xA2,           /* min, word, RW */
  93        0xA1,           /* max, word, RW */
  94};
  95#define DS1621_REG_CONF                 0xAC /* byte, RW */
  96#define DS1621_COM_START                0xEE /* no data */
  97#define DS1721_COM_START                0x51 /* no data */
  98#define DS1621_COM_STOP                 0x22 /* no data */
  99
 100/* The DS1621 configuration register */
 101#define DS1621_ALARM_TEMP_HIGH          0x40
 102#define DS1621_ALARM_TEMP_LOW           0x20
 103
 104/* Conversions */
 105#define ALARMS_FROM_REG(val) ((val) & \
 106                        (DS1621_ALARM_TEMP_HIGH | DS1621_ALARM_TEMP_LOW))
 107
 108/* Each client has this additional data */
 109struct ds1621_data {
 110        struct i2c_client *client;
 111        struct mutex update_lock;
 112        char valid;                     /* !=0 if following fields are valid */
 113        unsigned long last_updated;     /* In jiffies */
 114        enum chips kind;                /* device type */
 115
 116        u16 temp[3];                    /* Register values, word */
 117        u8 conf;                        /* Register encoding, combined */
 118        u8 zbits;                       /* Resolution encoded as number of
 119                                         * zero bits */
 120        u16 update_interval;            /* Conversion rate in milliseconds */
 121};
 122
 123static inline int DS1621_TEMP_FROM_REG(u16 reg)
 124{
 125        return DIV_ROUND_CLOSEST(((s16)reg / 16) * 625, 10);
 126}
 127
 128/*
 129 * TEMP: 0.001C/bit (-55C to +125C)
 130 * REG:
 131 *  - 1621, 1625: 0.5C/bit, 7 zero-bits
 132 *  - 1631, 1721, 1731: 0.0625C/bit, 4 zero-bits
 133 */
 134static inline u16 DS1621_TEMP_TO_REG(long temp, u8 zbits)
 135{
 136        temp = clamp_val(temp, DS1621_TEMP_MIN, DS1621_TEMP_MAX);
 137        temp = DIV_ROUND_CLOSEST(temp * (1 << (8 - zbits)), 1000) << zbits;
 138        return temp;
 139}
 140
 141static void ds1621_init_client(struct ds1621_data *data,
 142                               struct i2c_client *client)
 143{
 144        u8 conf, new_conf, sreg, resol;
 145
 146        new_conf = conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 147        /* switch to continuous conversion mode */
 148        new_conf &= ~DS1621_REG_CONFIG_1SHOT;
 149
 150        /* setup output polarity */
 151        if (polarity == 0)
 152                new_conf &= ~DS1621_REG_CONFIG_POLARITY;
 153        else if (polarity == 1)
 154                new_conf |= DS1621_REG_CONFIG_POLARITY;
 155
 156        if (conf != new_conf)
 157                i2c_smbus_write_byte_data(client, DS1621_REG_CONF, new_conf);
 158
 159        switch (data->kind) {
 160        case ds1625:
 161                data->update_interval = DS1625_CONVERSION_MAX;
 162                data->zbits = 7;
 163                sreg = DS1621_COM_START;
 164                break;
 165        case ds1631:
 166        case ds1721:
 167        case ds1731:
 168                resol = (new_conf & DS1621_REG_CONFIG_RESOL) >>
 169                         DS1621_REG_CONFIG_RESOL_SHIFT;
 170                data->update_interval = ds1721_convrates[resol];
 171                data->zbits = 7 - resol;
 172                sreg = DS1721_COM_START;
 173                break;
 174        default:
 175                data->update_interval = DS1621_CONVERSION_MAX;
 176                data->zbits = 7;
 177                sreg = DS1621_COM_START;
 178                break;
 179        }
 180
 181        /* start conversion */
 182        i2c_smbus_write_byte(client, sreg);
 183}
 184
 185static struct ds1621_data *ds1621_update_client(struct device *dev)
 186{
 187        struct ds1621_data *data = dev_get_drvdata(dev);
 188        struct i2c_client *client = data->client;
 189        u8 new_conf;
 190
 191        mutex_lock(&data->update_lock);
 192
 193        if (time_after(jiffies, data->last_updated + data->update_interval) ||
 194            !data->valid) {
 195                int i;
 196
 197                dev_dbg(&client->dev, "Starting ds1621 update\n");
 198
 199                data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 200
 201                for (i = 0; i < ARRAY_SIZE(data->temp); i++)
 202                        data->temp[i] = i2c_smbus_read_word_swapped(client,
 203                                                         DS1621_REG_TEMP[i]);
 204
 205                /* reset alarms if necessary */
 206                new_conf = data->conf;
 207                if (data->temp[0] > data->temp[1])      /* input > min */
 208                        new_conf &= ~DS1621_ALARM_TEMP_LOW;
 209                if (data->temp[0] < data->temp[2])      /* input < max */
 210                        new_conf &= ~DS1621_ALARM_TEMP_HIGH;
 211                if (data->conf != new_conf)
 212                        i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
 213                                                  new_conf);
 214
 215                data->last_updated = jiffies;
 216                data->valid = 1;
 217        }
 218
 219        mutex_unlock(&data->update_lock);
 220
 221        return data;
 222}
 223
 224static ssize_t temp_show(struct device *dev, struct device_attribute *da,
 225                         char *buf)
 226{
 227        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 228        struct ds1621_data *data = ds1621_update_client(dev);
 229        return sprintf(buf, "%d\n",
 230                       DS1621_TEMP_FROM_REG(data->temp[attr->index]));
 231}
 232
 233static ssize_t temp_store(struct device *dev, struct device_attribute *da,
 234                          const char *buf, size_t count)
 235{
 236        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 237        struct ds1621_data *data = dev_get_drvdata(dev);
 238        long val;
 239        int err;
 240
 241        err = kstrtol(buf, 10, &val);
 242        if (err)
 243                return err;
 244
 245        mutex_lock(&data->update_lock);
 246        data->temp[attr->index] = DS1621_TEMP_TO_REG(val, data->zbits);
 247        i2c_smbus_write_word_swapped(data->client, DS1621_REG_TEMP[attr->index],
 248                                     data->temp[attr->index]);
 249        mutex_unlock(&data->update_lock);
 250        return count;
 251}
 252
 253static ssize_t alarms_show(struct device *dev, struct device_attribute *da,
 254                           char *buf)
 255{
 256        struct ds1621_data *data = ds1621_update_client(dev);
 257        return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->conf));
 258}
 259
 260static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
 261                          char *buf)
 262{
 263        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 264        struct ds1621_data *data = ds1621_update_client(dev);
 265        return sprintf(buf, "%d\n", !!(data->conf & attr->index));
 266}
 267
 268static ssize_t update_interval_show(struct device *dev,
 269                                    struct device_attribute *da, char *buf)
 270{
 271        struct ds1621_data *data = dev_get_drvdata(dev);
 272        return scnprintf(buf, PAGE_SIZE, "%hu\n", data->update_interval);
 273}
 274
 275static ssize_t update_interval_store(struct device *dev,
 276                                     struct device_attribute *da,
 277                                     const char *buf, size_t count)
 278{
 279        struct ds1621_data *data = dev_get_drvdata(dev);
 280        struct i2c_client *client = data->client;
 281        unsigned long convrate;
 282        s32 err;
 283        int resol = 0;
 284
 285        err = kstrtoul(buf, 10, &convrate);
 286        if (err)
 287                return err;
 288
 289        /* Convert rate into resolution bits */
 290        while (resol < (ARRAY_SIZE(ds1721_convrates) - 1) &&
 291               convrate > ds1721_convrates[resol])
 292                resol++;
 293
 294        mutex_lock(&data->update_lock);
 295        data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
 296        data->conf &= ~DS1621_REG_CONFIG_RESOL;
 297        data->conf |= (resol << DS1621_REG_CONFIG_RESOL_SHIFT);
 298        i2c_smbus_write_byte_data(client, DS1621_REG_CONF, data->conf);
 299        data->update_interval = ds1721_convrates[resol];
 300        data->zbits = 7 - resol;
 301        mutex_unlock(&data->update_lock);
 302
 303        return count;
 304}
 305
 306static DEVICE_ATTR_RO(alarms);
 307static DEVICE_ATTR_RW(update_interval);
 308
 309static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
 310static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
 311static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
 312static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS1621_ALARM_TEMP_LOW);
 313static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS1621_ALARM_TEMP_HIGH);
 314
 315static struct attribute *ds1621_attributes[] = {
 316        &sensor_dev_attr_temp1_input.dev_attr.attr,
 317        &sensor_dev_attr_temp1_min.dev_attr.attr,
 318        &sensor_dev_attr_temp1_max.dev_attr.attr,
 319        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 320        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 321        &dev_attr_alarms.attr,
 322        &dev_attr_update_interval.attr,
 323        NULL
 324};
 325
 326static umode_t ds1621_attribute_visible(struct kobject *kobj,
 327                                        struct attribute *attr, int index)
 328{
 329        struct device *dev = kobj_to_dev(kobj);
 330        struct ds1621_data *data = dev_get_drvdata(dev);
 331
 332        if (attr == &dev_attr_update_interval.attr)
 333                if (data->kind == ds1621 || data->kind == ds1625)
 334                        /* shhh, we're hiding update_interval */
 335                        return 0;
 336        return attr->mode;
 337}
 338
 339static const struct attribute_group ds1621_group = {
 340        .attrs = ds1621_attributes,
 341        .is_visible = ds1621_attribute_visible
 342};
 343__ATTRIBUTE_GROUPS(ds1621);
 344
 345static const struct i2c_device_id ds1621_id[];
 346
 347static int ds1621_probe(struct i2c_client *client)
 348{
 349        struct ds1621_data *data;
 350        struct device *hwmon_dev;
 351
 352        data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 353                            GFP_KERNEL);
 354        if (!data)
 355                return -ENOMEM;
 356
 357        mutex_init(&data->update_lock);
 358
 359        data->kind = i2c_match_id(ds1621_id, client)->driver_data;
 360        data->client = client;
 361
 362        /* Initialize the DS1621 chip */
 363        ds1621_init_client(data, client);
 364
 365        hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 366                                                           client->name, data,
 367                                                           ds1621_groups);
 368        return PTR_ERR_OR_ZERO(hwmon_dev);
 369}
 370
 371static const struct i2c_device_id ds1621_id[] = {
 372        { "ds1621", ds1621 },
 373        { "ds1625", ds1625 },
 374        { "ds1631", ds1631 },
 375        { "ds1721", ds1721 },
 376        { "ds1731", ds1731 },
 377        { }
 378};
 379MODULE_DEVICE_TABLE(i2c, ds1621_id);
 380
 381/* This is the driver that will be inserted */
 382static struct i2c_driver ds1621_driver = {
 383        .class          = I2C_CLASS_HWMON,
 384        .driver = {
 385                .name   = "ds1621",
 386        },
 387        .probe_new      = ds1621_probe,
 388        .id_table       = ds1621_id,
 389};
 390
 391module_i2c_driver(ds1621_driver);
 392
 393MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 394MODULE_DESCRIPTION("DS1621 driver");
 395MODULE_LICENSE("GPL");
 396