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 */
  37 enum chips { ds1621, ds1625, ds1631, ds1721, ds1731 };
  38
  39 /* Insmod parameters */
  40 static int polarity = -1;
  41 module_param(polarity, int, 0);
  42 MODULE_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} */
  76 static 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 */
  90 static 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 */
 109 struct 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
 123 static 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  */
 134 static 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
 141 static 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
 185 static 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
 224 static 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
 233 static 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
 253 static 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
 260 static 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
 268 static 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
 275 static 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
 306 static DEVICE_ATTR_RO(alarms);
 307 static DEVICE_ATTR_RW(update_interval);
 308
 309 static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
 310 static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
 311 static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
 312 static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS1621_ALARM_TEMP_LOW);
 313 static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS1621_ALARM_TEMP_HIGH);
 314
 315 static 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
 326 static umode_t ds1621_attribute_visible(struct kobject *kobj,
 327                                         struct attribute *attr, int index)
 328 {
 329         struct device *dev = container_of(kobj, struct device, 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
 339 static const struct attribute_group ds1621_group = {
 340         .attrs = ds1621_attributes,
 341         .is_visible = ds1621_attribute_visible
 342 };
 343 __ATTRIBUTE_GROUPS(ds1621);
 344
 345 static int ds1621_probe(struct i2c_client *client,
 346                         const struct i2c_device_id *id)
 347 {
 348         struct ds1621_data *data;
 349         struct device *hwmon_dev;
 350
 351         data = devm_kzalloc(&client->dev, sizeof(struct ds1621_data),
 352                             GFP_KERNEL);
 353         if (!data)
 354                 return -ENOMEM;
 355
 356         mutex_init(&data->update_lock);
 357
 358         data->kind = id->driver_data;
 359         data->client = client;
 360
 361         /* Initialize the DS1621 chip */
 362         ds1621_init_client(data, client);
 363
 364         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 365                                                            client->name, data,
 366                                                            ds1621_groups);
 367         return PTR_ERR_OR_ZERO(hwmon_dev);
 368 }
 369
 370 static const struct i2c_device_id ds1621_id[] = {
 371         { "ds1621", ds1621 },
 372         { "ds1625", ds1625 },
 373         { "ds1631", ds1631 },
 374         { "ds1721", ds1721 },
 375         { "ds1731", ds1731 },
 376         { }
 377 };
 378 MODULE_DEVICE_TABLE(i2c, ds1621_id);
 379
 380 /* This is the driver that will be inserted */
 381 static struct i2c_driver ds1621_driver = {
 382         .class          = I2C_CLASS_HWMON,
 383         .driver = {
 384                 .name   = "ds1621",
 385         },
 386         .probe          = ds1621_probe,
 387         .id_table       = ds1621_id,
 388 };
 389
 390 module_i2c_driver(ds1621_driver);
 391
 392 MODULE_AUTHOR("Christian W. Zuckschwerdt <zany@triq.net>");
 393 MODULE_DESCRIPTION("DS1621 driver");
 394 MODULE_LICENSE("GPL");