drivers/hwmon/tmp421.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* tmp421.c
   3  *
   4  * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
   5  * Preliminary support by:
   6  * Melvin Rook, Raymond Ng
   7  */
   8
   9 /*
  10  * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
  11  * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/jiffies.h>
  18 #include <linux/i2c.h>
  19 #include <linux/hwmon.h>
  20 #include <linux/hwmon-sysfs.h>
  21 #include <linux/err.h>
  22 #include <linux/mutex.h>
  23 #include <linux/of.h>
  24 #include <linux/sysfs.h>
  25
  26 /* Addresses to scan */
  27 static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  28                                              I2C_CLIENT_END };
  29
  30 enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };
  31
  32 #define MAX_CHANNELS                            4
  33 /* The TMP421 registers */
  34 #define TMP421_STATUS_REG                       0x08
  35 #define TMP421_CONFIG_REG_1                     0x09
  36 #define TMP421_CONFIG_REG_2                     0x0A
  37 #define TMP421_CONFIG_REG_REN(x)                (BIT(3 + (x)))
  38 #define TMP421_CONFIG_REG_REN_MASK              GENMASK(6, 3)
  39 #define TMP421_CONVERSION_RATE_REG              0x0B
  40 #define TMP421_N_FACTOR_REG_1                   0x21
  41 #define TMP421_MANUFACTURER_ID_REG              0xFE
  42 #define TMP421_DEVICE_ID_REG                    0xFF
  43
  44 static const u8 TMP421_TEMP_MSB[MAX_CHANNELS]   = { 0x00, 0x01, 0x02, 0x03 };
  45 static const u8 TMP421_TEMP_LSB[MAX_CHANNELS]   = { 0x10, 0x11, 0x12, 0x13 };
  46
  47 /* Flags */
  48 #define TMP421_CONFIG_SHUTDOWN                  0x40
  49 #define TMP421_CONFIG_RANGE                     0x04
  50
  51 /* Manufacturer / Device ID's */
  52 #define TMP421_MANUFACTURER_ID                  0x55
  53 #define TMP421_DEVICE_ID                        0x21
  54 #define TMP422_DEVICE_ID                        0x22
  55 #define TMP423_DEVICE_ID                        0x23
  56 #define TMP441_DEVICE_ID                        0x41
  57 #define TMP442_DEVICE_ID                        0x42
  58
  59 static const struct i2c_device_id tmp421_id[] = {
  60         { "tmp421", 2 },
  61         { "tmp422", 3 },
  62         { "tmp423", 4 },
  63         { "tmp441", 2 },
  64         { "tmp442", 3 },
  65         { }
  66 };
  67 MODULE_DEVICE_TABLE(i2c, tmp421_id);
  68
  69 static const struct of_device_id __maybe_unused tmp421_of_match[] = {
  70         {
  71                 .compatible = "ti,tmp421",
  72                 .data = (void *)2
  73         },
  74         {
  75                 .compatible = "ti,tmp422",
  76                 .data = (void *)3
  77         },
  78         {
  79                 .compatible = "ti,tmp423",
  80                 .data = (void *)4
  81         },
  82         {
  83                 .compatible = "ti,tmp441",
  84                 .data = (void *)2
  85         },
  86         {
  87                 .compatible = "ti,tmp442",
  88                 .data = (void *)3
  89         },
  90         { },
  91 };
  92 MODULE_DEVICE_TABLE(of, tmp421_of_match);
  93
  94 struct tmp421_channel {
  95         const char *label;
  96         bool enabled;
  97         s16 temp;
  98 };
  99
 100 struct tmp421_data {
 101         struct i2c_client *client;
 102         struct mutex update_lock;
 103         u32 temp_config[MAX_CHANNELS + 1];
 104         struct hwmon_channel_info temp_info;
 105         const struct hwmon_channel_info *info[2];
 106         struct hwmon_chip_info chip;
 107         bool valid;
 108         unsigned long last_updated;
 109         unsigned long channels;
 110         u8 config;
 111         struct tmp421_channel channel[MAX_CHANNELS];
 112 };
 113
 114 static int temp_from_raw(u16 reg, bool extended)
 115 {
 116         /* Mask out status bits */
 117         int temp = reg & ~0xf;
 118
 119         if (extended)
 120                 temp = temp - 64 * 256;
 121         else
 122                 temp = (s16)temp;
 123
 124         return DIV_ROUND_CLOSEST(temp * 1000, 256);
 125 }
 126
 127 static int tmp421_update_device(struct tmp421_data *data)
 128 {
 129         struct i2c_client *client = data->client;
 130         int ret = 0;
 131         int i;
 132
 133         mutex_lock(&data->update_lock);
 134
 135         if (time_after(jiffies, data->last_updated + (HZ / 2)) ||
 136             !data->valid) {
 137                 ret = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 138                 if (ret < 0)
 139                         goto exit;
 140                 data->config = ret;
 141
 142                 for (i = 0; i < data->channels; i++) {
 143                         ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_MSB[i]);
 144                         if (ret < 0)
 145                                 goto exit;
 146                         data->channel[i].temp = ret << 8;
 147
 148                         ret = i2c_smbus_read_byte_data(client, TMP421_TEMP_LSB[i]);
 149                         if (ret < 0)
 150                                 goto exit;
 151                         data->channel[i].temp |= ret;
 152                 }
 153                 data->last_updated = jiffies;
 154                 data->valid = true;
 155         }
 156
 157 exit:
 158         mutex_unlock(&data->update_lock);
 159
 160         if (ret < 0) {
 161                 data->valid = false;
 162                 return ret;
 163         }
 164
 165         return 0;
 166 }
 167
 168 static int tmp421_enable_channels(struct tmp421_data *data)
 169 {
 170         int err;
 171         struct i2c_client *client = data->client;
 172         struct device *dev = &client->dev;
 173         int old = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_2);
 174         int new, i;
 175
 176         if (old < 0) {
 177                 dev_err(dev, "error reading register, can't disable channels\n");
 178                 return old;
 179         }
 180
 181         new = old & ~TMP421_CONFIG_REG_REN_MASK;
 182         for (i = 0; i < data->channels; i++)
 183                 if (data->channel[i].enabled)
 184                         new |= TMP421_CONFIG_REG_REN(i);
 185
 186         if (new == old)
 187                 return 0;
 188
 189         err = i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_2, new);
 190         if (err < 0)
 191                 dev_err(dev, "error writing register, can't disable channels\n");
 192
 193         return err;
 194 }
 195
 196 static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
 197                        u32 attr, int channel, long *val)
 198 {
 199         struct tmp421_data *tmp421 = dev_get_drvdata(dev);
 200         int ret = 0;
 201
 202         ret = tmp421_update_device(tmp421);
 203         if (ret)
 204                 return ret;
 205
 206         switch (attr) {
 207         case hwmon_temp_input:
 208                 if (!tmp421->channel[channel].enabled)
 209                         return -ENODATA;
 210                 *val = temp_from_raw(tmp421->channel[channel].temp,
 211                                      tmp421->config & TMP421_CONFIG_RANGE);
 212                 return 0;
 213         case hwmon_temp_fault:
 214                 if (!tmp421->channel[channel].enabled)
 215                         return -ENODATA;
 216                 /*
 217                  * Any of OPEN or /PVLD bits indicate a hardware mulfunction
 218                  * and the conversion result may be incorrect
 219                  */
 220                 *val = !!(tmp421->channel[channel].temp & 0x03);
 221                 return 0;
 222         case hwmon_temp_enable:
 223                 *val = tmp421->channel[channel].enabled;
 224                 return 0;
 225         default:
 226                 return -EOPNOTSUPP;
 227         }
 228
 229 }
 230
 231 static int tmp421_read_string(struct device *dev, enum hwmon_sensor_types type,
 232                              u32 attr, int channel, const char **str)
 233 {
 234         struct tmp421_data *data = dev_get_drvdata(dev);
 235
 236         *str = data->channel[channel].label;
 237
 238         return 0;
 239 }
 240
 241 static int tmp421_write(struct device *dev, enum hwmon_sensor_types type,
 242                         u32 attr, int channel, long val)
 243 {
 244         struct tmp421_data *data = dev_get_drvdata(dev);
 245         int ret;
 246
 247         switch (attr) {
 248         case hwmon_temp_enable:
 249                 data->channel[channel].enabled = val;
 250                 ret = tmp421_enable_channels(data);
 251                 break;
 252         default:
 253             ret = -EOPNOTSUPP;
 254         }
 255
 256         return ret;
 257 }
 258
 259 static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
 260                                  u32 attr, int channel)
 261 {
 262         switch (attr) {
 263         case hwmon_temp_fault:
 264         case hwmon_temp_input:
 265                 return 0444;
 266         case hwmon_temp_label:
 267                 return 0444;
 268         case hwmon_temp_enable:
 269                 return 0644;
 270         default:
 271                 return 0;
 272         }
 273 }
 274
 275 static int tmp421_init_client(struct tmp421_data *data)
 276 {
 277         int config, config_orig;
 278         struct i2c_client *client = data->client;
 279
 280         /* Set the conversion rate to 2 Hz */
 281         i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
 282
 283         /* Start conversions (disable shutdown if necessary) */
 284         config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
 285         if (config < 0) {
 286                 dev_err(&client->dev,
 287                         "Could not read configuration register (%d)\n", config);
 288                 return config;
 289         }
 290
 291         config_orig = config;
 292         config &= ~TMP421_CONFIG_SHUTDOWN;
 293
 294         if (config != config_orig) {
 295                 dev_info(&client->dev, "Enable monitoring chip\n");
 296                 i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
 297         }
 298
 299         return tmp421_enable_channels(data);
 300 }
 301
 302 static int tmp421_detect(struct i2c_client *client,
 303                          struct i2c_board_info *info)
 304 {
 305         enum chips kind;
 306         struct i2c_adapter *adapter = client->adapter;
 307         static const char * const names[] = {
 308                 "TMP421", "TMP422", "TMP423",
 309                 "TMP441", "TMP442"
 310         };
 311         int addr = client->addr;
 312         u8 reg;
 313
 314         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
 315                 return -ENODEV;
 316
 317         reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
 318         if (reg != TMP421_MANUFACTURER_ID)
 319                 return -ENODEV;
 320
 321         reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
 322         if (reg & 0xf8)
 323                 return -ENODEV;
 324
 325         reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
 326         if (reg & 0x7f)
 327                 return -ENODEV;
 328
 329         reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
 330         switch (reg) {
 331         case TMP421_DEVICE_ID:
 332                 kind = tmp421;
 333                 break;
 334         case TMP422_DEVICE_ID:
 335                 if (addr == 0x2a)
 336                         return -ENODEV;
 337                 kind = tmp422;
 338                 break;
 339         case TMP423_DEVICE_ID:
 340                 if (addr != 0x4c && addr != 0x4d)
 341                         return -ENODEV;
 342                 kind = tmp423;
 343                 break;
 344         case TMP441_DEVICE_ID:
 345                 kind = tmp441;
 346                 break;
 347         case TMP442_DEVICE_ID:
 348                 if (addr != 0x4c && addr != 0x4d)
 349                         return -ENODEV;
 350                 kind = tmp442;
 351                 break;
 352         default:
 353                 return -ENODEV;
 354         }
 355
 356         strscpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);
 357         dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
 358                  names[kind], client->addr);
 359
 360         return 0;
 361 }
 362
 363 static int tmp421_probe_child_from_dt(struct i2c_client *client,
 364                                       struct device_node *child,
 365                                       struct tmp421_data *data)
 366
 367 {
 368         struct device *dev = &client->dev;
 369         u32 i;
 370         s32 val;
 371         int err;
 372
 373         err = of_property_read_u32(child, "reg", &i);
 374         if (err) {
 375                 dev_err(dev, "missing reg property of %pOFn\n", child);
 376                 return err;
 377         }
 378
 379         if (i >= data->channels) {
 380                 dev_err(dev, "invalid reg %d of %pOFn\n", i, child);
 381                 return -EINVAL;
 382         }
 383
 384         of_property_read_string(child, "label", &data->channel[i].label);
 385         if (data->channel[i].label)
 386                 data->temp_config[i] |= HWMON_T_LABEL;
 387
 388         data->channel[i].enabled = of_device_is_available(child);
 389
 390         err = of_property_read_s32(child, "ti,n-factor", &val);
 391         if (!err) {
 392                 if (i == 0) {
 393                         dev_err(dev, "n-factor can't be set for internal channel\n");
 394                         return -EINVAL;
 395                 }
 396
 397                 if (val > 127 || val < -128) {
 398                         dev_err(dev, "n-factor for channel %d invalid (%d)\n",
 399                                 i, val);
 400                         return -EINVAL;
 401                 }
 402                 i2c_smbus_write_byte_data(client, TMP421_N_FACTOR_REG_1 + i - 1,
 403                                           val);
 404         }
 405
 406         return 0;
 407 }
 408
 409 static int tmp421_probe_from_dt(struct i2c_client *client, struct tmp421_data *data)
 410 {
 411         struct device *dev = &client->dev;
 412         const struct device_node *np = dev->of_node;
 413         int err;
 414
 415         for_each_child_of_node_scoped(np, child) {
 416                 if (strcmp(child->name, "channel"))
 417                         continue;
 418
 419                 err = tmp421_probe_child_from_dt(client, child, data);
 420                 if (err)
 421                         return err;
 422         }
 423
 424         return 0;
 425 }
 426
 427 static const struct hwmon_ops tmp421_ops = {
 428         .is_visible = tmp421_is_visible,
 429         .read = tmp421_read,
 430         .read_string = tmp421_read_string,
 431         .write = tmp421_write,
 432 };
 433
 434 static int tmp421_probe(struct i2c_client *client)
 435 {
 436         struct device *dev = &client->dev;
 437         struct device *hwmon_dev;
 438         struct tmp421_data *data;
 439         int i, err;
 440
 441         data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);
 442         if (!data)
 443                 return -ENOMEM;
 444
 445         mutex_init(&data->update_lock);
 446         data->channels = (unsigned long)i2c_get_match_data(client);
 447         data->client = client;
 448
 449         for (i = 0; i < data->channels; i++) {
 450                 data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT | HWMON_T_ENABLE;
 451                 data->channel[i].enabled = true;
 452         }
 453
 454         err = tmp421_probe_from_dt(client, data);
 455         if (err)
 456                 return err;
 457
 458         err = tmp421_init_client(data);
 459         if (err)
 460                 return err;
 461
 462         data->chip.ops = &tmp421_ops;
 463         data->chip.info = data->info;
 464
 465         data->info[0] = &data->temp_info;
 466
 467         data->temp_info.type = hwmon_temp;
 468         data->temp_info.config = data->temp_config;
 469
 470         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 471                                                          data,
 472                                                          &data->chip,
 473                                                          NULL);
 474         return PTR_ERR_OR_ZERO(hwmon_dev);
 475 }
 476
 477 static struct i2c_driver tmp421_driver = {
 478         .class = I2C_CLASS_HWMON,
 479         .driver = {
 480                 .name   = "tmp421",
 481                 .of_match_table = of_match_ptr(tmp421_of_match),
 482         },
 483         .probe = tmp421_probe,
 484         .id_table = tmp421_id,
 485         .detect = tmp421_detect,
 486         .address_list = normal_i2c,
 487 };
 488
 489 module_i2c_driver(tmp421_driver);
 490
 491 MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
 492 MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");
 493 MODULE_LICENSE("GPL");