drivers/hwmon/ina238.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Texas Instruments INA238 power monitor chip
   4  * Datasheet: https://www.ti.com/product/ina238
   5  *
   6  * Copyright (C) 2021 Nathan Rossi <nathan.rossi@digi.com>
   7  */
   8
   9 #include <linux/err.h>
  10 #include <linux/hwmon.h>
  11 #include <linux/i2c.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/regmap.h>
  17
  18 #include <linux/platform_data/ina2xx.h>
  19
  20 /* INA238 register definitions */
  21 #define INA238_CONFIG                   0x0
  22 #define INA238_ADC_CONFIG               0x1
  23 #define INA238_SHUNT_CALIBRATION        0x2
  24 #define INA238_SHUNT_VOLTAGE            0x4
  25 #define INA238_BUS_VOLTAGE              0x5
  26 #define INA238_DIE_TEMP                 0x6
  27 #define INA238_CURRENT                  0x7
  28 #define INA238_POWER                    0x8
  29 #define INA238_DIAG_ALERT               0xb
  30 #define INA238_SHUNT_OVER_VOLTAGE       0xc
  31 #define INA238_SHUNT_UNDER_VOLTAGE      0xd
  32 #define INA238_BUS_OVER_VOLTAGE         0xe
  33 #define INA238_BUS_UNDER_VOLTAGE        0xf
  34 #define INA238_TEMP_LIMIT               0x10
  35 #define INA238_POWER_LIMIT              0x11
  36 #define INA238_DEVICE_ID                0x3f /* not available on INA237 */
  37
  38 #define INA238_CONFIG_ADCRANGE          BIT(4)
  39
  40 #define INA238_DIAG_ALERT_TMPOL         BIT(7)
  41 #define INA238_DIAG_ALERT_SHNTOL        BIT(6)
  42 #define INA238_DIAG_ALERT_SHNTUL        BIT(5)
  43 #define INA238_DIAG_ALERT_BUSOL         BIT(4)
  44 #define INA238_DIAG_ALERT_BUSUL         BIT(3)
  45 #define INA238_DIAG_ALERT_POL           BIT(2)
  46
  47 #define INA238_REGISTERS                0x11
  48
  49 #define INA238_RSHUNT_DEFAULT           10000 /* uOhm */
  50
  51 /* Default configuration of device on reset. */
  52 #define INA238_CONFIG_DEFAULT           0
  53 /* 16 sample averaging, 1052us conversion time, continuous mode */
  54 #define INA238_ADC_CONFIG_DEFAULT       0xfb6a
  55 /* Configure alerts to be based on averaged value (SLOWALERT) */
  56 #define INA238_DIAG_ALERT_DEFAULT       0x2000
  57 /*
  58  * This driver uses a fixed calibration value in order to scale current/power
  59  * based on a fixed shunt resistor value. This allows for conversion within the
  60  * device to avoid integer limits whilst current/power accuracy is scaled
  61  * relative to the shunt resistor value within the driver. This is similar to
  62  * how the ina2xx driver handles current/power scaling.
  63  *
  64  * The end result of this is that increasing shunt values (from a fixed 20 mOhm
  65  * shunt) increase the effective current/power accuracy whilst limiting the
  66  * range and decreasing shunt values decrease the effective accuracy but
  67  * increase the range.
  68  *
  69  * The value of the Current register is calculated given the following:
  70  *   Current (A) = (shunt voltage register * 5) * calibration / 81920
  71  *
  72  * The maximum shunt voltage is 163.835 mV (0x7fff, ADC_RANGE = 0, gain = 4).
  73  * With the maximum current value of 0x7fff and a fixed shunt value results in
  74  * a calibration value of 16384 (0x4000).
  75  *
  76  *   0x7fff = (0x7fff * 5) * calibration / 81920
  77  *   calibration = 0x4000
  78  *
  79  * Equivalent calibration is applied for the Power register (maximum value for
  80  * bus voltage is 102396.875 mV, 0x7fff), where the maximum power that can
  81  * occur is ~16776192 uW (register value 0x147a8):
  82  *
  83  * This scaling means the resulting values for Current and Power registers need
  84  * to be scaled by the difference between the fixed shunt resistor and the
  85  * actual shunt resistor:
  86  *
  87  *  shunt = 0x4000 / (819.2 * 10^6) / 0.001 = 20000 uOhms (with 1mA/lsb)
  88  *
  89  *  Current (mA) = register value * 20000 / rshunt / 4 * gain
  90  *  Power (W) = 0.2 * register value * 20000 / rshunt / 4 * gain
  91  */
  92 #define INA238_CALIBRATION_VALUE        16384
  93 #define INA238_FIXED_SHUNT              20000
  94
  95 #define INA238_SHUNT_VOLTAGE_LSB        5 /* 5 uV/lsb */
  96 #define INA238_BUS_VOLTAGE_LSB          3125 /* 3.125 mV/lsb */
  97 #define INA238_DIE_TEMP_LSB             125 /* 125 mC/lsb */
  98
  99 static const struct regmap_config ina238_regmap_config = {
 100         .max_register = INA238_REGISTERS,
 101         .reg_bits = 8,
 102         .val_bits = 16,
 103 };
 104
 105 struct ina238_data {
 106         struct i2c_client *client;
 107         struct mutex config_lock;
 108         struct regmap *regmap;
 109         u32 rshunt;
 110         int gain;
 111 };
 112
 113 static int ina238_read_reg24(const struct i2c_client *client, u8 reg, u32 *val)
 114 {
 115         u8 data[3];
 116         int err;
 117
 118         /* 24-bit register read */
 119         err = i2c_smbus_read_i2c_block_data(client, reg, 3, data);
 120         if (err < 0)
 121                 return err;
 122         if (err != 3)
 123                 return -EIO;
 124         *val = (data[0] << 16) | (data[1] << 8) | data[2];
 125
 126         return 0;
 127 }
 128
 129 static int ina238_read_in(struct device *dev, u32 attr, int channel,
 130                           long *val)
 131 {
 132         struct ina238_data *data = dev_get_drvdata(dev);
 133         int reg, mask;
 134         int regval;
 135         int err;
 136
 137         switch (channel) {
 138         case 0:
 139                 switch (attr) {
 140                 case hwmon_in_input:
 141                         reg = INA238_SHUNT_VOLTAGE;
 142                         break;
 143                 case hwmon_in_max:
 144                         reg = INA238_SHUNT_OVER_VOLTAGE;
 145                         break;
 146                 case hwmon_in_min:
 147                         reg = INA238_SHUNT_UNDER_VOLTAGE;
 148                         break;
 149                 case hwmon_in_max_alarm:
 150                         reg = INA238_DIAG_ALERT;
 151                         mask = INA238_DIAG_ALERT_SHNTOL;
 152                         break;
 153                 case hwmon_in_min_alarm:
 154                         reg = INA238_DIAG_ALERT;
 155                         mask = INA238_DIAG_ALERT_SHNTUL;
 156                         break;
 157                 default:
 158                         return -EOPNOTSUPP;
 159                 }
 160                 break;
 161         case 1:
 162                 switch (attr) {
 163                 case hwmon_in_input:
 164                         reg = INA238_BUS_VOLTAGE;
 165                         break;
 166                 case hwmon_in_max:
 167                         reg = INA238_BUS_OVER_VOLTAGE;
 168                         break;
 169                 case hwmon_in_min:
 170                         reg = INA238_BUS_UNDER_VOLTAGE;
 171                         break;
 172                 case hwmon_in_max_alarm:
 173                         reg = INA238_DIAG_ALERT;
 174                         mask = INA238_DIAG_ALERT_BUSOL;
 175                         break;
 176                 case hwmon_in_min_alarm:
 177                         reg = INA238_DIAG_ALERT;
 178                         mask = INA238_DIAG_ALERT_BUSUL;
 179                         break;
 180                 default:
 181                         return -EOPNOTSUPP;
 182                 }
 183                 break;
 184         default:
 185                 return -EOPNOTSUPP;
 186         }
 187
 188         err = regmap_read(data->regmap, reg, &regval);
 189         if (err < 0)
 190                 return err;
 191
 192         switch (attr) {
 193         case hwmon_in_input:
 194         case hwmon_in_max:
 195         case hwmon_in_min:
 196                 /* signed register, value in mV */
 197                 regval = (s16)regval;
 198                 if (channel == 0)
 199                         /* gain of 1 -> LSB / 4 */
 200                         *val = (regval * INA238_SHUNT_VOLTAGE_LSB) /
 201                                (1000 * (4 - data->gain + 1));
 202                 else
 203                         *val = (regval * INA238_BUS_VOLTAGE_LSB) / 1000;
 204                 break;
 205         case hwmon_in_max_alarm:
 206         case hwmon_in_min_alarm:
 207                 *val = !!(regval & mask);
 208                 break;
 209         }
 210
 211         return 0;
 212 }
 213
 214 static int ina238_write_in(struct device *dev, u32 attr, int channel,
 215                            long val)
 216 {
 217         struct ina238_data *data = dev_get_drvdata(dev);
 218         int regval;
 219
 220         if (attr != hwmon_in_max && attr != hwmon_in_min)
 221                 return -EOPNOTSUPP;
 222
 223         /* convert decimal to register value */
 224         switch (channel) {
 225         case 0:
 226                 /* signed value, clamp to max range +/-163 mV */
 227                 regval = clamp_val(val, -163, 163);
 228                 regval = (regval * 1000 * (4 - data->gain + 1)) /
 229                          INA238_SHUNT_VOLTAGE_LSB;
 230                 regval = clamp_val(regval, S16_MIN, S16_MAX);
 231
 232                 switch (attr) {
 233                 case hwmon_in_max:
 234                         return regmap_write(data->regmap,
 235                                             INA238_SHUNT_OVER_VOLTAGE, regval);
 236                 case hwmon_in_min:
 237                         return regmap_write(data->regmap,
 238                                             INA238_SHUNT_UNDER_VOLTAGE, regval);
 239                 default:
 240                         return -EOPNOTSUPP;
 241                 }
 242         case 1:
 243                 /* signed value, positive values only. Clamp to max 102.396 V */
 244                 regval = clamp_val(val, 0, 102396);
 245                 regval = (regval * 1000) / INA238_BUS_VOLTAGE_LSB;
 246                 regval = clamp_val(regval, 0, S16_MAX);
 247
 248                 switch (attr) {
 249                 case hwmon_in_max:
 250                         return regmap_write(data->regmap,
 251                                             INA238_BUS_OVER_VOLTAGE, regval);
 252                 case hwmon_in_min:
 253                         return regmap_write(data->regmap,
 254                                             INA238_BUS_UNDER_VOLTAGE, regval);
 255                 default:
 256                         return -EOPNOTSUPP;
 257                 }
 258         default:
 259                 return -EOPNOTSUPP;
 260         }
 261 }
 262
 263 static int ina238_read_current(struct device *dev, u32 attr, long *val)
 264 {
 265         struct ina238_data *data = dev_get_drvdata(dev);
 266         int regval;
 267         int err;
 268
 269         switch (attr) {
 270         case hwmon_curr_input:
 271                 err = regmap_read(data->regmap, INA238_CURRENT, &regval);
 272                 if (err < 0)
 273                         return err;
 274
 275                 /* Signed register, fixed 1mA current lsb. result in mA */
 276                 *val = div_s64((s16)regval * INA238_FIXED_SHUNT * data->gain,
 277                                data->rshunt * 4);
 278                 break;
 279         default:
 280                 return -EOPNOTSUPP;
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int ina238_read_power(struct device *dev, u32 attr, long *val)
 287 {
 288         struct ina238_data *data = dev_get_drvdata(dev);
 289         long long power;
 290         int regval;
 291         int err;
 292
 293         switch (attr) {
 294         case hwmon_power_input:
 295                 err = ina238_read_reg24(data->client, INA238_POWER, &regval);
 296                 if (err)
 297                         return err;
 298
 299                 /* Fixed 1mA lsb, scaled by 1000000 to have result in uW */
 300                 power = div_u64(regval * 1000ULL * INA238_FIXED_SHUNT *
 301                                 data->gain, 20 * data->rshunt);
 302                 /* Clamp value to maximum value of long */
 303                 *val = clamp_val(power, 0, LONG_MAX);
 304                 break;
 305         case hwmon_power_max:
 306                 err = regmap_read(data->regmap, INA238_POWER_LIMIT, &regval);
 307                 if (err)
 308                         return err;
 309
 310                 /*
 311                  * Truncated 24-bit compare register, lower 8-bits are
 312                  * truncated. Same conversion to/from uW as POWER register.
 313                  */
 314                 power = div_u64((regval << 8) * 1000ULL * INA238_FIXED_SHUNT *
 315                                data->gain, 20 * data->rshunt);
 316                 /* Clamp value to maximum value of long */
 317                 *val = clamp_val(power, 0, LONG_MAX);
 318                 break;
 319         case hwmon_power_max_alarm:
 320                 err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
 321                 if (err)
 322                         return err;
 323
 324                 *val = !!(regval & INA238_DIAG_ALERT_POL);
 325                 break;
 326         default:
 327                 return -EOPNOTSUPP;
 328         }
 329
 330         return 0;
 331 }
 332
 333 static int ina238_write_power(struct device *dev, u32 attr, long val)
 334 {
 335         struct ina238_data *data = dev_get_drvdata(dev);
 336         long regval;
 337
 338         if (attr != hwmon_power_max)
 339                 return -EOPNOTSUPP;
 340
 341         /*
 342          * Unsigned postive values. Compared against the 24-bit power register,
 343          * lower 8-bits are truncated. Same conversion to/from uW as POWER
 344          * register.
 345          */
 346         regval = clamp_val(val, 0, LONG_MAX);
 347         regval = div_u64(val * 20ULL * data->rshunt,
 348                          1000ULL * INA238_FIXED_SHUNT * data->gain);
 349         regval = clamp_val(regval >> 8, 0, U16_MAX);
 350
 351         return regmap_write(data->regmap, INA238_POWER_LIMIT, regval);
 352 }
 353
 354 static int ina238_read_temp(struct device *dev, u32 attr, long *val)
 355 {
 356         struct ina238_data *data = dev_get_drvdata(dev);
 357         int regval;
 358         int err;
 359
 360         switch (attr) {
 361         case hwmon_temp_input:
 362                 err = regmap_read(data->regmap, INA238_DIE_TEMP, &regval);
 363                 if (err)
 364                         return err;
 365
 366                 /* Signed, bits 15-4 of register, result in mC */
 367                 *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;
 368                 break;
 369         case hwmon_temp_max:
 370                 err = regmap_read(data->regmap, INA238_TEMP_LIMIT, &regval);
 371                 if (err)
 372                         return err;
 373
 374                 /* Signed, bits 15-4 of register, result in mC */
 375                 *val = ((s16)regval >> 4) * INA238_DIE_TEMP_LSB;
 376                 break;
 377         case hwmon_temp_max_alarm:
 378                 err = regmap_read(data->regmap, INA238_DIAG_ALERT, &regval);
 379                 if (err)
 380                         return err;
 381
 382                 *val = !!(regval & INA238_DIAG_ALERT_TMPOL);
 383                 break;
 384         default:
 385                 return -EOPNOTSUPP;
 386         }
 387
 388         return 0;
 389 }
 390
 391 static int ina238_write_temp(struct device *dev, u32 attr, long val)
 392 {
 393         struct ina238_data *data = dev_get_drvdata(dev);
 394         int regval;
 395
 396         if (attr != hwmon_temp_max)
 397                 return -EOPNOTSUPP;
 398
 399         /* Signed, bits 15-4 of register */
 400         regval = (val / INA238_DIE_TEMP_LSB) << 4;
 401         regval = clamp_val(regval, S16_MIN, S16_MAX) & 0xfff0;
 402
 403         return regmap_write(data->regmap, INA238_TEMP_LIMIT, regval);
 404 }
 405
 406 static int ina238_read(struct device *dev, enum hwmon_sensor_types type,
 407                        u32 attr, int channel, long *val)
 408 {
 409         switch (type) {
 410         case hwmon_in:
 411                 return ina238_read_in(dev, attr, channel, val);
 412         case hwmon_curr:
 413                 return ina238_read_current(dev, attr, val);
 414         case hwmon_power:
 415                 return ina238_read_power(dev, attr, val);
 416         case hwmon_temp:
 417                 return ina238_read_temp(dev, attr, val);
 418         default:
 419                 return -EOPNOTSUPP;
 420         }
 421         return 0;
 422 }
 423
 424 static int ina238_write(struct device *dev, enum hwmon_sensor_types type,
 425                        u32 attr, int channel, long val)
 426 {
 427         struct ina238_data *data = dev_get_drvdata(dev);
 428         int err;
 429
 430         mutex_lock(&data->config_lock);
 431
 432         switch (type) {
 433         case hwmon_in:
 434                 err = ina238_write_in(dev, attr, channel, val);
 435                 break;
 436         case hwmon_power:
 437                 err = ina238_write_power(dev, attr, val);
 438                 break;
 439         case hwmon_temp:
 440                 err = ina238_write_temp(dev, attr, val);
 441                 break;
 442         default:
 443                 err = -EOPNOTSUPP;
 444                 break;
 445         }
 446
 447         mutex_unlock(&data->config_lock);
 448         return err;
 449 }
 450
 451 static umode_t ina238_is_visible(const void *drvdata,
 452                                  enum hwmon_sensor_types type,
 453                                  u32 attr, int channel)
 454 {
 455         switch (type) {
 456         case hwmon_in:
 457                 switch (attr) {
 458                 case hwmon_in_input:
 459                 case hwmon_in_max_alarm:
 460                 case hwmon_in_min_alarm:
 461                         return 0444;
 462                 case hwmon_in_max:
 463                 case hwmon_in_min:
 464                         return 0644;
 465                 default:
 466                         return 0;
 467                 }
 468         case hwmon_curr:
 469                 switch (attr) {
 470                 case hwmon_curr_input:
 471                         return 0444;
 472                 default:
 473                         return 0;
 474                 }
 475         case hwmon_power:
 476                 switch (attr) {
 477                 case hwmon_power_input:
 478                 case hwmon_power_max_alarm:
 479                         return 0444;
 480                 case hwmon_power_max:
 481                         return 0644;
 482                 default:
 483                         return 0;
 484                 }
 485         case hwmon_temp:
 486                 switch (attr) {
 487                 case hwmon_temp_input:
 488                 case hwmon_temp_max_alarm:
 489                         return 0444;
 490                 case hwmon_temp_max:
 491                         return 0644;
 492                 default:
 493                         return 0;
 494                 }
 495         default:
 496                 return 0;
 497         }
 498 }
 499
 500 #define INA238_HWMON_IN_CONFIG (HWMON_I_INPUT | \
 501                                 HWMON_I_MAX | HWMON_I_MAX_ALARM | \
 502                                 HWMON_I_MIN | HWMON_I_MIN_ALARM)
 503
 504 static const struct hwmon_channel_info * const ina238_info[] = {
 505         HWMON_CHANNEL_INFO(in,
 506                            /* 0: shunt voltage */
 507                            INA238_HWMON_IN_CONFIG,
 508                            /* 1: bus voltage */
 509                            INA238_HWMON_IN_CONFIG),
 510         HWMON_CHANNEL_INFO(curr,
 511                            /* 0: current through shunt */
 512                            HWMON_C_INPUT),
 513         HWMON_CHANNEL_INFO(power,
 514                            /* 0: power */
 515                            HWMON_P_INPUT | HWMON_P_MAX | HWMON_P_MAX_ALARM),
 516         HWMON_CHANNEL_INFO(temp,
 517                            /* 0: die temperature */
 518                            HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_ALARM),
 519         NULL
 520 };
 521
 522 static const struct hwmon_ops ina238_hwmon_ops = {
 523         .is_visible = ina238_is_visible,
 524         .read = ina238_read,
 525         .write = ina238_write,
 526 };
 527
 528 static const struct hwmon_chip_info ina238_chip_info = {
 529         .ops = &ina238_hwmon_ops,
 530         .info = ina238_info,
 531 };
 532
 533 static int ina238_probe(struct i2c_client *client)
 534 {
 535         struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
 536         struct device *dev = &client->dev;
 537         struct device *hwmon_dev;
 538         struct ina238_data *data;
 539         int config;
 540         int ret;
 541
 542         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 543         if (!data)
 544                 return -ENOMEM;
 545
 546         data->client = client;
 547         mutex_init(&data->config_lock);
 548
 549         data->regmap = devm_regmap_init_i2c(client, &ina238_regmap_config);
 550         if (IS_ERR(data->regmap)) {
 551                 dev_err(dev, "failed to allocate register map\n");
 552                 return PTR_ERR(data->regmap);
 553         }
 554
 555         /* load shunt value */
 556         data->rshunt = INA238_RSHUNT_DEFAULT;
 557         if (device_property_read_u32(dev, "shunt-resistor", &data->rshunt) < 0 && pdata)
 558                 data->rshunt = pdata->shunt_uohms;
 559         if (data->rshunt == 0) {
 560                 dev_err(dev, "invalid shunt resister value %u\n", data->rshunt);
 561                 return -EINVAL;
 562         }
 563
 564         /* load shunt gain value */
 565         if (device_property_read_u32(dev, "ti,shunt-gain", &data->gain) < 0)
 566                 data->gain = 4; /* Default of ADCRANGE = 0 */
 567         if (data->gain != 1 && data->gain != 4) {
 568                 dev_err(dev, "invalid shunt gain value %u\n", data->gain);
 569                 return -EINVAL;
 570         }
 571
 572         /* Setup CONFIG register */
 573         config = INA238_CONFIG_DEFAULT;
 574         if (data->gain == 1)
 575                 config |= INA238_CONFIG_ADCRANGE; /* ADCRANGE = 1 is /1 */
 576         ret = regmap_write(data->regmap, INA238_CONFIG, config);
 577         if (ret < 0) {
 578                 dev_err(dev, "error configuring the device: %d\n", ret);
 579                 return -ENODEV;
 580         }
 581
 582         /* Setup ADC_CONFIG register */
 583         ret = regmap_write(data->regmap, INA238_ADC_CONFIG,
 584                            INA238_ADC_CONFIG_DEFAULT);
 585         if (ret < 0) {
 586                 dev_err(dev, "error configuring the device: %d\n", ret);
 587                 return -ENODEV;
 588         }
 589
 590         /* Setup SHUNT_CALIBRATION register with fixed value */
 591         ret = regmap_write(data->regmap, INA238_SHUNT_CALIBRATION,
 592                            INA238_CALIBRATION_VALUE);
 593         if (ret < 0) {
 594                 dev_err(dev, "error configuring the device: %d\n", ret);
 595                 return -ENODEV;
 596         }
 597
 598         /* Setup alert/alarm configuration */
 599         ret = regmap_write(data->regmap, INA238_DIAG_ALERT,
 600                            INA238_DIAG_ALERT_DEFAULT);
 601         if (ret < 0) {
 602                 dev_err(dev, "error configuring the device: %d\n", ret);
 603                 return -ENODEV;
 604         }
 605
 606         hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
 607                                                          &ina238_chip_info,
 608                                                          NULL);
 609         if (IS_ERR(hwmon_dev))
 610                 return PTR_ERR(hwmon_dev);
 611
 612         dev_info(dev, "power monitor %s (Rshunt = %u uOhm, gain = %u)\n",
 613                  client->name, data->rshunt, data->gain);
 614
 615         return 0;
 616 }
 617
 618 static const struct i2c_device_id ina238_id[] = {
 619         { "ina238" },
 620         { }
 621 };
 622 MODULE_DEVICE_TABLE(i2c, ina238_id);
 623
 624 static const struct of_device_id __maybe_unused ina238_of_match[] = {
 625         { .compatible = "ti,ina237" },
 626         { .compatible = "ti,ina238" },
 627         { },
 628 };
 629 MODULE_DEVICE_TABLE(of, ina238_of_match);
 630
 631 static struct i2c_driver ina238_driver = {
 632         .driver = {
 633                 .name   = "ina238",
 634                 .of_match_table = of_match_ptr(ina238_of_match),
 635         },
 636         .probe          = ina238_probe,
 637         .id_table       = ina238_id,
 638 };
 639
 640 module_i2c_driver(ina238_driver);
 641
 642 MODULE_AUTHOR("Nathan Rossi <nathan.rossi@digi.com>");
 643 MODULE_DESCRIPTION("ina238 driver");
 644 MODULE_LICENSE("GPL");