drivers/hwmon/ina209.c

   1 /*
   2  * Driver for the Texas Instruments / Burr Brown INA209
   3  * Bidirectional Current/Power Monitor
   4  *
   5  * Copyright (C) 2012 Guenter Roeck <linux@roeck-us.net>
   6  *
   7  * Derived from Ira W. Snyder's original driver submission
   8  *      Copyright (C) 2008 Paul Hays <Paul.Hays@cattail.ca>
   9  *      Copyright (C) 2008-2009 Ira W. Snyder <iws@ovro.caltech.edu>
  10  *
  11  * Aligned with ina2xx driver
  12  *      Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
  13  *      Thanks to Jan Volkering
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation; version 2 of the License.
  18  *
  19  * Datasheet:
  20  * http://www.ti.com/lit/gpn/ina209
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/err.h>
  27 #include <linux/slab.h>
  28 #include <linux/bug.h>
  29 #include <linux/i2c.h>
  30 #include <linux/hwmon.h>
  31 #include <linux/hwmon-sysfs.h>
  32
  33 #include <linux/platform_data/ina2xx.h>
  34
  35 /* register definitions */
  36 #define INA209_CONFIGURATION            0x00
  37 #define INA209_STATUS                   0x01
  38 #define INA209_STATUS_MASK              0x02
  39 #define INA209_SHUNT_VOLTAGE            0x03
  40 #define INA209_BUS_VOLTAGE              0x04
  41 #define INA209_POWER                    0x05
  42 #define INA209_CURRENT                  0x06
  43 #define INA209_SHUNT_VOLTAGE_POS_PEAK   0x07
  44 #define INA209_SHUNT_VOLTAGE_NEG_PEAK   0x08
  45 #define INA209_BUS_VOLTAGE_MAX_PEAK     0x09
  46 #define INA209_BUS_VOLTAGE_MIN_PEAK     0x0a
  47 #define INA209_POWER_PEAK               0x0b
  48 #define INA209_SHUNT_VOLTAGE_POS_WARN   0x0c
  49 #define INA209_SHUNT_VOLTAGE_NEG_WARN   0x0d
  50 #define INA209_POWER_WARN               0x0e
  51 #define INA209_BUS_VOLTAGE_OVER_WARN    0x0f
  52 #define INA209_BUS_VOLTAGE_UNDER_WARN   0x10
  53 #define INA209_POWER_OVER_LIMIT         0x11
  54 #define INA209_BUS_VOLTAGE_OVER_LIMIT   0x12
  55 #define INA209_BUS_VOLTAGE_UNDER_LIMIT  0x13
  56 #define INA209_CRITICAL_DAC_POS         0x14
  57 #define INA209_CRITICAL_DAC_NEG         0x15
  58 #define INA209_CALIBRATION              0x16
  59
  60 #define INA209_REGISTERS                0x17
  61
  62 #define INA209_CONFIG_DEFAULT           0x3c47  /* PGA=8, full range */
  63 #define INA209_SHUNT_DEFAULT            10000   /* uOhm */
  64
  65 struct ina209_data {
  66         struct i2c_client *client;
  67
  68         struct mutex update_lock;
  69         bool valid;
  70         unsigned long last_updated;     /* in jiffies */
  71
  72         u16 regs[INA209_REGISTERS];     /* All chip registers */
  73
  74         u16 config_orig;                /* Original configuration */
  75         u16 calibration_orig;           /* Original calibration */
  76         u16 update_interval;
  77 };
  78
  79 static struct ina209_data *ina209_update_device(struct device *dev)
  80 {
  81         struct ina209_data *data = dev_get_drvdata(dev);
  82         struct i2c_client *client = data->client;
  83         struct ina209_data *ret = data;
  84         s32 val;
  85         int i;
  86
  87         mutex_lock(&data->update_lock);
  88
  89         if (!data->valid ||
  90             time_after(jiffies, data->last_updated + data->update_interval)) {
  91                 for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
  92                         val = i2c_smbus_read_word_swapped(client, i);
  93                         if (val < 0) {
  94                                 ret = ERR_PTR(val);
  95                                 goto abort;
  96                         }
  97                         data->regs[i] = val;
  98                 }
  99                 data->last_updated = jiffies;
 100                 data->valid = true;
 101         }
 102 abort:
 103         mutex_unlock(&data->update_lock);
 104         return ret;
 105 }
 106
 107 /*
 108  * Read a value from a device register and convert it to the
 109  * appropriate sysfs units
 110  */
 111 static long ina209_from_reg(const u8 reg, const u16 val)
 112 {
 113         switch (reg) {
 114         case INA209_SHUNT_VOLTAGE:
 115         case INA209_SHUNT_VOLTAGE_POS_PEAK:
 116         case INA209_SHUNT_VOLTAGE_NEG_PEAK:
 117         case INA209_SHUNT_VOLTAGE_POS_WARN:
 118         case INA209_SHUNT_VOLTAGE_NEG_WARN:
 119                 /* LSB=10 uV. Convert to mV. */
 120                 return DIV_ROUND_CLOSEST(val, 100);
 121
 122         case INA209_BUS_VOLTAGE:
 123         case INA209_BUS_VOLTAGE_MAX_PEAK:
 124         case INA209_BUS_VOLTAGE_MIN_PEAK:
 125         case INA209_BUS_VOLTAGE_OVER_WARN:
 126         case INA209_BUS_VOLTAGE_UNDER_WARN:
 127         case INA209_BUS_VOLTAGE_OVER_LIMIT:
 128         case INA209_BUS_VOLTAGE_UNDER_LIMIT:
 129                 /* LSB=4 mV, last 3 bits unused */
 130                 return (val >> 3) * 4;
 131
 132         case INA209_CRITICAL_DAC_POS:
 133                 /* LSB=1 mV, in the upper 8 bits */
 134                 return val >> 8;
 135
 136         case INA209_CRITICAL_DAC_NEG:
 137                 /* LSB=1 mV, in the upper 8 bits */
 138                 return -1 * (val >> 8);
 139
 140         case INA209_POWER:
 141         case INA209_POWER_PEAK:
 142         case INA209_POWER_WARN:
 143         case INA209_POWER_OVER_LIMIT:
 144                 /* LSB=20 mW. Convert to uW */
 145                 return val * 20 * 1000L;
 146
 147         case INA209_CURRENT:
 148                 /* LSB=1 mA (selected). Is in mA */
 149                 return val;
 150         }
 151
 152         /* programmer goofed */
 153         WARN_ON_ONCE(1);
 154         return 0;
 155 }
 156
 157 /*
 158  * Take a value and convert it to register format, clamping the value
 159  * to the appropriate range.
 160  */
 161 static int ina209_to_reg(u8 reg, u16 old, long val)
 162 {
 163         switch (reg) {
 164         case INA209_SHUNT_VOLTAGE_POS_WARN:
 165         case INA209_SHUNT_VOLTAGE_NEG_WARN:
 166                 /* Limit to +- 320 mV, 10 uV LSB */
 167                 return clamp_val(val, -320, 320) * 100;
 168
 169         case INA209_BUS_VOLTAGE_OVER_WARN:
 170         case INA209_BUS_VOLTAGE_UNDER_WARN:
 171         case INA209_BUS_VOLTAGE_OVER_LIMIT:
 172         case INA209_BUS_VOLTAGE_UNDER_LIMIT:
 173                 /*
 174                  * Limit to 0-32000 mV, 4 mV LSB
 175                  *
 176                  * The last three bits aren't part of the value, but we'll
 177                  * preserve them in their original state.
 178                  */
 179                 return (DIV_ROUND_CLOSEST(clamp_val(val, 0, 32000), 4) << 3)
 180                   | (old & 0x7);
 181
 182         case INA209_CRITICAL_DAC_NEG:
 183                 /*
 184                  * Limit to -255-0 mV, 1 mV LSB
 185                  * Convert the value to a positive value for the register
 186                  *
 187                  * The value lives in the top 8 bits only, be careful
 188                  * and keep original value of other bits.
 189                  */
 190                 return (clamp_val(-val, 0, 255) << 8) | (old & 0xff);
 191
 192         case INA209_CRITICAL_DAC_POS:
 193                 /*
 194                  * Limit to 0-255 mV, 1 mV LSB
 195                  *
 196                  * The value lives in the top 8 bits only, be careful
 197                  * and keep original value of other bits.
 198                  */
 199                 return (clamp_val(val, 0, 255) << 8) | (old & 0xff);
 200
 201         case INA209_POWER_WARN:
 202         case INA209_POWER_OVER_LIMIT:
 203                 /* 20 mW LSB */
 204                 return DIV_ROUND_CLOSEST(val, 20 * 1000);
 205         }
 206
 207         /* Other registers are read-only, return access error */
 208         return -EACCES;
 209 }
 210
 211 static int ina209_interval_from_reg(u16 reg)
 212 {
 213         return 68 >> (15 - ((reg >> 3) & 0x0f));
 214 }
 215
 216 static u16 ina209_reg_from_interval(u16 config, long interval)
 217 {
 218         int i, adc;
 219
 220         if (interval <= 0) {
 221                 adc = 8;
 222         } else {
 223                 adc = 15;
 224                 for (i = 34 + 34 / 2; i; i >>= 1) {
 225                         if (i < interval)
 226                                 break;
 227                         adc--;
 228                 }
 229         }
 230         return (config & 0xf807) | (adc << 3) | (adc << 7);
 231 }
 232
 233 static ssize_t ina209_set_interval(struct device *dev,
 234                                    struct device_attribute *da,
 235                                    const char *buf, size_t count)
 236 {
 237         struct ina209_data *data = ina209_update_device(dev);
 238         long val;
 239         u16 regval;
 240         int ret;
 241
 242         if (IS_ERR(data))
 243                 return PTR_ERR(data);
 244
 245         ret = kstrtol(buf, 10, &val);
 246         if (ret < 0)
 247                 return ret;
 248
 249         mutex_lock(&data->update_lock);
 250         regval = ina209_reg_from_interval(data->regs[INA209_CONFIGURATION],
 251                                           val);
 252         i2c_smbus_write_word_swapped(data->client, INA209_CONFIGURATION,
 253                                      regval);
 254         data->regs[INA209_CONFIGURATION] = regval;
 255         data->update_interval = ina209_interval_from_reg(regval);
 256         mutex_unlock(&data->update_lock);
 257         return count;
 258 }
 259
 260 static ssize_t ina209_show_interval(struct device *dev,
 261                                     struct device_attribute *da, char *buf)
 262 {
 263         struct ina209_data *data = dev_get_drvdata(dev);
 264
 265         return snprintf(buf, PAGE_SIZE, "%d\n", data->update_interval);
 266 }
 267
 268 /*
 269  * History is reset by writing 1 into bit 0 of the respective peak register.
 270  * Since more than one peak register may be affected by the scope of a
 271  * reset_history attribute write, use a bit mask in attr->index to identify
 272  * which registers are affected.
 273  */
 274 static u16 ina209_reset_history_regs[] = {
 275         INA209_SHUNT_VOLTAGE_POS_PEAK,
 276         INA209_SHUNT_VOLTAGE_NEG_PEAK,
 277         INA209_BUS_VOLTAGE_MAX_PEAK,
 278         INA209_BUS_VOLTAGE_MIN_PEAK,
 279         INA209_POWER_PEAK
 280 };
 281
 282 static ssize_t ina209_reset_history(struct device *dev,
 283                                     struct device_attribute *da,
 284                                     const char *buf,
 285                                     size_t count)
 286 {
 287         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 288         struct ina209_data *data = dev_get_drvdata(dev);
 289         struct i2c_client *client = data->client;
 290         u32 mask = attr->index;
 291         long val;
 292         int i, ret;
 293
 294         ret = kstrtol(buf, 10, &val);
 295         if (ret < 0)
 296                 return ret;
 297
 298         mutex_lock(&data->update_lock);
 299         for (i = 0; i < ARRAY_SIZE(ina209_reset_history_regs); i++) {
 300                 if (mask & (1 << i))
 301                         i2c_smbus_write_word_swapped(client,
 302                                         ina209_reset_history_regs[i], 1);
 303         }
 304         data->valid = false;
 305         mutex_unlock(&data->update_lock);
 306         return count;
 307 }
 308
 309 static ssize_t ina209_set_value(struct device *dev,
 310                                 struct device_attribute *da,
 311                                 const char *buf,
 312                                 size_t count)
 313 {
 314         struct ina209_data *data = ina209_update_device(dev);
 315         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 316         int reg = attr->index;
 317         long val;
 318         int ret;
 319
 320         if (IS_ERR(data))
 321                 return PTR_ERR(data);
 322
 323         ret = kstrtol(buf, 10, &val);
 324         if (ret < 0)
 325                 return ret;
 326
 327         mutex_lock(&data->update_lock);
 328         ret = ina209_to_reg(reg, data->regs[reg], val);
 329         if (ret < 0) {
 330                 count = ret;
 331                 goto abort;
 332         }
 333         i2c_smbus_write_word_swapped(data->client, reg, ret);
 334         data->regs[reg] = ret;
 335 abort:
 336         mutex_unlock(&data->update_lock);
 337         return count;
 338 }
 339
 340 static ssize_t ina209_show_value(struct device *dev,
 341                                  struct device_attribute *da,
 342                                  char *buf)
 343 {
 344         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 345         struct ina209_data *data = ina209_update_device(dev);
 346         long val;
 347
 348         if (IS_ERR(data))
 349                 return PTR_ERR(data);
 350
 351         val = ina209_from_reg(attr->index, data->regs[attr->index]);
 352         return snprintf(buf, PAGE_SIZE, "%ld\n", val);
 353 }
 354
 355 static ssize_t ina209_show_alarm(struct device *dev,
 356                                  struct device_attribute *da,
 357                                  char *buf)
 358 {
 359         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 360         struct ina209_data *data = ina209_update_device(dev);
 361         const unsigned int mask = attr->index;
 362         u16 status;
 363
 364         if (IS_ERR(data))
 365                 return PTR_ERR(data);
 366
 367         status = data->regs[INA209_STATUS];
 368
 369         /*
 370          * All alarms are in the INA209_STATUS register. To avoid a long
 371          * switch statement, the mask is passed in attr->index
 372          */
 373         return snprintf(buf, PAGE_SIZE, "%u\n", !!(status & mask));
 374 }
 375
 376 /* Shunt voltage, history, limits, alarms */
 377 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina209_show_value, NULL,
 378                           INA209_SHUNT_VOLTAGE);
 379 static SENSOR_DEVICE_ATTR(in0_input_highest, S_IRUGO, ina209_show_value, NULL,
 380                           INA209_SHUNT_VOLTAGE_POS_PEAK);
 381 static SENSOR_DEVICE_ATTR(in0_input_lowest, S_IRUGO, ina209_show_value, NULL,
 382                           INA209_SHUNT_VOLTAGE_NEG_PEAK);
 383 static SENSOR_DEVICE_ATTR(in0_reset_history, S_IWUSR, NULL,
 384                           ina209_reset_history, (1 << 0) | (1 << 1));
 385 static SENSOR_DEVICE_ATTR(in0_max, S_IRUGO | S_IWUSR, ina209_show_value,
 386                           ina209_set_value, INA209_SHUNT_VOLTAGE_POS_WARN);
 387 static SENSOR_DEVICE_ATTR(in0_min, S_IRUGO | S_IWUSR, ina209_show_value,
 388                           ina209_set_value, INA209_SHUNT_VOLTAGE_NEG_WARN);
 389 static SENSOR_DEVICE_ATTR(in0_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
 390                           ina209_set_value, INA209_CRITICAL_DAC_POS);
 391 static SENSOR_DEVICE_ATTR(in0_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
 392                           ina209_set_value, INA209_CRITICAL_DAC_NEG);
 393
 394 static SENSOR_DEVICE_ATTR(in0_min_alarm,  S_IRUGO, ina209_show_alarm, NULL,
 395                           1 << 11);
 396 static SENSOR_DEVICE_ATTR(in0_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 397                           1 << 12);
 398 static SENSOR_DEVICE_ATTR(in0_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 399                           1 << 6);
 400 static SENSOR_DEVICE_ATTR(in0_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 401                           1 << 7);
 402
 403 /* Bus voltage, history, limits, alarms */
 404 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina209_show_value, NULL,
 405                           INA209_BUS_VOLTAGE);
 406 static SENSOR_DEVICE_ATTR(in1_input_highest, S_IRUGO, ina209_show_value, NULL,
 407                           INA209_BUS_VOLTAGE_MAX_PEAK);
 408 static SENSOR_DEVICE_ATTR(in1_input_lowest, S_IRUGO, ina209_show_value, NULL,
 409                           INA209_BUS_VOLTAGE_MIN_PEAK);
 410 static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL,
 411                           ina209_reset_history, (1 << 2) | (1 << 3));
 412 static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ina209_show_value,
 413                           ina209_set_value, INA209_BUS_VOLTAGE_OVER_WARN);
 414 static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ina209_show_value,
 415                           ina209_set_value, INA209_BUS_VOLTAGE_UNDER_WARN);
 416 static SENSOR_DEVICE_ATTR(in1_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
 417                           ina209_set_value, INA209_BUS_VOLTAGE_OVER_LIMIT);
 418 static SENSOR_DEVICE_ATTR(in1_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
 419                           ina209_set_value, INA209_BUS_VOLTAGE_UNDER_LIMIT);
 420
 421 static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 422                           1 << 14);
 423 static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 424                           1 << 15);
 425 static SENSOR_DEVICE_ATTR(in1_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 426                           1 << 9);
 427 static SENSOR_DEVICE_ATTR(in1_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 428                           1 << 10);
 429
 430 /* Power */
 431 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina209_show_value, NULL,
 432                           INA209_POWER);
 433 static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ina209_show_value,
 434                           NULL, INA209_POWER_PEAK);
 435 static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL,
 436                           ina209_reset_history, 1 << 4);
 437 static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ina209_show_value,
 438                           ina209_set_value, INA209_POWER_WARN);
 439 static SENSOR_DEVICE_ATTR(power1_crit, S_IRUGO | S_IWUSR, ina209_show_value,
 440                           ina209_set_value, INA209_POWER_OVER_LIMIT);
 441
 442 static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 443                           1 << 13);
 444 static SENSOR_DEVICE_ATTR(power1_crit_alarm, S_IRUGO, ina209_show_alarm, NULL,
 445                           1 << 8);
 446
 447 /* Current */
 448 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina209_show_value, NULL,
 449                           INA209_CURRENT);
 450
 451 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 452                           ina209_show_interval, ina209_set_interval, 0);
 453
 454 /*
 455  * Finally, construct an array of pointers to members of the above objects,
 456  * as required for sysfs_create_group()
 457  */
 458 static struct attribute *ina209_attrs[] = {
 459         &sensor_dev_attr_in0_input.dev_attr.attr,
 460         &sensor_dev_attr_in0_input_highest.dev_attr.attr,
 461         &sensor_dev_attr_in0_input_lowest.dev_attr.attr,
 462         &sensor_dev_attr_in0_reset_history.dev_attr.attr,
 463         &sensor_dev_attr_in0_max.dev_attr.attr,
 464         &sensor_dev_attr_in0_min.dev_attr.attr,
 465         &sensor_dev_attr_in0_crit_max.dev_attr.attr,
 466         &sensor_dev_attr_in0_crit_min.dev_attr.attr,
 467         &sensor_dev_attr_in0_max_alarm.dev_attr.attr,
 468         &sensor_dev_attr_in0_min_alarm.dev_attr.attr,
 469         &sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
 470         &sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,
 471
 472         &sensor_dev_attr_in1_input.dev_attr.attr,
 473         &sensor_dev_attr_in1_input_highest.dev_attr.attr,
 474         &sensor_dev_attr_in1_input_lowest.dev_attr.attr,
 475         &sensor_dev_attr_in1_reset_history.dev_attr.attr,
 476         &sensor_dev_attr_in1_max.dev_attr.attr,
 477         &sensor_dev_attr_in1_min.dev_attr.attr,
 478         &sensor_dev_attr_in1_crit_max.dev_attr.attr,
 479         &sensor_dev_attr_in1_crit_min.dev_attr.attr,
 480         &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
 481         &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 482         &sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
 483         &sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,
 484
 485         &sensor_dev_attr_power1_input.dev_attr.attr,
 486         &sensor_dev_attr_power1_input_highest.dev_attr.attr,
 487         &sensor_dev_attr_power1_reset_history.dev_attr.attr,
 488         &sensor_dev_attr_power1_max.dev_attr.attr,
 489         &sensor_dev_attr_power1_crit.dev_attr.attr,
 490         &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
 491         &sensor_dev_attr_power1_crit_alarm.dev_attr.attr,
 492
 493         &sensor_dev_attr_curr1_input.dev_attr.attr,
 494
 495         &sensor_dev_attr_update_interval.dev_attr.attr,
 496
 497         NULL,
 498 };
 499 ATTRIBUTE_GROUPS(ina209);
 500
 501 static void ina209_restore_conf(struct i2c_client *client,
 502                                 struct ina209_data *data)
 503 {
 504         /* Restore initial configuration */
 505         i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
 506                                      data->config_orig);
 507         i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
 508                                      data->calibration_orig);
 509 }
 510
 511 static int ina209_init_client(struct i2c_client *client,
 512                               struct ina209_data *data)
 513 {
 514         struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
 515         u32 shunt;
 516         int reg;
 517
 518         reg = i2c_smbus_read_word_swapped(client, INA209_CALIBRATION);
 519         if (reg < 0)
 520                 return reg;
 521         data->calibration_orig = reg;
 522
 523         reg = i2c_smbus_read_word_swapped(client, INA209_CONFIGURATION);
 524         if (reg < 0)
 525                 return reg;
 526         data->config_orig = reg;
 527
 528         if (pdata) {
 529                 if (pdata->shunt_uohms <= 0)
 530                         return -EINVAL;
 531                 shunt = pdata->shunt_uohms;
 532         } else if (!of_property_read_u32(client->dev.of_node, "shunt-resistor",
 533                                          &shunt)) {
 534                 if (shunt == 0)
 535                         return -EINVAL;
 536         } else {
 537                 shunt = data->calibration_orig ?
 538                   40960000 / data->calibration_orig : INA209_SHUNT_DEFAULT;
 539         }
 540
 541         i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
 542                                      INA209_CONFIG_DEFAULT);
 543         data->update_interval = ina209_interval_from_reg(INA209_CONFIG_DEFAULT);
 544
 545         /*
 546          * Calibrate current LSB to 1mA. Shunt is in uOhms.
 547          * See equation 13 in datasheet.
 548          */
 549         i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
 550                                      clamp_val(40960000 / shunt, 1, 65535));
 551
 552         /* Clear status register */
 553         i2c_smbus_read_word_swapped(client, INA209_STATUS);
 554
 555         return 0;
 556 }
 557
 558 static int ina209_probe(struct i2c_client *client,
 559                         const struct i2c_device_id *id)
 560 {
 561         struct i2c_adapter *adapter = client->adapter;
 562         struct ina209_data *data;
 563         struct device *hwmon_dev;
 564         int ret;
 565
 566         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 567                 return -ENODEV;
 568
 569         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 570         if (!data)
 571                 return -ENOMEM;
 572
 573         i2c_set_clientdata(client, data);
 574         data->client = client;
 575         mutex_init(&data->update_lock);
 576
 577         ret = ina209_init_client(client, data);
 578         if (ret)
 579                 return ret;
 580
 581         hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
 582                                                            client->name,
 583                                                            data, ina209_groups);
 584         if (IS_ERR(hwmon_dev)) {
 585                 ret = PTR_ERR(hwmon_dev);
 586                 goto out_restore_conf;
 587         }
 588
 589         return 0;
 590
 591 out_restore_conf:
 592         ina209_restore_conf(client, data);
 593         return ret;
 594 }
 595
 596 static int ina209_remove(struct i2c_client *client)
 597 {
 598         struct ina209_data *data = i2c_get_clientdata(client);
 599
 600         ina209_restore_conf(client, data);
 601
 602         return 0;
 603 }
 604
 605 static const struct i2c_device_id ina209_id[] = {
 606         { "ina209", 0 },
 607         { }
 608 };
 609 MODULE_DEVICE_TABLE(i2c, ina209_id);
 610
 611 /* This is the driver that will be inserted */
 612 static struct i2c_driver ina209_driver = {
 613         .class          = I2C_CLASS_HWMON,
 614         .driver = {
 615                 .name   = "ina209",
 616         },
 617         .probe          = ina209_probe,
 618         .remove         = ina209_remove,
 619         .id_table       = ina209_id,
 620 };
 621
 622 module_i2c_driver(ina209_driver);
 623
 624 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>, Paul Hays <Paul.Hays@cattail.ca>, Guenter Roeck <linux@roeck-us.net>");
 625 MODULE_DESCRIPTION("INA209 driver");
 626 MODULE_LICENSE("GPL");