linux/drivers/hwmon/ina209.c
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   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
  65struct ina209_data {
  66        struct device *hwmon_dev;
  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
  79static struct ina209_data *ina209_update_device(struct device *dev)
  80{
  81        struct i2c_client *client = to_i2c_client(dev);
  82        struct ina209_data *data = i2c_get_clientdata(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        }
 102abort:
 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 */
 111static 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 */
 161static 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
 211static int ina209_interval_from_reg(u16 reg)
 212{
 213        return 68 >> (15 - ((reg >> 3) & 0x0f));
 214}
 215
 216static 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
 233static ssize_t ina209_set_interval(struct device *dev,
 234                                   struct device_attribute *da,
 235                                   const char *buf, size_t count)
 236{
 237        struct i2c_client *client = to_i2c_client(dev);
 238        struct ina209_data *data = ina209_update_device(dev);
 239        long val;
 240        u16 regval;
 241        int ret;
 242
 243        if (IS_ERR(data))
 244                return PTR_ERR(data);
 245
 246        ret = kstrtol(buf, 10, &val);
 247        if (ret < 0)
 248                return ret;
 249
 250        mutex_lock(&data->update_lock);
 251        regval = ina209_reg_from_interval(data->regs[INA209_CONFIGURATION],
 252                                          val);
 253        i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION, 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
 260static ssize_t ina209_show_interval(struct device *dev,
 261                                    struct device_attribute *da, char *buf)
 262{
 263        struct i2c_client *client = to_i2c_client(dev);
 264        struct ina209_data *data = i2c_get_clientdata(client);
 265
 266        return snprintf(buf, PAGE_SIZE, "%d\n", data->update_interval);
 267}
 268
 269/*
 270 * History is reset by writing 1 into bit 0 of the respective peak register.
 271 * Since more than one peak register may be affected by the scope of a
 272 * reset_history attribute write, use a bit mask in attr->index to identify
 273 * which registers are affected.
 274 */
 275static u16 ina209_reset_history_regs[] = {
 276        INA209_SHUNT_VOLTAGE_POS_PEAK,
 277        INA209_SHUNT_VOLTAGE_NEG_PEAK,
 278        INA209_BUS_VOLTAGE_MAX_PEAK,
 279        INA209_BUS_VOLTAGE_MIN_PEAK,
 280        INA209_POWER_PEAK
 281};
 282
 283static ssize_t ina209_reset_history(struct device *dev,
 284                                    struct device_attribute *da,
 285                                    const char *buf,
 286                                    size_t count)
 287{
 288        struct i2c_client *client = to_i2c_client(dev);
 289        struct ina209_data *data = i2c_get_clientdata(client);
 290        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 291        u32 mask = attr->index;
 292        long val;
 293        int i, ret;
 294
 295        ret = kstrtol(buf, 10, &val);
 296        if (ret < 0)
 297                return ret;
 298
 299        mutex_lock(&data->update_lock);
 300        for (i = 0; i < ARRAY_SIZE(ina209_reset_history_regs); i++) {
 301                if (mask & (1 << i))
 302                        i2c_smbus_write_word_swapped(client,
 303                                        ina209_reset_history_regs[i], 1);
 304        }
 305        data->valid = false;
 306        mutex_unlock(&data->update_lock);
 307        return count;
 308}
 309
 310static ssize_t ina209_set_value(struct device *dev,
 311                                struct device_attribute *da,
 312                                const char *buf,
 313                                size_t count)
 314{
 315        struct i2c_client *client = to_i2c_client(dev);
 316        struct ina209_data *data = ina209_update_device(dev);
 317        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 318        int reg = attr->index;
 319        long val;
 320        int ret;
 321
 322        if (IS_ERR(data))
 323                return PTR_ERR(data);
 324
 325        ret = kstrtol(buf, 10, &val);
 326        if (ret < 0)
 327                return ret;
 328
 329        mutex_lock(&data->update_lock);
 330        ret = ina209_to_reg(reg, data->regs[reg], val);
 331        if (ret < 0) {
 332                count = ret;
 333                goto abort;
 334        }
 335        i2c_smbus_write_word_swapped(client, reg, ret);
 336        data->regs[reg] = ret;
 337abort:
 338        mutex_unlock(&data->update_lock);
 339        return count;
 340}
 341
 342static ssize_t ina209_show_value(struct device *dev,
 343                                 struct device_attribute *da,
 344                                 char *buf)
 345{
 346        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 347        struct ina209_data *data = ina209_update_device(dev);
 348        long val;
 349
 350        if (IS_ERR(data))
 351                return PTR_ERR(data);
 352
 353        val = ina209_from_reg(attr->index, data->regs[attr->index]);
 354        return snprintf(buf, PAGE_SIZE, "%ld\n", val);
 355}
 356
 357static ssize_t ina209_show_alarm(struct device *dev,
 358                                 struct device_attribute *da,
 359                                 char *buf)
 360{
 361        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 362        struct ina209_data *data = ina209_update_device(dev);
 363        const unsigned int mask = attr->index;
 364        u16 status;
 365
 366        if (IS_ERR(data))
 367                return PTR_ERR(data);
 368
 369        status = data->regs[INA209_STATUS];
 370
 371        /*
 372         * All alarms are in the INA209_STATUS register. To avoid a long
 373         * switch statement, the mask is passed in attr->index
 374         */
 375        return snprintf(buf, PAGE_SIZE, "%u\n", !!(status & mask));
 376}
 377
 378/* Shunt voltage, history, limits, alarms */
 379static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina209_show_value, NULL,
 380                          INA209_SHUNT_VOLTAGE);
 381static SENSOR_DEVICE_ATTR(in0_input_highest, S_IRUGO, ina209_show_value, NULL,
 382                          INA209_SHUNT_VOLTAGE_POS_PEAK);
 383static SENSOR_DEVICE_ATTR(in0_input_lowest, S_IRUGO, ina209_show_value, NULL,
 384                          INA209_SHUNT_VOLTAGE_NEG_PEAK);
 385static SENSOR_DEVICE_ATTR(in0_reset_history, S_IWUSR, NULL,
 386                          ina209_reset_history, (1 << 0) | (1 << 1));
 387static SENSOR_DEVICE_ATTR(in0_max, S_IRUGO | S_IWUSR, ina209_show_value,
 388                          ina209_set_value, INA209_SHUNT_VOLTAGE_POS_WARN);
 389static SENSOR_DEVICE_ATTR(in0_min, S_IRUGO | S_IWUSR, ina209_show_value,
 390                          ina209_set_value, INA209_SHUNT_VOLTAGE_NEG_WARN);
 391static SENSOR_DEVICE_ATTR(in0_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
 392                          ina209_set_value, INA209_CRITICAL_DAC_POS);
 393static SENSOR_DEVICE_ATTR(in0_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
 394                          ina209_set_value, INA209_CRITICAL_DAC_NEG);
 395
 396static SENSOR_DEVICE_ATTR(in0_min_alarm,  S_IRUGO, ina209_show_alarm, NULL,
 397                          1 << 11);
 398static SENSOR_DEVICE_ATTR(in0_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 399                          1 << 12);
 400static SENSOR_DEVICE_ATTR(in0_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 401                          1 << 6);
 402static SENSOR_DEVICE_ATTR(in0_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 403                          1 << 7);
 404
 405/* Bus voltage, history, limits, alarms */
 406static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina209_show_value, NULL,
 407                          INA209_BUS_VOLTAGE);
 408static SENSOR_DEVICE_ATTR(in1_input_highest, S_IRUGO, ina209_show_value, NULL,
 409                          INA209_BUS_VOLTAGE_MAX_PEAK);
 410static SENSOR_DEVICE_ATTR(in1_input_lowest, S_IRUGO, ina209_show_value, NULL,
 411                          INA209_BUS_VOLTAGE_MIN_PEAK);
 412static SENSOR_DEVICE_ATTR(in1_reset_history, S_IWUSR, NULL,
 413                          ina209_reset_history, (1 << 2) | (1 << 3));
 414static SENSOR_DEVICE_ATTR(in1_max, S_IRUGO | S_IWUSR, ina209_show_value,
 415                          ina209_set_value, INA209_BUS_VOLTAGE_OVER_WARN);
 416static SENSOR_DEVICE_ATTR(in1_min, S_IRUGO | S_IWUSR, ina209_show_value,
 417                          ina209_set_value, INA209_BUS_VOLTAGE_UNDER_WARN);
 418static SENSOR_DEVICE_ATTR(in1_crit_max, S_IRUGO | S_IWUSR, ina209_show_value,
 419                          ina209_set_value, INA209_BUS_VOLTAGE_OVER_LIMIT);
 420static SENSOR_DEVICE_ATTR(in1_crit_min, S_IRUGO | S_IWUSR, ina209_show_value,
 421                          ina209_set_value, INA209_BUS_VOLTAGE_UNDER_LIMIT);
 422
 423static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 424                          1 << 14);
 425static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 426                          1 << 15);
 427static SENSOR_DEVICE_ATTR(in1_crit_min_alarm, S_IRUGO, ina209_show_alarm, NULL,
 428                          1 << 9);
 429static SENSOR_DEVICE_ATTR(in1_crit_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 430                          1 << 10);
 431
 432/* Power */
 433static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina209_show_value, NULL,
 434                          INA209_POWER);
 435static SENSOR_DEVICE_ATTR(power1_input_highest, S_IRUGO, ina209_show_value,
 436                          NULL, INA209_POWER_PEAK);
 437static SENSOR_DEVICE_ATTR(power1_reset_history, S_IWUSR, NULL,
 438                          ina209_reset_history, 1 << 4);
 439static SENSOR_DEVICE_ATTR(power1_max, S_IRUGO | S_IWUSR, ina209_show_value,
 440                          ina209_set_value, INA209_POWER_WARN);
 441static SENSOR_DEVICE_ATTR(power1_crit, S_IRUGO | S_IWUSR, ina209_show_value,
 442                          ina209_set_value, INA209_POWER_OVER_LIMIT);
 443
 444static SENSOR_DEVICE_ATTR(power1_max_alarm, S_IRUGO, ina209_show_alarm, NULL,
 445                          1 << 13);
 446static SENSOR_DEVICE_ATTR(power1_crit_alarm, S_IRUGO, ina209_show_alarm, NULL,
 447                          1 << 8);
 448
 449/* Current */
 450static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina209_show_value, NULL,
 451                          INA209_CURRENT);
 452
 453static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 454                          ina209_show_interval, ina209_set_interval, 0);
 455
 456/*
 457 * Finally, construct an array of pointers to members of the above objects,
 458 * as required for sysfs_create_group()
 459 */
 460static struct attribute *ina209_attributes[] = {
 461        &sensor_dev_attr_in0_input.dev_attr.attr,
 462        &sensor_dev_attr_in0_input_highest.dev_attr.attr,
 463        &sensor_dev_attr_in0_input_lowest.dev_attr.attr,
 464        &sensor_dev_attr_in0_reset_history.dev_attr.attr,
 465        &sensor_dev_attr_in0_max.dev_attr.attr,
 466        &sensor_dev_attr_in0_min.dev_attr.attr,
 467        &sensor_dev_attr_in0_crit_max.dev_attr.attr,
 468        &sensor_dev_attr_in0_crit_min.dev_attr.attr,
 469        &sensor_dev_attr_in0_max_alarm.dev_attr.attr,
 470        &sensor_dev_attr_in0_min_alarm.dev_attr.attr,
 471        &sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
 472        &sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,
 473
 474        &sensor_dev_attr_in1_input.dev_attr.attr,
 475        &sensor_dev_attr_in1_input_highest.dev_attr.attr,
 476        &sensor_dev_attr_in1_input_lowest.dev_attr.attr,
 477        &sensor_dev_attr_in1_reset_history.dev_attr.attr,
 478        &sensor_dev_attr_in1_max.dev_attr.attr,
 479        &sensor_dev_attr_in1_min.dev_attr.attr,
 480        &sensor_dev_attr_in1_crit_max.dev_attr.attr,
 481        &sensor_dev_attr_in1_crit_min.dev_attr.attr,
 482        &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
 483        &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 484        &sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
 485        &sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,
 486
 487        &sensor_dev_attr_power1_input.dev_attr.attr,
 488        &sensor_dev_attr_power1_input_highest.dev_attr.attr,
 489        &sensor_dev_attr_power1_reset_history.dev_attr.attr,
 490        &sensor_dev_attr_power1_max.dev_attr.attr,
 491        &sensor_dev_attr_power1_crit.dev_attr.attr,
 492        &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
 493        &sensor_dev_attr_power1_crit_alarm.dev_attr.attr,
 494
 495        &sensor_dev_attr_curr1_input.dev_attr.attr,
 496
 497        &sensor_dev_attr_update_interval.dev_attr.attr,
 498
 499        NULL,
 500};
 501
 502static const struct attribute_group ina209_group = {
 503        .attrs = ina209_attributes,
 504};
 505
 506static void ina209_restore_conf(struct i2c_client *client,
 507                                struct ina209_data *data)
 508{
 509        /* Restore initial configuration */
 510        i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
 511                                     data->config_orig);
 512        i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
 513                                     data->calibration_orig);
 514}
 515
 516static int ina209_init_client(struct i2c_client *client,
 517                              struct ina209_data *data)
 518{
 519        struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
 520        u32 shunt;
 521        int reg;
 522
 523        reg = i2c_smbus_read_word_swapped(client, INA209_CALIBRATION);
 524        if (reg < 0)
 525                return reg;
 526        data->calibration_orig = reg;
 527
 528        reg = i2c_smbus_read_word_swapped(client, INA209_CONFIGURATION);
 529        if (reg < 0)
 530                return reg;
 531        data->config_orig = reg;
 532
 533        if (pdata) {
 534                if (pdata->shunt_uohms <= 0)
 535                        return -EINVAL;
 536                shunt = pdata->shunt_uohms;
 537        } else if (!of_property_read_u32(client->dev.of_node, "shunt-resistor",
 538                                         &shunt)) {
 539                if (shunt == 0)
 540                        return -EINVAL;
 541        } else {
 542                shunt = data->calibration_orig ?
 543                  40960000 / data->calibration_orig : INA209_SHUNT_DEFAULT;
 544        }
 545
 546        i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
 547                                     INA209_CONFIG_DEFAULT);
 548        data->update_interval = ina209_interval_from_reg(INA209_CONFIG_DEFAULT);
 549
 550        /*
 551         * Calibrate current LSB to 1mA. Shunt is in uOhms.
 552         * See equation 13 in datasheet.
 553         */
 554        i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
 555                                     clamp_val(40960000 / shunt, 1, 65535));
 556
 557        /* Clear status register */
 558        i2c_smbus_read_word_swapped(client, INA209_STATUS);
 559
 560        return 0;
 561}
 562
 563static int ina209_probe(struct i2c_client *client,
 564                        const struct i2c_device_id *id)
 565{
 566        struct i2c_adapter *adapter = client->adapter;
 567        struct ina209_data *data;
 568        int ret;
 569
 570        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 571                return -ENODEV;
 572
 573        data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 574        if (!data)
 575                return -ENOMEM;
 576
 577        i2c_set_clientdata(client, data);
 578        mutex_init(&data->update_lock);
 579
 580        ret = ina209_init_client(client, data);
 581        if (ret)
 582                return ret;
 583
 584        /* Register sysfs hooks */
 585        ret = sysfs_create_group(&client->dev.kobj, &ina209_group);
 586        if (ret)
 587                goto out_restore_conf;
 588
 589        data->hwmon_dev = hwmon_device_register(&client->dev);
 590        if (IS_ERR(data->hwmon_dev)) {
 591                ret = PTR_ERR(data->hwmon_dev);
 592                goto out_hwmon_device_register;
 593        }
 594
 595        return 0;
 596
 597out_hwmon_device_register:
 598        sysfs_remove_group(&client->dev.kobj, &ina209_group);
 599out_restore_conf:
 600        ina209_restore_conf(client, data);
 601        return ret;
 602}
 603
 604static int ina209_remove(struct i2c_client *client)
 605{
 606        struct ina209_data *data = i2c_get_clientdata(client);
 607
 608        hwmon_device_unregister(data->hwmon_dev);
 609        sysfs_remove_group(&client->dev.kobj, &ina209_group);
 610        ina209_restore_conf(client, data);
 611
 612        return 0;
 613}
 614
 615static const struct i2c_device_id ina209_id[] = {
 616        { "ina209", 0 },
 617        { }
 618};
 619MODULE_DEVICE_TABLE(i2c, ina209_id);
 620
 621/* This is the driver that will be inserted */
 622static struct i2c_driver ina209_driver = {
 623        .class          = I2C_CLASS_HWMON,
 624        .driver = {
 625                .name   = "ina209",
 626        },
 627        .probe          = ina209_probe,
 628        .remove         = ina209_remove,
 629        .id_table       = ina209_id,
 630};
 631
 632module_i2c_driver(ina209_driver);
 633
 634MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>, Paul Hays <Paul.Hays@cattail.ca>, Guenter Roeck <linux@roeck-us.net>");
 635MODULE_DESCRIPTION("INA209 driver");
 636MODULE_LICENSE("GPL");
 637
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