linux/drivers/hwmon/ina2xx.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Driver for Texas Instruments INA219, INA226 power monitor chips
   4 *
   5 * INA219:
   6 * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
   7 * Datasheet: http://www.ti.com/product/ina219
   8 *
   9 * INA220:
  10 * Bi-Directional Current/Power Monitor with I2C Interface
  11 * Datasheet: http://www.ti.com/product/ina220
  12 *
  13 * INA226:
  14 * Bi-Directional Current/Power Monitor with I2C Interface
  15 * Datasheet: http://www.ti.com/product/ina226
  16 *
  17 * INA230:
  18 * Bi-directional Current/Power Monitor with I2C Interface
  19 * Datasheet: http://www.ti.com/product/ina230
  20 *
  21 * Copyright (C) 2012 Lothar Felten <lothar.felten@gmail.com>
  22 * Thanks to Jan Volkering
  23 */
  24
  25#include <linux/kernel.h>
  26#include <linux/module.h>
  27#include <linux/init.h>
  28#include <linux/err.h>
  29#include <linux/slab.h>
  30#include <linux/i2c.h>
  31#include <linux/hwmon.h>
  32#include <linux/hwmon-sysfs.h>
  33#include <linux/jiffies.h>
  34#include <linux/of_device.h>
  35#include <linux/of.h>
  36#include <linux/delay.h>
  37#include <linux/util_macros.h>
  38#include <linux/regmap.h>
  39
  40#include <linux/platform_data/ina2xx.h>
  41
  42/* common register definitions */
  43#define INA2XX_CONFIG                   0x00
  44#define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  45#define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  46#define INA2XX_POWER                    0x03 /* readonly */
  47#define INA2XX_CURRENT                  0x04 /* readonly */
  48#define INA2XX_CALIBRATION              0x05
  49
  50/* INA226 register definitions */
  51#define INA226_MASK_ENABLE              0x06
  52#define INA226_ALERT_LIMIT              0x07
  53#define INA226_DIE_ID                   0xFF
  54
  55/* register count */
  56#define INA219_REGISTERS                6
  57#define INA226_REGISTERS                8
  58
  59#define INA2XX_MAX_REGISTERS            8
  60
  61/* settings - depend on use case */
  62#define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  63#define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  64
  65/* worst case is 68.10 ms (~14.6Hz, ina219) */
  66#define INA2XX_CONVERSION_RATE          15
  67#define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  68
  69#define INA2XX_RSHUNT_DEFAULT           10000
  70
  71/* bit mask for reading the averaging setting in the configuration register */
  72#define INA226_AVG_RD_MASK              0x0E00
  73
  74#define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  75#define INA226_SHIFT_AVG(val)           ((val) << 9)
  76
  77/* common attrs, ina226 attrs and NULL */
  78#define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  79
  80/*
  81 * Both bus voltage and shunt voltage conversion times for ina226 are set
  82 * to 0b0100 on POR, which translates to 2200 microseconds in total.
  83 */
  84#define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  85
  86static struct regmap_config ina2xx_regmap_config = {
  87        .reg_bits = 8,
  88        .val_bits = 16,
  89};
  90
  91enum ina2xx_ids { ina219, ina226 };
  92
  93struct ina2xx_config {
  94        u16 config_default;
  95        int calibration_value;
  96        int registers;
  97        int shunt_div;
  98        int bus_voltage_shift;
  99        int bus_voltage_lsb;    /* uV */
 100        int power_lsb_factor;
 101};
 102
 103struct ina2xx_data {
 104        const struct ina2xx_config *config;
 105
 106        long rshunt;
 107        long current_lsb_uA;
 108        long power_lsb_uW;
 109        struct mutex config_lock;
 110        struct regmap *regmap;
 111
 112        const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 113};
 114
 115static const struct ina2xx_config ina2xx_config[] = {
 116        [ina219] = {
 117                .config_default = INA219_CONFIG_DEFAULT,
 118                .calibration_value = 4096,
 119                .registers = INA219_REGISTERS,
 120                .shunt_div = 100,
 121                .bus_voltage_shift = 3,
 122                .bus_voltage_lsb = 4000,
 123                .power_lsb_factor = 20,
 124        },
 125        [ina226] = {
 126                .config_default = INA226_CONFIG_DEFAULT,
 127                .calibration_value = 2048,
 128                .registers = INA226_REGISTERS,
 129                .shunt_div = 400,
 130                .bus_voltage_shift = 0,
 131                .bus_voltage_lsb = 1250,
 132                .power_lsb_factor = 25,
 133        },
 134};
 135
 136/*
 137 * Available averaging rates for ina226. The indices correspond with
 138 * the bit values expected by the chip (according to the ina226 datasheet,
 139 * table 3 AVG bit settings, found at
 140 * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 141 */
 142static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 143
 144static int ina226_reg_to_interval(u16 config)
 145{
 146        int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 147
 148        /*
 149         * Multiply the total conversion time by the number of averages.
 150         * Return the result in milliseconds.
 151         */
 152        return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 153}
 154
 155/*
 156 * Return the new, shifted AVG field value of CONFIG register,
 157 * to use with regmap_update_bits
 158 */
 159static u16 ina226_interval_to_reg(int interval)
 160{
 161        int avg, avg_bits;
 162
 163        avg = DIV_ROUND_CLOSEST(interval * 1000,
 164                                INA226_TOTAL_CONV_TIME_DEFAULT);
 165        avg_bits = find_closest(avg, ina226_avg_tab,
 166                                ARRAY_SIZE(ina226_avg_tab));
 167
 168        return INA226_SHIFT_AVG(avg_bits);
 169}
 170
 171/*
 172 * Calibration register is set to the best value, which eliminates
 173 * truncation errors on calculating current register in hardware.
 174 * According to datasheet (eq. 3) the best values are 2048 for
 175 * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
 176 */
 177static int ina2xx_calibrate(struct ina2xx_data *data)
 178{
 179        return regmap_write(data->regmap, INA2XX_CALIBRATION,
 180                            data->config->calibration_value);
 181}
 182
 183/*
 184 * Initialize the configuration and calibration registers.
 185 */
 186static int ina2xx_init(struct ina2xx_data *data)
 187{
 188        int ret = regmap_write(data->regmap, INA2XX_CONFIG,
 189                               data->config->config_default);
 190        if (ret < 0)
 191                return ret;
 192
 193        return ina2xx_calibrate(data);
 194}
 195
 196static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
 197{
 198        struct ina2xx_data *data = dev_get_drvdata(dev);
 199        int ret, retry;
 200
 201        dev_dbg(dev, "Starting register %d read\n", reg);
 202
 203        for (retry = 5; retry; retry--) {
 204
 205                ret = regmap_read(data->regmap, reg, regval);
 206                if (ret < 0)
 207                        return ret;
 208
 209                dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
 210
 211                /*
 212                 * If the current value in the calibration register is 0, the
 213                 * power and current registers will also remain at 0. In case
 214                 * the chip has been reset let's check the calibration
 215                 * register and reinitialize if needed.
 216                 * We do that extra read of the calibration register if there
 217                 * is some hint of a chip reset.
 218                 */
 219                if (*regval == 0) {
 220                        unsigned int cal;
 221
 222                        ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
 223                                          &cal);
 224                        if (ret < 0)
 225                                return ret;
 226
 227                        if (cal == 0) {
 228                                dev_warn(dev, "chip not calibrated, reinitializing\n");
 229
 230                                ret = ina2xx_init(data);
 231                                if (ret < 0)
 232                                        return ret;
 233                                /*
 234                                 * Let's make sure the power and current
 235                                 * registers have been updated before trying
 236                                 * again.
 237                                 */
 238                                msleep(INA2XX_MAX_DELAY);
 239                                continue;
 240                        }
 241                }
 242                return 0;
 243        }
 244
 245        /*
 246         * If we're here then although all write operations succeeded, the
 247         * chip still returns 0 in the calibration register. Nothing more we
 248         * can do here.
 249         */
 250        dev_err(dev, "unable to reinitialize the chip\n");
 251        return -ENODEV;
 252}
 253
 254static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
 255                            unsigned int regval)
 256{
 257        int val;
 258
 259        switch (reg) {
 260        case INA2XX_SHUNT_VOLTAGE:
 261                /* signed register */
 262                val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
 263                break;
 264        case INA2XX_BUS_VOLTAGE:
 265                val = (regval >> data->config->bus_voltage_shift)
 266                  * data->config->bus_voltage_lsb;
 267                val = DIV_ROUND_CLOSEST(val, 1000);
 268                break;
 269        case INA2XX_POWER:
 270                val = regval * data->power_lsb_uW;
 271                break;
 272        case INA2XX_CURRENT:
 273                /* signed register, result in mA */
 274                val = (s16)regval * data->current_lsb_uA;
 275                val = DIV_ROUND_CLOSEST(val, 1000);
 276                break;
 277        case INA2XX_CALIBRATION:
 278                val = regval;
 279                break;
 280        default:
 281                /* programmer goofed */
 282                WARN_ON_ONCE(1);
 283                val = 0;
 284                break;
 285        }
 286
 287        return val;
 288}
 289
 290static ssize_t ina2xx_value_show(struct device *dev,
 291                                 struct device_attribute *da, char *buf)
 292{
 293        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 294        struct ina2xx_data *data = dev_get_drvdata(dev);
 295        unsigned int regval;
 296
 297        int err = ina2xx_read_reg(dev, attr->index, &regval);
 298
 299        if (err < 0)
 300                return err;
 301
 302        return snprintf(buf, PAGE_SIZE, "%d\n",
 303                        ina2xx_get_value(data, attr->index, regval));
 304}
 305
 306/*
 307 * In order to keep calibration register value fixed, the product
 308 * of current_lsb and shunt_resistor should also be fixed and equal
 309 * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
 310 * to keep the scale.
 311 */
 312static int ina2xx_set_shunt(struct ina2xx_data *data, long val)
 313{
 314        unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
 315                                                  data->config->shunt_div);
 316        if (val <= 0 || val > dividend)
 317                return -EINVAL;
 318
 319        mutex_lock(&data->config_lock);
 320        data->rshunt = val;
 321        data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
 322        data->power_lsb_uW = data->config->power_lsb_factor *
 323                             data->current_lsb_uA;
 324        mutex_unlock(&data->config_lock);
 325
 326        return 0;
 327}
 328
 329static ssize_t ina2xx_shunt_show(struct device *dev,
 330                                 struct device_attribute *da, char *buf)
 331{
 332        struct ina2xx_data *data = dev_get_drvdata(dev);
 333
 334        return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
 335}
 336
 337static ssize_t ina2xx_shunt_store(struct device *dev,
 338                                  struct device_attribute *da,
 339                                  const char *buf, size_t count)
 340{
 341        unsigned long val;
 342        int status;
 343        struct ina2xx_data *data = dev_get_drvdata(dev);
 344
 345        status = kstrtoul(buf, 10, &val);
 346        if (status < 0)
 347                return status;
 348
 349        status = ina2xx_set_shunt(data, val);
 350        if (status < 0)
 351                return status;
 352        return count;
 353}
 354
 355static ssize_t ina226_interval_store(struct device *dev,
 356                                     struct device_attribute *da,
 357                                     const char *buf, size_t count)
 358{
 359        struct ina2xx_data *data = dev_get_drvdata(dev);
 360        unsigned long val;
 361        int status;
 362
 363        status = kstrtoul(buf, 10, &val);
 364        if (status < 0)
 365                return status;
 366
 367        if (val > INT_MAX || val == 0)
 368                return -EINVAL;
 369
 370        status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
 371                                    INA226_AVG_RD_MASK,
 372                                    ina226_interval_to_reg(val));
 373        if (status < 0)
 374                return status;
 375
 376        return count;
 377}
 378
 379static ssize_t ina226_interval_show(struct device *dev,
 380                                    struct device_attribute *da, char *buf)
 381{
 382        struct ina2xx_data *data = dev_get_drvdata(dev);
 383        int status;
 384        unsigned int regval;
 385
 386        status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
 387        if (status)
 388                return status;
 389
 390        return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
 391}
 392
 393/* shunt voltage */
 394static SENSOR_DEVICE_ATTR_RO(in0_input, ina2xx_value, INA2XX_SHUNT_VOLTAGE);
 395
 396/* bus voltage */
 397static SENSOR_DEVICE_ATTR_RO(in1_input, ina2xx_value, INA2XX_BUS_VOLTAGE);
 398
 399/* calculated current */
 400static SENSOR_DEVICE_ATTR_RO(curr1_input, ina2xx_value, INA2XX_CURRENT);
 401
 402/* calculated power */
 403static SENSOR_DEVICE_ATTR_RO(power1_input, ina2xx_value, INA2XX_POWER);
 404
 405/* shunt resistance */
 406static SENSOR_DEVICE_ATTR_RW(shunt_resistor, ina2xx_shunt, INA2XX_CALIBRATION);
 407
 408/* update interval (ina226 only) */
 409static SENSOR_DEVICE_ATTR_RW(update_interval, ina226_interval, 0);
 410
 411/* pointers to created device attributes */
 412static struct attribute *ina2xx_attrs[] = {
 413        &sensor_dev_attr_in0_input.dev_attr.attr,
 414        &sensor_dev_attr_in1_input.dev_attr.attr,
 415        &sensor_dev_attr_curr1_input.dev_attr.attr,
 416        &sensor_dev_attr_power1_input.dev_attr.attr,
 417        &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 418        NULL,
 419};
 420
 421static const struct attribute_group ina2xx_group = {
 422        .attrs = ina2xx_attrs,
 423};
 424
 425static struct attribute *ina226_attrs[] = {
 426        &sensor_dev_attr_update_interval.dev_attr.attr,
 427        NULL,
 428};
 429
 430static const struct attribute_group ina226_group = {
 431        .attrs = ina226_attrs,
 432};
 433
 434static int ina2xx_probe(struct i2c_client *client,
 435                        const struct i2c_device_id *id)
 436{
 437        struct device *dev = &client->dev;
 438        struct ina2xx_data *data;
 439        struct device *hwmon_dev;
 440        u32 val;
 441        int ret, group = 0;
 442        enum ina2xx_ids chip;
 443
 444        if (client->dev.of_node)
 445                chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
 446        else
 447                chip = id->driver_data;
 448
 449        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 450        if (!data)
 451                return -ENOMEM;
 452
 453        /* set the device type */
 454        data->config = &ina2xx_config[chip];
 455        mutex_init(&data->config_lock);
 456
 457        if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 458                struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
 459
 460                if (pdata)
 461                        val = pdata->shunt_uohms;
 462                else
 463                        val = INA2XX_RSHUNT_DEFAULT;
 464        }
 465
 466        ina2xx_set_shunt(data, val);
 467
 468        ina2xx_regmap_config.max_register = data->config->registers;
 469
 470        data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 471        if (IS_ERR(data->regmap)) {
 472                dev_err(dev, "failed to allocate register map\n");
 473                return PTR_ERR(data->regmap);
 474        }
 475
 476        ret = ina2xx_init(data);
 477        if (ret < 0) {
 478                dev_err(dev, "error configuring the device: %d\n", ret);
 479                return -ENODEV;
 480        }
 481
 482        data->groups[group++] = &ina2xx_group;
 483        if (chip == ina226)
 484                data->groups[group++] = &ina226_group;
 485
 486        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 487                                                           data, data->groups);
 488        if (IS_ERR(hwmon_dev))
 489                return PTR_ERR(hwmon_dev);
 490
 491        dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 492                 client->name, data->rshunt);
 493
 494        return 0;
 495}
 496
 497static const struct i2c_device_id ina2xx_id[] = {
 498        { "ina219", ina219 },
 499        { "ina220", ina219 },
 500        { "ina226", ina226 },
 501        { "ina230", ina226 },
 502        { "ina231", ina226 },
 503        { }
 504};
 505MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 506
 507static const struct of_device_id __maybe_unused ina2xx_of_match[] = {
 508        {
 509                .compatible = "ti,ina219",
 510                .data = (void *)ina219
 511        },
 512        {
 513                .compatible = "ti,ina220",
 514                .data = (void *)ina219
 515        },
 516        {
 517                .compatible = "ti,ina226",
 518                .data = (void *)ina226
 519        },
 520        {
 521                .compatible = "ti,ina230",
 522                .data = (void *)ina226
 523        },
 524        {
 525                .compatible = "ti,ina231",
 526                .data = (void *)ina226
 527        },
 528        { },
 529};
 530MODULE_DEVICE_TABLE(of, ina2xx_of_match);
 531
 532static struct i2c_driver ina2xx_driver = {
 533        .driver = {
 534                .name   = "ina2xx",
 535                .of_match_table = of_match_ptr(ina2xx_of_match),
 536        },
 537        .probe          = ina2xx_probe,
 538        .id_table       = ina2xx_id,
 539};
 540
 541module_i2c_driver(ina2xx_driver);
 542
 543MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 544MODULE_DESCRIPTION("ina2xx driver");
 545MODULE_LICENSE("GPL");
 546