drivers/hwmon/ina2xx.c

   1 /*
   2  * Driver for Texas Instruments INA219, INA226 power monitor chips
   3  *
   4  * INA219:
   5  * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
   6  * Datasheet: http://www.ti.com/product/ina219
   7  *
   8  * INA220:
   9  * Bi-Directional Current/Power Monitor with I2C Interface
  10  * Datasheet: http://www.ti.com/product/ina220
  11  *
  12  * INA226:
  13  * Bi-Directional Current/Power Monitor with I2C Interface
  14  * Datasheet: http://www.ti.com/product/ina226
  15  *
  16  * INA230:
  17  * Bi-directional Current/Power Monitor with I2C Interface
  18  * Datasheet: http://www.ti.com/product/ina230
  19  *
  20  * Copyright (C) 2012 Lothar Felten <lothar.felten@gmail.com>
  21  * Thanks to Jan Volkering
  22  *
  23  * This program is free software; you can redistribute it and/or modify
  24  * it under the terms of the GNU General Public License as published by
  25  * the Free Software Foundation; version 2 of the License.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31 #include <linux/err.h>
  32 #include <linux/slab.h>
  33 #include <linux/i2c.h>
  34 #include <linux/hwmon.h>
  35 #include <linux/hwmon-sysfs.h>
  36 #include <linux/jiffies.h>
  37 #include <linux/of.h>
  38 #include <linux/delay.h>
  39 #include <linux/util_macros.h>
  40 #include <linux/regmap.h>
  41
  42 #include <linux/platform_data/ina2xx.h>
  43
  44 /* common register definitions */
  45 #define INA2XX_CONFIG                   0x00
  46 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  47 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  48 #define INA2XX_POWER                    0x03 /* readonly */
  49 #define INA2XX_CURRENT                  0x04 /* readonly */
  50 #define INA2XX_CALIBRATION              0x05
  51
  52 /* INA226 register definitions */
  53 #define INA226_MASK_ENABLE              0x06
  54 #define INA226_ALERT_LIMIT              0x07
  55 #define INA226_DIE_ID                   0xFF
  56
  57 /* register count */
  58 #define INA219_REGISTERS                6
  59 #define INA226_REGISTERS                8
  60
  61 #define INA2XX_MAX_REGISTERS            8
  62
  63 /* settings - depend on use case */
  64 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  65 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  66
  67 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  68 #define INA2XX_CONVERSION_RATE          15
  69 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  70
  71 #define INA2XX_RSHUNT_DEFAULT           10000
  72
  73 /* bit mask for reading the averaging setting in the configuration register */
  74 #define INA226_AVG_RD_MASK              0x0E00
  75
  76 #define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  77 #define INA226_SHIFT_AVG(val)           ((val) << 9)
  78
  79 /* common attrs, ina226 attrs and NULL */
  80 #define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  81
  82 /*
  83  * Both bus voltage and shunt voltage conversion times for ina226 are set
  84  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  85  */
  86 #define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  87
  88 static struct regmap_config ina2xx_regmap_config = {
  89         .reg_bits = 8,
  90         .val_bits = 16,
  91 };
  92
  93 enum ina2xx_ids { ina219, ina226 };
  94
  95 struct ina2xx_config {
  96         u16 config_default;
  97         int calibration_value;
  98         int registers;
  99         int shunt_div;
 100         int bus_voltage_shift;
 101         int bus_voltage_lsb;    /* uV */
 102         int power_lsb_factor;
 103 };
 104
 105 struct ina2xx_data {
 106         const struct ina2xx_config *config;
 107
 108         long rshunt;
 109         long current_lsb_uA;
 110         long power_lsb_uW;
 111         struct mutex config_lock;
 112         struct regmap *regmap;
 113
 114         const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 115 };
 116
 117 static const struct ina2xx_config ina2xx_config[] = {
 118         [ina219] = {
 119                 .config_default = INA219_CONFIG_DEFAULT,
 120                 .calibration_value = 4096,
 121                 .registers = INA219_REGISTERS,
 122                 .shunt_div = 100,
 123                 .bus_voltage_shift = 3,
 124                 .bus_voltage_lsb = 4000,
 125                 .power_lsb_factor = 20,
 126         },
 127         [ina226] = {
 128                 .config_default = INA226_CONFIG_DEFAULT,
 129                 .calibration_value = 2048,
 130                 .registers = INA226_REGISTERS,
 131                 .shunt_div = 400,
 132                 .bus_voltage_shift = 0,
 133                 .bus_voltage_lsb = 1250,
 134                 .power_lsb_factor = 25,
 135         },
 136 };
 137
 138 /*
 139  * Available averaging rates for ina226. The indices correspond with
 140  * the bit values expected by the chip (according to the ina226 datasheet,
 141  * table 3 AVG bit settings, found at
 142  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 143  */
 144 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 145
 146 static int ina226_reg_to_interval(u16 config)
 147 {
 148         int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 149
 150         /*
 151          * Multiply the total conversion time by the number of averages.
 152          * Return the result in milliseconds.
 153          */
 154         return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 155 }
 156
 157 /*
 158  * Return the new, shifted AVG field value of CONFIG register,
 159  * to use with regmap_update_bits
 160  */
 161 static u16 ina226_interval_to_reg(int interval)
 162 {
 163         int avg, avg_bits;
 164
 165         avg = DIV_ROUND_CLOSEST(interval * 1000,
 166                                 INA226_TOTAL_CONV_TIME_DEFAULT);
 167         avg_bits = find_closest(avg, ina226_avg_tab,
 168                                 ARRAY_SIZE(ina226_avg_tab));
 169
 170         return INA226_SHIFT_AVG(avg_bits);
 171 }
 172
 173 /*
 174  * Calibration register is set to the best value, which eliminates
 175  * truncation errors on calculating current register in hardware.
 176  * According to datasheet (eq. 3) the best values are 2048 for
 177  * ina226 and 4096 for ina219. They are hardcoded as calibration_value.
 178  */
 179 static int ina2xx_calibrate(struct ina2xx_data *data)
 180 {
 181         return regmap_write(data->regmap, INA2XX_CALIBRATION,
 182                             data->config->calibration_value);
 183 }
 184
 185 /*
 186  * Initialize the configuration and calibration registers.
 187  */
 188 static int ina2xx_init(struct ina2xx_data *data)
 189 {
 190         int ret = regmap_write(data->regmap, INA2XX_CONFIG,
 191                                data->config->config_default);
 192         if (ret < 0)
 193                 return ret;
 194
 195         return ina2xx_calibrate(data);
 196 }
 197
 198 static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
 199 {
 200         struct ina2xx_data *data = dev_get_drvdata(dev);
 201         int ret, retry;
 202
 203         dev_dbg(dev, "Starting register %d read\n", reg);
 204
 205         for (retry = 5; retry; retry--) {
 206
 207                 ret = regmap_read(data->regmap, reg, regval);
 208                 if (ret < 0)
 209                         return ret;
 210
 211                 dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
 212
 213                 /*
 214                  * If the current value in the calibration register is 0, the
 215                  * power and current registers will also remain at 0. In case
 216                  * the chip has been reset let's check the calibration
 217                  * register and reinitialize if needed.
 218                  * We do that extra read of the calibration register if there
 219                  * is some hint of a chip reset.
 220                  */
 221                 if (*regval == 0) {
 222                         unsigned int cal;
 223
 224                         ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
 225                                           &cal);
 226                         if (ret < 0)
 227                                 return ret;
 228
 229                         if (cal == 0) {
 230                                 dev_warn(dev, "chip not calibrated, reinitializing\n");
 231
 232                                 ret = ina2xx_init(data);
 233                                 if (ret < 0)
 234                                         return ret;
 235                                 /*
 236                                  * Let's make sure the power and current
 237                                  * registers have been updated before trying
 238                                  * again.
 239                                  */
 240                                 msleep(INA2XX_MAX_DELAY);
 241                                 continue;
 242                         }
 243                 }
 244                 return 0;
 245         }
 246
 247         /*
 248          * If we're here then although all write operations succeeded, the
 249          * chip still returns 0 in the calibration register. Nothing more we
 250          * can do here.
 251          */
 252         dev_err(dev, "unable to reinitialize the chip\n");
 253         return -ENODEV;
 254 }
 255
 256 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
 257                             unsigned int regval)
 258 {
 259         int val;
 260
 261         switch (reg) {
 262         case INA2XX_SHUNT_VOLTAGE:
 263                 /* signed register */
 264                 val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
 265                 break;
 266         case INA2XX_BUS_VOLTAGE:
 267                 val = (regval >> data->config->bus_voltage_shift)
 268                   * data->config->bus_voltage_lsb;
 269                 val = DIV_ROUND_CLOSEST(val, 1000);
 270                 break;
 271         case INA2XX_POWER:
 272                 val = regval * data->power_lsb_uW;
 273                 break;
 274         case INA2XX_CURRENT:
 275                 /* signed register, result in mA */
 276                 val = (s16)regval * data->current_lsb_uA;
 277                 val = DIV_ROUND_CLOSEST(val, 1000);
 278                 break;
 279         case INA2XX_CALIBRATION:
 280                 val = regval;
 281                 break;
 282         default:
 283                 /* programmer goofed */
 284                 WARN_ON_ONCE(1);
 285                 val = 0;
 286                 break;
 287         }
 288
 289         return val;
 290 }
 291
 292 static ssize_t ina2xx_show_value(struct device *dev,
 293                                  struct device_attribute *da, char *buf)
 294 {
 295         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 296         struct ina2xx_data *data = dev_get_drvdata(dev);
 297         unsigned int regval;
 298
 299         int err = ina2xx_read_reg(dev, attr->index, &regval);
 300
 301         if (err < 0)
 302                 return err;
 303
 304         return snprintf(buf, PAGE_SIZE, "%d\n",
 305                         ina2xx_get_value(data, attr->index, regval));
 306 }
 307
 308 /*
 309  * In order to keep calibration register value fixed, the product
 310  * of current_lsb and shunt_resistor should also be fixed and equal
 311  * to shunt_voltage_lsb = 1 / shunt_div multiplied by 10^9 in order
 312  * to keep the scale.
 313  */
 314 static int ina2xx_set_shunt(struct ina2xx_data *data, long val)
 315 {
 316         unsigned int dividend = DIV_ROUND_CLOSEST(1000000000,
 317                                                   data->config->shunt_div);
 318         if (val <= 0 || val > dividend)
 319                 return -EINVAL;
 320
 321         mutex_lock(&data->config_lock);
 322         data->rshunt = val;
 323         data->current_lsb_uA = DIV_ROUND_CLOSEST(dividend, val);
 324         data->power_lsb_uW = data->config->power_lsb_factor *
 325                              data->current_lsb_uA;
 326         mutex_unlock(&data->config_lock);
 327
 328         return 0;
 329 }
 330
 331 static ssize_t ina2xx_show_shunt(struct device *dev,
 332                               struct device_attribute *da,
 333                               char *buf)
 334 {
 335         struct ina2xx_data *data = dev_get_drvdata(dev);
 336
 337         return snprintf(buf, PAGE_SIZE, "%li\n", data->rshunt);
 338 }
 339
 340 static ssize_t ina2xx_store_shunt(struct device *dev,
 341                                   struct device_attribute *da,
 342                                   const char *buf, size_t count)
 343 {
 344         unsigned long val;
 345         int status;
 346         struct ina2xx_data *data = dev_get_drvdata(dev);
 347
 348         status = kstrtoul(buf, 10, &val);
 349         if (status < 0)
 350                 return status;
 351
 352         status = ina2xx_set_shunt(data, val);
 353         if (status < 0)
 354                 return status;
 355         return count;
 356 }
 357
 358 static ssize_t ina226_set_interval(struct device *dev,
 359                                    struct device_attribute *da,
 360                                    const char *buf, size_t count)
 361 {
 362         struct ina2xx_data *data = dev_get_drvdata(dev);
 363         unsigned long val;
 364         int status;
 365
 366         status = kstrtoul(buf, 10, &val);
 367         if (status < 0)
 368                 return status;
 369
 370         if (val > INT_MAX || val == 0)
 371                 return -EINVAL;
 372
 373         status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
 374                                     INA226_AVG_RD_MASK,
 375                                     ina226_interval_to_reg(val));
 376         if (status < 0)
 377                 return status;
 378
 379         return count;
 380 }
 381
 382 static ssize_t ina226_show_interval(struct device *dev,
 383                                     struct device_attribute *da, char *buf)
 384 {
 385         struct ina2xx_data *data = dev_get_drvdata(dev);
 386         int status;
 387         unsigned int regval;
 388
 389         status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
 390         if (status)
 391                 return status;
 392
 393         return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
 394 }
 395
 396 /* shunt voltage */
 397 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 398                           INA2XX_SHUNT_VOLTAGE);
 399
 400 /* bus voltage */
 401 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 402                           INA2XX_BUS_VOLTAGE);
 403
 404 /* calculated current */
 405 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 406                           INA2XX_CURRENT);
 407
 408 /* calculated power */
 409 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 410                           INA2XX_POWER);
 411
 412 /* shunt resistance */
 413 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 414                           ina2xx_show_shunt, ina2xx_store_shunt,
 415                           INA2XX_CALIBRATION);
 416
 417 /* update interval (ina226 only) */
 418 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 419                           ina226_show_interval, ina226_set_interval, 0);
 420
 421 /* pointers to created device attributes */
 422 static struct attribute *ina2xx_attrs[] = {
 423         &sensor_dev_attr_in0_input.dev_attr.attr,
 424         &sensor_dev_attr_in1_input.dev_attr.attr,
 425         &sensor_dev_attr_curr1_input.dev_attr.attr,
 426         &sensor_dev_attr_power1_input.dev_attr.attr,
 427         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 428         NULL,
 429 };
 430
 431 static const struct attribute_group ina2xx_group = {
 432         .attrs = ina2xx_attrs,
 433 };
 434
 435 static struct attribute *ina226_attrs[] = {
 436         &sensor_dev_attr_update_interval.dev_attr.attr,
 437         NULL,
 438 };
 439
 440 static const struct attribute_group ina226_group = {
 441         .attrs = ina226_attrs,
 442 };
 443
 444 static int ina2xx_probe(struct i2c_client *client,
 445                         const struct i2c_device_id *id)
 446 {
 447         struct device *dev = &client->dev;
 448         struct ina2xx_data *data;
 449         struct device *hwmon_dev;
 450         u32 val;
 451         int ret, group = 0;
 452
 453         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 454         if (!data)
 455                 return -ENOMEM;
 456
 457         /* set the device type */
 458         data->config = &ina2xx_config[id->driver_data];
 459         mutex_init(&data->config_lock);
 460
 461         if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 462                 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
 463
 464                 if (pdata)
 465                         val = pdata->shunt_uohms;
 466                 else
 467                         val = INA2XX_RSHUNT_DEFAULT;
 468         }
 469
 470         ina2xx_set_shunt(data, val);
 471
 472         ina2xx_regmap_config.max_register = data->config->registers;
 473
 474         data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 475         if (IS_ERR(data->regmap)) {
 476                 dev_err(dev, "failed to allocate register map\n");
 477                 return PTR_ERR(data->regmap);
 478         }
 479
 480         ret = ina2xx_init(data);
 481         if (ret < 0) {
 482                 dev_err(dev, "error configuring the device: %d\n", ret);
 483                 return -ENODEV;
 484         }
 485
 486         data->groups[group++] = &ina2xx_group;
 487         if (id->driver_data == ina226)
 488                 data->groups[group++] = &ina226_group;
 489
 490         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 491                                                            data, data->groups);
 492         if (IS_ERR(hwmon_dev))
 493                 return PTR_ERR(hwmon_dev);
 494
 495         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 496                  id->name, data->rshunt);
 497
 498         return 0;
 499 }
 500
 501 static const struct i2c_device_id ina2xx_id[] = {
 502         { "ina219", ina219 },
 503         { "ina220", ina219 },
 504         { "ina226", ina226 },
 505         { "ina230", ina226 },
 506         { "ina231", ina226 },
 507         { }
 508 };
 509 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 510
 511 static struct i2c_driver ina2xx_driver = {
 512         .driver = {
 513                 .name   = "ina2xx",
 514         },
 515         .probe          = ina2xx_probe,
 516         .id_table       = ina2xx_id,
 517 };
 518
 519 module_i2c_driver(ina2xx_driver);
 520
 521 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 522 MODULE_DESCRIPTION("ina2xx driver");
 523 MODULE_LICENSE("GPL");