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 <l-felten@ti.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_device.h>
  38 #include <linux/of.h>
  39 #include <linux/delay.h>
  40 #include <linux/util_macros.h>
  41 #include <linux/regmap.h>
  42
  43 #include <linux/platform_data/ina2xx.h>
  44
  45 /* common register definitions */
  46 #define INA2XX_CONFIG                   0x00
  47 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  48 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  49 #define INA2XX_POWER                    0x03 /* readonly */
  50 #define INA2XX_CURRENT                  0x04 /* readonly */
  51 #define INA2XX_CALIBRATION              0x05
  52
  53 /* INA226 register definitions */
  54 #define INA226_MASK_ENABLE              0x06
  55 #define INA226_ALERT_LIMIT              0x07
  56 #define INA226_DIE_ID                   0xFF
  57
  58 /* register count */
  59 #define INA219_REGISTERS                6
  60 #define INA226_REGISTERS                8
  61
  62 #define INA2XX_MAX_REGISTERS            8
  63
  64 /* settings - depend on use case */
  65 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  66 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  67
  68 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  69 #define INA2XX_CONVERSION_RATE          15
  70 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  71
  72 #define INA2XX_RSHUNT_DEFAULT           10000
  73
  74 /* bit mask for reading the averaging setting in the configuration register */
  75 #define INA226_AVG_RD_MASK              0x0E00
  76
  77 #define INA226_READ_AVG(reg)            (((reg) & INA226_AVG_RD_MASK) >> 9)
  78 #define INA226_SHIFT_AVG(val)           ((val) << 9)
  79
  80 /* common attrs, ina226 attrs and NULL */
  81 #define INA2XX_MAX_ATTRIBUTE_GROUPS     3
  82
  83 /*
  84  * Both bus voltage and shunt voltage conversion times for ina226 are set
  85  * to 0b0100 on POR, which translates to 2200 microseconds in total.
  86  */
  87 #define INA226_TOTAL_CONV_TIME_DEFAULT  2200
  88
  89 static struct regmap_config ina2xx_regmap_config = {
  90         .reg_bits = 8,
  91         .val_bits = 16,
  92 };
  93
  94 enum ina2xx_ids { ina219, ina226 };
  95
  96 struct ina2xx_config {
  97         u16 config_default;
  98         int calibration_factor;
  99         int registers;
 100         int shunt_div;
 101         int bus_voltage_shift;
 102         int bus_voltage_lsb;    /* uV */
 103         int power_lsb;          /* uW */
 104 };
 105
 106 struct ina2xx_data {
 107         const struct ina2xx_config *config;
 108
 109         long rshunt;
 110         struct mutex config_lock;
 111         struct regmap *regmap;
 112
 113         const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
 114 };
 115
 116 static const struct ina2xx_config ina2xx_config[] = {
 117         [ina219] = {
 118                 .config_default = INA219_CONFIG_DEFAULT,
 119                 .calibration_factor = 40960000,
 120                 .registers = INA219_REGISTERS,
 121                 .shunt_div = 100,
 122                 .bus_voltage_shift = 3,
 123                 .bus_voltage_lsb = 4000,
 124                 .power_lsb = 20000,
 125         },
 126         [ina226] = {
 127                 .config_default = INA226_CONFIG_DEFAULT,
 128                 .calibration_factor = 5120000,
 129                 .registers = INA226_REGISTERS,
 130                 .shunt_div = 400,
 131                 .bus_voltage_shift = 0,
 132                 .bus_voltage_lsb = 1250,
 133                 .power_lsb = 25000,
 134         },
 135 };
 136
 137 /*
 138  * Available averaging rates for ina226. The indices correspond with
 139  * the bit values expected by the chip (according to the ina226 datasheet,
 140  * table 3 AVG bit settings, found at
 141  * http://www.ti.com/lit/ds/symlink/ina226.pdf.
 142  */
 143 static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
 144
 145 static int ina226_reg_to_interval(u16 config)
 146 {
 147         int avg = ina226_avg_tab[INA226_READ_AVG(config)];
 148
 149         /*
 150          * Multiply the total conversion time by the number of averages.
 151          * Return the result in milliseconds.
 152          */
 153         return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
 154 }
 155
 156 /*
 157  * Return the new, shifted AVG field value of CONFIG register,
 158  * to use with regmap_update_bits
 159  */
 160 static u16 ina226_interval_to_reg(int interval)
 161 {
 162         int avg, avg_bits;
 163
 164         avg = DIV_ROUND_CLOSEST(interval * 1000,
 165                                 INA226_TOTAL_CONV_TIME_DEFAULT);
 166         avg_bits = find_closest(avg, ina226_avg_tab,
 167                                 ARRAY_SIZE(ina226_avg_tab));
 168
 169         return INA226_SHIFT_AVG(avg_bits);
 170 }
 171
 172 static int ina2xx_calibrate(struct ina2xx_data *data)
 173 {
 174         u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 175                                     data->rshunt);
 176
 177         return regmap_write(data->regmap, INA2XX_CALIBRATION, val);
 178 }
 179
 180 /*
 181  * Initialize the configuration and calibration registers.
 182  */
 183 static int ina2xx_init(struct ina2xx_data *data)
 184 {
 185         int ret = regmap_write(data->regmap, INA2XX_CONFIG,
 186                                data->config->config_default);
 187         if (ret < 0)
 188                 return ret;
 189
 190         /*
 191          * Set current LSB to 1mA, shunt is in uOhms
 192          * (equation 13 in datasheet).
 193          */
 194         return ina2xx_calibrate(data);
 195 }
 196
 197 static int ina2xx_read_reg(struct device *dev, int reg, unsigned int *regval)
 198 {
 199         struct ina2xx_data *data = dev_get_drvdata(dev);
 200         int ret, retry;
 201
 202         dev_dbg(dev, "Starting register %d read\n", reg);
 203
 204         for (retry = 5; retry; retry--) {
 205
 206                 ret = regmap_read(data->regmap, reg, regval);
 207                 if (ret < 0)
 208                         return ret;
 209
 210                 dev_dbg(dev, "read %d, val = 0x%04x\n", reg, *regval);
 211
 212                 /*
 213                  * If the current value in the calibration register is 0, the
 214                  * power and current registers will also remain at 0. In case
 215                  * the chip has been reset let's check the calibration
 216                  * register and reinitialize if needed.
 217                  * We do that extra read of the calibration register if there
 218                  * is some hint of a chip reset.
 219                  */
 220                 if (*regval == 0) {
 221                         unsigned int cal;
 222
 223                         ret = regmap_read(data->regmap, INA2XX_CALIBRATION,
 224                                           &cal);
 225                         if (ret < 0)
 226                                 return ret;
 227
 228                         if (cal == 0) {
 229                                 dev_warn(dev, "chip not calibrated, reinitializing\n");
 230
 231                                 ret = ina2xx_init(data);
 232                                 if (ret < 0)
 233                                         return ret;
 234                                 /*
 235                                  * Let's make sure the power and current
 236                                  * registers have been updated before trying
 237                                  * again.
 238                                  */
 239                                 msleep(INA2XX_MAX_DELAY);
 240                                 continue;
 241                         }
 242                 }
 243                 return 0;
 244         }
 245
 246         /*
 247          * If we're here then although all write operations succeeded, the
 248          * chip still returns 0 in the calibration register. Nothing more we
 249          * can do here.
 250          */
 251         dev_err(dev, "unable to reinitialize the chip\n");
 252         return -ENODEV;
 253 }
 254
 255 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
 256                             unsigned int regval)
 257 {
 258         int val;
 259
 260         switch (reg) {
 261         case INA2XX_SHUNT_VOLTAGE:
 262                 /* signed register */
 263                 val = DIV_ROUND_CLOSEST((s16)regval, data->config->shunt_div);
 264                 break;
 265         case INA2XX_BUS_VOLTAGE:
 266                 val = (regval >> data->config->bus_voltage_shift)
 267                   * data->config->bus_voltage_lsb;
 268                 val = DIV_ROUND_CLOSEST(val, 1000);
 269                 break;
 270         case INA2XX_POWER:
 271                 val = regval * data->config->power_lsb;
 272                 break;
 273         case INA2XX_CURRENT:
 274                 /* signed register, LSB=1mA (selected), in mA */
 275                 val = (s16)regval;
 276                 break;
 277         case INA2XX_CALIBRATION:
 278                 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
 279                                         regval);
 280                 break;
 281         default:
 282                 /* programmer goofed */
 283                 WARN_ON_ONCE(1);
 284                 val = 0;
 285                 break;
 286         }
 287
 288         return val;
 289 }
 290
 291 static ssize_t ina2xx_show_value(struct device *dev,
 292                                  struct device_attribute *da, char *buf)
 293 {
 294         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 295         struct ina2xx_data *data = dev_get_drvdata(dev);
 296         unsigned int regval;
 297
 298         int err = ina2xx_read_reg(dev, attr->index, &regval);
 299
 300         if (err < 0)
 301                 return err;
 302
 303         return snprintf(buf, PAGE_SIZE, "%d\n",
 304                         ina2xx_get_value(data, attr->index, regval));
 305 }
 306
 307 static ssize_t ina2xx_set_shunt(struct device *dev,
 308                                 struct device_attribute *da,
 309                                 const char *buf, size_t count)
 310 {
 311         unsigned long val;
 312         int status;
 313         struct ina2xx_data *data = dev_get_drvdata(dev);
 314
 315         status = kstrtoul(buf, 10, &val);
 316         if (status < 0)
 317                 return status;
 318
 319         if (val == 0 ||
 320             /* Values greater than the calibration factor make no sense. */
 321             val > data->config->calibration_factor)
 322                 return -EINVAL;
 323
 324         mutex_lock(&data->config_lock);
 325         data->rshunt = val;
 326         status = ina2xx_calibrate(data);
 327         mutex_unlock(&data->config_lock);
 328         if (status < 0)
 329                 return status;
 330
 331         return count;
 332 }
 333
 334 static ssize_t ina226_set_interval(struct device *dev,
 335                                    struct device_attribute *da,
 336                                    const char *buf, size_t count)
 337 {
 338         struct ina2xx_data *data = dev_get_drvdata(dev);
 339         unsigned long val;
 340         int status;
 341
 342         status = kstrtoul(buf, 10, &val);
 343         if (status < 0)
 344                 return status;
 345
 346         if (val > INT_MAX || val == 0)
 347                 return -EINVAL;
 348
 349         status = regmap_update_bits(data->regmap, INA2XX_CONFIG,
 350                                     INA226_AVG_RD_MASK,
 351                                     ina226_interval_to_reg(val));
 352         if (status < 0)
 353                 return status;
 354
 355         return count;
 356 }
 357
 358 static ssize_t ina226_show_interval(struct device *dev,
 359                                     struct device_attribute *da, char *buf)
 360 {
 361         struct ina2xx_data *data = dev_get_drvdata(dev);
 362         int status;
 363         unsigned int regval;
 364
 365         status = regmap_read(data->regmap, INA2XX_CONFIG, &regval);
 366         if (status)
 367                 return status;
 368
 369         return snprintf(buf, PAGE_SIZE, "%d\n", ina226_reg_to_interval(regval));
 370 }
 371
 372 /* shunt voltage */
 373 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 374                           INA2XX_SHUNT_VOLTAGE);
 375
 376 /* bus voltage */
 377 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 378                           INA2XX_BUS_VOLTAGE);
 379
 380 /* calculated current */
 381 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 382                           INA2XX_CURRENT);
 383
 384 /* calculated power */
 385 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 386                           INA2XX_POWER);
 387
 388 /* shunt resistance */
 389 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 390                           ina2xx_show_value, ina2xx_set_shunt,
 391                           INA2XX_CALIBRATION);
 392
 393 /* update interval (ina226 only) */
 394 static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
 395                           ina226_show_interval, ina226_set_interval, 0);
 396
 397 /* pointers to created device attributes */
 398 static struct attribute *ina2xx_attrs[] = {
 399         &sensor_dev_attr_in0_input.dev_attr.attr,
 400         &sensor_dev_attr_in1_input.dev_attr.attr,
 401         &sensor_dev_attr_curr1_input.dev_attr.attr,
 402         &sensor_dev_attr_power1_input.dev_attr.attr,
 403         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 404         NULL,
 405 };
 406
 407 static const struct attribute_group ina2xx_group = {
 408         .attrs = ina2xx_attrs,
 409 };
 410
 411 static struct attribute *ina226_attrs[] = {
 412         &sensor_dev_attr_update_interval.dev_attr.attr,
 413         NULL,
 414 };
 415
 416 static const struct attribute_group ina226_group = {
 417         .attrs = ina226_attrs,
 418 };
 419
 420 static int ina2xx_probe(struct i2c_client *client,
 421                         const struct i2c_device_id *id)
 422 {
 423         struct device *dev = &client->dev;
 424         struct ina2xx_data *data;
 425         struct device *hwmon_dev;
 426         u32 val;
 427         int ret, group = 0;
 428         enum ina2xx_ids chip;
 429
 430         if (client->dev.of_node)
 431                 chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);
 432         else
 433                 chip = id->driver_data;
 434
 435         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 436         if (!data)
 437                 return -ENOMEM;
 438
 439         /* set the device type */
 440         data->config = &ina2xx_config[chip];
 441
 442         if (of_property_read_u32(dev->of_node, "shunt-resistor", &val) < 0) {
 443                 struct ina2xx_platform_data *pdata = dev_get_platdata(dev);
 444
 445                 if (pdata)
 446                         val = pdata->shunt_uohms;
 447                 else
 448                         val = INA2XX_RSHUNT_DEFAULT;
 449         }
 450
 451         if (val <= 0 || val > data->config->calibration_factor)
 452                 return -ENODEV;
 453
 454         data->rshunt = val;
 455
 456         ina2xx_regmap_config.max_register = data->config->registers;
 457
 458         data->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);
 459         if (IS_ERR(data->regmap)) {
 460                 dev_err(dev, "failed to allocate register map\n");
 461                 return PTR_ERR(data->regmap);
 462         }
 463
 464         ret = ina2xx_init(data);
 465         if (ret < 0) {
 466                 dev_err(dev, "error configuring the device: %d\n", ret);
 467                 return -ENODEV;
 468         }
 469
 470         mutex_init(&data->config_lock);
 471
 472         data->groups[group++] = &ina2xx_group;
 473         if (id->driver_data == ina226)
 474                 data->groups[group++] = &ina226_group;
 475
 476         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 477                                                            data, data->groups);
 478         if (IS_ERR(hwmon_dev))
 479                 return PTR_ERR(hwmon_dev);
 480
 481         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 482                  id->name, data->rshunt);
 483
 484         return 0;
 485 }
 486
 487 static const struct i2c_device_id ina2xx_id[] = {
 488         { "ina219", ina219 },
 489         { "ina220", ina219 },
 490         { "ina226", ina226 },
 491         { "ina230", ina226 },
 492         { "ina231", ina226 },
 493         { }
 494 };
 495 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 496
 497 static const struct of_device_id ina2xx_of_match[] = {
 498         {
 499                 .compatible = "ti,ina219",
 500                 .data = (void *)ina219
 501         },
 502         {
 503                 .compatible = "ti,ina220",
 504                 .data = (void *)ina219
 505         },
 506         {
 507                 .compatible = "ti,ina226",
 508                 .data = (void *)ina226
 509         },
 510         {
 511                 .compatible = "ti,ina230",
 512                 .data = (void *)ina226
 513         },
 514         {
 515                 .compatible = "ti,ina231",
 516                 .data = (void *)ina226
 517         },
 518         { },
 519 };
 520 MODULE_DEVICE_TABLE(of, ina2xx_of_match);
 521
 522 static struct i2c_driver ina2xx_driver = {
 523         .driver = {
 524                 .name   = "ina2xx",
 525                 .of_match_table = of_match_ptr(ina2xx_of_match),
 526         },
 527         .probe          = ina2xx_probe,
 528         .id_table       = ina2xx_id,
 529 };
 530
 531 module_i2c_driver(ina2xx_driver);
 532
 533 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 534 MODULE_DESCRIPTION("ina2xx driver");
 535 MODULE_LICENSE("GPL");