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.h>
  38 #include <linux/delay.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 enum ina2xx_ids { ina219, ina226 };
  72
  73 struct ina2xx_config {
  74         u16 config_default;
  75         int calibration_factor;
  76         int registers;
  77         int shunt_div;
  78         int bus_voltage_shift;
  79         int bus_voltage_lsb;    /* uV */
  80         int power_lsb;          /* uW */
  81 };
  82
  83 struct ina2xx_data {
  84         struct i2c_client *client;
  85         const struct ina2xx_config *config;
  86
  87         long rshunt;
  88
  89         struct mutex update_lock;
  90         bool valid;
  91         unsigned long last_updated;
  92
  93         int kind;
  94         u16 regs[INA2XX_MAX_REGISTERS];
  95 };
  96
  97 static const struct ina2xx_config ina2xx_config[] = {
  98         [ina219] = {
  99                 .config_default = INA219_CONFIG_DEFAULT,
 100                 .calibration_factor = 40960000,
 101                 .registers = INA219_REGISTERS,
 102                 .shunt_div = 100,
 103                 .bus_voltage_shift = 3,
 104                 .bus_voltage_lsb = 4000,
 105                 .power_lsb = 20000,
 106         },
 107         [ina226] = {
 108                 .config_default = INA226_CONFIG_DEFAULT,
 109                 .calibration_factor = 5120000,
 110                 .registers = INA226_REGISTERS,
 111                 .shunt_div = 400,
 112                 .bus_voltage_shift = 0,
 113                 .bus_voltage_lsb = 1250,
 114                 .power_lsb = 25000,
 115         },
 116 };
 117
 118 static int ina2xx_calibrate(struct ina2xx_data *data)
 119 {
 120         return i2c_smbus_write_word_swapped(data->client, INA2XX_CALIBRATION,
 121                         data->config->calibration_factor / data->rshunt);
 122 }
 123
 124 /*
 125  * Initialize the configuration and calibration registers.
 126  */
 127 static int ina2xx_init(struct ina2xx_data *data)
 128 {
 129         struct i2c_client *client = data->client;
 130         int ret;
 131
 132         /* device configuration */
 133         ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 134                                            data->config->config_default);
 135         if (ret < 0)
 136                 return ret;
 137
 138         /*
 139          * Set current LSB to 1mA, shunt is in uOhms
 140          * (equation 13 in datasheet).
 141          */
 142         return ina2xx_calibrate(data);
 143 }
 144
 145 static int ina2xx_do_update(struct device *dev)
 146 {
 147         struct ina2xx_data *data = dev_get_drvdata(dev);
 148         struct i2c_client *client = data->client;
 149         int i, rv, retry;
 150
 151         dev_dbg(&client->dev, "Starting ina2xx update\n");
 152
 153         for (retry = 5; retry; retry--) {
 154                 /* Read all registers */
 155                 for (i = 0; i < data->config->registers; i++) {
 156                         rv = i2c_smbus_read_word_swapped(client, i);
 157                         if (rv < 0)
 158                                 return rv;
 159                         data->regs[i] = rv;
 160                 }
 161
 162                 /*
 163                  * If the current value in the calibration register is 0, the
 164                  * power and current registers will also remain at 0. In case
 165                  * the chip has been reset let's check the calibration
 166                  * register and reinitialize if needed.
 167                  */
 168                 if (data->regs[INA2XX_CALIBRATION] == 0) {
 169                         dev_warn(dev, "chip not calibrated, reinitializing\n");
 170
 171                         rv = ina2xx_init(data);
 172                         if (rv < 0)
 173                                 return rv;
 174
 175                         /*
 176                          * Let's make sure the power and current registers
 177                          * have been updated before trying again.
 178                          */
 179                         msleep(INA2XX_MAX_DELAY);
 180                         continue;
 181                 }
 182
 183                 data->last_updated = jiffies;
 184                 data->valid = 1;
 185
 186                 return 0;
 187         }
 188
 189         /*
 190          * If we're here then although all write operations succeeded, the
 191          * chip still returns 0 in the calibration register. Nothing more we
 192          * can do here.
 193          */
 194         dev_err(dev, "unable to reinitialize the chip\n");
 195         return -ENODEV;
 196 }
 197
 198 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 199 {
 200         struct ina2xx_data *data = dev_get_drvdata(dev);
 201         struct ina2xx_data *ret = data;
 202         int rv;
 203
 204         mutex_lock(&data->update_lock);
 205
 206         if (time_after(jiffies, data->last_updated +
 207                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
 208                 rv = ina2xx_do_update(dev);
 209                 if (rv < 0)
 210                         ret = ERR_PTR(rv);
 211         }
 212
 213         mutex_unlock(&data->update_lock);
 214         return ret;
 215 }
 216
 217 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 218 {
 219         int val;
 220
 221         switch (reg) {
 222         case INA2XX_SHUNT_VOLTAGE:
 223                 /* signed register */
 224                 val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
 225                                         data->config->shunt_div);
 226                 break;
 227         case INA2XX_BUS_VOLTAGE:
 228                 val = (data->regs[reg] >> data->config->bus_voltage_shift)
 229                   * data->config->bus_voltage_lsb;
 230                 val = DIV_ROUND_CLOSEST(val, 1000);
 231                 break;
 232         case INA2XX_POWER:
 233                 val = data->regs[reg] * data->config->power_lsb;
 234                 break;
 235         case INA2XX_CURRENT:
 236                 /* signed register, LSB=1mA (selected), in mA */
 237                 val = (s16)data->regs[reg];
 238                 break;
 239         case INA2XX_CALIBRATION:
 240                 val = data->config->calibration_factor / data->regs[reg];
 241                 break;
 242         default:
 243                 /* programmer goofed */
 244                 WARN_ON_ONCE(1);
 245                 val = 0;
 246                 break;
 247         }
 248
 249         return val;
 250 }
 251
 252 static ssize_t ina2xx_show_value(struct device *dev,
 253                                  struct device_attribute *da, char *buf)
 254 {
 255         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 256         struct ina2xx_data *data = ina2xx_update_device(dev);
 257
 258         if (IS_ERR(data))
 259                 return PTR_ERR(data);
 260
 261         return snprintf(buf, PAGE_SIZE, "%d\n",
 262                         ina2xx_get_value(data, attr->index));
 263 }
 264
 265 static ssize_t ina2xx_set_shunt(struct device *dev,
 266                                 struct device_attribute *da,
 267                                 const char *buf, size_t count)
 268 {
 269         struct ina2xx_data *data = ina2xx_update_device(dev);
 270         unsigned long val;
 271         int status;
 272
 273         if (IS_ERR(data))
 274                 return PTR_ERR(data);
 275
 276         status = kstrtoul(buf, 10, &val);
 277         if (status < 0)
 278                 return status;
 279
 280         if (val == 0 ||
 281             /* Values greater than the calibration factor make no sense. */
 282             val > data->config->calibration_factor)
 283                 return -EINVAL;
 284
 285         mutex_lock(&data->update_lock);
 286         data->rshunt = val;
 287         status = ina2xx_calibrate(data);
 288         mutex_unlock(&data->update_lock);
 289         if (status < 0)
 290                 return status;
 291
 292         return count;
 293 }
 294
 295 /* shunt voltage */
 296 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 297                           INA2XX_SHUNT_VOLTAGE);
 298
 299 /* bus voltage */
 300 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 301                           INA2XX_BUS_VOLTAGE);
 302
 303 /* calculated current */
 304 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 305                           INA2XX_CURRENT);
 306
 307 /* calculated power */
 308 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 309                           INA2XX_POWER);
 310
 311 /* shunt resistance */
 312 static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
 313                           ina2xx_show_value, ina2xx_set_shunt,
 314                           INA2XX_CALIBRATION);
 315
 316 /* pointers to created device attributes */
 317 static struct attribute *ina2xx_attrs[] = {
 318         &sensor_dev_attr_in0_input.dev_attr.attr,
 319         &sensor_dev_attr_in1_input.dev_attr.attr,
 320         &sensor_dev_attr_curr1_input.dev_attr.attr,
 321         &sensor_dev_attr_power1_input.dev_attr.attr,
 322         &sensor_dev_attr_shunt_resistor.dev_attr.attr,
 323         NULL,
 324 };
 325 ATTRIBUTE_GROUPS(ina2xx);
 326
 327 static int ina2xx_probe(struct i2c_client *client,
 328                         const struct i2c_device_id *id)
 329 {
 330         struct i2c_adapter *adapter = client->adapter;
 331         struct ina2xx_platform_data *pdata;
 332         struct device *dev = &client->dev;
 333         struct ina2xx_data *data;
 334         struct device *hwmon_dev;
 335         u32 val;
 336         int ret;
 337
 338         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 339                 return -ENODEV;
 340
 341         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 342         if (!data)
 343                 return -ENOMEM;
 344
 345         if (dev_get_platdata(dev)) {
 346                 pdata = dev_get_platdata(dev);
 347                 data->rshunt = pdata->shunt_uohms;
 348         } else if (!of_property_read_u32(dev->of_node,
 349                                          "shunt-resistor", &val)) {
 350                 data->rshunt = val;
 351         } else {
 352                 data->rshunt = INA2XX_RSHUNT_DEFAULT;
 353         }
 354
 355         /* set the device type */
 356         data->kind = id->driver_data;
 357         data->config = &ina2xx_config[data->kind];
 358         data->client = client;
 359
 360         if (data->rshunt <= 0 ||
 361             data->rshunt > data->config->calibration_factor)
 362                 return -ENODEV;
 363
 364         ret = ina2xx_init(data);
 365         if (ret < 0) {
 366                 dev_err(dev, "error configuring the device: %d\n", ret);
 367                 return -ENODEV;
 368         }
 369
 370         mutex_init(&data->update_lock);
 371
 372         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 373                                                            data, ina2xx_groups);
 374         if (IS_ERR(hwmon_dev))
 375                 return PTR_ERR(hwmon_dev);
 376
 377         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 378                  id->name, data->rshunt);
 379
 380         return 0;
 381 }
 382
 383 static const struct i2c_device_id ina2xx_id[] = {
 384         { "ina219", ina219 },
 385         { "ina220", ina219 },
 386         { "ina226", ina226 },
 387         { "ina230", ina226 },
 388         { }
 389 };
 390 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 391
 392 static struct i2c_driver ina2xx_driver = {
 393         .driver = {
 394                 .name   = "ina2xx",
 395         },
 396         .probe          = ina2xx_probe,
 397         .id_table       = ina2xx_id,
 398 };
 399
 400 module_i2c_driver(ina2xx_driver);
 401
 402 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 403 MODULE_DESCRIPTION("ina2xx driver");
 404 MODULE_LICENSE("GPL");