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  * INA226:
   9  * Bi-Directional Current/Power Monitor with I2C Interface
  10  * Datasheet: http://www.ti.com/product/ina226
  11  *
  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
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23 #include <linux/err.h>
  24 #include <linux/slab.h>
  25 #include <linux/i2c.h>
  26 #include <linux/hwmon.h>
  27 #include <linux/hwmon-sysfs.h>
  28
  29 #include <linux/platform_data/ina2xx.h>
  30
  31 /* common register definitions */
  32 #define INA2XX_CONFIG                   0x00
  33 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  34 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  35 #define INA2XX_POWER                    0x03 /* readonly */
  36 #define INA2XX_CURRENT                  0x04 /* readonly */
  37 #define INA2XX_CALIBRATION              0x05
  38
  39 /* INA226 register definitions */
  40 #define INA226_MASK_ENABLE              0x06
  41 #define INA226_ALERT_LIMIT              0x07
  42 #define INA226_DIE_ID                   0xFF
  43
  44
  45 /* register count */
  46 #define INA219_REGISTERS                6
  47 #define INA226_REGISTERS                8
  48
  49 #define INA2XX_MAX_REGISTERS            8
  50
  51 /* settings - depend on use case */
  52 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  53 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  54
  55 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  56 #define INA2XX_CONVERSION_RATE          15
  57
  58 enum ina2xx_ids { ina219, ina226 };
  59
  60 struct ina2xx_data {
  61         struct device *hwmon_dev;
  62
  63         struct mutex update_lock;
  64         bool valid;
  65         unsigned long last_updated;
  66
  67         int kind;
  68         int registers;
  69         u16 regs[INA2XX_MAX_REGISTERS];
  70 };
  71
  72 int ina2xx_read_word(struct i2c_client *client, int reg)
  73 {
  74         int val = i2c_smbus_read_word_data(client, reg);
  75         if (unlikely(val < 0)) {
  76                 dev_dbg(&client->dev,
  77                         "Failed to read register: %d\n", reg);
  78                 return val;
  79         }
  80         return be16_to_cpu(val);
  81 }
  82
  83 void ina2xx_write_word(struct i2c_client *client, int reg, int data)
  84 {
  85         i2c_smbus_write_word_data(client, reg, cpu_to_be16(data));
  86 }
  87
  88 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
  89 {
  90         struct i2c_client *client = to_i2c_client(dev);
  91         struct ina2xx_data *data = i2c_get_clientdata(client);
  92         struct ina2xx_data *ret = data;
  93
  94         mutex_lock(&data->update_lock);
  95
  96         if (time_after(jiffies, data->last_updated +
  97                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
  98
  99                 int i;
 100
 101                 dev_dbg(&client->dev, "Starting ina2xx update\n");
 102
 103                 /* Read all registers */
 104                 for (i = 0; i < data->registers; i++) {
 105                         int rv = ina2xx_read_word(client, i);
 106                         if (rv < 0) {
 107                                 ret = ERR_PTR(rv);
 108                                 goto abort;
 109                         }
 110                         data->regs[i] = rv;
 111                 }
 112                 data->last_updated = jiffies;
 113                 data->valid = 1;
 114         }
 115 abort:
 116         mutex_unlock(&data->update_lock);
 117         return ret;
 118 }
 119
 120 static int ina219_get_value(struct ina2xx_data *data, u8 reg)
 121 {
 122         /*
 123          * calculate exact value for the given register
 124          * we assume default power-on reset settings:
 125          * bus voltage range 32V
 126          * gain = /8
 127          * adc 1 & 2 -> conversion time 532uS
 128          * mode is continuous shunt and bus
 129          * calibration value is INA219_CALIBRATION_VALUE
 130          */
 131         int val = data->regs[reg];
 132
 133         switch (reg) {
 134         case INA2XX_SHUNT_VOLTAGE:
 135                 /* LSB=10uV. Convert to mV. */
 136                 val = DIV_ROUND_CLOSEST(val, 100);
 137                 break;
 138         case INA2XX_BUS_VOLTAGE:
 139                 /* LSB=4mV. Register is not right aligned, convert to mV. */
 140                 val = (val >> 3) * 4;
 141                 break;
 142         case INA2XX_POWER:
 143                 /* LSB=20mW. Convert to uW */
 144                 val = val * 20 * 1000;
 145                 break;
 146         case INA2XX_CURRENT:
 147                 /* LSB=1mA (selected). Is in mA */
 148                 break;
 149         default:
 150                 /* programmer goofed */
 151                 WARN_ON_ONCE(1);
 152                 val = 0;
 153                 break;
 154         }
 155
 156         return val;
 157 }
 158
 159 static int ina226_get_value(struct ina2xx_data *data, u8 reg)
 160 {
 161         /*
 162          * calculate exact value for the given register
 163          * we assume default power-on reset settings:
 164          * bus voltage range 32V
 165          * gain = /8
 166          * adc 1 & 2 -> conversion time 532uS
 167          * mode is continuous shunt and bus
 168          * calibration value is INA226_CALIBRATION_VALUE
 169          */
 170         int val = data->regs[reg];
 171
 172         switch (reg) {
 173         case INA2XX_SHUNT_VOLTAGE:
 174                 /* LSB=2.5uV. Convert to mV. */
 175                 val = DIV_ROUND_CLOSEST(val, 400);
 176                 break;
 177         case INA2XX_BUS_VOLTAGE:
 178                 /* LSB=1.25mV. Convert to mV. */
 179                 val = val + DIV_ROUND_CLOSEST(val, 4);
 180                 break;
 181         case INA2XX_POWER:
 182                 /* LSB=25mW. Convert to uW */
 183                 val = val * 25 * 1000;
 184                 break;
 185         case INA2XX_CURRENT:
 186                 /* LSB=1mA (selected). Is in mA */
 187                 break;
 188         default:
 189                 /* programmer goofed */
 190                 WARN_ON_ONCE(1);
 191                 val = 0;
 192                 break;
 193         }
 194
 195         return val;
 196 }
 197
 198 static ssize_t ina2xx_show_value(struct device *dev,
 199                                  struct device_attribute *da, char *buf)
 200 {
 201         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 202         struct ina2xx_data *data = ina2xx_update_device(dev);
 203         int value = 0;
 204
 205         if (IS_ERR(data))
 206                 return PTR_ERR(data);
 207
 208         switch (data->kind) {
 209         case ina219:
 210                 value = ina219_get_value(data, attr->index);
 211                 break;
 212         case ina226:
 213                 value = ina226_get_value(data, attr->index);
 214                 break;
 215         default:
 216                 WARN_ON_ONCE(1);
 217                 break;
 218         }
 219         return snprintf(buf, PAGE_SIZE, "%d\n", value);
 220 }
 221
 222 /* shunt voltage */
 223 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
 224         ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
 225
 226 /* bus voltage */
 227 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
 228         ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
 229
 230 /* calculated current */
 231 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
 232         ina2xx_show_value, NULL, INA2XX_CURRENT);
 233
 234 /* calculated power */
 235 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
 236         ina2xx_show_value, NULL, INA2XX_POWER);
 237
 238 /* pointers to created device attributes */
 239 static struct attribute *ina2xx_attributes[] = {
 240         &sensor_dev_attr_in0_input.dev_attr.attr,
 241         &sensor_dev_attr_in1_input.dev_attr.attr,
 242         &sensor_dev_attr_curr1_input.dev_attr.attr,
 243         &sensor_dev_attr_power1_input.dev_attr.attr,
 244         NULL,
 245 };
 246
 247 static const struct attribute_group ina2xx_group = {
 248         .attrs = ina2xx_attributes,
 249 };
 250
 251 static int ina2xx_probe(struct i2c_client *client,
 252                         const struct i2c_device_id *id)
 253 {
 254         struct i2c_adapter *adapter = client->adapter;
 255         struct ina2xx_data *data;
 256         struct ina2xx_platform_data *pdata;
 257         int ret = 0;
 258         long shunt = 10000; /* default shunt value 10mOhms */
 259
 260         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 261                 return -ENODEV;
 262
 263         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 264         if (!data)
 265                 return -ENOMEM;
 266
 267         if (client->dev.platform_data) {
 268                 pdata =
 269                   (struct ina2xx_platform_data *)client->dev.platform_data;
 270                 shunt = pdata->shunt_uohms;
 271         }
 272
 273         if (shunt <= 0)
 274                 return -ENODEV;
 275
 276         /* set the device type */
 277         data->kind = id->driver_data;
 278
 279         switch (data->kind) {
 280         case ina219:
 281                 /* device configuration */
 282                 ina2xx_write_word(client, INA2XX_CONFIG, INA219_CONFIG_DEFAULT);
 283
 284                 /* set current LSB to 1mA, shunt is in uOhms */
 285                 /* (equation 13 in datasheet) */
 286                 ina2xx_write_word(client, INA2XX_CALIBRATION, 40960000 / shunt);
 287                 dev_info(&client->dev,
 288                          "power monitor INA219 (Rshunt = %li uOhm)\n", shunt);
 289                 data->registers = INA219_REGISTERS;
 290                 break;
 291         case ina226:
 292                 /* device configuration */
 293                 ina2xx_write_word(client, INA2XX_CONFIG, INA226_CONFIG_DEFAULT);
 294
 295                 /* set current LSB to 1mA, shunt is in uOhms */
 296                 /* (equation 1 in datasheet)*/
 297                 ina2xx_write_word(client, INA2XX_CALIBRATION, 5120000 / shunt);
 298                 dev_info(&client->dev,
 299                          "power monitor INA226 (Rshunt = %li uOhm)\n", shunt);
 300                 data->registers = INA226_REGISTERS;
 301                 break;
 302         default:
 303                 /* unknown device id */
 304                 return -ENODEV;
 305         }
 306
 307         i2c_set_clientdata(client, data);
 308         mutex_init(&data->update_lock);
 309
 310         ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
 311         if (ret)
 312                 return ret;
 313
 314         data->hwmon_dev = hwmon_device_register(&client->dev);
 315         if (IS_ERR(data->hwmon_dev)) {
 316                 ret = PTR_ERR(data->hwmon_dev);
 317                 goto out_err_hwmon;
 318         }
 319
 320         return 0;
 321
 322 out_err_hwmon:
 323         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 324         return ret;
 325 }
 326
 327 static int ina2xx_remove(struct i2c_client *client)
 328 {
 329         struct ina2xx_data *data = i2c_get_clientdata(client);
 330
 331         hwmon_device_unregister(data->hwmon_dev);
 332         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 333
 334         return 0;
 335 }
 336
 337 static const struct i2c_device_id ina2xx_id[] = {
 338         { "ina219", ina219 },
 339         { "ina226", ina226 },
 340         { }
 341 };
 342 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 343
 344 static struct i2c_driver ina2xx_driver = {
 345         .driver = {
 346                 .name   = "ina2xx",
 347         },
 348         .probe          = ina2xx_probe,
 349         .remove         = ina2xx_remove,
 350         .id_table       = ina2xx_id,
 351 };
 352
 353 static int __init ina2xx_init(void)
 354 {
 355         return i2c_add_driver(&ina2xx_driver);
 356 }
 357
 358 static void __exit ina2xx_exit(void)
 359 {
 360         i2c_del_driver(&ina2xx_driver);
 361 }
 362
 363 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 364 MODULE_DESCRIPTION("ina2xx driver");
 365 MODULE_LICENSE("GPL");
 366
 367 module_init(ina2xx_init);
 368 module_exit(ina2xx_exit);