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 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
  73 {
  74         struct i2c_client *client = to_i2c_client(dev);
  75         struct ina2xx_data *data = i2c_get_clientdata(client);
  76         struct ina2xx_data *ret = data;
  77
  78         mutex_lock(&data->update_lock);
  79
  80         if (time_after(jiffies, data->last_updated +
  81                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
  82
  83                 int i;
  84
  85                 dev_dbg(&client->dev, "Starting ina2xx update\n");
  86
  87                 /* Read all registers */
  88                 for (i = 0; i < data->registers; i++) {
  89                         int rv = i2c_smbus_read_word_swapped(client, i);
  90                         if (rv < 0) {
  91                                 ret = ERR_PTR(rv);
  92                                 goto abort;
  93                         }
  94                         data->regs[i] = rv;
  95                 }
  96                 data->last_updated = jiffies;
  97                 data->valid = 1;
  98         }
  99 abort:
 100         mutex_unlock(&data->update_lock);
 101         return ret;
 102 }
 103
 104 static int ina219_get_value(struct ina2xx_data *data, u8 reg)
 105 {
 106         /*
 107          * calculate exact value for the given register
 108          * we assume default power-on reset settings:
 109          * bus voltage range 32V
 110          * gain = /8
 111          * adc 1 & 2 -> conversion time 532uS
 112          * mode is continuous shunt and bus
 113          * calibration value is INA219_CALIBRATION_VALUE
 114          */
 115         int val = data->regs[reg];
 116
 117         switch (reg) {
 118         case INA2XX_SHUNT_VOLTAGE:
 119                 /* LSB=10uV. Convert to mV. */
 120                 val = DIV_ROUND_CLOSEST(val, 100);
 121                 break;
 122         case INA2XX_BUS_VOLTAGE:
 123                 /* LSB=4mV. Register is not right aligned, convert to mV. */
 124                 val = (val >> 3) * 4;
 125                 break;
 126         case INA2XX_POWER:
 127                 /* LSB=20mW. Convert to uW */
 128                 val = val * 20 * 1000;
 129                 break;
 130         case INA2XX_CURRENT:
 131                 /* LSB=1mA (selected). Is in mA */
 132                 break;
 133         default:
 134                 /* programmer goofed */
 135                 WARN_ON_ONCE(1);
 136                 val = 0;
 137                 break;
 138         }
 139
 140         return val;
 141 }
 142
 143 static int ina226_get_value(struct ina2xx_data *data, u8 reg)
 144 {
 145         /*
 146          * calculate exact value for the given register
 147          * we assume default power-on reset settings:
 148          * bus voltage range 32V
 149          * gain = /8
 150          * adc 1 & 2 -> conversion time 532uS
 151          * mode is continuous shunt and bus
 152          * calibration value is INA226_CALIBRATION_VALUE
 153          */
 154         int val = data->regs[reg];
 155
 156         switch (reg) {
 157         case INA2XX_SHUNT_VOLTAGE:
 158                 /* LSB=2.5uV. Convert to mV. */
 159                 val = DIV_ROUND_CLOSEST(val, 400);
 160                 break;
 161         case INA2XX_BUS_VOLTAGE:
 162                 /* LSB=1.25mV. Convert to mV. */
 163                 val = val + DIV_ROUND_CLOSEST(val, 4);
 164                 break;
 165         case INA2XX_POWER:
 166                 /* LSB=25mW. Convert to uW */
 167                 val = val * 25 * 1000;
 168                 break;
 169         case INA2XX_CURRENT:
 170                 /* LSB=1mA (selected). Is in mA */
 171                 break;
 172         default:
 173                 /* programmer goofed */
 174                 WARN_ON_ONCE(1);
 175                 val = 0;
 176                 break;
 177         }
 178
 179         return val;
 180 }
 181
 182 static ssize_t ina2xx_show_value(struct device *dev,
 183                                  struct device_attribute *da, char *buf)
 184 {
 185         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 186         struct ina2xx_data *data = ina2xx_update_device(dev);
 187         int value = 0;
 188
 189         if (IS_ERR(data))
 190                 return PTR_ERR(data);
 191
 192         switch (data->kind) {
 193         case ina219:
 194                 value = ina219_get_value(data, attr->index);
 195                 break;
 196         case ina226:
 197                 value = ina226_get_value(data, attr->index);
 198                 break;
 199         default:
 200                 WARN_ON_ONCE(1);
 201                 break;
 202         }
 203         return snprintf(buf, PAGE_SIZE, "%d\n", value);
 204 }
 205
 206 /* shunt voltage */
 207 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
 208         ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
 209
 210 /* bus voltage */
 211 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
 212         ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
 213
 214 /* calculated current */
 215 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
 216         ina2xx_show_value, NULL, INA2XX_CURRENT);
 217
 218 /* calculated power */
 219 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
 220         ina2xx_show_value, NULL, INA2XX_POWER);
 221
 222 /* pointers to created device attributes */
 223 static struct attribute *ina2xx_attributes[] = {
 224         &sensor_dev_attr_in0_input.dev_attr.attr,
 225         &sensor_dev_attr_in1_input.dev_attr.attr,
 226         &sensor_dev_attr_curr1_input.dev_attr.attr,
 227         &sensor_dev_attr_power1_input.dev_attr.attr,
 228         NULL,
 229 };
 230
 231 static const struct attribute_group ina2xx_group = {
 232         .attrs = ina2xx_attributes,
 233 };
 234
 235 static int ina2xx_probe(struct i2c_client *client,
 236                         const struct i2c_device_id *id)
 237 {
 238         struct i2c_adapter *adapter = client->adapter;
 239         struct ina2xx_data *data;
 240         struct ina2xx_platform_data *pdata;
 241         int ret = 0;
 242         long shunt = 10000; /* default shunt value 10mOhms */
 243
 244         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 245                 return -ENODEV;
 246
 247         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 248         if (!data)
 249                 return -ENOMEM;
 250
 251         if (client->dev.platform_data) {
 252                 pdata =
 253                   (struct ina2xx_platform_data *)client->dev.platform_data;
 254                 shunt = pdata->shunt_uohms;
 255         }
 256
 257         if (shunt <= 0)
 258                 return -ENODEV;
 259
 260         /* set the device type */
 261         data->kind = id->driver_data;
 262
 263         switch (data->kind) {
 264         case ina219:
 265                 /* device configuration */
 266                 i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 267                                              INA219_CONFIG_DEFAULT);
 268
 269                 /* set current LSB to 1mA, shunt is in uOhms */
 270                 /* (equation 13 in datasheet) */
 271                 i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 272                                              40960000 / shunt);
 273                 dev_info(&client->dev,
 274                          "power monitor INA219 (Rshunt = %li uOhm)\n", shunt);
 275                 data->registers = INA219_REGISTERS;
 276                 break;
 277         case ina226:
 278                 /* device configuration */
 279                 i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 280                                              INA226_CONFIG_DEFAULT);
 281
 282                 /* set current LSB to 1mA, shunt is in uOhms */
 283                 /* (equation 1 in datasheet)*/
 284                 i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 285                                              5120000 / shunt);
 286                 dev_info(&client->dev,
 287                          "power monitor INA226 (Rshunt = %li uOhm)\n", shunt);
 288                 data->registers = INA226_REGISTERS;
 289                 break;
 290         default:
 291                 /* unknown device id */
 292                 return -ENODEV;
 293         }
 294
 295         i2c_set_clientdata(client, data);
 296         mutex_init(&data->update_lock);
 297
 298         ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
 299         if (ret)
 300                 return ret;
 301
 302         data->hwmon_dev = hwmon_device_register(&client->dev);
 303         if (IS_ERR(data->hwmon_dev)) {
 304                 ret = PTR_ERR(data->hwmon_dev);
 305                 goto out_err_hwmon;
 306         }
 307
 308         return 0;
 309
 310 out_err_hwmon:
 311         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 312         return ret;
 313 }
 314
 315 static int ina2xx_remove(struct i2c_client *client)
 316 {
 317         struct ina2xx_data *data = i2c_get_clientdata(client);
 318
 319         hwmon_device_unregister(data->hwmon_dev);
 320         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 321
 322         return 0;
 323 }
 324
 325 static const struct i2c_device_id ina2xx_id[] = {
 326         { "ina219", ina219 },
 327         { "ina226", ina226 },
 328         { }
 329 };
 330 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 331
 332 static struct i2c_driver ina2xx_driver = {
 333         .driver = {
 334                 .name   = "ina2xx",
 335         },
 336         .probe          = ina2xx_probe,
 337         .remove         = ina2xx_remove,
 338         .id_table       = ina2xx_id,
 339 };
 340
 341 static int __init ina2xx_init(void)
 342 {
 343         return i2c_add_driver(&ina2xx_driver);
 344 }
 345
 346 static void __exit ina2xx_exit(void)
 347 {
 348         i2c_del_driver(&ina2xx_driver);
 349 }
 350
 351 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 352 MODULE_DESCRIPTION("ina2xx driver");
 353 MODULE_LICENSE("GPL");
 354
 355 module_init(ina2xx_init);
 356 module_exit(ina2xx_exit);