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
  37 #include <linux/platform_data/ina2xx.h>
  38
  39 /* common register definitions */
  40 #define INA2XX_CONFIG                   0x00
  41 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  42 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  43 #define INA2XX_POWER                    0x03 /* readonly */
  44 #define INA2XX_CURRENT                  0x04 /* readonly */
  45 #define INA2XX_CALIBRATION              0x05
  46
  47 /* INA226 register definitions */
  48 #define INA226_MASK_ENABLE              0x06
  49 #define INA226_ALERT_LIMIT              0x07
  50 #define INA226_DIE_ID                   0xFF
  51
  52
  53 /* register count */
  54 #define INA219_REGISTERS                6
  55 #define INA226_REGISTERS                8
  56
  57 #define INA2XX_MAX_REGISTERS            8
  58
  59 /* settings - depend on use case */
  60 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  61 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  62
  63 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  64 #define INA2XX_CONVERSION_RATE          15
  65
  66 enum ina2xx_ids { ina219, ina226 };
  67
  68 struct ina2xx_config {
  69         u16 config_default;
  70         int calibration_factor;
  71         int registers;
  72         int shunt_div;
  73         int bus_voltage_shift;
  74         int bus_voltage_lsb;    /* uV */
  75         int power_lsb;          /* uW */
  76 };
  77
  78 struct ina2xx_data {
  79         struct device *hwmon_dev;
  80         const struct ina2xx_config *config;
  81
  82         struct mutex update_lock;
  83         bool valid;
  84         unsigned long last_updated;
  85
  86         int kind;
  87         u16 regs[INA2XX_MAX_REGISTERS];
  88 };
  89
  90 static const struct ina2xx_config ina2xx_config[] = {
  91         [ina219] = {
  92                 .config_default = INA219_CONFIG_DEFAULT,
  93                 .calibration_factor = 40960000,
  94                 .registers = INA219_REGISTERS,
  95                 .shunt_div = 100,
  96                 .bus_voltage_shift = 3,
  97                 .bus_voltage_lsb = 4000,
  98                 .power_lsb = 20000,
  99         },
 100         [ina226] = {
 101                 .config_default = INA226_CONFIG_DEFAULT,
 102                 .calibration_factor = 5120000,
 103                 .registers = INA226_REGISTERS,
 104                 .shunt_div = 400,
 105                 .bus_voltage_shift = 0,
 106                 .bus_voltage_lsb = 1250,
 107                 .power_lsb = 25000,
 108         },
 109 };
 110
 111 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 112 {
 113         struct i2c_client *client = to_i2c_client(dev);
 114         struct ina2xx_data *data = i2c_get_clientdata(client);
 115         struct ina2xx_data *ret = data;
 116
 117         mutex_lock(&data->update_lock);
 118
 119         if (time_after(jiffies, data->last_updated +
 120                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
 121
 122                 int i;
 123
 124                 dev_dbg(&client->dev, "Starting ina2xx update\n");
 125
 126                 /* Read all registers */
 127                 for (i = 0; i < data->config->registers; i++) {
 128                         int rv = i2c_smbus_read_word_swapped(client, i);
 129                         if (rv < 0) {
 130                                 ret = ERR_PTR(rv);
 131                                 goto abort;
 132                         }
 133                         data->regs[i] = rv;
 134                 }
 135                 data->last_updated = jiffies;
 136                 data->valid = 1;
 137         }
 138 abort:
 139         mutex_unlock(&data->update_lock);
 140         return ret;
 141 }
 142
 143 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 144 {
 145         int val;
 146
 147         switch (reg) {
 148         case INA2XX_SHUNT_VOLTAGE:
 149                 val = DIV_ROUND_CLOSEST(data->regs[reg],
 150                                         data->config->shunt_div);
 151                 break;
 152         case INA2XX_BUS_VOLTAGE:
 153                 val = (data->regs[reg] >> data->config->bus_voltage_shift)
 154                   * data->config->bus_voltage_lsb;
 155                 val = DIV_ROUND_CLOSEST(val, 1000);
 156                 break;
 157         case INA2XX_POWER:
 158                 val = data->regs[reg] * data->config->power_lsb;
 159                 break;
 160         case INA2XX_CURRENT:
 161                 /* LSB=1mA (selected). Is in mA */
 162                 val = data->regs[reg];
 163                 break;
 164         default:
 165                 /* programmer goofed */
 166                 WARN_ON_ONCE(1);
 167                 val = 0;
 168                 break;
 169         }
 170
 171         return val;
 172 }
 173
 174 static ssize_t ina2xx_show_value(struct device *dev,
 175                                  struct device_attribute *da, char *buf)
 176 {
 177         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 178         struct ina2xx_data *data = ina2xx_update_device(dev);
 179
 180         if (IS_ERR(data))
 181                 return PTR_ERR(data);
 182
 183         return snprintf(buf, PAGE_SIZE, "%d\n",
 184                         ina2xx_get_value(data, attr->index));
 185 }
 186
 187 /* shunt voltage */
 188 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
 189         ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
 190
 191 /* bus voltage */
 192 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
 193         ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
 194
 195 /* calculated current */
 196 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
 197         ina2xx_show_value, NULL, INA2XX_CURRENT);
 198
 199 /* calculated power */
 200 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
 201         ina2xx_show_value, NULL, INA2XX_POWER);
 202
 203 /* pointers to created device attributes */
 204 static struct attribute *ina2xx_attributes[] = {
 205         &sensor_dev_attr_in0_input.dev_attr.attr,
 206         &sensor_dev_attr_in1_input.dev_attr.attr,
 207         &sensor_dev_attr_curr1_input.dev_attr.attr,
 208         &sensor_dev_attr_power1_input.dev_attr.attr,
 209         NULL,
 210 };
 211
 212 static const struct attribute_group ina2xx_group = {
 213         .attrs = ina2xx_attributes,
 214 };
 215
 216 static int ina2xx_probe(struct i2c_client *client,
 217                         const struct i2c_device_id *id)
 218 {
 219         struct i2c_adapter *adapter = client->adapter;
 220         struct ina2xx_data *data;
 221         struct ina2xx_platform_data *pdata;
 222         int ret;
 223         long shunt = 10000; /* default shunt value 10mOhms */
 224
 225         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 226                 return -ENODEV;
 227
 228         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 229         if (!data)
 230                 return -ENOMEM;
 231
 232         if (client->dev.platform_data) {
 233                 pdata =
 234                   (struct ina2xx_platform_data *)client->dev.platform_data;
 235                 shunt = pdata->shunt_uohms;
 236         }
 237
 238         if (shunt <= 0)
 239                 return -ENODEV;
 240
 241         /* set the device type */
 242         data->kind = id->driver_data;
 243         data->config = &ina2xx_config[data->kind];
 244
 245         /* device configuration */
 246         i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 247                                      data->config->config_default);
 248         /* set current LSB to 1mA, shunt is in uOhms */
 249         /* (equation 13 in datasheet) */
 250         i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 251                                      data->config->calibration_factor / shunt);
 252
 253         i2c_set_clientdata(client, data);
 254         mutex_init(&data->update_lock);
 255
 256         ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
 257         if (ret)
 258                 return ret;
 259
 260         data->hwmon_dev = hwmon_device_register(&client->dev);
 261         if (IS_ERR(data->hwmon_dev)) {
 262                 ret = PTR_ERR(data->hwmon_dev);
 263                 goto out_err_hwmon;
 264         }
 265
 266         dev_info(&client->dev, "power monitor %s (Rshunt = %li uOhm)\n",
 267                  id->name, shunt);
 268
 269         return 0;
 270
 271 out_err_hwmon:
 272         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 273         return ret;
 274 }
 275
 276 static int ina2xx_remove(struct i2c_client *client)
 277 {
 278         struct ina2xx_data *data = i2c_get_clientdata(client);
 279
 280         hwmon_device_unregister(data->hwmon_dev);
 281         sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 282
 283         return 0;
 284 }
 285
 286 static const struct i2c_device_id ina2xx_id[] = {
 287         { "ina219", ina219 },
 288         { "ina220", ina219 },
 289         { "ina226", ina226 },
 290         { "ina230", ina226 },
 291         { }
 292 };
 293 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 294
 295 static struct i2c_driver ina2xx_driver = {
 296         .driver = {
 297                 .name   = "ina2xx",
 298         },
 299         .probe          = ina2xx_probe,
 300         .remove         = ina2xx_remove,
 301         .id_table       = ina2xx_id,
 302 };
 303
 304 static int __init ina2xx_init(void)
 305 {
 306         return i2c_add_driver(&ina2xx_driver);
 307 }
 308
 309 static void __exit ina2xx_exit(void)
 310 {
 311         i2c_del_driver(&ina2xx_driver);
 312 }
 313
 314 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 315 MODULE_DESCRIPTION("ina2xx driver");
 316 MODULE_LICENSE("GPL");
 317
 318 module_init(ina2xx_init);
 319 module_exit(ina2xx_exit);