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
  56 /* register count */
  57 #define INA219_REGISTERS                6
  58 #define INA226_REGISTERS                8
  59
  60 #define INA2XX_MAX_REGISTERS            8
  61
  62 /* settings - depend on use case */
  63 #define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  64 #define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  65
  66 /* worst case is 68.10 ms (~14.6Hz, ina219) */
  67 #define INA2XX_CONVERSION_RATE          15
  68 #define INA2XX_MAX_DELAY                69 /* worst case delay in ms */
  69
  70 #define INA2XX_RSHUNT_DEFAULT           10000
  71
  72 enum ina2xx_ids { ina219, ina226 };
  73
  74 struct ina2xx_config {
  75         u16 config_default;
  76         int calibration_factor;
  77         int registers;
  78         int shunt_div;
  79         int bus_voltage_shift;
  80         int bus_voltage_lsb;    /* uV */
  81         int power_lsb;          /* uW */
  82 };
  83
  84 struct ina2xx_data {
  85         struct i2c_client *client;
  86         const struct ina2xx_config *config;
  87
  88         long rshunt;
  89
  90         struct mutex update_lock;
  91         bool valid;
  92         unsigned long last_updated;
  93
  94         int kind;
  95         u16 regs[INA2XX_MAX_REGISTERS];
  96 };
  97
  98 static const struct ina2xx_config ina2xx_config[] = {
  99         [ina219] = {
 100                 .config_default = INA219_CONFIG_DEFAULT,
 101                 .calibration_factor = 40960000,
 102                 .registers = INA219_REGISTERS,
 103                 .shunt_div = 100,
 104                 .bus_voltage_shift = 3,
 105                 .bus_voltage_lsb = 4000,
 106                 .power_lsb = 20000,
 107         },
 108         [ina226] = {
 109                 .config_default = INA226_CONFIG_DEFAULT,
 110                 .calibration_factor = 5120000,
 111                 .registers = INA226_REGISTERS,
 112                 .shunt_div = 400,
 113                 .bus_voltage_shift = 0,
 114                 .bus_voltage_lsb = 1250,
 115                 .power_lsb = 25000,
 116         },
 117 };
 118
 119 /*
 120  * Initialize the configuration and calibration registers.
 121  */
 122 static int ina2xx_init(struct ina2xx_data *data)
 123 {
 124         struct i2c_client *client = data->client;
 125         int ret;
 126
 127         /* device configuration */
 128         ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 129                                            data->config->config_default);
 130         if (ret < 0)
 131                 return ret;
 132
 133         /*
 134          * Set current LSB to 1mA, shunt is in uOhms
 135          * (equation 13 in datasheet).
 136          */
 137         return i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 138                         data->config->calibration_factor / data->rshunt);
 139 }
 140
 141 static int ina2xx_do_update(struct device *dev)
 142 {
 143         struct ina2xx_data *data = dev_get_drvdata(dev);
 144         struct i2c_client *client = data->client;
 145         int i, rv, retry;
 146
 147         dev_dbg(&client->dev, "Starting ina2xx update\n");
 148
 149         for (retry = 5; retry; retry--) {
 150                 /* Read all registers */
 151                 for (i = 0; i < data->config->registers; i++) {
 152                         rv = i2c_smbus_read_word_swapped(client, i);
 153                         if (rv < 0)
 154                                 return rv;
 155                         data->regs[i] = rv;
 156                 }
 157
 158                 /*
 159                  * If the current value in the calibration register is 0, the
 160                  * power and current registers will also remain at 0. In case
 161                  * the chip has been reset let's check the calibration
 162                  * register and reinitialize if needed.
 163                  */
 164                 if (data->regs[INA2XX_CALIBRATION] == 0) {
 165                         dev_warn(dev, "chip not calibrated, reinitializing\n");
 166
 167                         rv = ina2xx_init(data);
 168                         if (rv < 0)
 169                                 return rv;
 170
 171                         /*
 172                          * Let's make sure the power and current registers
 173                          * have been updated before trying again.
 174                          */
 175                         msleep(INA2XX_MAX_DELAY);
 176                         continue;
 177                 }
 178
 179                 data->last_updated = jiffies;
 180                 data->valid = 1;
 181
 182                 return 0;
 183         }
 184
 185         /*
 186          * If we're here then although all write operations succeeded, the
 187          * chip still returns 0 in the calibration register. Nothing more we
 188          * can do here.
 189          */
 190         dev_err(dev, "unable to reinitialize the chip\n");
 191         return -ENODEV;
 192 }
 193
 194 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 195 {
 196         struct ina2xx_data *data = dev_get_drvdata(dev);
 197         struct ina2xx_data *ret = data;
 198         int rv;
 199
 200         mutex_lock(&data->update_lock);
 201
 202         if (time_after(jiffies, data->last_updated +
 203                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
 204                 rv = ina2xx_do_update(dev);
 205                 if (rv < 0)
 206                         ret = ERR_PTR(rv);
 207         }
 208
 209         mutex_unlock(&data->update_lock);
 210         return ret;
 211 }
 212
 213 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 214 {
 215         int val;
 216
 217         switch (reg) {
 218         case INA2XX_SHUNT_VOLTAGE:
 219                 /* signed register */
 220                 val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
 221                                         data->config->shunt_div);
 222                 break;
 223         case INA2XX_BUS_VOLTAGE:
 224                 val = (data->regs[reg] >> data->config->bus_voltage_shift)
 225                   * data->config->bus_voltage_lsb;
 226                 val = DIV_ROUND_CLOSEST(val, 1000);
 227                 break;
 228         case INA2XX_POWER:
 229                 val = data->regs[reg] * data->config->power_lsb;
 230                 break;
 231         case INA2XX_CURRENT:
 232                 /* signed register, LSB=1mA (selected), in mA */
 233                 val = (s16)data->regs[reg];
 234                 break;
 235         default:
 236                 /* programmer goofed */
 237                 WARN_ON_ONCE(1);
 238                 val = 0;
 239                 break;
 240         }
 241
 242         return val;
 243 }
 244
 245 static ssize_t ina2xx_show_value(struct device *dev,
 246                                  struct device_attribute *da, char *buf)
 247 {
 248         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 249         struct ina2xx_data *data = ina2xx_update_device(dev);
 250
 251         if (IS_ERR(data))
 252                 return PTR_ERR(data);
 253
 254         return snprintf(buf, PAGE_SIZE, "%d\n",
 255                         ina2xx_get_value(data, attr->index));
 256 }
 257
 258 /* shunt voltage */
 259 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 260                           INA2XX_SHUNT_VOLTAGE);
 261
 262 /* bus voltage */
 263 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 264                           INA2XX_BUS_VOLTAGE);
 265
 266 /* calculated current */
 267 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 268                           INA2XX_CURRENT);
 269
 270 /* calculated power */
 271 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 272                           INA2XX_POWER);
 273
 274 /* pointers to created device attributes */
 275 static struct attribute *ina2xx_attrs[] = {
 276         &sensor_dev_attr_in0_input.dev_attr.attr,
 277         &sensor_dev_attr_in1_input.dev_attr.attr,
 278         &sensor_dev_attr_curr1_input.dev_attr.attr,
 279         &sensor_dev_attr_power1_input.dev_attr.attr,
 280         NULL,
 281 };
 282 ATTRIBUTE_GROUPS(ina2xx);
 283
 284 static int ina2xx_probe(struct i2c_client *client,
 285                         const struct i2c_device_id *id)
 286 {
 287         struct i2c_adapter *adapter = client->adapter;
 288         struct ina2xx_platform_data *pdata;
 289         struct device *dev = &client->dev;
 290         struct ina2xx_data *data;
 291         struct device *hwmon_dev;
 292         u32 val;
 293         int ret;
 294
 295         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 296                 return -ENODEV;
 297
 298         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 299         if (!data)
 300                 return -ENOMEM;
 301
 302         if (dev_get_platdata(dev)) {
 303                 pdata = dev_get_platdata(dev);
 304                 data->rshunt = pdata->shunt_uohms;
 305         } else if (!of_property_read_u32(dev->of_node,
 306                                          "shunt-resistor", &val)) {
 307                 data->rshunt = val;
 308         } else {
 309                 data->rshunt = INA2XX_RSHUNT_DEFAULT;
 310         }
 311
 312         /* set the device type */
 313         data->kind = id->driver_data;
 314         data->config = &ina2xx_config[data->kind];
 315         data->client = client;
 316
 317         if (data->rshunt <= 0)
 318                 return -ENODEV;
 319
 320         ret = ina2xx_init(data);
 321         if (ret < 0) {
 322                 dev_err(dev, "error configuring the device: %d\n", ret);
 323                 return -ENODEV;
 324         }
 325
 326         mutex_init(&data->update_lock);
 327
 328         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 329                                                            data, ina2xx_groups);
 330         if (IS_ERR(hwmon_dev))
 331                 return PTR_ERR(hwmon_dev);
 332
 333         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 334                  id->name, data->rshunt);
 335
 336         return 0;
 337 }
 338
 339 static const struct i2c_device_id ina2xx_id[] = {
 340         { "ina219", ina219 },
 341         { "ina220", ina219 },
 342         { "ina226", ina226 },
 343         { "ina230", ina226 },
 344         { }
 345 };
 346 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 347
 348 static struct i2c_driver ina2xx_driver = {
 349         .driver = {
 350                 .name   = "ina2xx",
 351         },
 352         .probe          = ina2xx_probe,
 353         .id_table       = ina2xx_id,
 354 };
 355
 356 module_i2c_driver(ina2xx_driver);
 357
 358 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 359 MODULE_DESCRIPTION("ina2xx driver");
 360 MODULE_LICENSE("GPL");