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