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
  39 #include <linux/platform_data/ina2xx.h>
  40
  41 /* common register definitions */
  42 #define INA2XX_CONFIG                   0x00
  43 #define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  44 #define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  45 #define INA2XX_POWER                    0x03 /* readonly */
  46 #define INA2XX_CURRENT                  0x04 /* readonly */
  47 #define INA2XX_CALIBRATION              0x05
  48
  49 /* INA226 register definitions */
  50 #define INA226_MASK_ENABLE              0x06
  51 #define INA226_ALERT_LIMIT              0x07
  52 #define INA226_DIE_ID                   0xFF
  53
  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
  68 enum ina2xx_ids { ina219, ina226 };
  69
  70 struct ina2xx_config {
  71         u16 config_default;
  72         int calibration_factor;
  73         int registers;
  74         int shunt_div;
  75         int bus_voltage_shift;
  76         int bus_voltage_lsb;    /* uV */
  77         int power_lsb;          /* uW */
  78 };
  79
  80 struct ina2xx_data {
  81         struct i2c_client *client;
  82         const struct ina2xx_config *config;
  83
  84         struct mutex update_lock;
  85         bool valid;
  86         unsigned long last_updated;
  87
  88         int kind;
  89         u16 regs[INA2XX_MAX_REGISTERS];
  90 };
  91
  92 static const struct ina2xx_config ina2xx_config[] = {
  93         [ina219] = {
  94                 .config_default = INA219_CONFIG_DEFAULT,
  95                 .calibration_factor = 40960000,
  96                 .registers = INA219_REGISTERS,
  97                 .shunt_div = 100,
  98                 .bus_voltage_shift = 3,
  99                 .bus_voltage_lsb = 4000,
 100                 .power_lsb = 20000,
 101         },
 102         [ina226] = {
 103                 .config_default = INA226_CONFIG_DEFAULT,
 104                 .calibration_factor = 5120000,
 105                 .registers = INA226_REGISTERS,
 106                 .shunt_div = 400,
 107                 .bus_voltage_shift = 0,
 108                 .bus_voltage_lsb = 1250,
 109                 .power_lsb = 25000,
 110         },
 111 };
 112
 113 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 114 {
 115         struct ina2xx_data *data = dev_get_drvdata(dev);
 116         struct i2c_client *client = data->client;
 117         struct ina2xx_data *ret = data;
 118
 119         mutex_lock(&data->update_lock);
 120
 121         if (time_after(jiffies, data->last_updated +
 122                        HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
 123
 124                 int i;
 125
 126                 dev_dbg(&client->dev, "Starting ina2xx update\n");
 127
 128                 /* Read all registers */
 129                 for (i = 0; i < data->config->registers; i++) {
 130                         int rv = i2c_smbus_read_word_swapped(client, i);
 131                         if (rv < 0) {
 132                                 ret = ERR_PTR(rv);
 133                                 goto abort;
 134                         }
 135                         data->regs[i] = rv;
 136                 }
 137                 data->last_updated = jiffies;
 138                 data->valid = 1;
 139         }
 140 abort:
 141         mutex_unlock(&data->update_lock);
 142         return ret;
 143 }
 144
 145 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 146 {
 147         int val;
 148
 149         switch (reg) {
 150         case INA2XX_SHUNT_VOLTAGE:
 151                 /* signed register */
 152                 val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
 153                                         data->config->shunt_div);
 154                 break;
 155         case INA2XX_BUS_VOLTAGE:
 156                 val = (data->regs[reg] >> data->config->bus_voltage_shift)
 157                   * data->config->bus_voltage_lsb;
 158                 val = DIV_ROUND_CLOSEST(val, 1000);
 159                 break;
 160         case INA2XX_POWER:
 161                 val = data->regs[reg] * data->config->power_lsb;
 162                 break;
 163         case INA2XX_CURRENT:
 164                 /* signed register, LSB=1mA (selected), in mA */
 165                 val = (s16)data->regs[reg];
 166                 break;
 167         default:
 168                 /* programmer goofed */
 169                 WARN_ON_ONCE(1);
 170                 val = 0;
 171                 break;
 172         }
 173
 174         return val;
 175 }
 176
 177 static ssize_t ina2xx_show_value(struct device *dev,
 178                                  struct device_attribute *da, char *buf)
 179 {
 180         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 181         struct ina2xx_data *data = ina2xx_update_device(dev);
 182
 183         if (IS_ERR(data))
 184                 return PTR_ERR(data);
 185
 186         return snprintf(buf, PAGE_SIZE, "%d\n",
 187                         ina2xx_get_value(data, attr->index));
 188 }
 189
 190 /* shunt voltage */
 191 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 192                           INA2XX_SHUNT_VOLTAGE);
 193
 194 /* bus voltage */
 195 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 196                           INA2XX_BUS_VOLTAGE);
 197
 198 /* calculated current */
 199 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 200                           INA2XX_CURRENT);
 201
 202 /* calculated power */
 203 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 204                           INA2XX_POWER);
 205
 206 /* pointers to created device attributes */
 207 static struct attribute *ina2xx_attrs[] = {
 208         &sensor_dev_attr_in0_input.dev_attr.attr,
 209         &sensor_dev_attr_in1_input.dev_attr.attr,
 210         &sensor_dev_attr_curr1_input.dev_attr.attr,
 211         &sensor_dev_attr_power1_input.dev_attr.attr,
 212         NULL,
 213 };
 214 ATTRIBUTE_GROUPS(ina2xx);
 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_platform_data *pdata;
 221         struct device *dev = &client->dev;
 222         struct ina2xx_data *data;
 223         struct device *hwmon_dev;
 224         long shunt = 10000; /* default shunt value 10mOhms */
 225         u32 val;
 226         int ret;
 227
 228         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 229                 return -ENODEV;
 230
 231         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 232         if (!data)
 233                 return -ENOMEM;
 234
 235         if (dev_get_platdata(dev)) {
 236                 pdata = dev_get_platdata(dev);
 237                 shunt = pdata->shunt_uohms;
 238         } else if (!of_property_read_u32(dev->of_node,
 239                                          "shunt-resistor", &val)) {
 240                 shunt = val;
 241         }
 242
 243         if (shunt <= 0)
 244                 return -ENODEV;
 245
 246         /* set the device type */
 247         data->kind = id->driver_data;
 248         data->config = &ina2xx_config[data->kind];
 249
 250         /* device configuration */
 251         ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 252                                            data->config->config_default);
 253         if (ret < 0) {
 254                 dev_err(dev,
 255                         "error writing to the config register: %d", ret);
 256                 return -ENODEV;
 257         }
 258
 259         /*
 260          * Set current LSB to 1mA, shunt is in uOhms
 261          * (equation 13 in datasheet).
 262          */
 263         ret = i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 264                                 data->config->calibration_factor / shunt);
 265         if (ret < 0) {
 266                 dev_err(dev,
 267                         "error writing to the calibration register: %d", ret);
 268                 return -ENODEV;
 269         }
 270
 271         data->client = client;
 272         mutex_init(&data->update_lock);
 273
 274         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 275                                                            data, ina2xx_groups);
 276         if (IS_ERR(hwmon_dev))
 277                 return PTR_ERR(hwmon_dev);
 278
 279         dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
 280                  id->name, shunt);
 281
 282         return 0;
 283 }
 284
 285 static const struct i2c_device_id ina2xx_id[] = {
 286         { "ina219", ina219 },
 287         { "ina220", ina219 },
 288         { "ina226", ina226 },
 289         { "ina230", ina226 },
 290         { }
 291 };
 292 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 293
 294 static struct i2c_driver ina2xx_driver = {
 295         .driver = {
 296                 .name   = "ina2xx",
 297         },
 298         .probe          = ina2xx_probe,
 299         .id_table       = ina2xx_id,
 300 };
 301
 302 module_i2c_driver(ina2xx_driver);
 303
 304 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 305 MODULE_DESCRIPTION("ina2xx driver");
 306 MODULE_LICENSE("GPL");