linux/drivers/hwmon/ina2xx.c
<<
>>
Prefs
   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
  68enum ina2xx_ids { ina219, ina226 };
  69
  70struct 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
  80struct ina2xx_data {
  81        struct device *hwmon_dev;
  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
  92static 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
 113static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 114{
 115        struct i2c_client *client = to_i2c_client(dev);
 116        struct ina2xx_data *data = i2c_get_clientdata(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        }
 140abort:
 141        mutex_unlock(&data->update_lock);
 142        return ret;
 143}
 144
 145static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 146{
 147        int val;
 148
 149        switch (reg) {
 150        case INA2XX_SHUNT_VOLTAGE:
 151                val = DIV_ROUND_CLOSEST(data->regs[reg],
 152                                        data->config->shunt_div);
 153                break;
 154        case INA2XX_BUS_VOLTAGE:
 155                val = (data->regs[reg] >> data->config->bus_voltage_shift)
 156                  * data->config->bus_voltage_lsb;
 157                val = DIV_ROUND_CLOSEST(val, 1000);
 158                break;
 159        case INA2XX_POWER:
 160                val = data->regs[reg] * data->config->power_lsb;
 161                break;
 162        case INA2XX_CURRENT:
 163                /* LSB=1mA (selected). Is in mA */
 164                val = data->regs[reg];
 165                break;
 166        default:
 167                /* programmer goofed */
 168                WARN_ON_ONCE(1);
 169                val = 0;
 170                break;
 171        }
 172
 173        return val;
 174}
 175
 176static ssize_t ina2xx_show_value(struct device *dev,
 177                                 struct device_attribute *da, char *buf)
 178{
 179        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 180        struct ina2xx_data *data = ina2xx_update_device(dev);
 181
 182        if (IS_ERR(data))
 183                return PTR_ERR(data);
 184
 185        return snprintf(buf, PAGE_SIZE, "%d\n",
 186                        ina2xx_get_value(data, attr->index));
 187}
 188
 189/* shunt voltage */
 190static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
 191                          INA2XX_SHUNT_VOLTAGE);
 192
 193/* bus voltage */
 194static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
 195                          INA2XX_BUS_VOLTAGE);
 196
 197/* calculated current */
 198static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
 199                          INA2XX_CURRENT);
 200
 201/* calculated power */
 202static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
 203                          INA2XX_POWER);
 204
 205/* pointers to created device attributes */
 206static struct attribute *ina2xx_attributes[] = {
 207        &sensor_dev_attr_in0_input.dev_attr.attr,
 208        &sensor_dev_attr_in1_input.dev_attr.attr,
 209        &sensor_dev_attr_curr1_input.dev_attr.attr,
 210        &sensor_dev_attr_power1_input.dev_attr.attr,
 211        NULL,
 212};
 213
 214static const struct attribute_group ina2xx_group = {
 215        .attrs = ina2xx_attributes,
 216};
 217
 218static int ina2xx_probe(struct i2c_client *client,
 219                        const struct i2c_device_id *id)
 220{
 221        struct i2c_adapter *adapter = client->adapter;
 222        struct ina2xx_data *data;
 223        struct ina2xx_platform_data *pdata;
 224        int ret;
 225        u32 val;
 226        long shunt = 10000; /* default shunt value 10mOhms */
 227
 228        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 229                return -ENODEV;
 230
 231        data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 232        if (!data)
 233                return -ENOMEM;
 234
 235        if (dev_get_platdata(&client->dev)) {
 236                pdata = dev_get_platdata(&client->dev);
 237                shunt = pdata->shunt_uohms;
 238        } else if (!of_property_read_u32(client->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        i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 252                                     data->config->config_default);
 253        /* set current LSB to 1mA, shunt is in uOhms */
 254        /* (equation 13 in datasheet) */
 255        i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 256                                     data->config->calibration_factor / shunt);
 257
 258        i2c_set_clientdata(client, data);
 259        mutex_init(&data->update_lock);
 260
 261        ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
 262        if (ret)
 263                return ret;
 264
 265        data->hwmon_dev = hwmon_device_register(&client->dev);
 266        if (IS_ERR(data->hwmon_dev)) {
 267                ret = PTR_ERR(data->hwmon_dev);
 268                goto out_err_hwmon;
 269        }
 270
 271        dev_info(&client->dev, "power monitor %s (Rshunt = %li uOhm)\n",
 272                 id->name, shunt);
 273
 274        return 0;
 275
 276out_err_hwmon:
 277        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 278        return ret;
 279}
 280
 281static int ina2xx_remove(struct i2c_client *client)
 282{
 283        struct ina2xx_data *data = i2c_get_clientdata(client);
 284
 285        hwmon_device_unregister(data->hwmon_dev);
 286        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 287
 288        return 0;
 289}
 290
 291static const struct i2c_device_id ina2xx_id[] = {
 292        { "ina219", ina219 },
 293        { "ina220", ina219 },
 294        { "ina226", ina226 },
 295        { "ina230", ina226 },
 296        { }
 297};
 298MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 299
 300static struct i2c_driver ina2xx_driver = {
 301        .driver = {
 302                .name   = "ina2xx",
 303        },
 304        .probe          = ina2xx_probe,
 305        .remove         = ina2xx_remove,
 306        .id_table       = ina2xx_id,
 307};
 308
 309module_i2c_driver(ina2xx_driver);
 310
 311MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 312MODULE_DESCRIPTION("ina2xx driver");
 313MODULE_LICENSE("GPL");
 314
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.