linux/drivers/hwmon/ina2xx.c
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   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
  38#include <linux/platform_data/ina2xx.h>
  39
  40/* common register definitions */
  41#define INA2XX_CONFIG                   0x00
  42#define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
  43#define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
  44#define INA2XX_POWER                    0x03 /* readonly */
  45#define INA2XX_CURRENT                  0x04 /* readonly */
  46#define INA2XX_CALIBRATION              0x05
  47
  48/* INA226 register definitions */
  49#define INA226_MASK_ENABLE              0x06
  50#define INA226_ALERT_LIMIT              0x07
  51#define INA226_DIE_ID                   0xFF
  52
  53
  54/* register count */
  55#define INA219_REGISTERS                6
  56#define INA226_REGISTERS                8
  57
  58#define INA2XX_MAX_REGISTERS            8
  59
  60/* settings - depend on use case */
  61#define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
  62#define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
  63
  64/* worst case is 68.10 ms (~14.6Hz, ina219) */
  65#define INA2XX_CONVERSION_RATE          15
  66
  67enum ina2xx_ids { ina219, ina226 };
  68
  69struct ina2xx_config {
  70        u16 config_default;
  71        int calibration_factor;
  72        int registers;
  73        int shunt_div;
  74        int bus_voltage_shift;
  75        int bus_voltage_lsb;    /* uV */
  76        int power_lsb;          /* uW */
  77};
  78
  79struct ina2xx_data {
  80        struct device *hwmon_dev;
  81        const struct ina2xx_config *config;
  82
  83        struct mutex update_lock;
  84        bool valid;
  85        unsigned long last_updated;
  86
  87        int kind;
  88        u16 regs[INA2XX_MAX_REGISTERS];
  89};
  90
  91static const struct ina2xx_config ina2xx_config[] = {
  92        [ina219] = {
  93                .config_default = INA219_CONFIG_DEFAULT,
  94                .calibration_factor = 40960000,
  95                .registers = INA219_REGISTERS,
  96                .shunt_div = 100,
  97                .bus_voltage_shift = 3,
  98                .bus_voltage_lsb = 4000,
  99                .power_lsb = 20000,
 100        },
 101        [ina226] = {
 102                .config_default = INA226_CONFIG_DEFAULT,
 103                .calibration_factor = 5120000,
 104                .registers = INA226_REGISTERS,
 105                .shunt_div = 400,
 106                .bus_voltage_shift = 0,
 107                .bus_voltage_lsb = 1250,
 108                .power_lsb = 25000,
 109        },
 110};
 111
 112static struct ina2xx_data *ina2xx_update_device(struct device *dev)
 113{
 114        struct i2c_client *client = to_i2c_client(dev);
 115        struct ina2xx_data *data = i2c_get_clientdata(client);
 116        struct ina2xx_data *ret = data;
 117
 118        mutex_lock(&data->update_lock);
 119
 120        if (time_after(jiffies, data->last_updated +
 121                       HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
 122
 123                int i;
 124
 125                dev_dbg(&client->dev, "Starting ina2xx update\n");
 126
 127                /* Read all registers */
 128                for (i = 0; i < data->config->registers; i++) {
 129                        int rv = i2c_smbus_read_word_swapped(client, i);
 130                        if (rv < 0) {
 131                                ret = ERR_PTR(rv);
 132                                goto abort;
 133                        }
 134                        data->regs[i] = rv;
 135                }
 136                data->last_updated = jiffies;
 137                data->valid = 1;
 138        }
 139abort:
 140        mutex_unlock(&data->update_lock);
 141        return ret;
 142}
 143
 144static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
 145{
 146        int val;
 147
 148        switch (reg) {
 149        case INA2XX_SHUNT_VOLTAGE:
 150                val = DIV_ROUND_CLOSEST(data->regs[reg],
 151                                        data->config->shunt_div);
 152                break;
 153        case INA2XX_BUS_VOLTAGE:
 154                val = (data->regs[reg] >> data->config->bus_voltage_shift)
 155                  * data->config->bus_voltage_lsb;
 156                val = DIV_ROUND_CLOSEST(val, 1000);
 157                break;
 158        case INA2XX_POWER:
 159                val = data->regs[reg] * data->config->power_lsb;
 160                break;
 161        case INA2XX_CURRENT:
 162                /* LSB=1mA (selected). Is in mA */
 163                val = data->regs[reg];
 164                break;
 165        default:
 166                /* programmer goofed */
 167                WARN_ON_ONCE(1);
 168                val = 0;
 169                break;
 170        }
 171
 172        return val;
 173}
 174
 175static ssize_t ina2xx_show_value(struct device *dev,
 176                                 struct device_attribute *da, char *buf)
 177{
 178        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 179        struct ina2xx_data *data = ina2xx_update_device(dev);
 180
 181        if (IS_ERR(data))
 182                return PTR_ERR(data);
 183
 184        return snprintf(buf, PAGE_SIZE, "%d\n",
 185                        ina2xx_get_value(data, attr->index));
 186}
 187
 188/* shunt voltage */
 189static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
 190        ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
 191
 192/* bus voltage */
 193static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
 194        ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
 195
 196/* calculated current */
 197static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
 198        ina2xx_show_value, NULL, INA2XX_CURRENT);
 199
 200/* calculated power */
 201static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
 202        ina2xx_show_value, NULL, INA2XX_POWER);
 203
 204/* pointers to created device attributes */
 205static struct attribute *ina2xx_attributes[] = {
 206        &sensor_dev_attr_in0_input.dev_attr.attr,
 207        &sensor_dev_attr_in1_input.dev_attr.attr,
 208        &sensor_dev_attr_curr1_input.dev_attr.attr,
 209        &sensor_dev_attr_power1_input.dev_attr.attr,
 210        NULL,
 211};
 212
 213static const struct attribute_group ina2xx_group = {
 214        .attrs = ina2xx_attributes,
 215};
 216
 217static int ina2xx_probe(struct i2c_client *client,
 218                        const struct i2c_device_id *id)
 219{
 220        struct i2c_adapter *adapter = client->adapter;
 221        struct ina2xx_data *data;
 222        struct ina2xx_platform_data *pdata;
 223        int ret;
 224        long shunt = 10000; /* default shunt value 10mOhms */
 225
 226        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 227                return -ENODEV;
 228
 229        data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 230        if (!data)
 231                return -ENOMEM;
 232
 233        if (client->dev.platform_data) {
 234                pdata =
 235                  (struct ina2xx_platform_data *)client->dev.platform_data;
 236                shunt = pdata->shunt_uohms;
 237        }
 238
 239        if (shunt <= 0)
 240                return -ENODEV;
 241
 242        /* set the device type */
 243        data->kind = id->driver_data;
 244        data->config = &ina2xx_config[data->kind];
 245
 246        /* device configuration */
 247        i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
 248                                     data->config->config_default);
 249        /* set current LSB to 1mA, shunt is in uOhms */
 250        /* (equation 13 in datasheet) */
 251        i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
 252                                     data->config->calibration_factor / shunt);
 253
 254        i2c_set_clientdata(client, data);
 255        mutex_init(&data->update_lock);
 256
 257        ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
 258        if (ret)
 259                return ret;
 260
 261        data->hwmon_dev = hwmon_device_register(&client->dev);
 262        if (IS_ERR(data->hwmon_dev)) {
 263                ret = PTR_ERR(data->hwmon_dev);
 264                goto out_err_hwmon;
 265        }
 266
 267        dev_info(&client->dev, "power monitor %s (Rshunt = %li uOhm)\n",
 268                 id->name, shunt);
 269
 270        return 0;
 271
 272out_err_hwmon:
 273        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 274        return ret;
 275}
 276
 277static int ina2xx_remove(struct i2c_client *client)
 278{
 279        struct ina2xx_data *data = i2c_get_clientdata(client);
 280
 281        hwmon_device_unregister(data->hwmon_dev);
 282        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
 283
 284        return 0;
 285}
 286
 287static const struct i2c_device_id ina2xx_id[] = {
 288        { "ina219", ina219 },
 289        { "ina220", ina219 },
 290        { "ina226", ina226 },
 291        { "ina230", ina226 },
 292        { }
 293};
 294MODULE_DEVICE_TABLE(i2c, ina2xx_id);
 295
 296static struct i2c_driver ina2xx_driver = {
 297        .driver = {
 298                .name   = "ina2xx",
 299        },
 300        .probe          = ina2xx_probe,
 301        .remove         = ina2xx_remove,
 302        .id_table       = ina2xx_id,
 303};
 304
 305module_i2c_driver(ina2xx_driver);
 306
 307MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
 308MODULE_DESCRIPTION("ina2xx driver");
 309MODULE_LICENSE("GPL");
 310
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