292 lines
7.1 KiB
C
292 lines
7.1 KiB
C
/*
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* Driver for Texas Instruments INA219, INA226 power monitor chips
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*
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* INA219:
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* Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
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* Datasheet: http://www.ti.com/product/ina219
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*
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* INA220:
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* Bi-Directional Current/Power Monitor with I2C Interface
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* Datasheet: http://www.ti.com/product/ina220
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*
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* INA226:
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* Bi-Directional Current/Power Monitor with I2C Interface
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* Datasheet: http://www.ti.com/product/ina226
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*
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* INA230:
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* Bi-directional Current/Power Monitor with I2C Interface
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* Datasheet: http://www.ti.com/product/ina230
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*
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* Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
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* Thanks to Jan Volkering
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/jiffies.h>
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#include <linux/of.h>
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#include <linux/platform_data/ina2xx.h>
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/* common register definitions */
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#define INA2XX_CONFIG 0x00
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#define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
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#define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
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#define INA2XX_POWER 0x03 /* readonly */
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#define INA2XX_CURRENT 0x04 /* readonly */
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#define INA2XX_CALIBRATION 0x05
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/* INA226 register definitions */
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#define INA226_MASK_ENABLE 0x06
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#define INA226_ALERT_LIMIT 0x07
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#define INA226_DIE_ID 0xFF
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/* register count */
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#define INA219_REGISTERS 6
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#define INA226_REGISTERS 8
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#define INA2XX_MAX_REGISTERS 8
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/* settings - depend on use case */
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#define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
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#define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */
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/* worst case is 68.10 ms (~14.6Hz, ina219) */
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#define INA2XX_CONVERSION_RATE 15
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enum ina2xx_ids { ina219, ina226 };
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struct ina2xx_config {
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u16 config_default;
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int calibration_factor;
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int registers;
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int shunt_div;
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int bus_voltage_shift;
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int bus_voltage_lsb; /* uV */
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int power_lsb; /* uW */
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};
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struct ina2xx_data {
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struct i2c_client *client;
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const struct ina2xx_config *config;
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struct mutex update_lock;
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bool valid;
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unsigned long last_updated;
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int kind;
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u16 regs[INA2XX_MAX_REGISTERS];
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};
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static const struct ina2xx_config ina2xx_config[] = {
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[ina219] = {
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.config_default = INA219_CONFIG_DEFAULT,
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.calibration_factor = 40960000,
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.registers = INA219_REGISTERS,
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.shunt_div = 100,
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.bus_voltage_shift = 3,
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.bus_voltage_lsb = 4000,
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.power_lsb = 20000,
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},
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[ina226] = {
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.config_default = INA226_CONFIG_DEFAULT,
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.calibration_factor = 5120000,
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.registers = INA226_REGISTERS,
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.shunt_div = 400,
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.bus_voltage_shift = 0,
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.bus_voltage_lsb = 1250,
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.power_lsb = 25000,
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},
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};
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static struct ina2xx_data *ina2xx_update_device(struct device *dev)
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{
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struct ina2xx_data *data = dev_get_drvdata(dev);
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struct i2c_client *client = data->client;
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struct ina2xx_data *ret = data;
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mutex_lock(&data->update_lock);
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if (time_after(jiffies, data->last_updated +
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HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
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int i;
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dev_dbg(&client->dev, "Starting ina2xx update\n");
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/* Read all registers */
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for (i = 0; i < data->config->registers; i++) {
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int rv = i2c_smbus_read_word_swapped(client, i);
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if (rv < 0) {
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ret = ERR_PTR(rv);
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goto abort;
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}
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data->regs[i] = rv;
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}
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data->last_updated = jiffies;
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data->valid = 1;
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}
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abort:
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mutex_unlock(&data->update_lock);
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return ret;
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}
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static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
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{
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int val;
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switch (reg) {
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case INA2XX_SHUNT_VOLTAGE:
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val = DIV_ROUND_CLOSEST(data->regs[reg],
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data->config->shunt_div);
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break;
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case INA2XX_BUS_VOLTAGE:
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val = (data->regs[reg] >> data->config->bus_voltage_shift)
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* data->config->bus_voltage_lsb;
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val = DIV_ROUND_CLOSEST(val, 1000);
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break;
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case INA2XX_POWER:
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val = data->regs[reg] * data->config->power_lsb;
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break;
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case INA2XX_CURRENT:
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/* LSB=1mA (selected). Is in mA */
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val = data->regs[reg];
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break;
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default:
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/* programmer goofed */
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WARN_ON_ONCE(1);
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val = 0;
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break;
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}
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return val;
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}
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static ssize_t ina2xx_show_value(struct device *dev,
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struct device_attribute *da, char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct ina2xx_data *data = ina2xx_update_device(dev);
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if (IS_ERR(data))
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return PTR_ERR(data);
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return snprintf(buf, PAGE_SIZE, "%d\n",
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ina2xx_get_value(data, attr->index));
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}
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/* shunt voltage */
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static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
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INA2XX_SHUNT_VOLTAGE);
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/* bus voltage */
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static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
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INA2XX_BUS_VOLTAGE);
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/* calculated current */
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static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
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INA2XX_CURRENT);
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/* calculated power */
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static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
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INA2XX_POWER);
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/* pointers to created device attributes */
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static struct attribute *ina2xx_attrs[] = {
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&sensor_dev_attr_in0_input.dev_attr.attr,
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&sensor_dev_attr_in1_input.dev_attr.attr,
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&sensor_dev_attr_curr1_input.dev_attr.attr,
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&sensor_dev_attr_power1_input.dev_attr.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(ina2xx);
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static int ina2xx_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = client->adapter;
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struct ina2xx_platform_data *pdata;
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struct device *dev = &client->dev;
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struct ina2xx_data *data;
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struct device *hwmon_dev;
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long shunt = 10000; /* default shunt value 10mOhms */
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u32 val;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
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return -ENODEV;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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if (dev_get_platdata(dev)) {
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pdata = dev_get_platdata(dev);
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shunt = pdata->shunt_uohms;
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} else if (!of_property_read_u32(dev->of_node,
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"shunt-resistor", &val)) {
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shunt = val;
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}
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if (shunt <= 0)
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return -ENODEV;
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/* set the device type */
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data->kind = id->driver_data;
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data->config = &ina2xx_config[data->kind];
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/* device configuration */
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i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
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data->config->config_default);
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/* set current LSB to 1mA, shunt is in uOhms */
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/* (equation 13 in datasheet) */
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i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
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data->config->calibration_factor / shunt);
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data->client = client;
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mutex_init(&data->update_lock);
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
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data, ina2xx_groups);
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if (IS_ERR(hwmon_dev))
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return PTR_ERR(hwmon_dev);
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dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
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id->name, shunt);
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return 0;
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}
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static const struct i2c_device_id ina2xx_id[] = {
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{ "ina219", ina219 },
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{ "ina220", ina219 },
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{ "ina226", ina226 },
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{ "ina230", ina226 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ina2xx_id);
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static struct i2c_driver ina2xx_driver = {
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.driver = {
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.name = "ina2xx",
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},
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.probe = ina2xx_probe,
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.id_table = ina2xx_id,
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};
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module_i2c_driver(ina2xx_driver);
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MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
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MODULE_DESCRIPTION("ina2xx driver");
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MODULE_LICENSE("GPL");
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