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linux-next/drivers/hwmon/ina2xx.c
Felten, Lothar f7c2fe386a hwmon: INA219 and INA226 support 
Add support for the Texas Instruments INA219 and INA226 power monitors.

Signed-off-by: Lothar Felten <l-felten@ti.com>
[guenter.roeck@ericsson.com: formatting cleanup; check for smbus word data;
 select PGA=8 for INA219]
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
2012-05-22 06:48:02 -07:00

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/*
* Driver for Texas Instruments INA219, INA226 power monitor chips
*
* INA219:
* Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina219
*
* INA226:
* Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina226
*
* Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
* Thanks to Jan Volkering
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/platform_data/ina2xx.h>
/* common register definitions */
#define INA2XX_CONFIG 0x00
#define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
#define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
#define INA2XX_POWER 0x03 /* readonly */
#define INA2XX_CURRENT 0x04 /* readonly */
#define INA2XX_CALIBRATION 0x05
/* INA226 register definitions */
#define INA226_MASK_ENABLE 0x06
#define INA226_ALERT_LIMIT 0x07
#define INA226_DIE_ID 0xFF
/* register count */
#define INA219_REGISTERS 6
#define INA226_REGISTERS 8
#define INA2XX_MAX_REGISTERS 8
/* settings - depend on use case */
#define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
#define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */
/* worst case is 68.10 ms (~14.6Hz, ina219) */
#define INA2XX_CONVERSION_RATE 15
enum ina2xx_ids { ina219, ina226 };
struct ina2xx_data {
struct device *hwmon_dev;
struct mutex update_lock;
bool valid;
unsigned long last_updated;
int kind;
int registers;
u16 regs[INA2XX_MAX_REGISTERS];
};
int ina2xx_read_word(struct i2c_client *client, int reg)
{
int val = i2c_smbus_read_word_data(client, reg);
if (unlikely(val < 0)) {
dev_dbg(&client->dev,
"Failed to read register: %d\n", reg);
return val;
}
return be16_to_cpu(val);
}
void ina2xx_write_word(struct i2c_client *client, int reg, int data)
{
i2c_smbus_write_word_data(client, reg, cpu_to_be16(data));
}
static struct ina2xx_data *ina2xx_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ina2xx_data *data = i2c_get_clientdata(client);
struct ina2xx_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated +
HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
int i;
dev_dbg(&client->dev, "Starting ina2xx update\n");
/* Read all registers */
for (i = 0; i < data->registers; i++) {
int rv = ina2xx_read_word(client, i);
if (rv < 0) {
ret = ERR_PTR(rv);
goto abort;
}
data->regs[i] = rv;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static int ina219_get_value(struct ina2xx_data *data, u8 reg)
{
/*
* calculate exact value for the given register
* we assume default power-on reset settings:
* bus voltage range 32V
* gain = /8
* adc 1 & 2 -> conversion time 532uS
* mode is continuous shunt and bus
* calibration value is INA219_CALIBRATION_VALUE
*/
int val = data->regs[reg];
switch (reg) {
case INA2XX_SHUNT_VOLTAGE:
/* LSB=10uV. Convert to mV. */
val = DIV_ROUND_CLOSEST(val, 100);
break;
case INA2XX_BUS_VOLTAGE:
/* LSB=4mV. Register is not right aligned, convert to mV. */
val = (val >> 3) * 4;
break;
case INA2XX_POWER:
/* LSB=20mW. Convert to uW */
val = val * 20 * 1000;
break;
case INA2XX_CURRENT:
/* LSB=1mA (selected). Is in mA */
break;
default:
/* programmer goofed */
WARN_ON_ONCE(1);
val = 0;
break;
}
return val;
}
static int ina226_get_value(struct ina2xx_data *data, u8 reg)
{
/*
* calculate exact value for the given register
* we assume default power-on reset settings:
* bus voltage range 32V
* gain = /8
* adc 1 & 2 -> conversion time 532uS
* mode is continuous shunt and bus
* calibration value is INA226_CALIBRATION_VALUE
*/
int val = data->regs[reg];
switch (reg) {
case INA2XX_SHUNT_VOLTAGE:
/* LSB=2.5uV. Convert to mV. */
val = DIV_ROUND_CLOSEST(val, 400);
break;
case INA2XX_BUS_VOLTAGE:
/* LSB=1.25mV. Convert to mV. */
val = val + DIV_ROUND_CLOSEST(val, 4);
break;
case INA2XX_POWER:
/* LSB=25mW. Convert to uW */
val = val * 25 * 1000;
break;
case INA2XX_CURRENT:
/* LSB=1mA (selected). Is in mA */
break;
default:
/* programmer goofed */
WARN_ON_ONCE(1);
val = 0;
break;
}
return val;
}
static ssize_t ina2xx_show_value(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ina2xx_data *data = ina2xx_update_device(dev);
int value = 0;
if (IS_ERR(data))
return PTR_ERR(data);
switch (data->kind) {
case ina219:
value = ina219_get_value(data, attr->index);
break;
case ina226:
value = ina226_get_value(data, attr->index);
break;
default:
WARN_ON_ONCE(1);
break;
}
return snprintf(buf, PAGE_SIZE, "%d\n", value);
}
/* shunt voltage */
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
/* bus voltage */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
/* calculated current */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
ina2xx_show_value, NULL, INA2XX_CURRENT);
/* calculated power */
static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
ina2xx_show_value, NULL, INA2XX_POWER);
/* pointers to created device attributes */
static struct attribute *ina2xx_attributes[] = {
&sensor_dev_attr_in0_input.dev_attr.attr,
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_power1_input.dev_attr.attr,
NULL,
};
static const struct attribute_group ina2xx_group = {
.attrs = ina2xx_attributes,
};
static int ina2xx_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct ina2xx_data *data;
struct ina2xx_platform_data *pdata;
int ret = 0;
long shunt = 10000; /* default shunt value 10mOhms */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
if (client->dev.platform_data) {
pdata =
(struct ina2xx_platform_data *)client->dev.platform_data;
shunt = pdata->shunt_uohms;
}
if (shunt <= 0)
return -ENODEV;
/* set the device type */
data->kind = id->driver_data;
switch (data->kind) {
case ina219:
/* device configuration */
ina2xx_write_word(client, INA2XX_CONFIG, INA219_CONFIG_DEFAULT);
/* set current LSB to 1mA, shunt is in uOhms */
/* (equation 13 in datasheet) */
ina2xx_write_word(client, INA2XX_CALIBRATION, 40960000 / shunt);
dev_info(&client->dev,
"power monitor INA219 (Rshunt = %li uOhm)\n", shunt);
data->registers = INA219_REGISTERS;
break;
case ina226:
/* device configuration */
ina2xx_write_word(client, INA2XX_CONFIG, INA226_CONFIG_DEFAULT);
/* set current LSB to 1mA, shunt is in uOhms */
/* (equation 1 in datasheet)*/
ina2xx_write_word(client, INA2XX_CALIBRATION, 5120000 / shunt);
dev_info(&client->dev,
"power monitor INA226 (Rshunt = %li uOhm)\n", shunt);
data->registers = INA226_REGISTERS;
break;
default:
/* unknown device id */
return -ENODEV;
}
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
if (ret)
return ret;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
ret = PTR_ERR(data->hwmon_dev);
goto out_err_hwmon;
}
return 0;
out_err_hwmon:
sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
return ret;
}
static int ina2xx_remove(struct i2c_client *client)
{
struct ina2xx_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
return 0;
}
static const struct i2c_device_id ina2xx_id[] = {
{ "ina219", ina219 },
{ "ina226", ina226 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);
static struct i2c_driver ina2xx_driver = {
.driver = {
.name = "ina2xx",
},
.probe = ina2xx_probe,
.remove = ina2xx_remove,
.id_table = ina2xx_id,
};
static int __init ina2xx_init(void)
{
return i2c_add_driver(&ina2xx_driver);
}
static void __exit ina2xx_exit(void)
{
i2c_del_driver(&ina2xx_driver);
}
MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
MODULE_DESCRIPTION("ina2xx driver");
MODULE_LICENSE("GPL");
module_init(ina2xx_init);
module_exit(ina2xx_exit);
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