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linux-next/drivers/hwmon/ina2xx.c
Guenter Roeck 080b98e9ab hwmon: (ina2xx) Fix word size register read and write operations 
The driver uses be16_to_cpu and cpu_to_be16 to convert data in SMBus word
operations from chip to host byte order. However, the data passed from and to
the SMBus word API functions is in host byte order, not in chip byte order.
Conversion should therefore use swab16 instead of be16 to change the byte order.

Replace driver internal word conversion functions with SMBus API functions to
solve the problem.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable@vger.kernel.org # 3.5+
Acked-by: Jean Delvare <khali@linux-fr.org>
2012-09-12 06:42:11 -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];
};
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 = i2c_smbus_read_word_swapped(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 */
i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
INA219_CONFIG_DEFAULT);
/* set current LSB to 1mA, shunt is in uOhms */
/* (equation 13 in datasheet) */
i2c_smbus_write_word_swapped(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 */
i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
INA226_CONFIG_DEFAULT);
/* set current LSB to 1mA, shunt is in uOhms */
/* (equation 1 in datasheet)*/
i2c_smbus_write_word_swapped(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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