swh:1:snp:c2847dfd741eae21606027cf29250d1ebcd63fb4
Tip revision: 39a8804455fb23f09157341d3ba7db6d7ae6ee76 authored by Linus Torvalds on 12 April 2015, 22:12:50 UTC
Linux 4.0
Linux 4.0
Tip revision: 39a8804
ina2xx.c
/*
* 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
*
* INA220:
* Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina220
*
* INA226:
* Bi-Directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina226
*
* INA230:
* Bi-directional Current/Power Monitor with I2C Interface
* Datasheet: http://www.ti.com/product/ina230
*
* 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/jiffies.h>
#include <linux/of.h>
#include <linux/delay.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
#define INA2XX_MAX_DELAY 69 /* worst case delay in ms */
#define INA2XX_RSHUNT_DEFAULT 10000
/* bit mask for reading the averaging setting in the configuration register */
#define INA226_AVG_RD_MASK 0x0E00
#define INA226_READ_AVG(reg) (((reg) & INA226_AVG_RD_MASK) >> 9)
#define INA226_SHIFT_AVG(val) ((val) << 9)
/* common attrs, ina226 attrs and NULL */
#define INA2XX_MAX_ATTRIBUTE_GROUPS 3
/*
* Both bus voltage and shunt voltage conversion times for ina226 are set
* to 0b0100 on POR, which translates to 2200 microseconds in total.
*/
#define INA226_TOTAL_CONV_TIME_DEFAULT 2200
enum ina2xx_ids { ina219, ina226 };
struct ina2xx_config {
u16 config_default;
int calibration_factor;
int registers;
int shunt_div;
int bus_voltage_shift;
int bus_voltage_lsb; /* uV */
int power_lsb; /* uW */
};
struct ina2xx_data {
struct i2c_client *client;
const struct ina2xx_config *config;
long rshunt;
u16 curr_config;
struct mutex update_lock;
bool valid;
unsigned long last_updated;
int update_interval; /* in jiffies */
int kind;
const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
u16 regs[INA2XX_MAX_REGISTERS];
};
static const struct ina2xx_config ina2xx_config[] = {
[ina219] = {
.config_default = INA219_CONFIG_DEFAULT,
.calibration_factor = 40960000,
.registers = INA219_REGISTERS,
.shunt_div = 100,
.bus_voltage_shift = 3,
.bus_voltage_lsb = 4000,
.power_lsb = 20000,
},
[ina226] = {
.config_default = INA226_CONFIG_DEFAULT,
.calibration_factor = 5120000,
.registers = INA226_REGISTERS,
.shunt_div = 400,
.bus_voltage_shift = 0,
.bus_voltage_lsb = 1250,
.power_lsb = 25000,
},
};
/*
* Available averaging rates for ina226. The indices correspond with
* the bit values expected by the chip (according to the ina226 datasheet,
* table 3 AVG bit settings, found at
* http://www.ti.com/lit/ds/symlink/ina226.pdf.
*/
static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
static int ina226_avg_bits(int avg)
{
int i;
/* Get the closest average from the tab. */
for (i = 0; i < ARRAY_SIZE(ina226_avg_tab) - 1; i++) {
if (avg <= (ina226_avg_tab[i] + ina226_avg_tab[i + 1]) / 2)
break;
}
return i; /* Return 0b0111 for values greater than 1024. */
}
static int ina226_reg_to_interval(u16 config)
{
int avg = ina226_avg_tab[INA226_READ_AVG(config)];
/*
* Multiply the total conversion time by the number of averages.
* Return the result in milliseconds.
*/
return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
}
static u16 ina226_interval_to_reg(int interval, u16 config)
{
int avg, avg_bits;
avg = DIV_ROUND_CLOSEST(interval * 1000,
INA226_TOTAL_CONV_TIME_DEFAULT);
avg_bits = ina226_avg_bits(avg);
return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
}
static void ina226_set_update_interval(struct ina2xx_data *data)
{
int ms;
ms = ina226_reg_to_interval(data->curr_config);
data->update_interval = msecs_to_jiffies(ms);
}
static int ina2xx_calibrate(struct ina2xx_data *data)
{
u16 val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
data->rshunt);
return i2c_smbus_write_word_swapped(data->client,
INA2XX_CALIBRATION, val);
}
/*
* Initialize the configuration and calibration registers.
*/
static int ina2xx_init(struct ina2xx_data *data)
{
struct i2c_client *client = data->client;
int ret;
/* device configuration */
ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
data->curr_config);
if (ret < 0)
return ret;
/*
* Set current LSB to 1mA, shunt is in uOhms
* (equation 13 in datasheet).
*/
return ina2xx_calibrate(data);
}
static int ina2xx_do_update(struct device *dev)
{
struct ina2xx_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int i, rv, retry;
dev_dbg(&client->dev, "Starting ina2xx update\n");
for (retry = 5; retry; retry--) {
/* Read all registers */
for (i = 0; i < data->config->registers; i++) {
rv = i2c_smbus_read_word_swapped(client, i);
if (rv < 0)
return rv;
data->regs[i] = rv;
}
/*
* If the current value in the calibration register is 0, the
* power and current registers will also remain at 0. In case
* the chip has been reset let's check the calibration
* register and reinitialize if needed.
*/
if (data->regs[INA2XX_CALIBRATION] == 0) {
dev_warn(dev, "chip not calibrated, reinitializing\n");
rv = ina2xx_init(data);
if (rv < 0)
return rv;
/*
* Let's make sure the power and current registers
* have been updated before trying again.
*/
msleep(INA2XX_MAX_DELAY);
continue;
}
data->last_updated = jiffies;
data->valid = 1;
return 0;
}
/*
* If we're here then although all write operations succeeded, the
* chip still returns 0 in the calibration register. Nothing more we
* can do here.
*/
dev_err(dev, "unable to reinitialize the chip\n");
return -ENODEV;
}
static struct ina2xx_data *ina2xx_update_device(struct device *dev)
{
struct ina2xx_data *data = dev_get_drvdata(dev);
struct ina2xx_data *ret = data;
unsigned long after;
int rv;
mutex_lock(&data->update_lock);
after = data->last_updated + data->update_interval;
if (time_after(jiffies, after) || !data->valid) {
rv = ina2xx_do_update(dev);
if (rv < 0)
ret = ERR_PTR(rv);
}
mutex_unlock(&data->update_lock);
return ret;
}
static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
{
int val;
switch (reg) {
case INA2XX_SHUNT_VOLTAGE:
/* signed register */
val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
data->config->shunt_div);
break;
case INA2XX_BUS_VOLTAGE:
val = (data->regs[reg] >> data->config->bus_voltage_shift)
* data->config->bus_voltage_lsb;
val = DIV_ROUND_CLOSEST(val, 1000);
break;
case INA2XX_POWER:
val = data->regs[reg] * data->config->power_lsb;
break;
case INA2XX_CURRENT:
/* signed register, LSB=1mA (selected), in mA */
val = (s16)data->regs[reg];
break;
case INA2XX_CALIBRATION:
val = DIV_ROUND_CLOSEST(data->config->calibration_factor,
data->regs[reg]);
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);
if (IS_ERR(data))
return PTR_ERR(data);
return snprintf(buf, PAGE_SIZE, "%d\n",
ina2xx_get_value(data, attr->index));
}
static ssize_t ina2xx_set_shunt(struct device *dev,
struct device_attribute *da,
const char *buf, size_t count)
{
struct ina2xx_data *data = ina2xx_update_device(dev);
unsigned long val;
int status;
if (IS_ERR(data))
return PTR_ERR(data);
status = kstrtoul(buf, 10, &val);
if (status < 0)
return status;
if (val == 0 ||
/* Values greater than the calibration factor make no sense. */
val > data->config->calibration_factor)
return -EINVAL;
mutex_lock(&data->update_lock);
data->rshunt = val;
status = ina2xx_calibrate(data);
mutex_unlock(&data->update_lock);
if (status < 0)
return status;
return count;
}
static ssize_t ina226_set_interval(struct device *dev,
struct device_attribute *da,
const char *buf, size_t count)
{
struct ina2xx_data *data = dev_get_drvdata(dev);
unsigned long val;
int status;
status = kstrtoul(buf, 10, &val);
if (status < 0)
return status;
if (val > INT_MAX || val == 0)
return -EINVAL;
mutex_lock(&data->update_lock);
data->curr_config = ina226_interval_to_reg(val,
data->regs[INA2XX_CONFIG]);
status = i2c_smbus_write_word_swapped(data->client,
INA2XX_CONFIG,
data->curr_config);
ina226_set_update_interval(data);
/* Make sure the next access re-reads all registers. */
data->valid = 0;
mutex_unlock(&data->update_lock);
if (status < 0)
return status;
return count;
}
static ssize_t ina226_show_interval(struct device *dev,
struct device_attribute *da, char *buf)
{
struct ina2xx_data *data = ina2xx_update_device(dev);
if (IS_ERR(data))
return PTR_ERR(data);
/*
* We don't use data->update_interval here as we want to display
* the actual interval used by the chip and jiffies_to_msecs()
* doesn't seem to be accurate enough.
*/
return snprintf(buf, PAGE_SIZE, "%d\n",
ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
}
/* 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);
/* shunt resistance */
static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
ina2xx_show_value, ina2xx_set_shunt,
INA2XX_CALIBRATION);
/* update interval (ina226 only) */
static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
ina226_show_interval, ina226_set_interval, 0);
/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
&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,
&sensor_dev_attr_shunt_resistor.dev_attr.attr,
NULL,
};
static const struct attribute_group ina2xx_group = {
.attrs = ina2xx_attrs,
};
static struct attribute *ina226_attrs[] = {
&sensor_dev_attr_update_interval.dev_attr.attr,
NULL,
};
static const struct attribute_group ina226_group = {
.attrs = ina226_attrs,
};
static int ina2xx_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct ina2xx_platform_data *pdata;
struct device *dev = &client->dev;
struct ina2xx_data *data;
struct device *hwmon_dev;
u32 val;
int ret, group = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
if (dev_get_platdata(dev)) {
pdata = dev_get_platdata(dev);
data->rshunt = pdata->shunt_uohms;
} else if (!of_property_read_u32(dev->of_node,
"shunt-resistor", &val)) {
data->rshunt = val;
} else {
data->rshunt = INA2XX_RSHUNT_DEFAULT;
}
/* set the device type */
data->kind = id->driver_data;
data->config = &ina2xx_config[data->kind];
data->curr_config = data->config->config_default;
data->client = client;
/*
* Ina226 has a variable update_interval. For ina219 we
* use a constant value.
*/
if (data->kind == ina226)
ina226_set_update_interval(data);
else
data->update_interval = HZ / INA2XX_CONVERSION_RATE;
if (data->rshunt <= 0 ||
data->rshunt > data->config->calibration_factor)
return -ENODEV;
ret = ina2xx_init(data);
if (ret < 0) {
dev_err(dev, "error configuring the device: %d\n", ret);
return -ENODEV;
}
mutex_init(&data->update_lock);
data->groups[group++] = &ina2xx_group;
if (data->kind == ina226)
data->groups[group++] = &ina226_group;
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data, data->groups);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
id->name, data->rshunt);
return 0;
}
static const struct i2c_device_id ina2xx_id[] = {
{ "ina219", ina219 },
{ "ina220", ina219 },
{ "ina226", ina226 },
{ "ina230", ina226 },
{ "ina231", ina226 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ina2xx_id);
static struct i2c_driver ina2xx_driver = {
.driver = {
.name = "ina2xx",
},
.probe = ina2xx_probe,
.id_table = ina2xx_id,
};
module_i2c_driver(ina2xx_driver);
MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
MODULE_DESCRIPTION("ina2xx driver");
MODULE_LICENSE("GPL");