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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
*
* 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/util_macros.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_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 = find_closest(avg, ina226_avg_tab,
ARRAY_SIZE(ina226_avg_tab));
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
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