581 строка
15 KiB
C
581 строка
15 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* iio/adc/max9611.c
|
|
*
|
|
* Maxim max9611/max9612 high side current sense amplifier with
|
|
* 12-bit ADC interface.
|
|
*
|
|
* Copyright (C) 2017 Jacopo Mondi
|
|
*/
|
|
|
|
/*
|
|
* This driver supports input common-mode voltage, current-sense
|
|
* amplifier with programmable gains and die temperature reading from
|
|
* Maxim max9611/max9612.
|
|
*
|
|
* Op-amp, analog comparator, and watchdog functionalities are not
|
|
* supported by this driver.
|
|
*/
|
|
|
|
#include <linux/delay.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/iio/iio.h>
|
|
#include <linux/iio/sysfs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/of_device.h>
|
|
|
|
#define DRIVER_NAME "max9611"
|
|
|
|
/* max9611 register addresses */
|
|
#define MAX9611_REG_CSA_DATA 0x00
|
|
#define MAX9611_REG_RS_DATA 0x02
|
|
#define MAX9611_REG_TEMP_DATA 0x08
|
|
#define MAX9611_REG_CTRL1 0x0a
|
|
#define MAX9611_REG_CTRL2 0x0b
|
|
|
|
/* max9611 REG1 mux configuration options */
|
|
#define MAX9611_MUX_MASK GENMASK(3, 0)
|
|
#define MAX9611_MUX_SENSE_1x 0x00
|
|
#define MAX9611_MUX_SENSE_4x 0x01
|
|
#define MAX9611_MUX_SENSE_8x 0x02
|
|
#define MAX9611_INPUT_VOLT 0x03
|
|
#define MAX9611_MUX_TEMP 0x06
|
|
|
|
/* max9611 voltage (both csa and input) helper macros */
|
|
#define MAX9611_VOLTAGE_SHIFT 0x04
|
|
#define MAX9611_VOLTAGE_RAW(_r) ((_r) >> MAX9611_VOLTAGE_SHIFT)
|
|
|
|
/*
|
|
* max9611 current sense amplifier voltage output:
|
|
* LSB and offset values depends on selected gain (1x, 4x, 8x)
|
|
*
|
|
* GAIN LSB (nV) OFFSET (LSB steps)
|
|
* 1x 107500 1
|
|
* 4x 26880 1
|
|
* 8x 13440 3
|
|
*
|
|
* The complete formula to calculate current sense voltage is:
|
|
* (((adc_read >> 4) - offset) / ((1 / LSB) * 10^-3)
|
|
*/
|
|
#define MAX9611_CSA_1X_LSB_nV 107500
|
|
#define MAX9611_CSA_4X_LSB_nV 26880
|
|
#define MAX9611_CSA_8X_LSB_nV 13440
|
|
|
|
#define MAX9611_CSA_1X_OFFS_RAW 1
|
|
#define MAX9611_CSA_4X_OFFS_RAW 1
|
|
#define MAX9611_CSA_8X_OFFS_RAW 3
|
|
|
|
/*
|
|
* max9611 common input mode (CIM): LSB is 14mV, with 14mV offset at 25 C
|
|
*
|
|
* The complete formula to calculate input common voltage is:
|
|
* (((adc_read >> 4) * 1000) - offset) / (1 / 14 * 1000)
|
|
*/
|
|
#define MAX9611_CIM_LSB_mV 14
|
|
#define MAX9611_CIM_OFFSET_RAW 1
|
|
|
|
/*
|
|
* max9611 temperature reading: LSB is 480 milli degrees Celsius
|
|
*
|
|
* The complete formula to calculate temperature is:
|
|
* ((adc_read >> 7) * 1000) / (1 / 480 * 1000)
|
|
*/
|
|
#define MAX9611_TEMP_MAX_POS 0x7f80
|
|
#define MAX9611_TEMP_MAX_NEG 0xff80
|
|
#define MAX9611_TEMP_MIN_NEG 0xd980
|
|
#define MAX9611_TEMP_MASK GENMASK(7, 15)
|
|
#define MAX9611_TEMP_SHIFT 0x07
|
|
#define MAX9611_TEMP_RAW(_r) ((_r) >> MAX9611_TEMP_SHIFT)
|
|
#define MAX9611_TEMP_SCALE_NUM 1000000
|
|
#define MAX9611_TEMP_SCALE_DIV 2083
|
|
|
|
struct max9611_dev {
|
|
struct device *dev;
|
|
struct i2c_client *i2c_client;
|
|
struct mutex lock;
|
|
unsigned int shunt_resistor_uohm;
|
|
};
|
|
|
|
enum max9611_conf_ids {
|
|
CONF_SENSE_1x,
|
|
CONF_SENSE_4x,
|
|
CONF_SENSE_8x,
|
|
CONF_IN_VOLT,
|
|
CONF_TEMP,
|
|
};
|
|
|
|
/**
|
|
* max9611_mux_conf - associate ADC mux configuration with register address
|
|
* where data shall be read from
|
|
*/
|
|
static const unsigned int max9611_mux_conf[][2] = {
|
|
/* CONF_SENSE_1x */
|
|
{ MAX9611_MUX_SENSE_1x, MAX9611_REG_CSA_DATA },
|
|
/* CONF_SENSE_4x */
|
|
{ MAX9611_MUX_SENSE_4x, MAX9611_REG_CSA_DATA },
|
|
/* CONF_SENSE_8x */
|
|
{ MAX9611_MUX_SENSE_8x, MAX9611_REG_CSA_DATA },
|
|
/* CONF_IN_VOLT */
|
|
{ MAX9611_INPUT_VOLT, MAX9611_REG_RS_DATA },
|
|
/* CONF_TEMP */
|
|
{ MAX9611_MUX_TEMP, MAX9611_REG_TEMP_DATA },
|
|
};
|
|
|
|
enum max9611_csa_gain {
|
|
CSA_GAIN_1x,
|
|
CSA_GAIN_4x,
|
|
CSA_GAIN_8x,
|
|
};
|
|
|
|
enum max9611_csa_gain_params {
|
|
CSA_GAIN_LSB_nV,
|
|
CSA_GAIN_OFFS_RAW,
|
|
};
|
|
|
|
/**
|
|
* max9611_csa_gain_conf - associate gain multiplier with LSB and
|
|
* offset values.
|
|
*
|
|
* Group together parameters associated with configurable gain
|
|
* on current sense amplifier path to ADC interface.
|
|
* Current sense read routine adjusts gain until it gets a meaningful
|
|
* value; use this structure to retrieve the correct LSB and offset values.
|
|
*/
|
|
static const unsigned int max9611_gain_conf[][2] = {
|
|
{ /* [0] CSA_GAIN_1x */
|
|
MAX9611_CSA_1X_LSB_nV,
|
|
MAX9611_CSA_1X_OFFS_RAW,
|
|
},
|
|
{ /* [1] CSA_GAIN_4x */
|
|
MAX9611_CSA_4X_LSB_nV,
|
|
MAX9611_CSA_4X_OFFS_RAW,
|
|
},
|
|
{ /* [2] CSA_GAIN_8x */
|
|
MAX9611_CSA_8X_LSB_nV,
|
|
MAX9611_CSA_8X_OFFS_RAW,
|
|
},
|
|
};
|
|
|
|
enum max9611_chan_addrs {
|
|
MAX9611_CHAN_VOLTAGE_INPUT,
|
|
MAX9611_CHAN_VOLTAGE_SENSE,
|
|
MAX9611_CHAN_TEMPERATURE,
|
|
MAX9611_CHAN_CURRENT_LOAD,
|
|
MAX9611_CHAN_POWER_LOAD,
|
|
};
|
|
|
|
static const struct iio_chan_spec max9611_channels[] = {
|
|
{
|
|
.type = IIO_TEMP,
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
|
|
BIT(IIO_CHAN_INFO_SCALE),
|
|
.address = MAX9611_CHAN_TEMPERATURE,
|
|
},
|
|
{
|
|
.type = IIO_VOLTAGE,
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
|
|
.address = MAX9611_CHAN_VOLTAGE_SENSE,
|
|
.indexed = 1,
|
|
.channel = 0,
|
|
},
|
|
{
|
|
.type = IIO_VOLTAGE,
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
|
|
BIT(IIO_CHAN_INFO_SCALE) |
|
|
BIT(IIO_CHAN_INFO_OFFSET),
|
|
.address = MAX9611_CHAN_VOLTAGE_INPUT,
|
|
.indexed = 1,
|
|
.channel = 1,
|
|
},
|
|
{
|
|
.type = IIO_CURRENT,
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
|
|
.address = MAX9611_CHAN_CURRENT_LOAD,
|
|
},
|
|
{
|
|
.type = IIO_POWER,
|
|
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
|
|
.address = MAX9611_CHAN_POWER_LOAD
|
|
},
|
|
};
|
|
|
|
/**
|
|
* max9611_read_single() - read a single value from ADC interface
|
|
*
|
|
* Data registers are 16 bit long, spread between two 8 bit registers
|
|
* with consecutive addresses.
|
|
* Configure ADC mux first, then read register at address "reg_addr".
|
|
* The smbus_read_word routine asks for 16 bits and the ADC is kind enough
|
|
* to return values from "reg_addr" and "reg_addr + 1" consecutively.
|
|
* Data are transmitted with big-endian ordering: MSB arrives first.
|
|
*
|
|
* @max9611: max9611 device
|
|
* @selector: index for mux and register configuration
|
|
* @raw_val: the value returned from ADC
|
|
*/
|
|
static int max9611_read_single(struct max9611_dev *max9611,
|
|
enum max9611_conf_ids selector,
|
|
u16 *raw_val)
|
|
{
|
|
int ret;
|
|
|
|
u8 mux_conf = max9611_mux_conf[selector][0] & MAX9611_MUX_MASK;
|
|
u8 reg_addr = max9611_mux_conf[selector][1];
|
|
|
|
/*
|
|
* Keep mutex lock held during read-write to avoid mux register
|
|
* (CTRL1) re-configuration.
|
|
*/
|
|
mutex_lock(&max9611->lock);
|
|
ret = i2c_smbus_write_byte_data(max9611->i2c_client,
|
|
MAX9611_REG_CTRL1, mux_conf);
|
|
if (ret) {
|
|
dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",
|
|
MAX9611_REG_CTRL1, mux_conf);
|
|
mutex_unlock(&max9611->lock);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* need a delay here to make register configuration
|
|
* stabilize. 1 msec at least, from empirical testing.
|
|
*/
|
|
usleep_range(1000, 2000);
|
|
|
|
ret = i2c_smbus_read_word_swapped(max9611->i2c_client, reg_addr);
|
|
if (ret < 0) {
|
|
dev_err(max9611->dev, "i2c read word from 0x%2x failed\n",
|
|
reg_addr);
|
|
mutex_unlock(&max9611->lock);
|
|
return ret;
|
|
}
|
|
|
|
*raw_val = ret;
|
|
mutex_unlock(&max9611->lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* max9611_read_csa_voltage() - read current sense amplifier output voltage
|
|
*
|
|
* Current sense amplifier output voltage is read through a configurable
|
|
* 1x, 4x or 8x gain.
|
|
* Start with plain 1x gain, and adjust gain control properly until a
|
|
* meaningful value is read from ADC output.
|
|
*
|
|
* @max9611: max9611 device
|
|
* @adc_raw: raw value read from ADC output
|
|
* @csa_gain: gain configuration option selector
|
|
*/
|
|
static int max9611_read_csa_voltage(struct max9611_dev *max9611,
|
|
u16 *adc_raw,
|
|
enum max9611_csa_gain *csa_gain)
|
|
{
|
|
enum max9611_conf_ids gain_selectors[] = {
|
|
CONF_SENSE_1x,
|
|
CONF_SENSE_4x,
|
|
CONF_SENSE_8x
|
|
};
|
|
unsigned int i;
|
|
int ret;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(gain_selectors); ++i) {
|
|
ret = max9611_read_single(max9611, gain_selectors[i], adc_raw);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (*adc_raw > 0) {
|
|
*csa_gain = (enum max9611_csa_gain)gain_selectors[i];
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return -EIO;
|
|
}
|
|
|
|
static int max9611_read_raw(struct iio_dev *indio_dev,
|
|
struct iio_chan_spec const *chan,
|
|
int *val, int *val2, long mask)
|
|
{
|
|
struct max9611_dev *dev = iio_priv(indio_dev);
|
|
enum max9611_csa_gain gain_selector;
|
|
const unsigned int *csa_gain;
|
|
u16 adc_data;
|
|
int ret;
|
|
|
|
switch (mask) {
|
|
case IIO_CHAN_INFO_RAW:
|
|
|
|
switch (chan->address) {
|
|
case MAX9611_CHAN_TEMPERATURE:
|
|
ret = max9611_read_single(dev, CONF_TEMP,
|
|
&adc_data);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
*val = MAX9611_TEMP_RAW(adc_data);
|
|
return IIO_VAL_INT;
|
|
|
|
case MAX9611_CHAN_VOLTAGE_INPUT:
|
|
ret = max9611_read_single(dev, CONF_IN_VOLT,
|
|
&adc_data);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
*val = MAX9611_VOLTAGE_RAW(adc_data);
|
|
return IIO_VAL_INT;
|
|
}
|
|
|
|
break;
|
|
|
|
case IIO_CHAN_INFO_OFFSET:
|
|
/* MAX9611_CHAN_VOLTAGE_INPUT */
|
|
*val = MAX9611_CIM_OFFSET_RAW;
|
|
|
|
return IIO_VAL_INT;
|
|
|
|
case IIO_CHAN_INFO_SCALE:
|
|
|
|
switch (chan->address) {
|
|
case MAX9611_CHAN_TEMPERATURE:
|
|
*val = MAX9611_TEMP_SCALE_NUM;
|
|
*val2 = MAX9611_TEMP_SCALE_DIV;
|
|
|
|
return IIO_VAL_FRACTIONAL;
|
|
|
|
case MAX9611_CHAN_VOLTAGE_INPUT:
|
|
*val = MAX9611_CIM_LSB_mV;
|
|
|
|
return IIO_VAL_INT;
|
|
}
|
|
|
|
break;
|
|
|
|
case IIO_CHAN_INFO_PROCESSED:
|
|
|
|
switch (chan->address) {
|
|
case MAX9611_CHAN_VOLTAGE_SENSE:
|
|
/*
|
|
* processed (mV): (raw - offset) * LSB (nV) / 10^6
|
|
*
|
|
* Even if max9611 can output raw csa voltage readings,
|
|
* use a produced value as scale depends on gain.
|
|
*/
|
|
ret = max9611_read_csa_voltage(dev, &adc_data,
|
|
&gain_selector);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
csa_gain = max9611_gain_conf[gain_selector];
|
|
|
|
adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];
|
|
*val = MAX9611_VOLTAGE_RAW(adc_data) *
|
|
csa_gain[CSA_GAIN_LSB_nV];
|
|
*val2 = 1000000;
|
|
|
|
return IIO_VAL_FRACTIONAL;
|
|
|
|
case MAX9611_CHAN_CURRENT_LOAD:
|
|
/* processed (mA): Vcsa (nV) / Rshunt (uOhm) */
|
|
ret = max9611_read_csa_voltage(dev, &adc_data,
|
|
&gain_selector);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
csa_gain = max9611_gain_conf[gain_selector];
|
|
|
|
adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];
|
|
*val = MAX9611_VOLTAGE_RAW(adc_data) *
|
|
csa_gain[CSA_GAIN_LSB_nV];
|
|
*val2 = dev->shunt_resistor_uohm;
|
|
|
|
return IIO_VAL_FRACTIONAL;
|
|
|
|
case MAX9611_CHAN_POWER_LOAD:
|
|
/*
|
|
* processed (mW): Vin (mV) * Vcsa (uV) /
|
|
* Rshunt (uOhm)
|
|
*/
|
|
ret = max9611_read_single(dev, CONF_IN_VOLT,
|
|
&adc_data);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
adc_data -= MAX9611_CIM_OFFSET_RAW;
|
|
*val = MAX9611_VOLTAGE_RAW(adc_data) *
|
|
MAX9611_CIM_LSB_mV;
|
|
|
|
ret = max9611_read_csa_voltage(dev, &adc_data,
|
|
&gain_selector);
|
|
if (ret)
|
|
return -EINVAL;
|
|
|
|
csa_gain = max9611_gain_conf[gain_selector];
|
|
|
|
/* divide by 10^3 here to avoid 32bit overflow */
|
|
adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];
|
|
*val *= MAX9611_VOLTAGE_RAW(adc_data) *
|
|
csa_gain[CSA_GAIN_LSB_nV] / 1000;
|
|
*val2 = dev->shunt_resistor_uohm;
|
|
|
|
return IIO_VAL_FRACTIONAL;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static ssize_t max9611_shunt_resistor_show(struct device *dev,
|
|
struct device_attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct max9611_dev *max9611 = iio_priv(dev_to_iio_dev(dev));
|
|
unsigned int i, r;
|
|
|
|
i = max9611->shunt_resistor_uohm / 1000000;
|
|
r = max9611->shunt_resistor_uohm % 1000000;
|
|
|
|
return sprintf(buf, "%u.%06u\n", i, r);
|
|
}
|
|
|
|
static IIO_DEVICE_ATTR(in_power_shunt_resistor, 0444,
|
|
max9611_shunt_resistor_show, NULL, 0);
|
|
static IIO_DEVICE_ATTR(in_current_shunt_resistor, 0444,
|
|
max9611_shunt_resistor_show, NULL, 0);
|
|
|
|
static struct attribute *max9611_attributes[] = {
|
|
&iio_dev_attr_in_power_shunt_resistor.dev_attr.attr,
|
|
&iio_dev_attr_in_current_shunt_resistor.dev_attr.attr,
|
|
NULL,
|
|
};
|
|
|
|
static const struct attribute_group max9611_attribute_group = {
|
|
.attrs = max9611_attributes,
|
|
};
|
|
|
|
static const struct iio_info indio_info = {
|
|
.read_raw = max9611_read_raw,
|
|
.attrs = &max9611_attribute_group,
|
|
};
|
|
|
|
static int max9611_init(struct max9611_dev *max9611)
|
|
{
|
|
struct i2c_client *client = max9611->i2c_client;
|
|
u16 regval;
|
|
int ret;
|
|
|
|
if (!i2c_check_functionality(client->adapter,
|
|
I2C_FUNC_SMBUS_WRITE_BYTE |
|
|
I2C_FUNC_SMBUS_READ_WORD_DATA)) {
|
|
dev_err(max9611->dev,
|
|
"I2c adapter does not support smbus write_byte or read_word functionalities: aborting probe.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Make sure die temperature is in range to test communications. */
|
|
ret = max9611_read_single(max9611, CONF_TEMP, ®val);
|
|
if (ret)
|
|
return ret;
|
|
|
|
regval = ret & MAX9611_TEMP_MASK;
|
|
|
|
if ((regval > MAX9611_TEMP_MAX_POS &&
|
|
regval < MAX9611_TEMP_MIN_NEG) ||
|
|
regval > MAX9611_TEMP_MAX_NEG) {
|
|
dev_err(max9611->dev,
|
|
"Invalid value received from ADC 0x%4x: aborting\n",
|
|
regval);
|
|
return -EIO;
|
|
}
|
|
|
|
/* Mux shall be zeroed back before applying other configurations */
|
|
ret = i2c_smbus_write_byte_data(max9611->i2c_client,
|
|
MAX9611_REG_CTRL1, 0);
|
|
if (ret) {
|
|
dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",
|
|
MAX9611_REG_CTRL1, 0);
|
|
return ret;
|
|
}
|
|
|
|
ret = i2c_smbus_write_byte_data(max9611->i2c_client,
|
|
MAX9611_REG_CTRL2, 0);
|
|
if (ret) {
|
|
dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",
|
|
MAX9611_REG_CTRL2, 0);
|
|
return ret;
|
|
}
|
|
usleep_range(1000, 2000);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id max9611_of_table[] = {
|
|
{.compatible = "maxim,max9611", .data = "max9611"},
|
|
{.compatible = "maxim,max9612", .data = "max9612"},
|
|
{ },
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(of, max9611_of_table);
|
|
static int max9611_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
const char * const shunt_res_prop = "shunt-resistor-micro-ohms";
|
|
const struct device_node *of_node = client->dev.of_node;
|
|
const struct of_device_id *of_id =
|
|
of_match_device(max9611_of_table, &client->dev);
|
|
struct max9611_dev *max9611;
|
|
struct iio_dev *indio_dev;
|
|
unsigned int of_shunt;
|
|
int ret;
|
|
|
|
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*max9611));
|
|
if (!indio_dev)
|
|
return -ENOMEM;
|
|
|
|
i2c_set_clientdata(client, indio_dev);
|
|
|
|
max9611 = iio_priv(indio_dev);
|
|
max9611->dev = &client->dev;
|
|
max9611->i2c_client = client;
|
|
mutex_init(&max9611->lock);
|
|
|
|
ret = of_property_read_u32(of_node, shunt_res_prop, &of_shunt);
|
|
if (ret) {
|
|
dev_err(&client->dev,
|
|
"Missing %s property for %pOF node\n",
|
|
shunt_res_prop, of_node);
|
|
return ret;
|
|
}
|
|
max9611->shunt_resistor_uohm = of_shunt;
|
|
|
|
ret = max9611_init(max9611);
|
|
if (ret)
|
|
return ret;
|
|
|
|
indio_dev->dev.parent = &client->dev;
|
|
indio_dev->dev.of_node = client->dev.of_node;
|
|
indio_dev->name = of_id->data;
|
|
indio_dev->modes = INDIO_DIRECT_MODE;
|
|
indio_dev->info = &indio_info;
|
|
indio_dev->channels = max9611_channels;
|
|
indio_dev->num_channels = ARRAY_SIZE(max9611_channels);
|
|
|
|
return devm_iio_device_register(&client->dev, indio_dev);
|
|
}
|
|
|
|
static struct i2c_driver max9611_driver = {
|
|
.driver = {
|
|
.name = DRIVER_NAME,
|
|
.of_match_table = max9611_of_table,
|
|
},
|
|
.probe = max9611_probe,
|
|
};
|
|
module_i2c_driver(max9611_driver);
|
|
|
|
MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>");
|
|
MODULE_DESCRIPTION("Maxim max9611/12 current sense amplifier with 12bit ADC");
|
|
MODULE_LICENSE("GPL v2");
|