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linux_dsm_epyc7002/drivers/iio/adc/max9611.c
Jacopo Mondi b9ddd50911 iio: adc: max9611: Fix temperature reading in probe 
The max9611 driver reads the die temperature at probe time to validate
the communication channel. Use the actual read value to perform the test
instead of the read function return value, which was mistakenly used so
far.

The temperature reading test was only successful because the 0 return
value is in the range of supported temperatures.

Fixes: 69780a3bbc ("iio: adc: Add Maxim max9611 ADC driver")
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-08-05 17:42:24 +01:00

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// 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(15, 7)
#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, &regval);
if (ret)
return ret;
regval &= 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");
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