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linux/drivers/iio/pressure/bmp280-core.c
Andreas Klinger dee2dabc0e iio: bmp280: fix compensation of humidity 
Limit the output of humidity compensation to the range between 0 and 100
percent.

Depending on the calibration parameters of the individual sensor it
happens, that a humidity above 100 percent or below 0 percent is
calculated, which don't make sense in terms of relative humidity.

Add a clamp to the compensation formula as described in the datasheet of
the sensor in chapter 4.2.3.

Although this clamp is documented, it was never in the driver of the
kernel.

It depends on the circumstances (calibration parameters, temperature,
humidity) if one can see a value above 100 percent without the clamp.
The writer of this patch was working with this type of sensor without
noting this error. So it seems to be a rare event when this bug occures.

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-05-11 20:19:19 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2010 Christoph Mair <christoph.mair@gmail.com>
* Copyright (c) 2012 Bosch Sensortec GmbH
* Copyright (c) 2012 Unixphere AB
* Copyright (c) 2014 Intel Corporation
* Copyright (c) 2016 Linus Walleij <linus.walleij@linaro.org>
*
* Driver for Bosch Sensortec BMP180 and BMP280 digital pressure sensor.
*
* Datasheet:
* https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP180-DS000-121.pdf
* https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001-12.pdf
* https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME280_DS001-11.pdf
*/
#define pr_fmt(fmt) "bmp280: " fmt
#include <linux/device.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/gpio/consumer.h>
#include <linux/regulator/consumer.h>
#include <linux/interrupt.h>
#include <linux/irq.h> /* For irq_get_irq_data() */
#include <linux/completion.h>
#include <linux/pm_runtime.h>
#include <linux/random.h>
#include "bmp280.h"
/*
* These enums are used for indexing into the array of calibration
* coefficients for BMP180.
*/
enum { AC1, AC2, AC3, AC4, AC5, AC6, B1, B2, MB, MC, MD };
struct bmp180_calib {
s16 AC1;
s16 AC2;
s16 AC3;
u16 AC4;
u16 AC5;
u16 AC6;
s16 B1;
s16 B2;
s16 MB;
s16 MC;
s16 MD;
};
/* See datasheet Section 4.2.2. */
struct bmp280_calib {
u16 T1;
s16 T2;
s16 T3;
u16 P1;
s16 P2;
s16 P3;
s16 P4;
s16 P5;
s16 P6;
s16 P7;
s16 P8;
s16 P9;
u8 H1;
s16 H2;
u8 H3;
s16 H4;
s16 H5;
s8 H6;
};
static const char *const bmp280_supply_names[] = {
"vddd", "vdda"
};
#define BMP280_NUM_SUPPLIES ARRAY_SIZE(bmp280_supply_names)
struct bmp280_data {
struct device *dev;
struct mutex lock;
struct regmap *regmap;
struct completion done;
bool use_eoc;
const struct bmp280_chip_info *chip_info;
union {
struct bmp180_calib bmp180;
struct bmp280_calib bmp280;
} calib;
struct regulator_bulk_data supplies[BMP280_NUM_SUPPLIES];
unsigned int start_up_time; /* in microseconds */
/* log of base 2 of oversampling rate */
u8 oversampling_press;
u8 oversampling_temp;
u8 oversampling_humid;
/*
* Carryover value from temperature conversion, used in pressure
* calculation.
*/
s32 t_fine;
};
struct bmp280_chip_info {
const int *oversampling_temp_avail;
int num_oversampling_temp_avail;
const int *oversampling_press_avail;
int num_oversampling_press_avail;
const int *oversampling_humid_avail;
int num_oversampling_humid_avail;
int (*chip_config)(struct bmp280_data *);
int (*read_temp)(struct bmp280_data *, int *);
int (*read_press)(struct bmp280_data *, int *, int *);
int (*read_humid)(struct bmp280_data *, int *, int *);
};
/*
* These enums are used for indexing into the array of compensation
* parameters for BMP280.
*/
enum { T1, T2, T3 };
enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 };
static const struct iio_chan_spec bmp280_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
},
{
.type = IIO_HUMIDITYRELATIVE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
},
};
static int bmp280_read_calib(struct bmp280_data *data,
struct bmp280_calib *calib,
unsigned int chip)
{
int ret;
unsigned int tmp;
__le16 l16;
__be16 b16;
struct device *dev = data->dev;
__le16 t_buf[BMP280_COMP_TEMP_REG_COUNT / 2];
__le16 p_buf[BMP280_COMP_PRESS_REG_COUNT / 2];
/* Read temperature calibration values. */
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START,
t_buf, BMP280_COMP_TEMP_REG_COUNT);
if (ret < 0) {
dev_err(data->dev,
"failed to read temperature calibration parameters\n");
return ret;
}
/* Toss the temperature calibration data into the entropy pool */
add_device_randomness(t_buf, sizeof(t_buf));
calib->T1 = le16_to_cpu(t_buf[T1]);
calib->T2 = le16_to_cpu(t_buf[T2]);
calib->T3 = le16_to_cpu(t_buf[T3]);
/* Read pressure calibration values. */
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START,
p_buf, BMP280_COMP_PRESS_REG_COUNT);
if (ret < 0) {
dev_err(data->dev,
"failed to read pressure calibration parameters\n");
return ret;
}
/* Toss the pressure calibration data into the entropy pool */
add_device_randomness(p_buf, sizeof(p_buf));
calib->P1 = le16_to_cpu(p_buf[P1]);
calib->P2 = le16_to_cpu(p_buf[P2]);
calib->P3 = le16_to_cpu(p_buf[P3]);
calib->P4 = le16_to_cpu(p_buf[P4]);
calib->P5 = le16_to_cpu(p_buf[P5]);
calib->P6 = le16_to_cpu(p_buf[P6]);
calib->P7 = le16_to_cpu(p_buf[P7]);
calib->P8 = le16_to_cpu(p_buf[P8]);
calib->P9 = le16_to_cpu(p_buf[P9]);
/*
* Read humidity calibration values.
* Due to some odd register addressing we cannot just
* do a big bulk read. Instead, we have to read each Hx
* value separately and sometimes do some bit shifting...
* Humidity data is only available on BME280.
*/
if (chip != BME280_CHIP_ID)
return 0;
ret = regmap_read(data->regmap, BMP280_REG_COMP_H1, &tmp);
if (ret < 0) {
dev_err(dev, "failed to read H1 comp value\n");
return ret;
}
calib->H1 = tmp;
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H2, &l16, 2);
if (ret < 0) {
dev_err(dev, "failed to read H2 comp value\n");
return ret;
}
calib->H2 = sign_extend32(le16_to_cpu(l16), 15);
ret = regmap_read(data->regmap, BMP280_REG_COMP_H3, &tmp);
if (ret < 0) {
dev_err(dev, "failed to read H3 comp value\n");
return ret;
}
calib->H3 = tmp;
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H4, &b16, 2);
if (ret < 0) {
dev_err(dev, "failed to read H4 comp value\n");
return ret;
}
calib->H4 = sign_extend32(((be16_to_cpu(b16) >> 4) & 0xff0) |
(be16_to_cpu(b16) & 0xf), 11);
ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H5, &l16, 2);
if (ret < 0) {
dev_err(dev, "failed to read H5 comp value\n");
return ret;
}
calib->H5 = sign_extend32(((le16_to_cpu(l16) >> 4) & 0xfff), 11);
ret = regmap_read(data->regmap, BMP280_REG_COMP_H6, &tmp);
if (ret < 0) {
dev_err(dev, "failed to read H6 comp value\n");
return ret;
}
calib->H6 = sign_extend32(tmp, 7);
return 0;
}
/*
* Returns humidity in percent, resolution is 0.01 percent. Output value of
* "47445" represents 47445/1024 = 46.333 %RH.
*
* Taken from BME280 datasheet, Section 4.2.3, "Compensation formula".
*/
static u32 bmp280_compensate_humidity(struct bmp280_data *data,
s32 adc_humidity)
{
s32 var;
struct bmp280_calib *calib = &data->calib.bmp280;
var = ((s32)data->t_fine) - (s32)76800;
var = ((((adc_humidity << 14) - (calib->H4 << 20) - (calib->H5 * var))
+ (s32)16384) >> 15) * (((((((var * calib->H6) >> 10)
* (((var * (s32)calib->H3) >> 11) + (s32)32768)) >> 10)
+ (s32)2097152) * calib->H2 + 8192) >> 14);
var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)calib->H1) >> 4;
var = clamp_val(var, 0, 419430400);
return var >> 12;
};
/*
* Returns temperature in DegC, resolution is 0.01 DegC. Output value of
* "5123" equals 51.23 DegC. t_fine carries fine temperature as global
* value.
*
* Taken from datasheet, Section 3.11.3, "Compensation formula".
*/
static s32 bmp280_compensate_temp(struct bmp280_data *data,
s32 adc_temp)
{
s32 var1, var2;
struct bmp280_calib *calib = &data->calib.bmp280;
var1 = (((adc_temp >> 3) - ((s32)calib->T1 << 1)) *
((s32)calib->T2)) >> 11;
var2 = (((((adc_temp >> 4) - ((s32)calib->T1)) *
((adc_temp >> 4) - ((s32)calib->T1))) >> 12) *
((s32)calib->T3)) >> 14;
data->t_fine = var1 + var2;
return (data->t_fine * 5 + 128) >> 8;
}
/*
* Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24
* integer bits and 8 fractional bits). Output value of "24674867"
* represents 24674867/256 = 96386.2 Pa = 963.862 hPa
*
* Taken from datasheet, Section 3.11.3, "Compensation formula".
*/
static u32 bmp280_compensate_press(struct bmp280_data *data,
s32 adc_press)
{
s64 var1, var2, p;
struct bmp280_calib *calib = &data->calib.bmp280;
var1 = ((s64)data->t_fine) - 128000;
var2 = var1 * var1 * (s64)calib->P6;
var2 += (var1 * (s64)calib->P5) << 17;
var2 += ((s64)calib->P4) << 35;
var1 = ((var1 * var1 * (s64)calib->P3) >> 8) +
((var1 * (s64)calib->P2) << 12);
var1 = ((((s64)1) << 47) + var1) * ((s64)calib->P1) >> 33;
if (var1 == 0)
return 0;
p = ((((s64)1048576 - adc_press) << 31) - var2) * 3125;
p = div64_s64(p, var1);
var1 = (((s64)calib->P9) * (p >> 13) * (p >> 13)) >> 25;
var2 = ((s64)(calib->P8) * p) >> 19;
p = ((p + var1 + var2) >> 8) + (((s64)calib->P7) << 4);
return (u32)p;
}
static int bmp280_read_temp(struct bmp280_data *data,
int *val)
{
int ret;
__be32 tmp = 0;
s32 adc_temp, comp_temp;
ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, &tmp, 3);
if (ret < 0) {
dev_err(data->dev, "failed to read temperature\n");
return ret;
}
adc_temp = be32_to_cpu(tmp) >> 12;
if (adc_temp == BMP280_TEMP_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading temperature skipped\n");
return -EIO;
}
comp_temp = bmp280_compensate_temp(data, adc_temp);
/*
* val might be NULL if we're called by the read_press routine,
* who only cares about the carry over t_fine value.
*/
if (val) {
*val = comp_temp * 10;
return IIO_VAL_INT;
}
return 0;
}
static int bmp280_read_press(struct bmp280_data *data,
int *val, int *val2)
{
int ret;
__be32 tmp = 0;
s32 adc_press;
u32 comp_press;
/* Read and compensate temperature so we get a reading of t_fine. */
ret = bmp280_read_temp(data, NULL);
if (ret < 0)
return ret;
ret = regmap_bulk_read(data->regmap, BMP280_REG_PRESS_MSB, &tmp, 3);
if (ret < 0) {
dev_err(data->dev, "failed to read pressure\n");
return ret;
}
adc_press = be32_to_cpu(tmp) >> 12;
if (adc_press == BMP280_PRESS_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading pressure skipped\n");
return -EIO;
}
comp_press = bmp280_compensate_press(data, adc_press);
*val = comp_press;
*val2 = 256000;
return IIO_VAL_FRACTIONAL;
}
static int bmp280_read_humid(struct bmp280_data *data, int *val, int *val2)
{
__be16 tmp;
int ret;
s32 adc_humidity;
u32 comp_humidity;
/* Read and compensate temperature so we get a reading of t_fine. */
ret = bmp280_read_temp(data, NULL);
if (ret < 0)
return ret;
ret = regmap_bulk_read(data->regmap, BMP280_REG_HUMIDITY_MSB, &tmp, 2);
if (ret < 0) {
dev_err(data->dev, "failed to read humidity\n");
return ret;
}
adc_humidity = be16_to_cpu(tmp);
if (adc_humidity == BMP280_HUMIDITY_SKIPPED) {
/* reading was skipped */
dev_err(data->dev, "reading humidity skipped\n");
return -EIO;
}
comp_humidity = bmp280_compensate_humidity(data, adc_humidity);
*val = comp_humidity * 1000 / 1024;
return IIO_VAL_INT;
}
static int bmp280_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret;
struct bmp280_data *data = iio_priv(indio_dev);
pm_runtime_get_sync(data->dev);
mutex_lock(&data->lock);
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
switch (chan->type) {
case IIO_HUMIDITYRELATIVE:
ret = data->chip_info->read_humid(data, val, val2);
break;
case IIO_PRESSURE:
ret = data->chip_info->read_press(data, val, val2);
break;
case IIO_TEMP:
ret = data->chip_info->read_temp(data, val);
break;
default:
ret = -EINVAL;
break;
}
break;
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
switch (chan->type) {
case IIO_HUMIDITYRELATIVE:
*val = 1 << data->oversampling_humid;
ret = IIO_VAL_INT;
break;
case IIO_PRESSURE:
*val = 1 << data->oversampling_press;
ret = IIO_VAL_INT;
break;
case IIO_TEMP:
*val = 1 << data->oversampling_temp;
ret = IIO_VAL_INT;
break;
default:
ret = -EINVAL;
break;
}
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->lock);
pm_runtime_mark_last_busy(data->dev);
pm_runtime_put_autosuspend(data->dev);
return ret;
}
static int bmp280_write_oversampling_ratio_humid(struct bmp280_data *data,
int val)
{
int i;
const int *avail = data->chip_info->oversampling_humid_avail;
const int n = data->chip_info->num_oversampling_humid_avail;
for (i = 0; i < n; i++) {
if (avail[i] == val) {
data->oversampling_humid = ilog2(val);
return data->chip_info->chip_config(data);
}
}
return -EINVAL;
}
static int bmp280_write_oversampling_ratio_temp(struct bmp280_data *data,
int val)
{
int i;
const int *avail = data->chip_info->oversampling_temp_avail;
const int n = data->chip_info->num_oversampling_temp_avail;
for (i = 0; i < n; i++) {
if (avail[i] == val) {
data->oversampling_temp = ilog2(val);
return data->chip_info->chip_config(data);
}
}
return -EINVAL;
}
static int bmp280_write_oversampling_ratio_press(struct bmp280_data *data,
int val)
{
int i;
const int *avail = data->chip_info->oversampling_press_avail;
const int n = data->chip_info->num_oversampling_press_avail;
for (i = 0; i < n; i++) {
if (avail[i] == val) {
data->oversampling_press = ilog2(val);
return data->chip_info->chip_config(data);
}
}
return -EINVAL;
}
static int bmp280_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
int ret = 0;
struct bmp280_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
pm_runtime_get_sync(data->dev);
mutex_lock(&data->lock);
switch (chan->type) {
case IIO_HUMIDITYRELATIVE:
ret = bmp280_write_oversampling_ratio_humid(data, val);
break;
case IIO_PRESSURE:
ret = bmp280_write_oversampling_ratio_press(data, val);
break;
case IIO_TEMP:
ret = bmp280_write_oversampling_ratio_temp(data, val);
break;
default:
ret = -EINVAL;
break;
}
mutex_unlock(&data->lock);
pm_runtime_mark_last_busy(data->dev);
pm_runtime_put_autosuspend(data->dev);
break;
default:
return -EINVAL;
}
return ret;
}
static int bmp280_read_avail(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
const int **vals, int *type, int *length,
long mask)
{
struct bmp280_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
switch (chan->type) {
case IIO_PRESSURE:
*vals = data->chip_info->oversampling_press_avail;
*length = data->chip_info->num_oversampling_press_avail;
break;
case IIO_TEMP:
*vals = data->chip_info->oversampling_temp_avail;
*length = data->chip_info->num_oversampling_temp_avail;
break;
default:
return -EINVAL;
}
*type = IIO_VAL_INT;
return IIO_AVAIL_LIST;
default:
return -EINVAL;
}
}
static const struct iio_info bmp280_info = {
.read_raw = &bmp280_read_raw,
.read_avail = &bmp280_read_avail,
.write_raw = &bmp280_write_raw,
};
static int bmp280_chip_config(struct bmp280_data *data)
{
int ret;
u8 osrs = BMP280_OSRS_TEMP_X(data->oversampling_temp + 1) |
BMP280_OSRS_PRESS_X(data->oversampling_press + 1);
ret = regmap_write_bits(data->regmap, BMP280_REG_CTRL_MEAS,
BMP280_OSRS_TEMP_MASK |
BMP280_OSRS_PRESS_MASK |
BMP280_MODE_MASK,
osrs | BMP280_MODE_NORMAL);
if (ret < 0) {
dev_err(data->dev,
"failed to write ctrl_meas register\n");
return ret;
}
ret = regmap_update_bits(data->regmap, BMP280_REG_CONFIG,
BMP280_FILTER_MASK,
BMP280_FILTER_4X);
if (ret < 0) {
dev_err(data->dev,
"failed to write config register\n");
return ret;
}
return ret;
}
static const int bmp280_oversampling_avail[] = { 1, 2, 4, 8, 16 };
static const struct bmp280_chip_info bmp280_chip_info = {
.oversampling_temp_avail = bmp280_oversampling_avail,
.num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
.oversampling_press_avail = bmp280_oversampling_avail,
.num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
.chip_config = bmp280_chip_config,
.read_temp = bmp280_read_temp,
.read_press = bmp280_read_press,
};
static int bme280_chip_config(struct bmp280_data *data)
{
int ret;
u8 osrs = BMP280_OSRS_HUMIDITIY_X(data->oversampling_humid + 1);
/*
* Oversampling of humidity must be set before oversampling of
* temperature/pressure is set to become effective.
*/
ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY,
BMP280_OSRS_HUMIDITY_MASK, osrs);
if (ret < 0)
return ret;
return bmp280_chip_config(data);
}
static const struct bmp280_chip_info bme280_chip_info = {
.oversampling_temp_avail = bmp280_oversampling_avail,
.num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
.oversampling_press_avail = bmp280_oversampling_avail,
.num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
.oversampling_humid_avail = bmp280_oversampling_avail,
.num_oversampling_humid_avail = ARRAY_SIZE(bmp280_oversampling_avail),
.chip_config = bme280_chip_config,
.read_temp = bmp280_read_temp,
.read_press = bmp280_read_press,
.read_humid = bmp280_read_humid,
};
static int bmp180_measure(struct bmp280_data *data, u8 ctrl_meas)
{
int ret;
const int conversion_time_max[] = { 4500, 7500, 13500, 25500 };
unsigned int delay_us;
unsigned int ctrl;
if (data->use_eoc)
reinit_completion(&data->done);
ret = regmap_write(data->regmap, BMP280_REG_CTRL_MEAS, ctrl_meas);
if (ret)
return ret;
if (data->use_eoc) {
/*
* If we have a completion interrupt, use it, wait up to
* 100ms. The longest conversion time listed is 76.5 ms for
* advanced resolution mode.
*/
ret = wait_for_completion_timeout(&data->done,
1 + msecs_to_jiffies(100));
if (!ret)
dev_err(data->dev, "timeout waiting for completion\n");
} else {
if (ctrl_meas == BMP180_MEAS_TEMP)
delay_us = 4500;
else
delay_us =
conversion_time_max[data->oversampling_press];
usleep_range(delay_us, delay_us + 1000);
}
ret = regmap_read(data->regmap, BMP280_REG_CTRL_MEAS, &ctrl);
if (ret)
return ret;
/* The value of this bit reset to "0" after conversion is complete */
if (ctrl & BMP180_MEAS_SCO)
return -EIO;
return 0;
}
static int bmp180_read_adc_temp(struct bmp280_data *data, int *val)
{
__be16 tmp;
int ret;
ret = bmp180_measure(data, BMP180_MEAS_TEMP);
if (ret)
return ret;
ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, &tmp, 2);
if (ret)
return ret;
*val = be16_to_cpu(tmp);
return 0;
}
static int bmp180_read_calib(struct bmp280_data *data,
struct bmp180_calib *calib)
{
int ret;
int i;
__be16 buf[BMP180_REG_CALIB_COUNT / 2];
ret = regmap_bulk_read(data->regmap, BMP180_REG_CALIB_START, buf,
sizeof(buf));
if (ret < 0)
return ret;
/* None of the words has the value 0 or 0xFFFF */
for (i = 0; i < ARRAY_SIZE(buf); i++) {
if (buf[i] == cpu_to_be16(0) || buf[i] == cpu_to_be16(0xffff))
return -EIO;
}
/* Toss the calibration data into the entropy pool */
add_device_randomness(buf, sizeof(buf));
calib->AC1 = be16_to_cpu(buf[AC1]);
calib->AC2 = be16_to_cpu(buf[AC2]);
calib->AC3 = be16_to_cpu(buf[AC3]);
calib->AC4 = be16_to_cpu(buf[AC4]);
calib->AC5 = be16_to_cpu(buf[AC5]);
calib->AC6 = be16_to_cpu(buf[AC6]);
calib->B1 = be16_to_cpu(buf[B1]);
calib->B2 = be16_to_cpu(buf[B2]);
calib->MB = be16_to_cpu(buf[MB]);
calib->MC = be16_to_cpu(buf[MC]);
calib->MD = be16_to_cpu(buf[MD]);
return 0;
}
/*
* Returns temperature in DegC, resolution is 0.1 DegC.
* t_fine carries fine temperature as global value.
*
* Taken from datasheet, Section 3.5, "Calculating pressure and temperature".
*/
static s32 bmp180_compensate_temp(struct bmp280_data *data, s32 adc_temp)
{
s32 x1, x2;
struct bmp180_calib *calib = &data->calib.bmp180;
x1 = ((adc_temp - calib->AC6) * calib->AC5) >> 15;
x2 = (calib->MC << 11) / (x1 + calib->MD);
data->t_fine = x1 + x2;
return (data->t_fine + 8) >> 4;
}
static int bmp180_read_temp(struct bmp280_data *data, int *val)
{
int ret;
s32 adc_temp, comp_temp;
ret = bmp180_read_adc_temp(data, &adc_temp);
if (ret)
return ret;
comp_temp = bmp180_compensate_temp(data, adc_temp);
/*
* val might be NULL if we're called by the read_press routine,
* who only cares about the carry over t_fine value.
*/
if (val) {
*val = comp_temp * 100;
return IIO_VAL_INT;
}
return 0;
}
static int bmp180_read_adc_press(struct bmp280_data *data, int *val)
{
int ret;
__be32 tmp = 0;
u8 oss = data->oversampling_press;
ret = bmp180_measure(data, BMP180_MEAS_PRESS_X(oss));
if (ret)
return ret;
ret = regmap_bulk_read(data->regmap, BMP180_REG_OUT_MSB, &tmp, 3);
if (ret)
return ret;
*val = (be32_to_cpu(tmp) >> 8) >> (8 - oss);
return 0;
}
/*
* Returns pressure in Pa, resolution is 1 Pa.
*
* Taken from datasheet, Section 3.5, "Calculating pressure and temperature".
*/
static u32 bmp180_compensate_press(struct bmp280_data *data, s32 adc_press)
{
s32 x1, x2, x3, p;
s32 b3, b6;
u32 b4, b7;
s32 oss = data->oversampling_press;
struct bmp180_calib *calib = &data->calib.bmp180;
b6 = data->t_fine - 4000;
x1 = (calib->B2 * (b6 * b6 >> 12)) >> 11;
x2 = calib->AC2 * b6 >> 11;
x3 = x1 + x2;
b3 = ((((s32)calib->AC1 * 4 + x3) << oss) + 2) / 4;
x1 = calib->AC3 * b6 >> 13;
x2 = (calib->B1 * ((b6 * b6) >> 12)) >> 16;
x3 = (x1 + x2 + 2) >> 2;
b4 = calib->AC4 * (u32)(x3 + 32768) >> 15;
b7 = ((u32)adc_press - b3) * (50000 >> oss);
if (b7 < 0x80000000)
p = (b7 * 2) / b4;
else
p = (b7 / b4) * 2;
x1 = (p >> 8) * (p >> 8);
x1 = (x1 * 3038) >> 16;
x2 = (-7357 * p) >> 16;
return p + ((x1 + x2 + 3791) >> 4);
}
static int bmp180_read_press(struct bmp280_data *data,
int *val, int *val2)
{
int ret;
s32 adc_press;
u32 comp_press;
/* Read and compensate temperature so we get a reading of t_fine. */
ret = bmp180_read_temp(data, NULL);
if (ret)
return ret;
ret = bmp180_read_adc_press(data, &adc_press);
if (ret)
return ret;
comp_press = bmp180_compensate_press(data, adc_press);
*val = comp_press;
*val2 = 1000;
return IIO_VAL_FRACTIONAL;
}
static int bmp180_chip_config(struct bmp280_data *data)
{
return 0;
}
static const int bmp180_oversampling_temp_avail[] = { 1 };
static const int bmp180_oversampling_press_avail[] = { 1, 2, 4, 8 };
static const struct bmp280_chip_info bmp180_chip_info = {
.oversampling_temp_avail = bmp180_oversampling_temp_avail,
.num_oversampling_temp_avail =
ARRAY_SIZE(bmp180_oversampling_temp_avail),
.oversampling_press_avail = bmp180_oversampling_press_avail,
.num_oversampling_press_avail =
ARRAY_SIZE(bmp180_oversampling_press_avail),
.chip_config = bmp180_chip_config,
.read_temp = bmp180_read_temp,
.read_press = bmp180_read_press,
};
static irqreturn_t bmp085_eoc_irq(int irq, void *d)
{
struct bmp280_data *data = d;
complete(&data->done);
return IRQ_HANDLED;
}
static int bmp085_fetch_eoc_irq(struct device *dev,
const char *name,
int irq,
struct bmp280_data *data)
{
unsigned long irq_trig;
int ret;
irq_trig = irqd_get_trigger_type(irq_get_irq_data(irq));
if (irq_trig != IRQF_TRIGGER_RISING) {
dev_err(dev, "non-rising trigger given for EOC interrupt, trying to enforce it\n");
irq_trig = IRQF_TRIGGER_RISING;
}
init_completion(&data->done);
ret = devm_request_threaded_irq(dev,
irq,
bmp085_eoc_irq,
NULL,
irq_trig,
name,
data);
if (ret) {
/* Bail out without IRQ but keep the driver in place */
dev_err(dev, "unable to request DRDY IRQ\n");
return 0;
}
data->use_eoc = true;
return 0;
}
static void bmp280_pm_disable(void *data)
{
struct device *dev = data;
pm_runtime_get_sync(dev);
pm_runtime_put_noidle(dev);
pm_runtime_disable(dev);
}
static void bmp280_regulators_disable(void *data)
{
struct regulator_bulk_data *supplies = data;
regulator_bulk_disable(BMP280_NUM_SUPPLIES, supplies);
}
int bmp280_common_probe(struct device *dev,
struct regmap *regmap,
unsigned int chip,
const char *name,
int irq)
{
int ret;
struct iio_dev *indio_dev;
struct bmp280_data *data;
unsigned int chip_id;
struct gpio_desc *gpiod;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
mutex_init(&data->lock);
data->dev = dev;
indio_dev->dev.parent = dev;
indio_dev->name = name;
indio_dev->channels = bmp280_channels;
indio_dev->info = &bmp280_info;
indio_dev->modes = INDIO_DIRECT_MODE;
switch (chip) {
case BMP180_CHIP_ID:
indio_dev->num_channels = 2;
data->chip_info = &bmp180_chip_info;
data->oversampling_press = ilog2(8);
data->oversampling_temp = ilog2(1);
data->start_up_time = 10000;
break;
case BMP280_CHIP_ID:
indio_dev->num_channels = 2;
data->chip_info = &bmp280_chip_info;
data->oversampling_press = ilog2(16);
data->oversampling_temp = ilog2(2);
data->start_up_time = 2000;
break;
case BME280_CHIP_ID:
indio_dev->num_channels = 3;
data->chip_info = &bme280_chip_info;
data->oversampling_press = ilog2(16);
data->oversampling_humid = ilog2(16);
data->oversampling_temp = ilog2(2);
data->start_up_time = 2000;
break;
default:
return -EINVAL;
}
/* Bring up regulators */
regulator_bulk_set_supply_names(data->supplies,
bmp280_supply_names,
BMP280_NUM_SUPPLIES);
ret = devm_regulator_bulk_get(dev,
BMP280_NUM_SUPPLIES, data->supplies);
if (ret) {
dev_err(dev, "failed to get regulators\n");
return ret;
}
ret = regulator_bulk_enable(BMP280_NUM_SUPPLIES, data->supplies);
if (ret) {
dev_err(dev, "failed to enable regulators\n");
return ret;
}
ret = devm_add_action_or_reset(dev, bmp280_regulators_disable,
data->supplies);
if (ret)
return ret;
/* Wait to make sure we started up properly */
usleep_range(data->start_up_time, data->start_up_time + 100);
/* Bring chip out of reset if there is an assigned GPIO line */
gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
/* Deassert the signal */
if (gpiod) {
dev_info(dev, "release reset\n");
gpiod_set_value(gpiod, 0);
}
data->regmap = regmap;
ret = regmap_read(regmap, BMP280_REG_ID, &chip_id);
if (ret < 0)
return ret;
if (chip_id != chip) {
dev_err(dev, "bad chip id: expected %x got %x\n",
chip, chip_id);
return -EINVAL;
}
ret = data->chip_info->chip_config(data);
if (ret < 0)
return ret;
dev_set_drvdata(dev, indio_dev);
/*
* Some chips have calibration parameters "programmed into the devices'
* non-volatile memory during production". Let's read them out at probe
* time once. They will not change.
*/
if (chip_id == BMP180_CHIP_ID) {
ret = bmp180_read_calib(data, &data->calib.bmp180);
if (ret < 0) {
dev_err(data->dev,
"failed to read calibration coefficients\n");
return ret;
}
} else if (chip_id == BMP280_CHIP_ID || chip_id == BME280_CHIP_ID) {
ret = bmp280_read_calib(data, &data->calib.bmp280, chip_id);
if (ret < 0) {
dev_err(data->dev,
"failed to read calibration coefficients\n");
return ret;
}
}
/*
* Attempt to grab an optional EOC IRQ - only the BMP085 has this
* however as it happens, the BMP085 shares the chip ID of BMP180
* so we look for an IRQ if we have that.
*/
if (irq > 0 || (chip_id == BMP180_CHIP_ID)) {
ret = bmp085_fetch_eoc_irq(dev, name, irq, data);
if (ret)
return ret;
}
/* Enable runtime PM */
pm_runtime_get_noresume(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
/*
* Set autosuspend to two orders of magnitude larger than the
* start-up time.
*/
pm_runtime_set_autosuspend_delay(dev, data->start_up_time / 10);
pm_runtime_use_autosuspend(dev);
pm_runtime_put(dev);
ret = devm_add_action_or_reset(dev, bmp280_pm_disable, dev);
if (ret)
return ret;
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL(bmp280_common_probe);
#ifdef CONFIG_PM
static int bmp280_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct bmp280_data *data = iio_priv(indio_dev);
return regulator_bulk_disable(BMP280_NUM_SUPPLIES, data->supplies);
}
static int bmp280_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct bmp280_data *data = iio_priv(indio_dev);
int ret;
ret = regulator_bulk_enable(BMP280_NUM_SUPPLIES, data->supplies);
if (ret)
return ret;
usleep_range(data->start_up_time, data->start_up_time + 100);
return data->chip_info->chip_config(data);
}
#endif /* CONFIG_PM */
const struct dev_pm_ops bmp280_dev_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
pm_runtime_force_resume)
SET_RUNTIME_PM_OPS(bmp280_runtime_suspend,
bmp280_runtime_resume, NULL)
};
EXPORT_SYMBOL(bmp280_dev_pm_ops);
MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>");
MODULE_DESCRIPTION("Driver for Bosch Sensortec BMP180/BMP280 pressure and temperature sensor");
MODULE_LICENSE("GPL v2");
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