linux/drivers/iio/pressure/ms5611_core.c
Alexander Zangerl fd39d9668f iio: pressure: ms5611: ms5611_prom_is_valid false negative bug
The ms5611 driver falsely rejects lots of MS5607-02BA03-50 chips
with "PROM integrity check failed" because it doesn't accept a prom crc
value of zero as legitimate.

According to the datasheet for this chip (and the manufacturer's
application note about the PROM CRC), none of the possible values for the
CRC are excluded - but the current code in ms5611_prom_is_valid() ends with

return crc_orig != 0x0000 && crc == crc_orig

Discussed with the driver author (Tomasz Duszynski) and he indicated that
at that time (2015) he was dealing with some faulty chip samples which
returned blank data under some circumstances and/or followed example code
which indicated CRC zero being bad.

As far as I can tell this exception should not be applied anymore; We've
got a few hundred custom boards here with this chip where large numbers
of the prom have a legitimate CRC value 0, and do work fine, but which the
current driver code wrongly rejects.

Signed-off-by: Alexander Zangerl <az@breathe-safe.com>
Fixes: c0644160a8 ("iio: pressure: add support for MS5611 pressure and temperature sensor")
Link: https://lore.kernel.org/r/2535-1695168070.831792@Ze3y.dhYT.s3fx
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2023-10-05 18:06:46 +01:00

457 lines
9.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* MS5611 pressure and temperature sensor driver
*
* Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
*
* Data sheet:
* http://www.meas-spec.com/downloads/MS5611-01BA03.pdf
* http://www.meas-spec.com/downloads/MS5607-02BA03.pdf
*
*/
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/delay.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include "ms5611.h"
#define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \
{ .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate }
static const struct ms5611_osr ms5611_avail_pressure_osr[] = {
MS5611_INIT_OSR(0x40, 600, 256),
MS5611_INIT_OSR(0x42, 1170, 512),
MS5611_INIT_OSR(0x44, 2280, 1024),
MS5611_INIT_OSR(0x46, 4540, 2048),
MS5611_INIT_OSR(0x48, 9040, 4096)
};
static const struct ms5611_osr ms5611_avail_temp_osr[] = {
MS5611_INIT_OSR(0x50, 600, 256),
MS5611_INIT_OSR(0x52, 1170, 512),
MS5611_INIT_OSR(0x54, 2280, 1024),
MS5611_INIT_OSR(0x56, 4540, 2048),
MS5611_INIT_OSR(0x58, 9040, 4096)
};
static const char ms5611_show_osr[] = "256 512 1024 2048 4096";
static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr);
static struct attribute *ms5611_attributes[] = {
&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
NULL,
};
static const struct attribute_group ms5611_attribute_group = {
.attrs = ms5611_attributes,
};
static bool ms5611_prom_is_valid(u16 *prom, size_t len)
{
int i, j;
uint16_t crc = 0, crc_orig = prom[7] & 0x000F;
prom[7] &= 0xFF00;
for (i = 0; i < len * 2; i++) {
if (i % 2 == 1)
crc ^= prom[i >> 1] & 0x00FF;
else
crc ^= prom[i >> 1] >> 8;
for (j = 0; j < 8; j++) {
if (crc & 0x8000)
crc = (crc << 1) ^ 0x3000;
else
crc <<= 1;
}
}
crc = (crc >> 12) & 0x000F;
return crc == crc_orig;
}
static int ms5611_read_prom(struct iio_dev *indio_dev)
{
int ret, i;
struct ms5611_state *st = iio_priv(indio_dev);
for (i = 0; i < MS5611_PROM_WORDS_NB; i++) {
ret = st->read_prom_word(st, i, &st->prom[i]);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read prom at %d\n", i);
return ret;
}
}
if (!ms5611_prom_is_valid(st->prom, MS5611_PROM_WORDS_NB)) {
dev_err(&indio_dev->dev, "PROM integrity check failed\n");
return -ENODEV;
}
return 0;
}
static int ms5611_read_temp_and_pressure(struct iio_dev *indio_dev,
s32 *temp, s32 *pressure)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->read_adc_temp_and_pressure(st, temp, pressure);
if (ret < 0) {
dev_err(&indio_dev->dev,
"failed to read temperature and pressure\n");
return ret;
}
return st->compensate_temp_and_pressure(st, temp, pressure);
}
static int ms5611_temp_and_pressure_compensate(struct ms5611_state *st,
s32 *temp, s32 *pressure)
{
s32 t = *temp, p = *pressure;
s64 off, sens, dt;
dt = t - (st->prom[5] << 8);
off = ((s64)st->prom[2] << 16) + ((st->prom[4] * dt) >> 7);
sens = ((s64)st->prom[1] << 15) + ((st->prom[3] * dt) >> 8);
t = 2000 + ((st->prom[6] * dt) >> 23);
if (t < 2000) {
s64 off2, sens2, t2;
t2 = (dt * dt) >> 31;
off2 = (5 * (t - 2000) * (t - 2000)) >> 1;
sens2 = off2 >> 1;
if (t < -1500) {
s64 tmp = (t + 1500) * (t + 1500);
off2 += 7 * tmp;
sens2 += (11 * tmp) >> 1;
}
t -= t2;
off -= off2;
sens -= sens2;
}
*temp = t;
*pressure = (((p * sens) >> 21) - off) >> 15;
return 0;
}
static int ms5607_temp_and_pressure_compensate(struct ms5611_state *st,
s32 *temp, s32 *pressure)
{
s32 t = *temp, p = *pressure;
s64 off, sens, dt;
dt = t - (st->prom[5] << 8);
off = ((s64)st->prom[2] << 17) + ((st->prom[4] * dt) >> 6);
sens = ((s64)st->prom[1] << 16) + ((st->prom[3] * dt) >> 7);
t = 2000 + ((st->prom[6] * dt) >> 23);
if (t < 2000) {
s64 off2, sens2, t2, tmp;
t2 = (dt * dt) >> 31;
tmp = (t - 2000) * (t - 2000);
off2 = (61 * tmp) >> 4;
sens2 = tmp << 1;
if (t < -1500) {
tmp = (t + 1500) * (t + 1500);
off2 += 15 * tmp;
sens2 += 8 * tmp;
}
t -= t2;
off -= off2;
sens -= sens2;
}
*temp = t;
*pressure = (((p * sens) >> 21) - off) >> 15;
return 0;
}
static int ms5611_reset(struct iio_dev *indio_dev)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
ret = st->reset(st);
if (ret < 0) {
dev_err(&indio_dev->dev, "failed to reset device\n");
return ret;
}
usleep_range(3000, 4000);
return 0;
}
static irqreturn_t ms5611_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ms5611_state *st = iio_priv(indio_dev);
/* Ensure buffer elements are naturally aligned */
struct {
s32 channels[2];
s64 ts __aligned(8);
} scan;
int ret;
mutex_lock(&st->lock);
ret = ms5611_read_temp_and_pressure(indio_dev, &scan.channels[1],
&scan.channels[0]);
mutex_unlock(&st->lock);
if (ret < 0)
goto err;
iio_push_to_buffers_with_timestamp(indio_dev, &scan,
iio_get_time_ns(indio_dev));
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static int ms5611_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
int ret;
s32 temp, pressure;
struct ms5611_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
mutex_lock(&st->lock);
ret = ms5611_read_temp_and_pressure(indio_dev,
&temp, &pressure);
mutex_unlock(&st->lock);
if (ret < 0)
return ret;
switch (chan->type) {
case IIO_TEMP:
*val = temp * 10;
return IIO_VAL_INT;
case IIO_PRESSURE:
*val = pressure / 1000;
*val2 = (pressure % 1000) * 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_TEMP:
*val = 10;
return IIO_VAL_INT;
case IIO_PRESSURE:
*val = 0;
*val2 = 1000;
return IIO_VAL_INT_PLUS_MICRO;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE)
break;
mutex_lock(&st->lock);
if (chan->type == IIO_TEMP)
*val = (int)st->temp_osr->rate;
else
*val = (int)st->pressure_osr->rate;
mutex_unlock(&st->lock);
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct ms5611_osr *ms5611_find_osr(int rate,
const struct ms5611_osr *osr,
size_t count)
{
unsigned int r;
for (r = 0; r < count; r++)
if ((unsigned short)rate == osr[r].rate)
break;
if (r >= count)
return NULL;
return &osr[r];
}
static int ms5611_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ms5611_state *st = iio_priv(indio_dev);
const struct ms5611_osr *osr = NULL;
int ret;
if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
return -EINVAL;
if (chan->type == IIO_TEMP)
osr = ms5611_find_osr(val, ms5611_avail_temp_osr,
ARRAY_SIZE(ms5611_avail_temp_osr));
else if (chan->type == IIO_PRESSURE)
osr = ms5611_find_osr(val, ms5611_avail_pressure_osr,
ARRAY_SIZE(ms5611_avail_pressure_osr));
if (!osr)
return -EINVAL;
ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
return ret;
mutex_lock(&st->lock);
if (chan->type == IIO_TEMP)
st->temp_osr = osr;
else
st->pressure_osr = osr;
mutex_unlock(&st->lock);
iio_device_release_direct_mode(indio_dev);
return 0;
}
static const unsigned long ms5611_scan_masks[] = {0x3, 0};
static const struct iio_chan_spec ms5611_channels[] = {
{
.type = IIO_PRESSURE,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.scan_index = 0,
.scan_type = {
.sign = 's',
.realbits = 32,
.storagebits = 32,
.endianness = IIO_CPU,
},
},
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
.scan_index = 1,
.scan_type = {
.sign = 's',
.realbits = 32,
.storagebits = 32,
.endianness = IIO_CPU,
},
},
IIO_CHAN_SOFT_TIMESTAMP(2),
};
static const struct iio_info ms5611_info = {
.read_raw = &ms5611_read_raw,
.write_raw = &ms5611_write_raw,
.attrs = &ms5611_attribute_group,
};
static int ms5611_init(struct iio_dev *indio_dev)
{
int ret;
/* Enable attached regulator if any. */
ret = devm_regulator_get_enable(indio_dev->dev.parent, "vdd");
if (ret)
return ret;
ret = ms5611_reset(indio_dev);
if (ret < 0)
return ret;
ret = ms5611_read_prom(indio_dev);
if (ret < 0)
return ret;
return 0;
}
int ms5611_probe(struct iio_dev *indio_dev, struct device *dev,
const char *name, int type)
{
int ret;
struct ms5611_state *st = iio_priv(indio_dev);
mutex_init(&st->lock);
switch (type) {
case MS5611:
st->compensate_temp_and_pressure =
ms5611_temp_and_pressure_compensate;
break;
case MS5607:
st->compensate_temp_and_pressure =
ms5607_temp_and_pressure_compensate;
break;
default:
return -EINVAL;
}
st->temp_osr =
&ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1];
st->pressure_osr =
&ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr)
- 1];
indio_dev->name = name;
indio_dev->info = &ms5611_info;
indio_dev->channels = ms5611_channels;
indio_dev->num_channels = ARRAY_SIZE(ms5611_channels);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->available_scan_masks = ms5611_scan_masks;
ret = ms5611_init(indio_dev);
if (ret < 0)
return ret;
ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
ms5611_trigger_handler, NULL);
if (ret < 0) {
dev_err(dev, "iio triggered buffer setup failed\n");
return ret;
}
ret = devm_iio_device_register(dev, indio_dev);
if (ret < 0) {
dev_err(dev, "unable to register iio device\n");
return ret;
}
return 0;
}
EXPORT_SYMBOL_NS(ms5611_probe, IIO_MS5611);
MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
MODULE_DESCRIPTION("MS5611 core driver");
MODULE_LICENSE("GPL v2");