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iio: pressure: mprls0025pa: fix pressure calculation

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A sign change is needed for proper calculation of the pressure.

This is a minor fix since it only affects users that might have custom
silicon from Honeywell that has honeywell,pmin-pascal != 0.

Also due to the fact that raw pressure values can not be lower
than output_min (400k-3.3M) there is no need to calculate a decimal for
the offset.

Fixes: 713337d914 ("iio: pressure: Honeywell mprls0025pa pressure sensor")
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Petre Rodan 2026-01-14 18:55:34 +02:00 committed by Jonathan Cameron
parent 8a228e0369
commit d63403d4e3
2 changed files with 11 additions and 17 deletions
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26
drivers/iio/pressure/mprls0025pa.c
View File

@ -59,7 +59,7 @@
*
* Values given to the userspace in sysfs interface:
* * raw - press_cnt
* * offset - (-1 * outputmin) - pmin / scale
* * offset - (-1 * outputmin) + pmin / scale
* note: With all sensors from the datasheet pmin = 0
* which reduces the offset to (-1 * outputmin)
*/
@ -313,8 +313,7 @@ static int mpr_read_raw(struct iio_dev *indio_dev,
return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_OFFSET:
*val = data->offset;
*val2 = data->offset2;
return IIO_VAL_INT_PLUS_NANO;
return IIO_VAL_INT;
default:
return -EINVAL;
}
@ -330,8 +329,9 @@ int mpr_common_probe(struct device *dev, const struct mpr_ops *ops, int irq)
struct mpr_data *data;
struct iio_dev *indio_dev;
const char *triplet;
s64 scale, offset;
s64 odelta, pdelta;
u32 func;
s32 tmp;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
@ -405,17 +405,13 @@ int mpr_common_probe(struct device *dev, const struct mpr_ops *ops, int irq)
data->outmin = mpr_func_spec[data->function].output_min;
data->outmax = mpr_func_spec[data->function].output_max;
/* use 64 bit calculation for preserving a reasonable precision */
scale = div_s64(((s64)(data->pmax - data->pmin)) * NANO,
data->outmax - data->outmin);
data->scale = div_s64_rem(scale, NANO, &data->scale2);
/*
* multiply with NANO before dividing by scale and later divide by NANO
* again.
*/
offset = ((-1LL) * (s64)data->outmin) * NANO -
div_s64(div_s64((s64)data->pmin * NANO, scale), NANO);
data->offset = div_s64_rem(offset, NANO, &data->offset2);
odelta = data->outmax - data->outmin;
pdelta = data->pmax - data->pmin;
data->scale = div_s64_rem(div_s64(pdelta * NANO, odelta), NANO, &tmp);
data->scale2 = tmp;
data->offset = div_s64(odelta * data->pmin, pdelta) - data->outmin;
if (data->irq > 0) {
ret = devm_request_irq(dev, data->irq, mpr_eoc_handler, 0,

2
drivers/iio/pressure/mprls0025pa.h
View File

@ -53,7 +53,6 @@ enum mpr_func_id {
* @scale: pressure scale
* @scale2: pressure scale, decimal number
* @offset: pressure offset
* @offset2: pressure offset, decimal number
* @gpiod_reset: reset
* @irq: end of conversion irq. used to distinguish between irq mode and
* reading in a loop until data is ready
@ -75,7 +74,6 @@ struct mpr_data {
int scale;
int scale2;
int offset;
int offset2;
struct gpio_desc *gpiod_reset;
int irq;
struct completion completion;