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iio: pressure: bmp280: correct meas_time_us calculation

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Correction of meas_time_us initialization based on an observation and
partial patch by David Lechner.

The constant part of the measurement time (as described in the
datasheet and implemented in the BM(P/E)2 Sensor API) was apparently
forgotten (it was already correctly applied for the BMP380) and is now
used.

There was also another thinko in bmp280_wait_conv:
data->oversampling_humid can actually have a value of 0 (for an
oversampling_ratio of 1), so it can not be used to detect the presence
of the humidity measurement capability.  Use
data->chip_info->oversampling_humid_avail instead, which is NULL for
chips that cannot measure humidity and therefore must skip that part
of the calculation.

Closes: https://lore.kernel.org/linux-iio/875xgfg0wz.fsf@Gerda.invalid/
Fixes: 26ccfaa9dd ("iio: pressure: bmp280: Use sleep and forced mode for oneshot captures")
Suggested-by: David Lechner <dlechner@baylibre.com>
Tested-by: Achim Gratz <Achim.Gratz@Stromeko.DE>
Signed-off-by: Achim Gratz <Achim.Gratz@Stromeko.DE>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Achim Gratz
2025-09-28 19:26:28 +02:00
committed by Jonathan Cameron
parent 8a6b7989ff
commit 0bf1bfde53
1 changed files with 9 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/iio/pressure/bmp280-core.c
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@@ -1040,13 +1040,16 @@ static int bmp280_wait_conv(struct bmp280_data *data)
unsigned int reg, meas_time_us;
int ret;
/* Check if we are using a BME280 device */
if (data->oversampling_humid)
meas_time_us = BMP280_PRESS_HUMID_MEAS_OFFSET +
BIT(data->oversampling_humid) * BMP280_MEAS_DUR;
/* Constant part of the measurement time */
meas_time_us = BMP280_MEAS_OFFSET;
else
meas_time_us = 0;
/*
* Check if we are using a BME280 device,
* Humidity measurement time
*/
if (data->chip_info->oversampling_humid_avail)
meas_time_us += BMP280_PRESS_HUMID_MEAS_OFFSET +
BIT(data->oversampling_humid) * BMP280_MEAS_DUR;
/* Pressure measurement time */
meas_time_us += BMP280_PRESS_HUMID_MEAS_OFFSET +