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authorAchim Gratz <Achim.Gratz@Stromeko.DE>2025-09-28 19:26:28 +0200
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2025-10-13 08:38:08 +0100
commit0bf1bfde53b30da7fd7f4a6c3db5b8e77888958d (patch)
tree6a7e27946d7c58d61110ff32036820f88a11f3c4
parent8a6b7989ff0cd0a95c93be1927f2af7ad10f28de (diff)
iio: pressure: bmp280: correct meas_time_us calculation
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: 26ccfaa9ddaa ("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>
-rw-r--r--drivers/iio/pressure/bmp280-core.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index c04e8bb4c993..d983ce9c0b99 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -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 +