[PATCH v3] iio: chemical: bme680: Fix measurement wait duration calculation

[PATCH v3] iio: chemical: bme680: Fix measurement wait duration calculation

[Chris Spencer]

This function refers to the Bosch BME680 API as the source of the
calculation, but one of the constants does not match the Bosch
implementation. This appears to be a simple transposition of two digits,
resulting in a wait time that is too short. This can cause the following
'device measurement cycle incomplete' check to occasionally fail, returning
EBUSY to user space.

Adjust the constant to match the Bosch implementation and resolve the EBUSY
errors.

Fixes: 4241665e6ea0 ("iio: chemical: bme680: Fix sensor data read operation")
Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L521
Signed-off-by: Chris Spencer <spencercw@gmail.com>
Acked-by: Vasileios Amoiridis <vassilisamir@gmail.com>
Cc: stable@vger.kernel.org
---
v2: add Acked-by: Vasileios
v3: revise commit message; add Cc: stable
---
 drivers/iio/chemical/bme680_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/chemical/bme680_core.c b/drivers/iio/chemical/bme680_core.c
index 70f81c4a96ba..24e0b59e2fdf 100644
--- a/drivers/iio/chemical/bme680_core.c
+++ b/drivers/iio/chemical/bme680_core.c
@@ -613,7 +613,7 @@ static int bme680_wait_for_eoc(struct bme680_data *data)
 	 * + heater duration
 	 */
 	int wait_eoc_us = ((data->oversampling_temp + data->oversampling_press +
-			   data->oversampling_humid) * 1936) + (477 * 4) +
+			   data->oversampling_humid) * 1963) + (477 * 4) +
 			   (477 * 5) + 1000 + (data->heater_dur * 1000);
 
 	fsleep(wait_eoc_us);
-- 
2.43.0

Re: [PATCH v3] iio: chemical: bme680: Fix measurement wait duration calculation

[Jonathan Cameron]

On Thu,  5 Feb 2026 14:55:45 +0000
Chris Spencer <spencercw@gmail.com> wrote:

> This function refers to the Bosch BME680 API as the source of the
> calculation, but one of the constants does not match the Bosch
> implementation. This appears to be a simple transposition of two digits,
> resulting in a wait time that is too short. This can cause the following
> 'device measurement cycle incomplete' check to occasionally fail, returning
> EBUSY to user space.
> 
> Adjust the constant to match the Bosch implementation and resolve the EBUSY
> errors.
> 
> Fixes: 4241665e6ea0 ("iio: chemical: bme680: Fix sensor data read operation")
> Link: https://github.com/boschsensortec/BME68x_SensorAPI/blob/v4.4.8/bme68x.c#L521
> Signed-off-by: Chris Spencer <spencercw@gmail.com>
> Acked-by: Vasileios Amoiridis <vassilisamir@gmail.com>
> Cc: stable@vger.kernel.org
Applied to the fixes-togreg branch of iio.git

Thanks.

Jonathan