[PATCH v2] iio: chemical: bme680: Fix measurement wait duration calculation

[PATCH v2] 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.

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>
---
v2: add Acked-by: Vasileios
---
 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 v2] iio: chemical: bme680: Fix measurement wait duration calculation

[Markus Elfring]

…
> resulting in a wait time that is too short. This can cause the following
> 'device measurement cycle incomplete' check to occasionally fail.

* Were any source code analysis tools involved here?

* See also once more:
  + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc8#n94

  + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst?h=v6.19-rc8#n34


Regards,
Markus

Re: [PATCH v2] iio: chemical: bme680: Fix measurement wait duration calculation

[Chris Spencer]

Hi Markus,

On Thu, 5 Feb 2026 at 13:15, Markus Elfring <Markus.Elfring@web.de> wrote:
>
> …
> > resulting in a wait time that is too short. This can cause the following
> > 'device measurement cycle incomplete' check to occasionally fail.
>
> * Were any source code analysis tools involved here?

No. I identified this issue myself while investigating the
aforementioned 'device measurement cycle incomplete' error by manually
comparing the kernel implementation against the linked Bosch
implementation.

> * See also once more:
>   + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc8#n94

Can you please clarify what is wrong with the commit message? I have
used the imperative mood in the subject, but the rest of the message
is simply background information. How would you suggest rewording
this?

>   + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst?h=v6.19-rc8#n34

Ok I will CC stable in the next revision.

Thanks,
Chris

Re: [v2] iio: chemical: bme680: Fix measurement wait duration calculation

[Markus Elfring]

>> * See also once more:
>>   + https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc8#n94
> 
> Can you please clarify what is wrong with the commit message? I have
> used the imperative mood in the subject, but the rest of the message
> is simply background information. How would you suggest rewording
> this?

I propose to mention another action in the change description.

Possible wording:
Thus adjust an inappropriate value.

Regards,
Markus