[PATCH] iio: imu: bmi270: fix zero timestamp in triggered buffer

[PATCH] iio: imu: bmi270: fix zero timestamp in triggered buffer

[Liu Yufei]

When the device's own data ready trigger is used, the trigger is
polled with iio_trigger_poll_nested() from the threaded IRQ handler.
In that path the pollfunc top half, iio_pollfunc_store_time(), is
never run, so pf->timestamp is left at zero and every sample pushed
to the buffer carries a zero timestamp.

Take the timestamp in the trigger handler itself and drop the top
half, so that a valid timestamp is provided for all triggers.

Fixes: a1854d55f54b ("iio: imu: bmi270: add support for data ready interrupt trigger")
Cc: stable@vger.kernel.org
Signed-off-by: Liu Yufei <lyf98405@gmail.com>
---
 drivers/iio/imu/bmi270/bmi270_core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/imu/bmi270/bmi270_core.c b/drivers/iio/imu/bmi270/bmi270_core.c
index fbcf6bb87acc..40ed1ee5ac58 100644
--- a/drivers/iio/imu/bmi270/bmi270_core.c
+++ b/drivers/iio/imu/bmi270/bmi270_core.c
@@ -840,6 +840,7 @@ static irqreturn_t bmi270_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct bmi270_data *data = iio_priv(indio_dev);
+	s64 timestamp = iio_get_time_ns(indio_dev);
 	int ret;
 
 	guard(mutex)(&data->mutex);
@@ -852,7 +853,7 @@ static irqreturn_t bmi270_trigger_handler(int irq, void *p)
 		goto done;
 
 	iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
-					   pf->timestamp);
+					   timestamp);
 done:
 	iio_trigger_notify_done(indio_dev->trig);
 	return IRQ_HANDLED;
@@ -1630,8 +1631,7 @@ int bmi270_core_probe(struct device *dev, struct regmap *regmap,
 	if (ret)
 		return ret;
 
-	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
-					      iio_pollfunc_store_time,
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 					      bmi270_trigger_handler, NULL);
 	if (ret)
 		return ret;

---
base-commit: 09f742b49cb2728086d78be2b0b35e4d1d71fc85
change-id: 20261028-bmi270-fix-timestamp-48a194b69db1

Best regards,
--  
Liu Yufei <lyf98405@gmail.com>

Re: [PATCH] iio: imu: bmi270: fix zero timestamp in triggered buffer

[Andy Shevchenko]

On Wed, Oct 28, 2026 at 10:59:26AM +0800, Liu Yufei wrote:
> When the device's own data ready trigger is used, the trigger is
> polled with iio_trigger_poll_nested() from the threaded IRQ handler.
> In that path the pollfunc top half, iio_pollfunc_store_time(), is
> never run, so pf->timestamp is left at zero and every sample pushed
> to the buffer carries a zero timestamp.
> 
> Take the timestamp in the trigger handler itself and drop the top
> half, so that a valid timestamp is provided for all triggers.

...

> +	s64 timestamp = iio_get_time_ns(indio_dev);

Do we need this variable? Why not call it directly?

>  	iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
> -					   pf->timestamp);
> +					   timestamp);

					   iio_get_time_ns(indio_dev);

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] iio: imu: bmi270: fix zero timestamp in triggered buffer

[Liu Yufei]

On Wed, Oct 28, 2026 at 10:58:25AM +0200, Andy Shevchenko wrote:
> On Wed, Oct 28, 2026 at 10:59:26AM +0800, Liu Yufei wrote:

...

> > +	s64 timestamp = iio_get_time_ns(indio_dev);
>
> Do we need this variable? Why not call it directly?

The intent was to capture the timestamp before the bus read, so it is
as close as possible to the data ready event rather than after the
regmap_bulk_read() over I2C/SPI.

If that difference is not considered significant here, I'm happy to
call it directly in v2.

Thanks,
Liu Yufei