[PATCH] iio: imu: inv_mpu6050: stabilized timestamping in interrupt

[PATCH] iio: imu: inv_mpu6050: stabilized timestamping in interrupt

[inv.git-commit]

From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>

Use IRQ ONESHOT flag to ensure the timestamp is not updated in the
hard handler during the thread handler. And use a fixed value of 1
sample that correspond to this first timestamp.

This way we can ensure the timestamp is always corresponding to the
value used by the timestamping mechanism. Otherwise, it is possible
that between FIFO count read and FIFO processing the timestamp is
overwritten in the hard handler.

Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
---
 drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c    | 4 ++--
 drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
index 0dc0f22a5582..3d3b27f28c9d 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
@@ -100,8 +100,8 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
 		goto end_session;
 	/* Each FIFO data contains all sensors, so same number for FIFO and sensor data */
 	fifo_period = NSEC_PER_SEC / INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
-	inv_sensors_timestamp_interrupt(&st->timestamp, nb, pf->timestamp);
-	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, nb, 0);
+	inv_sensors_timestamp_interrupt(&st->timestamp, 1, pf->timestamp);
+	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, 1, 0);
 
 	/* clear internal data buffer for avoiding kernel data leak */
 	memset(data, 0, sizeof(data));
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
index 1b603567ccc8..84273660ca2e 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
@@ -300,6 +300,7 @@ int inv_mpu6050_probe_trigger(struct iio_dev *indio_dev, int irq_type)
 	if (!st->trig)
 		return -ENOMEM;
 
+	irq_type |= IRQF_ONESHOT;
 	ret = devm_request_threaded_irq(&indio_dev->dev, st->irq,
 					&inv_mpu6050_interrupt_timestamp,
 					&inv_mpu6050_interrupt_handle,
-- 
2.34.1

Re: [PATCH] iio: imu: inv_mpu6050: stabilized timestamping in interrupt

[Jonathan Cameron]

On Thu, 23 May 2024 13:52:45 +0000
inv.git-commit@tdk.com wrote:

> From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> 
> Use IRQ ONESHOT flag to ensure the timestamp is not updated in the
> hard handler during the thread handler. And use a fixed value of 1
> sample that correspond to this first timestamp.
> 
> This way we can ensure the timestamp is always corresponding to the
> value used by the timestamping mechanism. Otherwise, it is possible
> that between FIFO count read and FIFO processing the timestamp is
> overwritten in the hard handler.
> 
> Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Fixes tag appropriate?

Otherwise LGTM
> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c    | 4 ++--
>  drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 1 +
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> index 0dc0f22a5582..3d3b27f28c9d 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> @@ -100,8 +100,8 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
>  		goto end_session;
>  	/* Each FIFO data contains all sensors, so same number for FIFO and sensor data */
>  	fifo_period = NSEC_PER_SEC / INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
> -	inv_sensors_timestamp_interrupt(&st->timestamp, nb, pf->timestamp);
> -	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, nb, 0);
> +	inv_sensors_timestamp_interrupt(&st->timestamp, 1, pf->timestamp);
> +	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, 1, 0);
>  
>  	/* clear internal data buffer for avoiding kernel data leak */
>  	memset(data, 0, sizeof(data));
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> index 1b603567ccc8..84273660ca2e 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> @@ -300,6 +300,7 @@ int inv_mpu6050_probe_trigger(struct iio_dev *indio_dev, int irq_type)
>  	if (!st->trig)
>  		return -ENOMEM;
>  
> +	irq_type |= IRQF_ONESHOT;
>  	ret = devm_request_threaded_irq(&indio_dev->dev, st->irq,
>  					&inv_mpu6050_interrupt_timestamp,
>  					&inv_mpu6050_interrupt_handle,

Re: [PATCH] iio: imu: inv_mpu6050: stabilized timestamping in interrupt

[Jean-Baptiste Maneyrol]

Hi Jonathan,

I wasn't expecting first to do a Fixes tag, but you're right it would be better to backport this fix and it is quite small.

I will send a V2 with the appropriate Fixes tag.

Thanks,
JB

________________________________________
From: Jonathan Cameron <jic23@kernel.org>
Sent: Saturday, May 25, 2024 19:22
To: INV Git Commit <INV.git-commit@tdk.com>
Cc: lars@metafoo.de <lars@metafoo.de>; linux-iio@vger.kernel.org <linux-iio@vger.kernel.org>; Jean-Baptiste Maneyrol <Jean-Baptiste.Maneyrol@tdk.com>
Subject: Re: [PATCH] iio: imu: inv_mpu6050: stabilized timestamping in interrupt
 
This Message Is From an External Sender
This message came from outside your organization.
 
On Thu, 23 May 2024 13:52:45 +0000
inv.git-commit@tdk.com wrote:

> From: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
> 
> Use IRQ ONESHOT flag to ensure the timestamp is not updated in the
> hard handler during the thread handler. And use a fixed value of 1
> sample that correspond to this first timestamp.
> 
> This way we can ensure the timestamp is always corresponding to the
> value used by the timestamping mechanism. Otherwise, it is possible
> that between FIFO count read and FIFO processing the timestamp is
> overwritten in the hard handler.
> 
> Signed-off-by: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Fixes tag appropriate?

Otherwise LGTM
> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c    | 4 ++--
>  drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 1 +
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> index 0dc0f22a5582..3d3b27f28c9d 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
> @@ -100,8 +100,8 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
>  		goto end_session;
>  	/* Each FIFO data contains all sensors, so same number for FIFO and sensor data */
>  	fifo_period = NSEC_PER_SEC / INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
> -	inv_sensors_timestamp_interrupt(&st->timestamp, nb, pf->timestamp);
> -	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, nb, 0);
> +	inv_sensors_timestamp_interrupt(&st->timestamp, 1, pf->timestamp);
> +	inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, 1, 0);
>  
>  	/* clear internal data buffer for avoiding kernel data leak */
>  	memset(data, 0, sizeof(data));
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> index 1b603567ccc8..84273660ca2e 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> @@ -300,6 +300,7 @@ int inv_mpu6050_probe_trigger(struct iio_dev *indio_dev, int irq_type)
>  	if (!st->trig)
>  		return -ENOMEM;
>  
> +	irq_type |= IRQF_ONESHOT;
>  	ret = devm_request_threaded_irq(&indio_dev->dev, st->irq,
>  					&inv_mpu6050_interrupt_timestamp,
>  					&inv_mpu6050_interrupt_handle,