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iio: imu: inv_mpu6050: fix FIFO parsing when empty

PATCH In review [email protected] 2 participants 2 messages Feb 19, 2024 – Feb 24, 2024

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Stable branch IIO Invensense mpu-6050 IMU driver
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PATCH v2 1/1 iio: imu: inv_mpu6050: fix FIFO parsing when empty

From: Jean-Baptiste Maneyrol <[email protected]>

Now that we are reading the full FIFO in the interrupt handler, it is possible to have an emply FIFO since we are still receiving 1 interrupt per data. Handle correctly this case instead of having an error causing a reset of the FIFO.

Fixes 0829edc43e0a ("iio: imu: inv_mpu6050: read the full fifo when processing data")
Cc [email protected]
Signed-off-by Jean-Baptiste Maneyrol <[email protected]>

---
V2: add missing stable tag

 drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c +2 -0
index 66d4ba088e70..d4f9b5d8d28d 100644
@@ -109,6 +109,8 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
 	/* compute and process only all complete datum */
 	nb = fifo_count / bytes_per_datum;
 	fifo_count = nb * bytes_per_datum;
+	if (nb == 0)
+		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, fifo_period, nb, nb, pf->timestamp);

--
2.34.1

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#1 lore raw
Quoted 10 lines · On Mon, 19 Feb 2024 15:48:25 +0000 [email protected] wrote:

From: Jean-Baptiste Maneyrol <[email protected]>

Now that we are reading the full FIFO in the interrupt handler, it is possible to have an emply FIFO since we are still receiving 1 interrupt per data. Handle correctly this case instead of having an error causing a reset of the FIFO.

Fixes 0829edc43e0a ("iio: imu: inv_mpu6050: read the full fifo when processing data")
Cc [email protected]
Signed-off-by Jean-Baptiste Maneyrol <[email protected]>

Would have been nice to call out that the error comes from a zero length read (I think!).

Anyhow, applied to the fixes-togreg branch of iio.git.

I might pull this into my queue for the next merge window as we are getting close to the end of the cycle.

Jonathan

Quoted 22 lines

---
V2: add missing stable tag

 drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 2 ++
 1 file changed, 2 insertions(+)
drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c +2 -1
index 66d4ba088e70..d4f9b5d8d28d 100644
@@ -109,6 +109,8 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
 	/* compute and process only all complete datum */
 	nb = fifo_count / bytes_per_datum;
 	fifo_count = nb * bytes_per_datum;
+	if (nb == 0)
+		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, fifo_period, nb, nb, pf->timestamp);
--

2.34.1