Commit d7bd4736 authored by Jean-Baptiste Maneyrol's avatar Jean-Baptiste Maneyrol Committed by Jonathan Cameron
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iio: imu: inv_icm42600: stabilized timestamp in interrupt 



Use IRQF_ONESHOT flag to ensure the timestamp is not updated in the
hard handler during the thread handler. And compute and use the
effective watermark value 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.

Fixes: ec74ae9f ("iio: imu: inv_icm42600: add accurate timestamping")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJean-Baptiste Maneyrol <jean-baptiste.maneyrol@tdk.com>
Link: https://lore.kernel.org/r/20240529154717.651863-1-inv.git-commit@tdk.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 95444b9e

drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.c

+17 −2
Original line number Diff line number Diff line
@@ -222,10 +222,15 @@ int inv_icm42600_buffer_update_watermark(struct inv_icm42600_state *st) 
	latency_accel = period_accel * wm_accel;



	/* 0 value for watermark means that the sensor is turned off */

	if (wm_gyro == 0 && wm_accel == 0)

		return 0;



	if (latency_gyro == 0) {

		watermark = wm_accel;

		st->fifo.watermark.eff_accel = wm_accel;

	} else if (latency_accel == 0) {

		watermark = wm_gyro;

		st->fifo.watermark.eff_gyro = wm_gyro;

	} else {

		/* compute the smallest latency that is a multiple of both */

		if (latency_gyro <= latency_accel)
@@ -241,6 +246,13 @@ int inv_icm42600_buffer_update_watermark(struct inv_icm42600_state *st) 
		watermark = latency / period;

		if (watermark < 1)

			watermark = 1;

		/* update effective watermark */

		st->fifo.watermark.eff_gyro = latency / period_gyro;

		if (st->fifo.watermark.eff_gyro < 1)

			st->fifo.watermark.eff_gyro = 1;

		st->fifo.watermark.eff_accel = latency / period_accel;

		if (st->fifo.watermark.eff_accel < 1)

			st->fifo.watermark.eff_accel = 1;

	}



	/* compute watermark value in bytes */
@@ -514,7 +526,7 @@ int inv_icm42600_buffer_fifo_parse(struct inv_icm42600_state *st) 
	/* handle gyroscope timestamp and FIFO data parsing */

	if (st->fifo.nb.gyro > 0) {

		ts = &gyro_st->ts;

		inv_sensors_timestamp_interrupt(ts, st->fifo.nb.gyro,

		inv_sensors_timestamp_interrupt(ts, st->fifo.watermark.eff_gyro,

						st->timestamp.gyro);

		ret = inv_icm42600_gyro_parse_fifo(st->indio_gyro);

		if (ret)
@@ -524,7 +536,7 @@ int inv_icm42600_buffer_fifo_parse(struct inv_icm42600_state *st) 
	/* handle accelerometer timestamp and FIFO data parsing */

	if (st->fifo.nb.accel > 0) {

		ts = &accel_st->ts;

		inv_sensors_timestamp_interrupt(ts, st->fifo.nb.accel,

		inv_sensors_timestamp_interrupt(ts, st->fifo.watermark.eff_accel,

						st->timestamp.accel);

		ret = inv_icm42600_accel_parse_fifo(st->indio_accel);

		if (ret)
@@ -577,6 +589,9 @@ int inv_icm42600_buffer_init(struct inv_icm42600_state *st) 
	unsigned int val;

	int ret;



	st->fifo.watermark.eff_gyro = 1;

	st->fifo.watermark.eff_accel = 1;



	/*

	 * Default FIFO configuration (bits 7 to 5)

	 * - use invalid value

drivers/iio/imu/inv_icm42600/inv_icm42600_buffer.h

+2 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ struct inv_icm42600_fifo { 
	struct {

		unsigned int gyro;

		unsigned int accel;

		unsigned int eff_gyro;

		unsigned int eff_accel;

	} watermark;

	size_t count;

	struct {

drivers/iio/imu/inv_icm42600/inv_icm42600_core.c

+1 −0
Original line number Diff line number Diff line
@@ -537,6 +537,7 @@ static int inv_icm42600_irq_init(struct inv_icm42600_state *st, int irq, 
	if (ret)

		return ret;



	irq_type |= IRQF_ONESHOT;

	return devm_request_threaded_irq(dev, irq, inv_icm42600_irq_timestamp,

					 inv_icm42600_irq_handler, irq_type,

					 "inv_icm42600", st);