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iio: gyro: bmg160: wait full startup time after mode change at probe

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commit 088fcb9b56 upstream.

bmg160_chip_init() calls bmg160_set_mode(BMG160_MODE_NORMAL) and
then waits only 500-1000 us. Per the BMG160 datasheet
(BST-BMG160-DS000-07 Rev. 1.0, May 2013), the start-up and wake-up
times (tsu, twusm) are 30 ms.

The same file already waits BMG160_MAX_STARTUP_TIME_MS (80 ms)
in bmg160_runtime_resume() after the same set_mode(NORMAL)
operation. The 500 us value at probe was likely a unit mix-up;
the old comment said "500 ms" while the code used microseconds.

Reuse the same constant via msleep() and add a code comment
explaining the datasheet basis for the wait. Without this,
register writes that follow the mode change can hit the chip
before it is ready.

Fixes: 22b46c45fb ("iio:gyro:bmg160 Gyro Sensor driver")
Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stepan Ionichev
2026-07-24 16:02:40 +02:00
committed by Greg Kroah-Hartman
parent 8d202515ba
commit 5240dd5cf0
1 changed files with 8 additions and 2 deletions
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drivers/iio/gyro/bmg160_core.c
+8 -2
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@@ -267,8 +267,14 @@ static int bmg160_chip_init(struct bmg160_data *data)
if (ret < 0)
return ret;
/* Wait upto 500 ms to be ready after changing mode */
usleep_range(500, 1000);
/*
* Wait for the chip to be ready after switching to normal mode.
* The BMG160 datasheet (BST-BMG160-DS000-07 Rev. 1.0, May 2013)
* specifies a start-up / wake-up time (tsu, twusm) of 30 ms; use
* BMG160_MAX_STARTUP_TIME_MS (80 ms) as a safety margin, matching
* what bmg160_runtime_resume() already does.
*/
msleep(BMG160_MAX_STARTUP_TIME_MS);
/* Set Bandwidth */
ret = bmg160_set_bw(data, BMG160_DEF_BW);