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Subject[PATCH 4.10 016/110] iio: bmg160: reset chip when probing
4.10-stable review patch.  If anyone has any objections, please let me know.


From: Quentin Schulz <>

commit 4bdc9029685ac03be50b320b29691766d2326c2b upstream.

The gyroscope chip might need to be reset to be used.

Without the chip being reset, the driver stopped at the first
regmap_read (to get the CHIP_ID) and failed to probe.

The datasheet of the gyroscope says that a minimum wait of 30ms after
the reset has to be done.

This patch has been checked on a BMX055 and the datasheet of the BMG160
and the BMI055 give the same reset register and bits.

Signed-off-by: Quentin Schulz <>
Signed-off-by: Jonathan Cameron <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/iio/gyro/bmg160_core.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

--- a/drivers/iio/gyro/bmg160_core.c
+++ b/drivers/iio/gyro/bmg160_core.c
@@ -27,6 +27,7 @@
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/regmap.h>
+#include <linux/delay.h>
#include "bmg160.h"

#define BMG160_IRQ_NAME "bmg160_event"
@@ -52,6 +53,9 @@
#define BMG160_DEF_BW 100
#define BMG160_REG_PMU_BW_RES BIT(7)

+#define BMG160_GYRO_REG_RESET 0x14
+#define BMG160_GYRO_RESET_VAL 0xb6
#define BMG160_REG_INT_MAP_0 0x17
#define BMG160_INT_MAP_0_BIT_ANY BIT(1)

@@ -236,6 +240,14 @@ static int bmg160_chip_init(struct bmg16
int ret;
unsigned int val;

+ /*
+ * Reset chip to get it in a known good state. A delay of 30ms after
+ * reset is required according to the datasheet.
+ */
+ regmap_write(data->regmap, BMG160_GYRO_REG_RESET,
+ usleep_range(30000, 30700);
ret = regmap_read(data->regmap, BMG160_REG_CHIP_ID, &val);
if (ret < 0) {
dev_err(dev, "Error reading reg_chip_id\n");

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