diff options
| author | Quentin Schulz <quentin.schulz@free-electrons.com> | 2017-03-21 16:52:14 +0100 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2017-03-25 16:36:25 +0000 |
| commit | 4bdc9029685ac03be50b320b29691766d2326c2b (patch) | |
| tree | cf7a68dce085db6da6e82b92a4c2170384d5704b /drivers | |
| parent | a096926ed4532eac38d4ec92aaba8c7f2149d89a (diff) | |
| download | linux-4bdc9029685ac03be50b320b29691766d2326c2b.tar.bz2 | |
iio: bmg160: reset chip when probing
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 <quentin.schulz@free-electrons.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/gyro/bmg160_core.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c index f7fcfa886f72..821919dd245b 100644 --- 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 bmg160_data *data) 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, + BMG160_GYRO_RESET_VAL); + 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"); |