| Message ID | 20170321155214.18060-1-quentin.schulz@free-electrons.com |
|---|---|
| State | Accepted |
| Commit | 4bdc9029685ac03be50b320b29691766d2326c2b |
| Headers | show |
On 21/03/17 15:52, Quentin Schulz wrote: > 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> Applied to the fixes-togreg branch of iio.git and marked for stable. Thanks, Jonathan > --- > drivers/iio/gyro/bmg160_core.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c > index f7fcfa8..821919d 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"); >
diff --git a/drivers/iio/gyro/bmg160_core.c b/drivers/iio/gyro/bmg160_core.c index f7fcfa8..821919d 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");
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> --- drivers/iio/gyro/bmg160_core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) -- 2.9.3