projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| f99637f6 GKH |
1 | From 4bdc9029685ac03be50b320b29691766d2326c2b Mon Sep 17 00:00:00 2001 |
| 2 | From: Quentin Schulz <quentin.schulz@free-electrons.com> | |
| 3 | Date: Tue, 21 Mar 2017 16:52:14 +0100 | |
| 4 | Subject: iio: bmg160: reset chip when probing | |
| 5 | ||
| 6 | From: Quentin Schulz <quentin.schulz@free-electrons.com> | |
| 7 | ||
| 8 | commit 4bdc9029685ac03be50b320b29691766d2326c2b upstream. | |
| 9 | ||
| 10 | The gyroscope chip might need to be reset to be used. | |
| 11 | ||
| 12 | Without the chip being reset, the driver stopped at the first | |
| 13 | regmap_read (to get the CHIP_ID) and failed to probe. | |
| 14 | ||
| 15 | The datasheet of the gyroscope says that a minimum wait of 30ms after | |
| 16 | the reset has to be done. | |
| 17 | ||
| 18 | This patch has been checked on a BMX055 and the datasheet of the BMG160 | |
| 19 | and the BMI055 give the same reset register and bits. | |
| 20 | ||
| 21 | Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com> | |
| 22 | Signed-off-by: Jonathan Cameron <jic23@kernel.org> | |
| 23 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 24 | ||
| 25 | --- | |
| 26 | drivers/iio/gyro/bmg160_core.c | 12 ++++++++++++ | |
| 27 | 1 file changed, 12 insertions(+) | |
| 28 | ||
| 29 | --- a/drivers/iio/gyro/bmg160_core.c | |
| 30 | +++ b/drivers/iio/gyro/bmg160_core.c | |
| 31 | @@ -28,6 +28,7 @@ | |
| 32 | #include <linux/iio/trigger_consumer.h> | |
| 33 | #include <linux/iio/triggered_buffer.h> | |
| 34 | #include <linux/regmap.h> | |
| 35 | +#include <linux/delay.h> | |
| 36 | #include "bmg160.h" | |
| 37 | ||
| 38 | #define BMG160_IRQ_NAME "bmg160_event" | |
| 39 | @@ -53,6 +54,9 @@ | |
| 40 | #define BMG160_NO_FILTER 0 | |
| 41 | #define BMG160_DEF_BW 100 | |
| 42 | ||
| 43 | +#define BMG160_GYRO_REG_RESET 0x14 | |
| 44 | +#define BMG160_GYRO_RESET_VAL 0xb6 | |
| 45 | + | |
| 46 | #define BMG160_REG_INT_MAP_0 0x17 | |
| 47 | #define BMG160_INT_MAP_0_BIT_ANY BIT(1) | |
| 48 | ||
| 49 | @@ -186,6 +190,14 @@ static int bmg160_chip_init(struct bmg16 | |
| 50 | int ret; | |
| 51 | unsigned int val; | |
| 52 | ||
| 53 | + /* | |
| 54 | + * Reset chip to get it in a known good state. A delay of 30ms after | |
| 55 | + * reset is required according to the datasheet. | |
| 56 | + */ | |
| 57 | + regmap_write(data->regmap, BMG160_GYRO_REG_RESET, | |
| 58 | + BMG160_GYRO_RESET_VAL); | |
| 59 | + usleep_range(30000, 30700); | |
| 60 | + | |
| 61 | ret = regmap_read(data->regmap, BMG160_REG_CHIP_ID, &val); | |
| 62 | if (ret < 0) { | |
| 63 | dev_err(data->dev, "Error reading reg_chip_id\n"); |