| From 9d7075f646e86e83b25387b0293b2db081d49e6d Mon Sep 17 00:00:00 2001 |
| From: Quentin Schulz <quentin.schulz@free-electrons.com> |
| Date: Tue, 21 Mar 2017 16:52:14 +0100 |
| Subject: [PATCH] iio: bmg160: reset chip when probing |
| |
| 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 <quentin.schulz@free-electrons.com> |
| Cc: <Stable@vger.kernel.org> |
| Signed-off-by: Jonathan Cameron <jic23@kernel.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| 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"); |
| -- |
| 2.12.0 |
| |