[PATCH 4.14 18/70] iio: gyro: mpu3050: fix chip ID reading

Greg Kroah-Hartman
2019-04-24T17:26:35Z

From: Sergey Larin <cerg2010cerg2010@mail.ru>

commit 409a51e0a4a5f908763191fae2c29008632eb712 upstream.

According to the datasheet, the last bit of CHIP_ID register controls
I2C bus, and the first one is unused. Handle this correctly.

Note that there are chips out there that have a value such that
the id check currently fails.

Signed-off-by: Sergey Larin <cerg2010cerg2010@mail.ru>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/iio/gyro/mpu3050-core.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/iio/gyro/mpu3050-core.c
+++ b/drivers/iio/gyro/mpu3050-core.c
@@ -29,7 +29,8 @@

#include "mpu3050.h"

-#define MPU3050_CHIP_ID 0x69
+#define MPU3050_CHIP_ID 0x68
+#define MPU3050_CHIP_ID_MASK 0x7E

/*
* Register map: anything suffixed *_H is a big-endian high byte and always
@@ -1178,8 +1179,9 @@ int mpu3050_common_probe(struct device *
goto err_power_down;
}

- if (val != MPU3050_CHIP_ID) {
- dev_err(dev, "unsupported chip id %02x\n", (u8)val);
+ if ((val & MPU3050_CHIP_ID_MASK) != MPU3050_CHIP_ID) {
+ dev_err(dev, "unsupported chip id %02x\n",
+ (u8)(val & MPU3050_CHIP_ID_MASK));
ret = -ENODEV;
goto err_power_down;
}