[PATCH 3/3] iio: imu: bmi160: Remove potential undefined behavior in bmi160_config_pin()

[Josh Poimboeuf <jpoimboe@kernel.org>]

If 'pin' is not one of its expected values, the value of
'int_out_ctrl_shift' is undefined.  With UBSAN enabled, this causes
Clang to generate undefined behavior, resulting in the following
warning:

  drivers/iio/imu/bmi160/bmi160_core.o: warning: objtool: bmi160_setup_irq() falls through to next function __cfi_bmi160_core_runtime_resume()

Prevent the UB and improve error handling by adding a BUG() if 'pin' has
an unexpected value.

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: David Lechner <dlechner@baylibre.com>
CC: Nuno Sá <nuno.sa@analog.com>
Cc: Andy Shevchenko <andy@kernel.org>
Fixes: 895bf81e6bbf ("iio:bmi160: add drdy interrupt support")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 drivers/iio/imu/bmi160/bmi160_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/imu/bmi160/bmi160_core.c b/drivers/iio/imu/bmi160/bmi160_core.c
index 5f47708b4c5d..e5326df75e49 100644
--- a/drivers/iio/imu/bmi160/bmi160_core.c
+++ b/drivers/iio/imu/bmi160/bmi160_core.c
@@ -579,6 +579,8 @@ static int bmi160_config_pin(struct regmap *regmap, enum bmi160_int_pin pin,
 		int_latch_mask = BMI160_INT2_LATCH_MASK;
 		int_map_mask = BMI160_INT2_MAP_DRDY_EN;
 		break;
+	default:
+		BUG();
 	}
 	int_out_ctrl_mask = BMI160_INT_OUT_CTRL_MASK << int_out_ctrl_shift;
 
-- 
2.53.0