Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")SMS bitfiled is mode + 1. After reset, upon boot, SMS = 0. When reading from sysfs, stm32_get_quadrature_mode() returns -1 (e.g. -EPERM) which is wrong error code here. So, check SMS bitfiled matches valid encoder mode, or return -EINVAL. Signed-off-by: Fabrice Gasnier <[email protected]> --- drivers/iio/trigger/stm32-timer-trigger.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c index d22bc56..6aa73d6 100644 --- a/drivers/iio/trigger/stm32-timer-trigger.c +++ b/drivers/iio/trigger/stm32-timer-trigger.c @@ -571,11 +571,14 @@ static int stm32_get_quadrature_mode(struct iio_dev *indio_dev, { struct stm32_timer_trigger *priv = iio_priv(indio_dev); u32 smcr; + int mode; regmap_read(priv->regmap, TIM_SMCR, &smcr); - smcr &= TIM_SMCR_SMS; + mode = (smcr & TIM_SMCR_SMS) - 1; + if ((mode < 0) || (mode > ARRAY_SIZE(stm32_quadrature_modes))) + return -EINVAL; - return smcr - 1; + return mode; } static const struct iio_enum stm32_quadrature_mode_enum = { -- 1.9.1
