Currently, setting preset value (ARR) will update directly 'Auto reload value' only on 1st write access. But then, ARPE is set. This makes ARR a shadow register. Preset value should be updated upon each write request: ensure ARPE is 0. This fixes successive writes to preset attribute. Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> --- drivers/iio/trigger/stm32-timer-trigger.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c index 9b90534..34cc25b 100644 --- a/drivers/iio/trigger/stm32-timer-trigger.c +++ b/drivers/iio/trigger/stm32-timer-trigger.c @@ -715,8 +715,9 @@ static ssize_t stm32_count_set_preset(struct iio_dev *indio_dev, if (ret) return ret; + /* TIMx_ARR register shouldn't be buffered (ARPE=0) */ + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0); regmap_write(priv->regmap, TIM_ARR, preset); - regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE); return len; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html