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Subject[PATCH 1/3] iio: trigger: stm32-timer: preset shouldn't be buffered
Date
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@st.com>
---
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
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