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iio: trigger: stm32-timer: preset shouldn't be buffered 

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: 4adec7da05 ("iio: stm32 trigger: Add quadrature encoder device")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Fabrice Gasnier 2017-09-18 12:05:30 +02:00 committed by Jonathan Cameron
parent 53063846af
commit 0a56eabc4e
1 changed files with 2 additions and 1 deletions
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3
drivers/iio/trigger/stm32-timer-trigger.c
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@ -681,8 +681,9 @@ 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;
}