Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753354AbdIRKGt (ORCPT ); Mon, 18 Sep 2017 06:06:49 -0400 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:33950 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753248AbdIRKGr (ORCPT ); Mon, 18 Sep 2017 06:06:47 -0400 From: Fabrice Gasnier To: CC: , , , , , , , , , , Subject: [PATCH 1/3] iio: trigger: stm32-timer: preset shouldn't be buffered Date: Mon, 18 Sep 2017 12:05:30 +0200 Message-ID: <1505729132-1369-2-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1505729132-1369-1-git-send-email-fabrice.gasnier@st.com> References: <1505729132-1369-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.75.127.48] X-ClientProxiedBy: SFHDAG4NODE1.st.com (10.75.127.10) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-09-18_02:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1128 Lines: 30 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 --- 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