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Message-ID: <20180128081925.524a3e08@archlinux>
Date: Sun, 28 Jan 2018 08:19:25 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: Fabrice Gasnier <fabrice.gasnier@...com>
Cc: <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <mcoquelin.stm32@...il.com>,
<alexandre.torgue@...com>, <linux-iio@...r.kernel.org>,
<lars@...afoo.de>, <knaack.h@....de>, <pmeerw@...erw.net>
Subject: Re: [PATCH] iio: adc: stm32: fix stm32h7_adc_enable error handling
On Tue, 23 Jan 2018 17:04:56 +0100
Fabrice Gasnier <fabrice.gasnier@...com> wrote:
> Error handling in stm32h7_adc_enable routine doesn't unwind enable
> sequence correctly. ADEN can only be cleared by hardware (e.g. by
> writing one to ADDIS).
> It's also better to clear ADRDY just after it's been set by hardware.
>
> Fixes: 95e339b6e85d ("iio: adc: stm32: add support for STM32H7")
>
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...com>
Applied to fixes-togreg-post-rc1 branch of iio.git and marked for
stable.
Thanks,
Jonathan
> ---
> drivers/iio/adc/stm32-adc.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index ca3b865..8177a92 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -735,8 +735,6 @@ static int stm32h7_adc_enable(struct stm32_adc *adc)
> int ret;
> u32 val;
>
> - /* Clear ADRDY by writing one, then enable ADC */
> - stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
> stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
>
> /* Poll for ADRDY to be set (after adc startup time) */
> @@ -744,8 +742,11 @@ static int stm32h7_adc_enable(struct stm32_adc *adc)
> val & STM32H7_ADRDY,
> 100, STM32_ADC_TIMEOUT_US);
> if (ret) {
> - stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_ADEN);
> + stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
> dev_err(&indio_dev->dev, "Failed to enable ADC\n");
> + } else {
> + /* Clear ADRDY by writing one */
> + stm32_adc_set_bits(adc, STM32H7_ADC_ISR, STM32H7_ADRDY);
> }
>
> return ret;
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