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* [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state
@ 2022-06-20 15:47 ` Olivier Moysan
  0 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On ADC startup a calibration is launched.
A prerequisite for ADC calibration is to have ADC in disabled state.
After kernel boot, the ADC state may be unknown as the ADC may have been left enabled by boot stage.

Call ADC disable routine systematically before launching calibration.
Adapt ADC disable routine to perform disabling sequence according to current ADC state.

Olivier Moysan (2):
  iio: adc: stm32-adc: make safe adc disable
  iio: adc: stm32-adc: disable adc before calibration

 drivers/iio/adc/stm32-adc.c | 6 ++++++
 1 file changed, 6 insertions(+)

-- 
2.25.1


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state
@ 2022-06-20 15:47 ` Olivier Moysan
  0 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On ADC startup a calibration is launched.
A prerequisite for ADC calibration is to have ADC in disabled state.
After kernel boot, the ADC state may be unknown as the ADC may have been left enabled by boot stage.

Call ADC disable routine systematically before launching calibration.
Adapt ADC disable routine to perform disabling sequence according to current ADC state.

Olivier Moysan (2):
  iio: adc: stm32-adc: make safe adc disable
  iio: adc: stm32-adc: disable adc before calibration

 drivers/iio/adc/stm32-adc.c | 6 ++++++
 1 file changed, 6 insertions(+)

-- 
2.25.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 12+ messages in thread
* [PATCH 1/2] iio: adc: stm32-adc: make safe adc disable
  2022-06-20 15:47 ` Olivier Moysan
@ 2022-06-20 15:47   ` Olivier Moysan
  -1 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

From ADC reference manual the software is allowed to write the
control bit ADDIS of the ADC_CR register only if the ADC is enabled.
Return immediately from stm32h7_adc_disable() if ADC is already disabled.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 drivers/iio/adc/stm32-adc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index a68ecbda6480..80e333f65ddd 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -876,6 +876,9 @@ static void stm32h7_adc_disable(struct iio_dev *indio_dev)
 	int ret;
 	u32 val;
 
+	if (!(stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_ADEN))
+		return;
+
 	/* Disable ADC and wait until it's effectively disabled */
 	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
 	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH 1/2] iio: adc: stm32-adc: make safe adc disable
@ 2022-06-20 15:47   ` Olivier Moysan
  0 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

From ADC reference manual the software is allowed to write the
control bit ADDIS of the ADC_CR register only if the ADC is enabled.
Return immediately from stm32h7_adc_disable() if ADC is already disabled.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 drivers/iio/adc/stm32-adc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index a68ecbda6480..80e333f65ddd 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -876,6 +876,9 @@ static void stm32h7_adc_disable(struct iio_dev *indio_dev)
 	int ret;
 	u32 val;
 
+	if (!(stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_ADEN))
+		return;
+
 	/* Disable ADC and wait until it's effectively disabled */
 	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
 	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,
-- 
2.25.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH 2/2] iio: adc: stm32-adc: disable adc before calibration
  2022-06-20 15:47 ` Olivier Moysan
@ 2022-06-20 15:47   ` Olivier Moysan
  -1 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

The calibration is launched from prepare callback.
The ADC state when entering this function may be unknown as the
ADC may have been left enabled by boot stage.
One prerequisite for ADC calibration is to have ADC in disabled state.
If the calibration is started when ADC is still enabled, the behavior is
unpredictable, and the calibration may fail with a timeout error.

Force ADC to disabled state in stm32h7_adc_selfcalib().
ADC enabling is ensured by stm32h7_adc_enable() call,
before leaving prepare callback.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 drivers/iio/adc/stm32-adc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 80e333f65ddd..3985fe972892 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1019,6 +1019,9 @@ static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
 	if (adc->cal.calibrated)
 		return true;
 
+	/* ADC must be disabled for calibration */
+	stm32h7_adc_disable(indio_dev);
+
 	/*
 	 * Select calibration mode:
 	 * - Offset calibration for single ended inputs
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 12+ messages in thread
* [PATCH 2/2] iio: adc: stm32-adc: disable adc before calibration
@ 2022-06-20 15:47   ` Olivier Moysan
  0 siblings, 0 replies; 12+ messages in thread
From: Olivier Moysan @ 2022-06-20 15:47 UTC (permalink / raw)
  To: Alexandre Torgue, Fabrice Gasnier, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Olivier Moysan,
	Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

The calibration is launched from prepare callback.
The ADC state when entering this function may be unknown as the
ADC may have been left enabled by boot stage.
One prerequisite for ADC calibration is to have ADC in disabled state.
If the calibration is started when ADC is still enabled, the behavior is
unpredictable, and the calibration may fail with a timeout error.

Force ADC to disabled state in stm32h7_adc_selfcalib().
ADC enabling is ensured by stm32h7_adc_enable() call,
before leaving prepare callback.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 drivers/iio/adc/stm32-adc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 80e333f65ddd..3985fe972892 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1019,6 +1019,9 @@ static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
 	if (adc->cal.calibrated)
 		return true;
 
+	/* ADC must be disabled for calibration */
+	stm32h7_adc_disable(indio_dev);
+
 	/*
 	 * Select calibration mode:
 	 * - Offset calibration for single ended inputs
-- 
2.25.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 12+ messages in thread
* Re: [PATCH 1/2] iio: adc: stm32-adc: make safe adc disable
  2022-06-20 15:47   ` Olivier Moysan
@ 2022-06-21 15:38     ` Fabrice Gasnier
  -1 siblings, 0 replies; 12+ messages in thread
From: Fabrice Gasnier @ 2022-06-21 15:38 UTC (permalink / raw)
  To: Olivier Moysan, Alexandre Torgue, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On 6/20/22 17:47, Olivier Moysan wrote:
> From ADC reference manual the software is allowed to write the
> control bit ADDIS of the ADC_CR register only if the ADC is enabled.
> Return immediately from stm32h7_adc_disable() if ADC is already disabled.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>

Hi Olivier,

You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Thanks,
Fabrice

> ---
>  drivers/iio/adc/stm32-adc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index a68ecbda6480..80e333f65ddd 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -876,6 +876,9 @@ static void stm32h7_adc_disable(struct iio_dev *indio_dev)
>  	int ret;
>  	u32 val;
>  
> +	if (!(stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_ADEN))
> +		return;
> +
>  	/* Disable ADC and wait until it's effectively disabled */
>  	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
>  	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH 1/2] iio: adc: stm32-adc: make safe adc disable
@ 2022-06-21 15:38     ` Fabrice Gasnier
  0 siblings, 0 replies; 12+ messages in thread
From: Fabrice Gasnier @ 2022-06-21 15:38 UTC (permalink / raw)
  To: Olivier Moysan, Alexandre Torgue, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On 6/20/22 17:47, Olivier Moysan wrote:
> From ADC reference manual the software is allowed to write the
> control bit ADDIS of the ADC_CR register only if the ADC is enabled.
> Return immediately from stm32h7_adc_disable() if ADC is already disabled.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>

Hi Olivier,

You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Thanks,
Fabrice

> ---
>  drivers/iio/adc/stm32-adc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index a68ecbda6480..80e333f65ddd 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -876,6 +876,9 @@ static void stm32h7_adc_disable(struct iio_dev *indio_dev)
>  	int ret;
>  	u32 val;
>  
> +	if (!(stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_ADEN))
> +		return;
> +
>  	/* Disable ADC and wait until it's effectively disabled */
>  	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADDIS);
>  	ret = stm32_adc_readl_poll_timeout(STM32H7_ADC_CR, val,

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] iio: adc: stm32-adc: disable adc before calibration
  2022-06-20 15:47   ` Olivier Moysan
@ 2022-06-21 15:39     ` Fabrice Gasnier
  -1 siblings, 0 replies; 12+ messages in thread
From: Fabrice Gasnier @ 2022-06-21 15:39 UTC (permalink / raw)
  To: Olivier Moysan, Alexandre Torgue, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On 6/20/22 17:47, Olivier Moysan wrote:
> The calibration is launched from prepare callback.
> The ADC state when entering this function may be unknown as the
> ADC may have been left enabled by boot stage.
> One prerequisite for ADC calibration is to have ADC in disabled state.
> If the calibration is started when ADC is still enabled, the behavior is
> unpredictable, and the calibration may fail with a timeout error.
> 
> Force ADC to disabled state in stm32h7_adc_selfcalib().
> ADC enabling is ensured by stm32h7_adc_enable() call,
> before leaving prepare callback.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>

Hi Olivier,

You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Thanks,
Fabrice

> ---
>  drivers/iio/adc/stm32-adc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 80e333f65ddd..3985fe972892 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -1019,6 +1019,9 @@ static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
>  	if (adc->cal.calibrated)
>  		return true;
>  
> +	/* ADC must be disabled for calibration */
> +	stm32h7_adc_disable(indio_dev);
> +
>  	/*
>  	 * Select calibration mode:
>  	 * - Offset calibration for single ended inputs

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH 2/2] iio: adc: stm32-adc: disable adc before calibration
@ 2022-06-21 15:39     ` Fabrice Gasnier
  0 siblings, 0 replies; 12+ messages in thread
From: Fabrice Gasnier @ 2022-06-21 15:39 UTC (permalink / raw)
  To: Olivier Moysan, Alexandre Torgue, Jonathan Cameron,
	Lars-Peter Clausen, Maxime Coquelin, Paul Cercueil, Wan Jiabing
  Cc: linux-arm-kernel, linux-iio, linux-kernel, linux-stm32

On 6/20/22 17:47, Olivier Moysan wrote:
> The calibration is launched from prepare callback.
> The ADC state when entering this function may be unknown as the
> ADC may have been left enabled by boot stage.
> One prerequisite for ADC calibration is to have ADC in disabled state.
> If the calibration is started when ADC is still enabled, the behavior is
> unpredictable, and the calibration may fail with a timeout error.
> 
> Force ADC to disabled state in stm32h7_adc_selfcalib().
> ADC enabling is ensured by stm32h7_adc_enable() call,
> before leaving prepare callback.
> 
> Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>

Hi Olivier,

You can add my:
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Thanks,
Fabrice

> ---
>  drivers/iio/adc/stm32-adc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index 80e333f65ddd..3985fe972892 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -1019,6 +1019,9 @@ static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
>  	if (adc->cal.calibrated)
>  		return true;
>  
> +	/* ADC must be disabled for calibration */
> +	stm32h7_adc_disable(indio_dev);
> +
>  	/*
>  	 * Select calibration mode:
>  	 * - Offset calibration for single ended inputs

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state
  2022-06-20 15:47 ` Olivier Moysan
@ 2022-06-25 13:28   ` Jonathan Cameron
  -1 siblings, 0 replies; 12+ messages in thread
From: Jonathan Cameron @ 2022-06-25 13:28 UTC (permalink / raw)
  To: Olivier Moysan
  Cc: Alexandre Torgue, Fabrice Gasnier, Lars-Peter Clausen,
	Maxime Coquelin, Paul Cercueil, Wan Jiabing, linux-arm-kernel,
	linux-iio, linux-kernel, linux-stm32

On Mon, 20 Jun 2022 17:47:36 +0200
Olivier Moysan <olivier.moysan@foss.st.com> wrote:

> On ADC startup a calibration is launched.
> A prerequisite for ADC calibration is to have ADC in disabled state.
> After kernel boot, the ADC state may be unknown as the ADC may have been left enabled by boot stage.
> 
> Call ADC disable routine systematically before launching calibration.
> Adapt ADC disable routine to perform disabling sequence according to current ADC state.
> 
> Olivier Moysan (2):
>   iio: adc: stm32-adc: make safe adc disable
>   iio: adc: stm32-adc: disable adc before calibration
> 
>  drivers/iio/adc/stm32-adc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Series applied to the togreg branch and pushed out as testing
for all the normal reasons.

Thanks,

Jonathan


^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state
@ 2022-06-25 13:28   ` Jonathan Cameron
  0 siblings, 0 replies; 12+ messages in thread
From: Jonathan Cameron @ 2022-06-25 13:28 UTC (permalink / raw)
  To: Olivier Moysan
  Cc: Alexandre Torgue, Fabrice Gasnier, Lars-Peter Clausen,
	Maxime Coquelin, Paul Cercueil, Wan Jiabing, linux-arm-kernel,
	linux-iio, linux-kernel, linux-stm32

On Mon, 20 Jun 2022 17:47:36 +0200
Olivier Moysan <olivier.moysan@foss.st.com> wrote:

> On ADC startup a calibration is launched.
> A prerequisite for ADC calibration is to have ADC in disabled state.
> After kernel boot, the ADC state may be unknown as the ADC may have been left enabled by boot stage.
> 
> Call ADC disable routine systematically before launching calibration.
> Adapt ADC disable routine to perform disabling sequence according to current ADC state.
> 
> Olivier Moysan (2):
>   iio: adc: stm32-adc: make safe adc disable
>   iio: adc: stm32-adc: disable adc before calibration
> 
>  drivers/iio/adc/stm32-adc.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Series applied to the togreg branch and pushed out as testing
for all the normal reasons.

Thanks,

Jonathan


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2022-06-25 13:19 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-20 15:47 [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state Olivier Moysan
2022-06-20 15:47 ` Olivier Moysan
2022-06-20 15:47 ` [PATCH 1/2] iio: adc: stm32-adc: make safe adc disable Olivier Moysan
2022-06-20 15:47   ` Olivier Moysan
2022-06-21 15:38   ` Fabrice Gasnier
2022-06-21 15:38     ` Fabrice Gasnier
2022-06-20 15:47 ` [PATCH 2/2] iio: adc: stm32-adc: disable adc before calibration Olivier Moysan
2022-06-20 15:47   ` Olivier Moysan
2022-06-21 15:39   ` Fabrice Gasnier
2022-06-21 15:39     ` Fabrice Gasnier
2022-06-25 13:28 ` [PATCH 0/2] iio: adc: stm32-adc: add checks on adc state Jonathan Cameron
2022-06-25 13:28   ` Jonathan Cameron

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