[v2] reset: Add devm_reset_control_array_get_exclusive_released()

[PATCH v2 2/2] spi: stm32-ospi: Make usage of reset_control_acquire/release() API

Posted by Patrice Chotard 8 months, 1 week ago

As ospi reset is consumed by both OMM and OSPI drivers, use the reset
acquire/release mechanism which ensure exclusive reset usage.

This avoid to call reset_control_get/put() in OMM driver each time
we need to reset OSPI children and guarantee the reset line stays
deasserted.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
---
 drivers/spi/spi-stm32-ospi.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-stm32-ospi.c b/drivers/spi/spi-stm32-ospi.c
index d002b9c16714684e4e4623f9255a7f2660c46fd1..ef840f377459891b559be6d6c0435408fb58a1e9 100644
--- a/drivers/spi/spi-stm32-ospi.c
+++ b/drivers/spi/spi-stm32-ospi.c
@@ -804,7 +804,7 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
 		return ret;
 	}
 
-	ospi->rstc = devm_reset_control_array_get_exclusive(dev);
+	ospi->rstc = devm_reset_control_array_get_exclusive_released(dev);
 	if (IS_ERR(ospi->rstc))
 		return dev_err_probe(dev, PTR_ERR(ospi->rstc),
 				     "Can't get reset\n");
@@ -936,11 +936,14 @@ static int stm32_ospi_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_pm_enable;
 
-	if (ospi->rstc) {
-		reset_control_assert(ospi->rstc);
-		udelay(2);
-		reset_control_deassert(ospi->rstc);
-	}
+	ret = reset_control_acquire(ospi->rstc);
+	if (ret)
+		return dev_err_probe(dev, ret, "Can not acquire reset %d\n", ret);
+
+	reset_control_assert(ospi->rstc);
+	udelay(2);
+	reset_control_deassert(ospi->rstc);
+	reset_control_release(ospi->rstc);
 
 	ret = spi_register_controller(ctrl);
 	if (ret) {

-- 
2.25.1

Re: [PATCH v2 2/2] spi: stm32-ospi: Make usage of reset_control_acquire/release() API

Posted by Philipp Zabel 7 months, 2 weeks ago

Hi Patrice,

On Fr, 2025-04-11 at 14:41 +0200, Patrice Chotard wrote:
> As ospi reset is consumed by both OMM and OSPI drivers, use the reset
> acquire/release mechanism which ensure exclusive reset usage.
> 
> This avoid to call reset_control_get/put() in OMM driver each time
> we need to reset OSPI children and guarantee the reset line stays
> deasserted.
> 
> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
> ---
>  drivers/spi/spi-stm32-ospi.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/spi/spi-stm32-ospi.c b/drivers/spi/spi-stm32-ospi.c
> index d002b9c16714684e4e4623f9255a7f2660c46fd1..ef840f377459891b559be6d6c0435408fb58a1e9 100644
> --- a/drivers/spi/spi-stm32-ospi.c
> +++ b/drivers/spi/spi-stm32-ospi.c
> @@ -804,7 +804,7 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ospi->rstc = devm_reset_control_array_get_exclusive(dev);
> +	ospi->rstc = devm_reset_control_array_get_exclusive_released(dev);
>  	if (IS_ERR(ospi->rstc))
>  		return dev_err_probe(dev, PTR_ERR(ospi->rstc),
>  				     "Can't get reset\n");
> @@ -936,11 +936,14 @@ static int stm32_ospi_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		goto err_pm_enable;
>  
> -	if (ospi->rstc) {
> -		reset_control_assert(ospi->rstc);
> -		udelay(2);
> -		reset_control_deassert(ospi->rstc);
> -	}
> +	ret = reset_control_acquire(ospi->rstc);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Can not acquire reset %d\n", ret);
> +
> +	reset_control_assert(ospi->rstc);
> +	udelay(2);
> +	reset_control_deassert(ospi->rstc);
> +	reset_control_release(ospi->rstc);

Could you keep the reset control (mostly) acquired from probe() to
remove()? The reset control would have to be released/acquired in OSPI
suspend/resume so that OMM can temporarily acquire control during OMM
resume.

regards
Philipp

Re: [PATCH v2 2/2] spi: stm32-ospi: Make usage of reset_control_acquire/release() API

Posted by Patrice CHOTARD 7 months, 2 weeks ago


On 5/5/25 15:12, Philipp Zabel wrote:
> Hi Patrice,
> 
> On Fr, 2025-04-11 at 14:41 +0200, Patrice Chotard wrote:
>> As ospi reset is consumed by both OMM and OSPI drivers, use the reset
>> acquire/release mechanism which ensure exclusive reset usage.
>>
>> This avoid to call reset_control_get/put() in OMM driver each time
>> we need to reset OSPI children and guarantee the reset line stays
>> deasserted.
>>
>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
>> ---
>>  drivers/spi/spi-stm32-ospi.c | 15 +++++++++------
>>  1 file changed, 9 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/spi/spi-stm32-ospi.c b/drivers/spi/spi-stm32-ospi.c
>> index d002b9c16714684e4e4623f9255a7f2660c46fd1..ef840f377459891b559be6d6c0435408fb58a1e9 100644
>> --- a/drivers/spi/spi-stm32-ospi.c
>> +++ b/drivers/spi/spi-stm32-ospi.c
>> @@ -804,7 +804,7 @@ static int stm32_ospi_get_resources(struct platform_device *pdev)
>>  		return ret;
>>  	}
>>  
>> -	ospi->rstc = devm_reset_control_array_get_exclusive(dev);
>> +	ospi->rstc = devm_reset_control_array_get_exclusive_released(dev);
>>  	if (IS_ERR(ospi->rstc))
>>  		return dev_err_probe(dev, PTR_ERR(ospi->rstc),
>>  				     "Can't get reset\n");
>> @@ -936,11 +936,14 @@ static int stm32_ospi_probe(struct platform_device *pdev)
>>  	if (ret < 0)
>>  		goto err_pm_enable;
>>  
>> -	if (ospi->rstc) {
>> -		reset_control_assert(ospi->rstc);
>> -		udelay(2);
>> -		reset_control_deassert(ospi->rstc);
>> -	}
>> +	ret = reset_control_acquire(ospi->rstc);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "Can not acquire reset %d\n", ret);
>> +
>> +	reset_control_assert(ospi->rstc);
>> +	udelay(2);
>> +	reset_control_deassert(ospi->rstc);
>> +	reset_control_release(ospi->rstc);
> 
> Could you keep the reset control (mostly) acquired from probe() to
> remove()? The reset control would have to be released/acquired in OSPI
> suspend/resume so that OMM can temporarily acquire control during OMM
> resume.

Ok

Thanks
Patrice

> 
> regards
> Philipp