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

[Philipp Zabel <p.zabel@pengutronix.de>]

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