linux-kernel - Re: [PATCH v7 14/33] crypto: rockchip: handle reset also in PM

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Date:   Mon, 20 Jun 2022 12:04:24 +0100
From:   John Keeping <john@...anate.com>
To:     Corentin Labbe <clabbe@...libre.com>
Cc:     heiko@...ech.de, ardb@...nel.org, herbert@...dor.apana.org.au,
        krzysztof.kozlowski+dt@...aro.org, robh+dt@...nel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org
Subject: Re: [PATCH v7 14/33] crypto: rockchip: handle reset also in PM

On Sun, May 08, 2022 at 06:59:38PM +0000, Corentin Labbe wrote:
> reset could be handled by PM functions.

Is there any further rationale for this?

After this change there is no longer a guaranteed reset pulse on probe
since the reset control may already be de-asserted.  This is normally
the most important case for a reset as it's the only time when the state
of the hardware is unknown.

The original use of devm_add_action_or_reset() seems a bit weird already
since there doesn't seem to be any need to assert reset when the driver
is unloaded.

> Signed-off-by: Corentin Labbe <clabbe@...libre.com>
> ---
>  drivers/crypto/rockchip/rk3288_crypto.c | 19 ++++---------------
>  1 file changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/crypto/rockchip/rk3288_crypto.c b/drivers/crypto/rockchip/rk3288_crypto.c
> index d9258b9e71b3..a11a92e1f3fd 100644
> --- a/drivers/crypto/rockchip/rk3288_crypto.c
> +++ b/drivers/crypto/rockchip/rk3288_crypto.c
> @@ -73,6 +73,8 @@ static int rk_crypto_pm_suspend(struct device *dev)
>  {
>  	struct rk_crypto_info *rkdev = dev_get_drvdata(dev);
>  
> +	reset_control_assert(rkdev->rst);
> +
>  	rk_crypto_disable_clk(rkdev);
>  	return 0;
>  }
> @@ -81,6 +83,8 @@ static int rk_crypto_pm_resume(struct device *dev)
>  {
>  	struct rk_crypto_info *rkdev = dev_get_drvdata(dev);
>  
> +	reset_control_deassert(rkdev->rst);
> +
>  	return rk_crypto_enable_clk(rkdev);
>  }
>  
> @@ -222,13 +226,6 @@ static void rk_crypto_unregister(void)
>  	}
>  }
>  
> -static void rk_crypto_action(void *data)
> -{
> -	struct rk_crypto_info *crypto_info = data;
> -
> -	reset_control_assert(crypto_info->rst);
> -}
> -
>  static const struct of_device_id crypto_of_id_table[] = {
>  	{ .compatible = "rockchip,rk3288-crypto" },
>  	{}
> @@ -254,14 +251,6 @@ static int rk_crypto_probe(struct platform_device *pdev)
>  		goto err_crypto;
>  	}
>  
> -	reset_control_assert(crypto_info->rst);
> -	usleep_range(10, 20);
> -	reset_control_deassert(crypto_info->rst);
> -
> -	err = devm_add_action_or_reset(dev, rk_crypto_action, crypto_info);
> -	if (err)
> -		goto err_crypto;
> -
>  	crypto_info->reg = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(crypto_info->reg)) {
>  		err = PTR_ERR(crypto_info->reg);
> -- 
> 2.35.1