netdev - Re: [PATCH] can: rcar_can: Fix suspend/resume

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Date:   Tue, 21 Sep 2021 12:38:13 +0200 (CEST)
From:   Ulrich Hecht <uli@...nd.eu>
To:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        wg@...ndegger.com, mkl@...gutronix.de
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Ayumi Nakamichi <ayumi.nakamichi.kf@...esas.com>
Subject: Re: [PATCH] can: rcar_can: Fix suspend/resume


> On 09/21/2021 7:19 AM Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com> wrote:
> 
>  
> If the driver was not opened, rcar_can_suspend() should not call
> clk_disable() because the clock was not enabled.
> 
> Fixes: fd1159318e55 ("can: add Renesas R-Car CAN driver")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> Tested-by: Ayumi Nakamichi <ayumi.nakamichi.kf@...esas.com>
> ---
>  drivers/net/can/rcar/rcar_can.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/can/rcar/rcar_can.c b/drivers/net/can/rcar/rcar_can.c
> index 00e4533c8bdd..6b4eefb03044 100644
> --- a/drivers/net/can/rcar/rcar_can.c
> +++ b/drivers/net/can/rcar/rcar_can.c
> @@ -846,10 +846,12 @@ static int __maybe_unused rcar_can_suspend(struct device *dev)
>  	struct rcar_can_priv *priv = netdev_priv(ndev);
>  	u16 ctlr;
>  
> -	if (netif_running(ndev)) {
> -		netif_stop_queue(ndev);
> -		netif_device_detach(ndev);
> -	}
> +	if (!netif_running(ndev))
> +		return 0;
> +
> +	netif_stop_queue(ndev);
> +	netif_device_detach(ndev);
> +
>  	ctlr = readw(&priv->regs->ctlr);
>  	ctlr |= RCAR_CAN_CTLR_CANM_HALT;
>  	writew(ctlr, &priv->regs->ctlr);
> @@ -858,6 +860,7 @@ static int __maybe_unused rcar_can_suspend(struct device *dev)
>  	priv->can.state = CAN_STATE_SLEEPING;
>  
>  	clk_disable(priv->clk);
> +
>  	return 0;
>  }
>  
> @@ -868,6 +871,9 @@ static int __maybe_unused rcar_can_resume(struct device *dev)
>  	u16 ctlr;
>  	int err;
>  
> +	if (!netif_running(ndev))
> +		return 0;
> +
>  	err = clk_enable(priv->clk);
>  	if (err) {
>  		netdev_err(ndev, "clk_enable() failed, error %d\n", err);
> @@ -881,10 +887,9 @@ static int __maybe_unused rcar_can_resume(struct device *dev)
>  	writew(ctlr, &priv->regs->ctlr);
>  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
>  
> -	if (netif_running(ndev)) {
> -		netif_device_attach(ndev);
> -		netif_start_queue(ndev);
> -	}
> +	netif_device_attach(ndev);
> +	netif_start_queue(ndev);
> +
>  	return 0;
>  }
>  
> -- 
> 2.25.1

Reviewed-by: Ulrich Hecht <uli+renesas@...nd.eu>

CU
Uli