linux-kernel - Re: [PATCH net-next v3 7/8] net: ethernet: fs_enet: simplify clock handling with devm accessors

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Message-ID: <4e4defa9-ef2f-4ff1-95ca-6627c24db20c@wanadoo.fr>
Date: Fri, 13 Sep 2024 22:24:28 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Maxime Chevallier <maxime.chevallier@...tlin.com>, davem@...emloft.net,
 Pantelis Antoniou <pantelis.antoniou@...il.com>, Andrew Lunn
 <andrew@...n.ch>, Jakub Kicinski <kuba@...nel.org>,
 Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
 Russell King <linux@...linux.org.uk>,
 Christophe Leroy <christophe.leroy@...roup.eu>,
 Florian Fainelli <f.fainelli@...il.com>,
 Heiner Kallweit <hkallweit1@...il.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 thomas.petazzoni@...tlin.com, Herve Codina <herve.codina@...tlin.com>,
 linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH net-next v3 7/8] net: ethernet: fs_enet: simplify clock
 handling with devm accessors

Le 04/09/2024 à 19:18, Maxime Chevallier a écrit :
> devm_clock_get_enabled() can be used to simplify clock handling for the
> PER register clock.
> 
> Reviewed-by: Andrew Lunn <andrew@...n.ch>
> Signed-off-by: Maxime Chevallier <maxime.chevallier@...tlin.com>
> ---
>   .../ethernet/freescale/fs_enet/fs_enet-main.c    | 16 ++++------------
>   drivers/net/ethernet/freescale/fs_enet/fs_enet.h |  2 --
>   2 files changed, 4 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
> index c96a6b9e1445..ec43b71c0eba 100644
> --- a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
> +++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
> @@ -900,14 +900,9 @@ static int fs_enet_probe(struct platform_device *ofdev)
>   	 * but require enable to succeed when a clock was specified/found,
>   	 * keep a reference to the clock upon successful acquisition
>   	 */
> -	clk = devm_clk_get(&ofdev->dev, "per");
> -	if (!IS_ERR(clk)) {
> -		ret = clk_prepare_enable(clk);
> -		if (ret)
> -			goto out_deregister_fixed_link;
> -
> -		fpi->clk_per = clk;
> -	}
> +	clk = devm_clk_get_enabled(&ofdev->dev, "per");
> +	if (IS_ERR(clk))
> +		goto out_deregister_fixed_link;

Hi,

I don't know if this can lead to the same issue, but a similar change 
broke a use case in another driver. See the discussion at[1].

It ended to using devm_clk_get_optional_enabled() to keep the same 
behavior as before.

CJ

[1]: 
https://lore.kernel.org/all/20240912104630.1868285-2-ardb+git@google.com/

>   
>   	privsize = sizeof(*fep) +
>   		   sizeof(struct sk_buff **) *
> @@ -917,7 +912,7 @@ static int fs_enet_probe(struct platform_device *ofdev)
>   	ndev = alloc_etherdev(privsize);
>   	if (!ndev) {
>   		ret = -ENOMEM;
> -		goto out_put;
> +		goto out_deregister_fixed_link;
>   	}
>   
>   	SET_NETDEV_DEV(ndev, &ofdev->dev);
> @@ -979,8 +974,6 @@ static int fs_enet_probe(struct platform_device *ofdev)
>   	fep->ops->cleanup_data(ndev);
>   out_free_dev:
>   	free_netdev(ndev);
> -out_put:
> -	clk_disable_unprepare(fpi->clk_per);
>   out_deregister_fixed_link:
>   	of_node_put(fpi->phy_node);
>   	if (of_phy_is_fixed_link(ofdev->dev.of_node))
> @@ -1001,7 +994,6 @@ static void fs_enet_remove(struct platform_device *ofdev)
>   	fep->ops->cleanup_data(ndev);
>   	dev_set_drvdata(fep->dev, NULL);
>   	of_node_put(fep->fpi->phy_node);
> -	clk_disable_unprepare(fep->fpi->clk_per);
>   	if (of_phy_is_fixed_link(ofdev->dev.of_node))
>   		of_phy_deregister_fixed_link(ofdev->dev.of_node);
>   	free_netdev(ndev);
> diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet.h b/drivers/net/ethernet/freescale/fs_enet/fs_enet.h
> index ee49749a3202..6ebb1b4404c7 100644
> --- a/drivers/net/ethernet/freescale/fs_enet/fs_enet.h
> +++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet.h
> @@ -119,8 +119,6 @@ struct fs_platform_info {
>   	int napi_weight;	/* NAPI weight			*/
>   
>   	int use_rmii;		/* use RMII mode		*/
> -
> -	struct clk *clk_per;	/* 'per' clock for register access */
>   };
>   
>   struct fs_enet_private {