netdev - Re: [PATCH net-next] net: bcmgenet: Remove checks on clock handles

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Message-ID: <CAGXr9JEtRD0eY9aS1_M+cVYueoa8xnPBSwtCs1LEHyeyrDyLxA@mail.gmail.com>
Date:	Wed, 22 Jul 2015 16:52:00 -0700
From:	Petri Gynther <pgynther@...gle.com>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	netdev <netdev@...r.kernel.org>,
	David Miller <davem@...emloft.net>,
	Jaedon Shin <jaedon.shin@...il.com>
Subject: Re: [PATCH net-next] net: bcmgenet: Remove checks on clock handles

On Wed, Jul 22, 2015 at 3:11 PM, Florian Fainelli <f.fainelli@...il.com> wrote:
>
> Instead of multiplying the number of checks for IS_ERR(priv->clk),
> simply NULLify the 'struct clk' pointer which is something the Linux
> common clock framework perfectly deals with and does early return for
> each and every single clk_* API functions.
>
> Having every single function check for !IS_ERR(priv->clk) is both
> redundant and error prone, as it turns out, we were doing it for the
> main GENET clock: priv->clk, but not for the Wake-on-LAN or EEE clock,
> so let's just be consistent here.
>
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---
>  drivers/net/ethernet/broadcom/genet/bcmgenet.c | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> index 5bf7ce0ae221..133bb10fdd34 100644
> --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> @@ -2625,8 +2625,7 @@ static int bcmgenet_open(struct net_device *dev)
>         netif_dbg(priv, ifup, dev, "bcmgenet_open\n");
>
>         /* Turn on the clock */
> -       if (!IS_ERR(priv->clk))
> -               clk_prepare_enable(priv->clk);
> +       clk_prepare_enable(priv->clk);
>
>         /* If this is an internal GPHY, power it back on now, before UniMAC is
>          * brought out of reset as absolutely no UniMAC activity is allowed
> @@ -2703,8 +2702,7 @@ err_irq0:
>  err_fini_dma:
>         bcmgenet_fini_dma(priv);
>  err_clk_disable:
> -       if (!IS_ERR(priv->clk))
> -               clk_disable_unprepare(priv->clk);
> +       clk_disable_unprepare(priv->clk);
>         return ret;
>  }
>
> @@ -2761,8 +2759,7 @@ static int bcmgenet_close(struct net_device *dev)
>         if (priv->internal_phy)
>                 ret = bcmgenet_power_down(priv, GENET_POWER_PASSIVE);
>
> -       if (!IS_ERR(priv->clk))
> -               clk_disable_unprepare(priv->clk);
> +       clk_disable_unprepare(priv->clk);
>
>         return ret;
>  }
> @@ -3215,11 +3212,12 @@ static int bcmgenet_probe(struct platform_device *pdev)
>                 priv->version = pd->genet_version;
>
>         priv->clk = devm_clk_get(&priv->pdev->dev, "enet");
> -       if (IS_ERR(priv->clk))
> +       if (IS_ERR(priv->clk)) {
>                 dev_warn(&priv->pdev->dev, "failed to get enet clock\n");
> +               priv->clk = NULL;
> +       }

Wouldn't the above be a fatal error? If you can't get the enet main
clock, any point to go further in this code?

>
> -       if (!IS_ERR(priv->clk))
> -               clk_prepare_enable(priv->clk);
> +       clk_prepare_enable(priv->clk);
>
>         bcmgenet_set_hw_params(priv);
>
> @@ -3230,8 +3228,10 @@ static int bcmgenet_probe(struct platform_device *pdev)
>         INIT_WORK(&priv->bcmgenet_irq_work, bcmgenet_irq_task);
>
>         priv->clk_wol = devm_clk_get(&priv->pdev->dev, "enet-wol");
> -       if (IS_ERR(priv->clk_wol))
> +       if (IS_ERR(priv->clk_wol)) {
>                 dev_warn(&priv->pdev->dev, "failed to get enet-wol clock\n");
> +               priv->clk_wol = NULL;
> +       }
>
>         priv->clk_eee = devm_clk_get(&priv->pdev->dev, "enet-eee");
>         if (IS_ERR(priv->clk_eee)) {
> --
> 2.1.0
>

Looking at the rest of the code in bcmgenet_probe(), I still see:
        /* Turn off the main clock, WOL clock is handled separately */
        if (!IS_ERR(priv->clk))
                clk_disable_unprepare(priv->clk);

err_clk_disable:
        if (!IS_ERR(priv->clk))
                clk_disable_unprepare(priv->clk);

you probably want to convert those as well, right?
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