linux-kernel - Re: [PATCH v2] phy: renesas: rcar-gen3-usb2: fix imbalance powered flag

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Date:   Fri, 7 Jun 2019 15:23:07 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH v2] phy: renesas: rcar-gen3-usb2: fix imbalance powered flag

Hi Shimoda-san,

Thanks for the update!

On Fri, Jun 7, 2019 at 12:07 PM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@...esas.com> wrote:
> The powered flag should be set for any other phys anyway. Also
> the flag should be locked by the channel. Otherwise, after we have
> revised the device tree for the usb phy, the following warning
> happened during a second system suspend. And if the driver doesn't
> lock the flag, enabling the regulator is possible to be imbalance

I think it reads better as:

..., an imbalance is possible when enabling the regulator ...

> during system resume. So, this patch fixes the issues.

> --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
> +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c

> @@ -106,6 +107,7 @@ struct rcar_gen3_chan {
>         struct rcar_gen3_phy rphys[NUM_OF_PHYS];
>         struct regulator *vbus;
>         struct work_struct work;
> +       struct mutex lock;

It is always a good idea to document what is protected by the mutex:

        struct mutex lock;    /* protects rphys[...].powered */

Checkpatch does have a check for this, but unfortunately it is enabled for
drivers/net/, net/, and drivers/staging/ only:

    CHECK: struct mutex definition without comment

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

and the imbalance is gone:
Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>


Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds