linux-kernel - Re: [PATCH] fpga altera-hps2fpga: disable/unprepare clock on error in alt_fpga_bridge

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Message-ID: <CANk1AXQOH+6sZ-JHuwXviPw6--Qpa4C8xkHg3wu5-1e4ABgRHg@mail.gmail.com>
Date:   Tue, 11 Apr 2017 09:53:38 -0500
From:   Alan Tull <atull@...nel.org>
To:     Tobias Klauser <tklauser@...tanz.ch>
Cc:     Moritz Fischer <moritz.fischer@...us.com>,
        linux-fpga@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] fpga altera-hps2fpga: disable/unprepare clock on error in alt_fpga_bridge_probe()

On Tue, Apr 11, 2017 at 4:22 AM, Tobias Klauser <tklauser@...tanz.ch> wrote:

Hi Tobias,

Thanks!

> If either _alt_hps2fpga_enable_set() or fpga_bridge_register() fail in
> alt_fpga_bridge_probe(), the clock remains enabled and prepared. Also,
> in the error path for _alt_hps2fpga_enable_set() a call to
> fpga_bridge_unregister() is made even though the bridge was not
> registered yet.
>
> Remove the unnecessary call to fpga_bridge_unregister() and call
> clk_disable_unprepare() in both error paths in order to make sure the
> clock gets properly disabled and unprepared.
>
> Signed-off-by: Tobias Klauser <tklauser@...tanz.ch>

Signed-off-by: Alan Tull <atull@...nel.org>

> ---
>  drivers/fpga/altera-hps2fpga.c | 15 +++++++++------
>  1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c
> index 4b354c79be31..3066b805f2d0 100644
> --- a/drivers/fpga/altera-hps2fpga.c
> +++ b/drivers/fpga/altera-hps2fpga.c
> @@ -181,15 +181,18 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
>                                  (enable ? "enabling" : "disabling"));
>
>                         ret = _alt_hps2fpga_enable_set(priv, enable);
> -                       if (ret) {
> -                               fpga_bridge_unregister(&pdev->dev);
> -                               return ret;
> -                       }
> +                       if (ret)
> +                               goto err;
>                 }
>         }
>
> -       return fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
> -                                   priv);
> +       ret = fpga_bridge_register(dev, priv->name, &altera_hps2fpga_br_ops,
> +                                  priv);
> +err:
> +       if (ret)
> +               clk_disable_unprepare(priv->clk);
> +
> +       return ret;
>  }
>
>  static int alt_fpga_bridge_remove(struct platform_device *pdev)
> --
> 2.12.2
>
>