linux-kernel - Re: [PATCH v2] w1: mxc_w1: Enable clock before calling clk_get

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Message-Id: <692971525777337@web22j.yandex.ru>
Date:   Tue, 08 May 2018 14:02:17 +0300
From:   Evgeniy Polyakov <zbr@...emap.net>
To:     Stefan Potyra <stefan.potyra@...ktrobit.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "ldv-project@...uxtesting.org" <ldv-project@...uxtesting.org>,
        "sil2review@...ts.osadl.org" <sil2review@...ts.osadl.org>
Subject: Re: [PATCH v2] w1: mxc_w1: Enable clock before calling clk_get_rate() on it

Hi Stefan

02.05.2018, 11:55, "Stefan Potyra" <stefan.potyra@...ktrobit.com>:
> According to the API, you may only call clk_get_rate() after actually
> enabling it.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Fixes: a5fd9139f74c ("w1: add 1-wire master driver for i.MX27 / i.MX31")
> Signed-off-by: Stefan Potyra <Stefan.Potyra@...ktrobit.com>

Looks good to me, thank you!
Greg, please pull it into your tree, this also sounds like stable material, is it?

Acked-by: Evgeniy Polyakov <zbr@...emap.net>

> ---
>  drivers/w1/masters/mxc_w1.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
> index 74f2e6e6202a..8851d441e5fd 100644
> --- a/drivers/w1/masters/mxc_w1.c
> +++ b/drivers/w1/masters/mxc_w1.c
> @@ -112,6 +112,10 @@ static int mxc_w1_probe(struct platform_device *pdev)
>          if (IS_ERR(mdev->clk))
>                  return PTR_ERR(mdev->clk);
>
> + err = clk_prepare_enable(mdev->clk);
> + if (err)
> + return err;
> +
>          clkrate = clk_get_rate(mdev->clk);
>          if (clkrate < 10000000)
>                  dev_warn(&pdev->dev,
> @@ -125,12 +129,10 @@ static int mxc_w1_probe(struct platform_device *pdev)
>
>          res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>          mdev->regs = devm_ioremap_resource(&pdev->dev, res);
> - if (IS_ERR(mdev->regs))
> - return PTR_ERR(mdev->regs);
> -
> - err = clk_prepare_enable(mdev->clk);
> - if (err)
> - return err;
> + if (IS_ERR(mdev->regs)) {
> + err = PTR_ERR(mdev->regs);
> + goto out_disable_clk;
> + }
>
>          /* Software reset 1-Wire module */
>          writeb(MXC_W1_RESET_RST, mdev->regs + MXC_W1_RESET);
> @@ -146,8 +148,12 @@ static int mxc_w1_probe(struct platform_device *pdev)
>
>          err = w1_add_master_device(&mdev->bus_master);
>          if (err)
> - clk_disable_unprepare(mdev->clk);
> + goto out_disable_clk;
>
> + return 0;
> +
> +out_disable_clk:
> + clk_disable_unprepare(mdev->clk);
>          return err;
>  }
>
> --
> 2.17.0