linux-kernel - Re: [PATCH v2] watchdog: of_xilinx_wdt: Use devm_clk_get

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Date:   Mon, 2 Jan 2023 11:54:52 +0100
From:   Michal Simek <michal.simek@....com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Michal Simek <michal.simek@...inx.com>,
        "Goud, Srinivas" <srinivas.goud@....com>,
        "Neeli, Srinivas" <srinivas.neeli@....com>
CC:     <linux-kernel@...r.kernel.org>, <kernel-janitors@...r.kernel.org>,
        <linux-watchdog@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2] watchdog: of_xilinx_wdt: Use devm_clk_get_enabled()
 helper

++

On 12/31/22 13:57, Christophe JAILLET wrote:
> The devm_clk_get_enabled() helper:
>     - calls devm_clk_get()
>     - calls clk_prepare_enable() and registers what is needed in order to
>       call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code and avoids the need of a dedicated function used
> with devm_add_action_or_reset().
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> V2: remove xwdt_clk_disable_unprepare() as-well
> 
> Note that the order of operations is slightly modified by this patch. The
> clk is now prepare_enable()'ed before calling clk_get_rate().
> ---
>   drivers/watchdog/of_xilinx_wdt.c | 16 +---------------
>   1 file changed, 1 insertion(+), 15 deletions(-)
> 
> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
> index 3318544366b8..2a079ca04aa3 100644
> --- a/drivers/watchdog/of_xilinx_wdt.c
> +++ b/drivers/watchdog/of_xilinx_wdt.c
> @@ -154,11 +154,6 @@ static u32 xwdt_selftest(struct xwdt_device *xdev)
>                  return XWT_TIMER_FAILED;
>   }
> 
> -static void xwdt_clk_disable_unprepare(void *data)
> -{
> -       clk_disable_unprepare(data);
> -}
> -
>   static int xwdt_probe(struct platform_device *pdev)
>   {
>          struct device *dev = &pdev->dev;
> @@ -193,7 +188,7 @@ static int xwdt_probe(struct platform_device *pdev)
> 
>          watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
> 
> -       xdev->clk = devm_clk_get(dev, NULL);
> +       xdev->clk = devm_clk_get_enabled(dev, NULL);
>          if (IS_ERR(xdev->clk)) {
>                  if (PTR_ERR(xdev->clk) != -ENOENT)
>                          return PTR_ERR(xdev->clk);
> @@ -211,15 +206,6 @@ static int xwdt_probe(struct platform_device *pdev)
>                                   "The watchdog clock freq cannot be obtained\n");
>          } else {
>                  pfreq = clk_get_rate(xdev->clk);
> -               rc = clk_prepare_enable(xdev->clk);
> -               if (rc) {
> -                       dev_err(dev, "unable to enable clock\n");
> -                       return rc;
> -               }
> -               rc = devm_add_action_or_reset(dev, xwdt_clk_disable_unprepare,
> -                                             xdev->clk);
> -               if (rc)
> -                       return rc;
>          }
> 
>          /*
> --
> 2.34.1
> 

Srinivas: Please retest but it looks good to me.

Acked-by: Michal Simek <michal.simek@....com>

Thanks,
Michal