linux-kernel - Re: [PATCH 07/10] watchdog: xilinx: Fix OF binding

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Message-ID: <CAL_JsqJ+Dc9PFVYcxHvLiG9unKQX-kEc1fsYsieyTjf-AN3j=A@mail.gmail.com>
Date:	Fri, 31 Jan 2014 11:33:50 -0600
From:	Rob Herring <robherring2@...il.com>
To:	Michal Simek <michal.simek@...inx.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Michal Simek <monstr@...str.eu>,
	Wim Van Sebroeck <wim@...ana.be>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	linux-watchdog@...r.kernel.org,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 07/10] watchdog: xilinx: Fix OF binding

On Fri, Jan 31, 2014 at 8:18 AM, Michal Simek <michal.simek@...inx.com> wrote:
> Use of_property_read_u32 functions to clean OF probing.

The subject is a bit misleading as this doesn't really fix anything.

>
> Signed-off-by: Michal Simek <michal.simek@...inx.com>
> ---
>
>  drivers/watchdog/of_xilinx_wdt.c | 25 ++++++++++---------------
>  1 file changed, 10 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
> index c229cc4..475440a6 100644
> --- a/drivers/watchdog/of_xilinx_wdt.c
> +++ b/drivers/watchdog/of_xilinx_wdt.c
> @@ -147,8 +147,7 @@ static u32 xwdt_selftest(struct xwdt_device *xdev)
>  static int xwdt_probe(struct platform_device *pdev)
>  {
>         int rc;
> -       u32 *tmptr;
> -       u32 *pfreq;
> +       u32 pfreq, enable_once;
>         struct resource *res;
>         struct xwdt_device *xdev;
>         bool no_timeout = false;
> @@ -168,28 +167,24 @@ static int xwdt_probe(struct platform_device *pdev)
>         if (IS_ERR(xdev->base))
>                 return PTR_ERR(xdev->base);
>
> -       pfreq = (u32 *)of_get_property(pdev->dev.of_node,
> -                                       "clock-frequency", NULL);
> -
> -       if (pfreq == NULL) {
> +       rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency", &pfreq);
> +       if (rc) {
>                 dev_warn(&pdev->dev,
>                          "The watchdog clock frequency cannot be obtained\n");
>                 no_timeout = true;

You can kill this...

>         }
>
> -       tmptr = (u32 *)of_get_property(pdev->dev.of_node,
> -                                       "xlnx,wdt-interval", NULL);
> -       if (tmptr == NULL) {
> +       rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
> +                                 &xdev->wdt_interval);
> +       if (rc) {
>                 dev_warn(&pdev->dev,
>                          "Parameter \"xlnx,wdt-interval\" not found\n");
>                 no_timeout = true;

and this...

> -       } else {
> -               xdev->wdt_interval = *tmptr;
>         }
>
> -       tmptr = (u32 *)of_get_property(pdev->dev.of_node,
> -                                       "xlnx,wdt-enable-once", NULL);
> -       if (tmptr == NULL) {
> +       rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
> +                                 &enable_once);
> +       if (!rc && enable_once) {
>                 dev_warn(&pdev->dev,
>                          "Parameter \"xlnx,wdt-enable-once\" not found\n");
>                 watchdog_set_nowayout(xilinx_wdt_wdd, true);
> @@ -201,7 +196,7 @@ static int xwdt_probe(struct platform_device *pdev)
>   */
>         if (!no_timeout)

and use "if (pfreq && xdev->wdt_interval)" if you initialize pfreq to 0.

>                 xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
> -                                         *pfreq);
> +                                         pfreq);

Is the wdog really usable if the timeout properties are missing? Seems
like you should fail to probe rather than warn.

Rob
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