Re: [PATCH 1/2] watchdog: s3c2410_wdt: Use Use devm_clk_get[_optional]_enabled() helpers

[Guenter Roeck]

On 3/4/23 13:46, Christophe JAILLET wrote:
> Le 04/03/2023 à 17:56, Guenter Roeck a écrit :
> > The devm_clk_get[_optional]_enabled() helpers:
> >      - call devm_clk_get[_optional]()
> >      - call clk_prepare_enable() and register what is needed in order to
> >        call clk_disable_unprepare() when needed, as a managed resource.
> >
> > This simplifies the code and avoids the calls to clk_disable_unprepare().
> >
> > While at it, use dev_err_probe consistently, and use its return value
> > to return the error code.
> >
> > Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >   drivers/watchdog/s3c2410_wdt.c | 45 +++++++---------------------------
> >   1 file changed, 9 insertions(+), 36 deletions(-)
> >
> > diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> > index 200ba236a72e..a1fcb79b0b7c 100644
> > --- a/drivers/watchdog/s3c2410_wdt.c
> > +++ b/drivers/watchdog/s3c2410_wdt.c
> > @@ -661,35 +661,17 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
> >       if (IS_ERR(wdt->reg_base))
> >           return PTR_ERR(wdt->reg_base);
> > -    wdt->bus_clk = devm_clk_get(dev, "watchdog");
> > -    if (IS_ERR(wdt->bus_clk)) {
> > -        dev_err(dev, "failed to find bus clock\n");
> > -        return PTR_ERR(wdt->bus_clk);
> > -    }
> > -
> > -    ret = clk_prepare_enable(wdt->bus_clk);
> > -    if (ret < 0) {
> > -        dev_err(dev, "failed to enable bus clock\n");
> > -        return ret;
> > -    }
> > +    wdt->bus_clk = devm_clk_get_enabled(dev, "watchdog");
> > +    if (IS_ERR(wdt->bus_clk))
> > +        return dev_err_probe(dev, PTR_ERR(wdt->bus_clk), "failed to get bus clock\n");
> >       /*
> >        * "watchdog_src" clock is optional; if it's not present -- just skip it
> >        * and use "watchdog" clock as both bus and source clock.
> >        */
> > -    wdt->src_clk = devm_clk_get_optional(dev, "watchdog_src");
> > -    if (IS_ERR(wdt->src_clk)) {
> > -        dev_err_probe(dev, PTR_ERR(wdt->src_clk),
> > -                  "failed to get source clock\n");
> > -        ret = PTR_ERR(wdt->src_clk);
> > -        goto err_bus_clk;
> > -    }
> > -
> > -    ret = clk_prepare_enable(wdt->src_clk);
> > -    if (ret) {
> > -        dev_err(dev, "failed to enable source clock\n");
> > -        goto err_bus_clk;
> > -    }
> > +    wdt->src_clk = devm_clk_get_optional_enabled(dev, "watchdog_src");
> > +    if (IS_ERR(wdt->src_clk))
> > +        return dev_err_probe(dev, PTR_ERR(wdt->src_clk), "failed to get source clock\n");
> >       wdt->wdt_device.min_timeout = 1;
> >       wdt->wdt_device.max_timeout = s3c2410wdt_max_timeout(wdt);
> > @@ -710,7 +692,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
> >                    S3C2410_WATCHDOG_DEFAULT_TIME);
> >           } else {
> >               dev_err(dev, "failed to use default timeout\n");
> > -            goto err_src_clk;
> > +            return ret;
>
> Hi,
>
> Nit: this also could be "return dev_err_probe()"
>
> >           }
> >       }
> > @@ -718,7 +700,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
> >                      pdev->name, pdev);
> >       if (ret != 0) {
> >           dev_err(dev, "failed to install irq (%d)\n", ret);
> > -        goto err_src_clk;
> > +        return ret;
>
> Nit: this also could be "return dev_err_probe()"

The primary reason to call dev_err_probe() is that the error may be
-EPROBE_DEFER, in which case the error message is suppressed.
That is not the case for those two functions; they never return
-EPROBE_DEFER. Calling dev_err_probe() would give the false impression
that the functions _might_ return -EPROBE_DEFER.

Thanks,
Guenter