linux-kernel - Re: [PATCH v2 3/4] cpufreq: s5pv210: Defer probe if getting regulators fail

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Date:   Fri, 11 Jan 2019 10:46:26 +0100
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
Cc:     kgene@...nel.org, robh+dt@...nel.org, mark.rutland@....com,
        linux@...linux.org.uk, viresh.kumar@...aro.org, rjw@...ysocki.net,
        linux-arm-kernel@...ts.infradead.org,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 3/4] cpufreq: s5pv210: Defer probe if getting
 regulators fail

On Thu, 10 Jan 2019 at 21:53, Paweł Chmiel
<pawel.mikolaj.chmiel@...il.com> wrote:
>
> There is possibility, that when probing driver, regulators are not yet
> initialized. In this case we should return EPROBE_DEFER and wait till
> they're initialized, since they're required currently for cpufreq driver
> to work. Also move regulator initialization code at beginning of probe,
> so we can defer as fast as posibble.
>
> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@...il.com>
> ---
> Changes from v1:
>   - Fix compilation error
>   - Reorganize code so it's smaller
> ---
>  drivers/cpufreq/s5pv210-cpufreq.c | 32 ++++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
> index f51697f1e0b3..6df95941ba96 100644
> --- a/drivers/cpufreq/s5pv210-cpufreq.c
> +++ b/drivers/cpufreq/s5pv210-cpufreq.c
> @@ -594,6 +594,25 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
>          * this whole driver as soon as S5PV210 gets migrated to use
>          * cpufreq-dt driver.
>          */
> +       arm_regulator = regulator_get(NULL, "vddarm");
> +       if (IS_ERR(arm_regulator)) {
> +               if (PTR_ERR(arm_regulator) == -EPROBE_DEFER)
> +                       pr_debug("vddarm regulator not ready, defer\n");
> +               else
> +                       pr_err("failed to get regulator vddarm\n");
> +               return PTR_ERR(arm_regulator);
> +       }
> +
> +       int_regulator = regulator_get(NULL, "vddint");
> +       if (IS_ERR(int_regulator)) {
> +               if (PTR_ERR(int_regulator) == -EPROBE_DEFER)
> +                       pr_debug("vddint regulator not ready, defer\n");
> +               else
> +                       pr_err("failed to get regulator vddint\n");
> +               regulator_put(arm_regulator);
> +               return PTR_ERR(int_regulator);
> +       }
> +

Error paths are now not correct. You should put the regulators when
returning later. The previous code had these error paths wrong as well
- not iounmapping - but if you move things around, maybe let's fix
things.

Best regards,
Krzysztof