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

From: Viresh Kumar
Date: Thu Jan 10 2019 - 02:01:36 EST


On 08-01-19, 21:05, PaweÅ Chmiel 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: PaweÅ Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
> ---
> drivers/cpufreq/s5pv210-cpufreq.c | 33 +++++++++++++++++++------------
> 1 file changed, 20 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/cpufreq/s5pv210-cpufreq.c b/drivers/cpufreq/s5pv210-cpufreq.c
> index f51697f1e0b3..2d0e4dc7ede7 100644
> --- a/drivers/cpufreq/s5pv210-cpufreq.c
> +++ b/drivers/cpufreq/s5pv210-cpufreq.c
> @@ -594,6 +594,26 @@ 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 (PTR_ERR(arm_regulator) == -EPROBE_DEFER) {
> + pr_dbg("vddarm regulator not ready, defer\n");
> + return -EPROBE_DEFER;
> + } else if (IS_ERR(arm_regulator)) {
> + pr_err("failed to get regulator vddarm\n");
> + return PTR_ERR(arm_regulator);
> + }

The only difference between the two cases is pr_dbg vs pr_err, its
ugly that we have to add special code for that :(

Maybe write it as:

if (IS_ERR(arm_regulator)) {
if (PTR_ERR(arm_regulator) == -EPROBE_DEFER)
pr_dbg...
else
pr_err
return PTR_ERR(arm_regulator);
}

> +
> + int_regulator = regulator_get(NULL, "vddint");
> + if (PTR_ERR(int_regulator == -EPROBE_DEFER) {

Does this even compile ?

> + regulator_put(arm_regulator);
> + pr_dbg("vddint regulator not ready, defer\n");
> + return -EPROBE_DEFER;
> + } else if (IS_ERR(int_regulator)) {
> + regulator_put(arm_regulator);
> + pr_err("failed to get regulator vddint\n");
> + return PTR_ERR(int_regulator);
> + }
> +
> np = of_find_compatible_node(NULL, NULL, "samsung,s5pv210-clock");
> if (!np) {
> pr_err("%s: failed to find clock controller DT node\n",
> @@ -633,19 +653,6 @@ static int s5pv210_cpufreq_probe(struct platform_device *pdev)
> }
> }
>
> - arm_regulator = regulator_get(NULL, "vddarm");
> - if (IS_ERR(arm_regulator)) {
> - pr_err("failed to get regulator vddarm\n");
> - return PTR_ERR(arm_regulator);
> - }
> -
> - int_regulator = regulator_get(NULL, "vddint");
> - if (IS_ERR(int_regulator)) {
> - pr_err("failed to get regulator vddint\n");
> - regulator_put(arm_regulator);
> - return PTR_ERR(int_regulator);
> - }
> -
> register_reboot_notifier(&s5pv210_cpufreq_reboot_notifier);
>
> return cpufreq_register_driver(&s5pv210_driver);
> --
> 2.17.1

--
viresh