linux-kernel - Re: [PATCH 00/13 v2] Regulator ena

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Date:   Tue, 4 Dec 2018 10:31:19 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 00/13 v2] Regulator ena_gpiod fixups

Hi Marek,

first, thanks a *lot* for testing this, it is is much, much appreciated!

On Mon, Dec 3, 2018 at 3:35 PM Marek Szyprowski
<m.szyprowski@...sung.com> wrote:

> The idea is good imho, but it looks that there are some missing cases in
> the code. Here are some logs from the boards I have access to:

OK let's fix this!

> Artik5 evaluation board (arch/arm/boot/dts/exynos3250-artik5-eval.dtb):
> s2mps11-pmic s2mps14-regulator: Failed to get control GPIO for 11/LDO12

Question: this is supposed to fail, right? It is something
like a probe deferral or nonexisting GPIO controller?

I look in the upstream tree:
arch/arm/boot/dts/exynos3250-artik5.dtsi
where s2mps14 is defined:

ldo12_reg: LDO12 {
    /* VDD72 ~ VDD73 */
    regulator-name = "VLDO12_2.8V";
    regulator-min-microvolt = <2800000>;
    regulator-max-microvolt = <2800000>;
    samsung,ext-control-gpios = <&gpk0 2 GPIO_ACTIVE_HIGH>;
};

I didn't really change anything about this, so this missing
GPIO descriptor looks worrysome.

Anyways what happens is this:

gpio[reg] = devm_gpiod_get_from_of_node(...)
if (IS_ERR(gpio[reg]))
(...)
            continue;

So this IS_ERR descriptor is left around. So we should
probably handle erronoeus or NULL descriptors in
gpiod_unhinge().

If you add this on top, does it start working?

diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
index 5864e758d7f2..e35751bf0ea8 100644
--- a/drivers/gpio/gpiolib-devres.c
+++ b/drivers/gpio/gpiolib-devres.c
@@ -332,6 +332,8 @@ EXPORT_SYMBOL(devm_gpiod_put);

 void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc)
 {
+       if (IS_ERR_OR_NULL(desc))
+               return;
        WARN_ON(devres_destroy(dev, devm_gpiod_release,
                               devm_gpiod_match, desc));
 }

Yours,
Linus Walleij