linux-kernel - Re: [PATCH v7] regulator: fixed: Convert to use GPIO descriptor only

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Date:   Mon, 1 Oct 2018 17:37:02 -0300
From:   Fabio Estevam <festevam@...il.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Leonard Crestez <leonard.crestez@....com>,
        John Stultz <john.stultz@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Fugang Duan <fugang.duan@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Shawn Guo <shawnguo@...nel.org>,
        Yongcai Huang <anson.huang@....com>,
        Tony Lindgren <tony@...mide.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>, jmkrzyszt@...il.com
Subject: Re: [PATCH v7] regulator: fixed: Convert to use GPIO descriptor only

Hi Linus,

On Mon, Oct 1, 2018 at 5:17 PM Linus Walleij <linus.walleij@...aro.org> wrote:

> > reg_enet_3v3: regulator-enet-3v3 {
> >         compatible = "regulator-fixed";
> >         pinctrl-names = "default";
> >         pinctrl-0 = <&pinctrl_enet_3v3>;
> >         regulator-name = "enet_3v3";
> >         regulator-min-microvolt = <3300000>;
> >         regulator-max-microvolt = <3300000>;
> >         gpios = <&gpio2 6 GPIO_ACTIVE_LOW>;
> > };
>
> This is a bit odd actually, the GPIO_ACTIVE_LOW flag will
> be ignored as you see:

Yes, the flag will be ignored by the regulator driver, but the dts
description is correct: it is an active low GPIO that turns on the
reg_enet_3v3 regulator.

The 'enable-active-high' flag needs to be passed to indicate an active
high polarity.

> > [    0.153171] reg_fixed_voltage_probe(179): regulator-enet-3v3 call gpiod_get_optional gflags=0x7 ena_gpio_invert
> > [    0.153218] regulator-enet-3v3 GPIO handle specifies active low - ignored
> > [    0.153233] of_gpio_flags_quirks(83): regulator-enet-3v3 set active low because !enable-active-high
>
> Because regulators don't specify active high/low in the second
> cell because of legacy bindings.
>
> So this should not be in the device tree anyway, it should be
> GPIO_ACTIVE_HIGH or just 0.

Then it would provide a wrong description that does not describe the reality.