linux-kernel - Re: [PATCH v2 RESEND] PCI: imx6: Replace legacy gpio interface for gpiod interface

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Message-ID: <CAH7FV3nyyLndqTdJYN8HDxU4C7pW0-DLu6ZSOLof2=tEEHbHxQ@mail.gmail.com>
Date:   Mon, 1 Nov 2021 11:44:45 -0300
From:   Maíra Canal <maira.canal@....br>
To:     Lucas Stach <l.stach@...gutronix.de>
Cc:     hongxing.zhu@....com, lorenzo.pieralisi@....com, robh@...nel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Bjorn Helgaas <helgaas@...nel.org>, shawnguo@...nel.org,
        s.hauer@...gutronix.de, kernel@...gutronix.de, linux-imx@....com,
        linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 RESEND] PCI: imx6: Replace legacy gpio interface for
 gpiod interface

?
> >       /* Some boards don't have PCIe reset GPIO. */
> > -     if (gpio_is_valid(imx6_pcie->reset_gpio)) {
> > -             gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > +     if (imx6_pcie->reset_gpio) {
> > +             gpiod_set_value_cansleep(imx6_pcie->reset_gpio,
> >                                       imx6_pcie->gpio_active_high);
> >               msleep(100);
> > -             gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > +             gpiod_set_value_cansleep(imx6_pcie->reset_gpio,
> >                                       !imx6_pcie->gpio_active_high);
>
> I don't think this is correct. gpiod_set_value sets the logical line
> state, so if the GPIO is specified as active-low in the DT, the real
> line state will be negated. The only reason why the reset-gpio-active-
> high property even exists is that old DTs might specify the wrong GPIO
> polarity in the reset-gpio DT description. I think you need to use to
> gpiod_set_raw_value API here to get the expected real line state even
> with a broken DT description.
>
> Regards,
> Lucas
>

I'm a beginner in kernel development, so I'm sorry for the question.
If I change gpiod_set_value_cansleep for gpiod_set_raw_value, wouldn't
I change the behavior of the driver? I replaced
gpio_set_value_cansleep for gpiod_set_value_cansleep because they have
the same behavior and I didn't change the logic states. Thank you for
the feedback!

Regards,
Maíra