linux-kernel - Re: [PATCH v2 2/2] pinctrl: nuvoton: add NPCM7xx pinctrl and GPIO driver

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Message-ID: <CACRpkdbcqA4gBv7W2SNSFJRQ26GGCE315UsDDG9zr458GK709g@mail.gmail.com>
Date:   Sun, 29 Jul 2018 23:59:45 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     tmaimon77@...il.com
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, avifishman70@...il.com,
        Nancy Yuen <yuenn@...gle.com>,
        Brendan Higgins <brendanhiggins@...gle.com>,
        Patrick Venture <venture@...gle.com>,
        Joel Stanley <joel@....id.au>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        OpenBMC Maillist <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH v2 2/2] pinctrl: nuvoton: add NPCM7xx pinctrl and GPIO driver

On Thu, Jul 26, 2018 at 2:01 AM Tomer Maimon <tmaimon77@...il.com> wrote:

> I initialize bgpio as follow:
>
>                         ret = bgpio_init(&pctrl->gpio_bank[id].gc,
>                                          pctrl->dev, 4,
>                                          pctrl->gpio_bank[id].base +
>                                          NPCM7XX_GP_N_DIN,
>                                          pctrl->gpio_bank[id].base +
>                                          NPCM7XX_GP_N_DOUT,
>                                          NULL,
>                                          NULL,
>                                          pctrl->gpio_bank[id].base +
>                                          NPCM7XX_GP_N_IEM,
>                                          BGPIOF_READ_OUTPUT_REG_SET);

(...)
> The problem occur when reading the GPIO value from bgpio_get_set function,
> because the directions value are inverse it reading the wrong I/O registers
>
> For direction out it reading dat register (instead of set register)
>
> For direction in it calling set register (instead of dat register)

Hm I don't quite get it... sorry. Maybe if you show your fix and what
you expect to happen I can understand better?

Do you mean that because you write the inverse value to
IEM this happens, and the BGPIO code assumes that
you always write 1 to set a line as input and 0 to set it
as output?

I would say if this causes the problem we should just add
a new BGPIOF_INVERTED_REG_DIR with comment in
include/linux/gpio/driver.h and make the necessary fix to
respect this flag in the gpio-mmio.c core so it works right.

If you do this as a separate patch I would be grateful :)

Yours,
Linus Walleij