linux-kernel - Re: [PATCH v3 1/3] gpio: nct6116d: add new driver for several Nuvoton super io chips

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Date:   Tue, 12 Jul 2022 16:49:13 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Henning Schild <henning.schild@...mens.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        Tasanakorn Phaipool <tasanakorn@...il.com>,
        Sheng-Yuan Huang <syhuang3@...oton.com>,
        Kuan-Wei Ho <cwho@...oton.com>
Subject: Re: [PATCH v3 1/3] gpio: nct6116d: add new driver for several Nuvoton
 super io chips

On Tue, Jul 12, 2022 at 4:32 PM Henning Schild
<henning.schild@...mens.com> wrote:
>
> This patch adds gpio support for several Nuvoton NCTXXX chips. These
> Super-I/O chips offer multiple functions of which several already have
> drivers in the kernel, i.e. hwmon and watchdog.

...

> +#include <linux/gpio/driver.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>

+ bits.h
+ types.h.

...

> +static inline int superio_enter(int base)
> +{
> +       /* Don't step on other drivers' I/O space by accident. */
> +       if (!request_muxed_region(base, 2, KBUILD_MODNAME)) {
> +               pr_err("I/O address 0x%04x already in use\n", base);
> +               return -EBUSY;
> +       }
> +
> +       /* According to the datasheet the key must be send twice. */

sent

> +       outb(SIO_UNLOCK_KEY, base);
> +       outb(SIO_UNLOCK_KEY, base);
> +
> +       return 0;
> +}

...

> +#define gpio_dir(base) ((base) + 0)
> +#define gpio_data(base) ((base) + 1)

Dunno, why haven't you changed this? It might be a hidden mine for the
future GPIO library development. I recommend using namespace whenever
it feels right, and here it's exactly the case.

> +       if (dir & 1 << offset)

Another ignored comment... BIT(offset)

I'm stopping here to let you double check what version you have sent.

-- 
With Best Regards,
Andy Shevchenko