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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Thu, 16 Apr 2020 11:20:38 +0200
Message-ID: <CACRpkdZPZ4nFQ6B3tGG9wvceoTWqAkfY0r1UKs2pf_c=ZNBG=w@mail.gmail.com>
Subject: Re: [PATCH v2 10/16] gpio: add a reusable generic gpio_chip using regmap
To:     Michael Walle <michael@walle.cc>
Cc:     Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        linux-gpio <linux-gpio@vger.kernel.org>,
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On Tue, Apr 14, 2020 at 9:57 PM Michael Walle <michael@walle.cc> wrote:

> So what about the following:
>
> #define GPIO_REGMAP_ADDR_ZERO (unsigned int)(-1)

Yeah with regmap explicitly using int I guess we can't use
S32_MAX, so that is fair.

> So this way the user might assign the base addresses the normal way
> except when he wants to use zero, in that case he has to use
>
>    ->base_adr = GPIO_REGMAP_ADDR_ZERO;
>
> gpio-regmap.c could use then:
>
> if (base_addr)
>    something_useful(gpio_regmap_addr(base_addr));
>
> unsigned int gpio_regmap_addr(unsigned int addr)
> {
>    return (addr == GPIO_REGMAP_ADDR_ZERO) ? 0 : addr;
> }

That's reasonably clean.

Yours,
Linus Walleij