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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 21 Mar 2018 17:32:03 +0200
Message-ID: <CAHp75VcdimgN3u5O5zye2=pXvCkWuZzCf3e0wOQozQoKz7W8yA@mail.gmail.com>
Subject: Re: [PATCH v3 2/8] gpio: 104-idio-16: Implement get_multiple callback
To:     William Breathitt Gray <vilhelm.gray@gmail.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-iio@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
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On Sat, Mar 17, 2018 at 5:50 PM, William Breathitt Gray
<vilhelm.gray@gmail.com> wrote:
> The ACCES I/O 104-IDIO-16 series of devices provides 16
> optically-isolated digital inputs accessed via two 8-bit ports. Since
> eight input lines are acquired on a single port input read, the
> 104-IDIO-16 GPIO driver may improve multiple input reads by utilizing a
> get_multiple callback. This patch implements the
> idio_16_gpio_get_multiple function which serves as the respective
> get_multiple callback.

> +static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
> +       unsigned long *mask, unsigned long *bits)
> +{
> +       struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
> +
> +       *bits = 0;

> +       if (*mask & 0xFF0000)

GENMASK(23, 16) ?

> +               *bits |= (unsigned long)inb(idio16gpio->base + 1) << 16;

Do you need casting?

> +       if (*mask & 0xFF000000)

GENMASK(31, 24) ?

Alternative (and for above):

(*mask >> 24) & 0xff

(*mask >> 16) & 0xff


> +               *bits |= (unsigned long)inb(idio16gpio->base + 5) << 24;

Do you need casting?

> +
> +       return 0;
> +}
> +
>  static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
>  {
>         struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
> @@ -244,6 +258,7 @@ static int idio_16_probe(struct device *dev, unsigned int id)
>         idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
>         idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
>         idio16gpio->chip.get = idio_16_gpio_get;
> +       idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
>         idio16gpio->chip.set = idio_16_gpio_set;
>         idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
>         idio16gpio->base = base[id];
> --
> 2.16.2
>


-- 
With Best Regards,
Andy Shevchenko