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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Sun, 25 Feb 2018 14:19:51 +0200
Message-ID: <CAHp75VdvLDEmNs-YUFYf+Og18kaU6j6zAxXc1w31X2vw26ACHQ@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] gpio: Add Spreadtrum PMIC EIC driver support
To:     Baolin Wang <baolin.wang@linaro.org>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Mark Brown <broonie@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Sat, Feb 24, 2018 at 12:44 PM, Baolin Wang <baolin.wang@linaro.org> wrote:
> The Spreadtrum PMIC EIC controller contains only one bank of debounce EIC,
> and this bank contains 16 EICs. Each EIC can only be used as input mode,
> as well as supporting the debounce and the capability to trigger interrupts
> when detecting input signals.

> +/*
> + * These registers are modified under the irq bus lock and cached to avoid
> + * unnecessary writes in bus_sync_unlock.
> + */
> +enum { REG_IEV, REG_IE, REG_TRIG, CACHE_NR_REGS };

One item per line.

> +static int sprd_pmic_eic_direction_input(struct gpio_chip *chip,
> +                                        unsigned int offset)
> +{
> +       /* EICs are always input, nothing need to do here. */
> +       return 0;
> +}
> +
> +static void sprd_pmic_eic_set(struct gpio_chip *chip, unsigned int offset,
> +                             int value)
> +{
> +       /* EICs are always input, nothing need to do here. */
> +}

Remove both.

Look at what GPIO core does.

> +       value |= debounce / 1000;

Possible overflow.

> +       for (n = 0; n < chip->ngpio; n++) {
> +               if (!(BIT(n) & val))

for_each_set_bit().

At some point you may need just to go across lib/ in the kernel and
see what we have there.

-- 
With Best Regards,
Andy Shevchenko