linux-kernel - Re: [PATCH v1 1/5] gpio: max77620: Initialize interrupts state

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Message-ID: <CAHp75VdFVGgKxR+n5TUMuFnWDy_uEmEeG=TvR9s7Xbe=jOdObg@mail.gmail.com>
Date:   Wed, 8 Jul 2020 11:51:06 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-tegra@...r.kernel.org,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/5] gpio: max77620: Initialize interrupts state

On Wed, Jul 8, 2020 at 11:29 AM Dmitry Osipenko <digetx@...il.com> wrote:
>
> I noticed on Nexus 7 that after rebooting from downstream kernel to
> upstream, the GPIO interrupt is triggering non-stop despite of interrupts
> being disabled for all of GPIOs. This happens because Nexus 7 uses a
> soft-reboot, meaning that bootloader should take care of resetting
> hardware, but bootloader doesn't do it well. In a result, GPIO interrupt
> may be left ON at a boot time. Let's mask all GPIO interrupts at the
> driver's probe time in order to resolve the issue.

...

> +               err = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(i),
> +                                        MAX77620_CNFG_GPIO_INT_MASK, 0);
> +               if (err < 0)

Does ' < 0' meaningful here?

> +                       dev_err(mgpio->dev, "failed to disable interrupt: %d\n",
> +                               err);

One line.

...

> +       max77620_gpio_initialize(mgpio);

I guess we have special callback for that, i.e.
https://elixir.bootlin.com/linux/v5.8-rc3/C/ident/init_hw.


-- 
With Best Regards,
Andy Shevchenko