linux-kernel - Re: [PATCH v1 5/5] gpiolib: Replace open coded gpiochip_irqchip_add_allocated

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Message-ID: <CACRpkdZKLtg4wNZqY7ujrcOa=h8gazXxhwdCmPeDbgOSze0mXw@mail.gmail.com>
Date:   Tue, 4 Jul 2023 00:25:58 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Andy Shevchenko <andy@...nel.org>
Subject: Re: [PATCH v1 5/5] gpiolib: Replace open coded gpiochip_irqchip_add_allocated_domain()

On Fri, Jun 30, 2023 at 3:58 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:

> While at it, I would like to ask on ->to_irq() callback. IIUC
> assigning it with an IRQ chip makes a dead code in the driver. Am I
> correct?

It's fine to assign it with an IRQ chip but not with GPIOLIB_IRQCHIP,
i.e. gc->irq better be NULL.

> If not, can somebody shed some light on how the RT5677
> driver, for example, works with GPIO IRQ?

That is theoretically fine (I don't know this HW in particular).
It looks a bit fragile...

It's just a helper to translate a GPIO line to the corresponding Linux
IRQ number and when using GPIOLIB_IRQCHIP the GPIO core
will do this using the irqdomain, else it is up to the driver.

Yours,
Linus Walleij