linux-kernel - Re: [PATCH v3] gpio: pl061: Support implementations without GPIOINTR line

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Message-ID: <028a836c-9343-f08a-3f1b-22e45f291d1a@nokia.com>
Date:   Fri, 19 Mar 2021 16:32:48 +0100
From:   Alexander Sverdlin <alexander.sverdlin@...ia.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] gpio: pl061: Support implementations without GPIOINTR
 line

Hello Andy,

>> From: Alexander Sverdlin <alexander.sverdlin@...ia.com>
>>
>> There are several implementations of PL061 which lack GPIOINTR signal in
>> hardware and only have individual GPIOMIS[7:0] interrupts. Use the
>> hierarchical interrupt support of the gpiolib in these cases (if at least 8
>> IRQs are configured for the PL061).
>>
>> One in-tree example is arch/arm/boot/dts/axm55xx.dtsi, PL061 instances have
>> 8 IRQs defined, but current driver supports only the first one, so only one
>> pin would work as IRQ trigger.
> 
> an IRQ
> 
> I'm wondering if the GPIO library support for IRQ hierarchy is what
> you are looking for.

do you have a better suggestion? That's why I reference the below discussion from 2017, where 
Linus Walleij suggested to use it. Well, the initial patch was just 11-liner and PL061 is
rather counterexample and doesn't fit well into the existing hierarchical infrastructure. 

>> Link: https://lore.kernel.org/linux-gpio/CACRpkdZpYzpMDWqJobSYH=JHgB74HbCQihOtexs+sVyo6SRJdA@mail.gmail.com/

[...]

>> --- a/drivers/gpio/Kconfig
>> +++ b/drivers/gpio/Kconfig
>> @@ -469,6 +469,7 @@ config GPIO_PL061
>>         depends on ARM_AMBA
>>         select IRQ_DOMAIN
>>         select GPIOLIB_IRQCHIP
>> +       select IRQ_DOMAIN_HIERARCHY

-- 
Best regards,
Alexander Sverdlin.