linux-kernel - Re: [PATCH v2 0/2] Add GPIO level-sensitive interrupt support

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Message-ID: <088e786c-511e-cf95-fc41-5343b8134407@denx.de>
Date:   Tue, 18 Feb 2020 19:13:31 +0100
From:   Marek Vasut <marex@...x.de>
To:     Alexandre Torgue <alexandre.torgue@...com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Linus Walleij <linus.walleij@...aro.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org
Subject: Re: [PATCH v2 0/2] Add GPIO level-sensitive interrupt support

On 2/18/20 7:10 PM, Alexandre Torgue wrote:
> Hi Marek

Hi,

> On 2/18/20 5:25 PM, Marek Vasut wrote:
>> On 2/18/20 2:12 PM, Alexandre Torgue wrote:
>>> This series adds the possibility to handle gpio interrupts on level.
>>>
>>> GPIO hardware block is directly linked to EXTI block but EXTI handles
>>> external interrupts only on edge. To be able to handle GPIO interrupt on
>>> level a "hack" is done in gpio irq chip: parent interrupt (exti irq
>>> chip)
>>> is retriggered following interrupt type and gpio line value.
>>>
>>> In exti irq chip, retrigger ops function is added.
>>
>> btw. this might be unrelated, but is it possible to have e.g. gpioC2 set
>> as trigger-level-low and gpioD2 set as trigger-edge-falling ? It seems
>> 8eb2dfee9fb1 ("pinctrl: stm32: add lock mechanism for irqmux selection")
>> prevents that.
>>
> 
> No it's not possible. Each gpio line doesn't have a dedicated Exti line
> Each Exti line is muxing between gpio banks.

OK, that confirms my assumption.

> Mapping is done as following:
> 
> EXTI0 = A0 or B0 or C0 .... or Z0 : selected by Mux
> EXTI1 = A1 or B1 or C1 ....or Z1 : selected by Mux
> EXTI2 = A2 or B2 or C2 ....or Z2 : selected by Mux
> ...

Is it at least possible to have IRQs of the same type on the same exti
line? E.g. gpioA2 of trigger-edge-falling and gpioB2 trigger-edge-falling ?