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

From: Alexandre Torgue
Date: Tue Feb 18 2020 - 13:10:37 EST

Hi Marek

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.

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