Re: [PATCH v2 1/2] pinctrl: Add driver for Awinic AW9523/B I2C GPIO Expander

[AngeloGioacchino Del Regno]

Il 22/01/21 10:59, Linus Walleij ha scritto:
> On Mon, Jan 18, 2021 at 3:38 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@xxxxxxxxxxxxxx> wrote:
>
> > By the way, this is really LEVEL irq, not EDGE... To avoid any
> > misunderstanding, I think that the best way to show you what I
> > am seeing is to just copy-paste the relevant piece from the
> > datasheet for this hardware (it's not a confidential datasheet
> > and freely found on the internet).
> >
> > Check this out:
> > " External MCU is required acknowledge by INTN pin. INTN is open-drain
> > out-
> > put, low-level active, and need external pull-up resistor.
>
> This talks about what polarity (active low) the pin from the expander
> to the SoC/CPU is. It has nothing to do with the line into the
> expander.
>
> > When AW9523B detect port change, any input state from high-level to
> > low-level or from
> >    low-level to high-level will generate interrupt after
> > 8us internal deglitch. "
> >
> > ...but since the datasheet is sometimes unclear about "things" (I am
> > mostly sure that they have translated it to english from chinese), I
> > have actually checked whether the INTN pin was pushed LOW when one of
> > the inputs goes from HIGH to LOW.. and.. it does... and as you imagine
> > yeah.. it's slow.. and yes, as slow as you can imagine. :)
> >
> > So, in short, this chip is raising an interrupt when any input changes
> > state, regardless of the change being LOW->HIGH or HIGH->LOW.
>
> This means that the expander only supports
> IRQ_TYPE_EDGE_BOTH and nothing else.
>
> "port change" above means edges.
>
> Augment your driver to only accept this type.
>
> The consumers better request IRQ_TYPE_EDGE_BOTH
> (from a device tree for example) and consumers better
> handle the fact that they get interrupts on both rising
> and falling edge as well, else they may need special
> code to handle it. This is not a very nice feature of
> the expander, it would be more helpful to users to
> get interrupts on only rising or only falling edges, but
> as written, it will generate interrupts on both transitions.
>
> Yours,
> Linus Walleij

I see the reading mistake now... oh wow, that was... sad, from me.
I will fix this ASAP and will send back a v3.

Thank you!

- Angelo