Hi Geert,
> -----Original Message-----
> From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> Sent: 01 July 2025 12:50
> Subject: Re: [PATCH] arm64: dts: renesas: r9a09g047e57-smarc: Add gpio keys
>
> Hi Biju,
>
> On Tue, 1 Jul 2025 at 13:40, Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> On Mon, 14 Apr 2025
> > > at 17:38, Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > RZ/G3E SMARC EVK has 3 user buttons called USER_SW1, USER_SW2 and
> > > > USER_SW3. Add a DT node in device tree to instantiate the
> > > > gpio-keys driver for these buttons.
> > > >
> > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
>
> > > > --- a/arch/arm64/boot/dts/renesas/renesas-smarc2.dtsi
> > > > +++ b/arch/arm64/boot/dts/renesas/renesas-smarc2.dtsi
> > > > @@ -12,8 +12,13 @@
> > > > * SW_SDIO_M2E:
> > > > * 0 - SMARC SDIO signal is connected to uSD1
> > > > * 1 - SMARC SDIO signal is connected to M.2 Key E connector
> > > > + *
> > > > + * GPIO keys are enabled by default. Use PMOD_GPIO macros to
> > > > + disable them
> > > > + * if needed.
> > > > */
> > > >
> > > > +#include <dt-bindings/input/input.h>
> > > > +
> > > > / {
> > > > model = "Renesas RZ SMARC Carrier-II Board";
> > > > compatible = "renesas,smarc2-evk"; @@ -27,6 +32,31 @@
> > > > aliases {
> > > > serial3 = &scif0;
> > > > mmc1 = &sdhi1;
> > > > };
> > > > +
> > > > + keys: keys {
> > > > + compatible = "gpio-keys";
> > > > +
> > > > + key-1 {
> > > > + interrupts-extended = <&pinctrl KEY_1_GPIO
> > > > + IRQ_TYPE_EDGE_FALLING>;
> > >
> > > So you are using them as interrupts. Don't you need to configure pin
> > > control for that (function 15 = IRQ14)?
> >
> > The same pin can be configured as TINT or IRQ15, currently it is configured as TINT IRQ.
> > Is it ok?
>
> OK.
>
> > > Alternatively, can't you use them as gpios with interrupt facilities?
> >
> > interrupts-extended = <&pinctrl KEY_1_GPIO IRQ_TYPE_EDGE_FALLING>;
> >
> > The TINT IRQ will provide the same right? Am I missing anything here?
>
> When you use interrupts directly, the system will detect only key presses, and fake (timer-based) key
> releases.
> When you use GPIOs with interrupt-capability, the system can detect both key presses and releases.
>
> See also commit cab3511ea7a0b1fc ("ARM: dts: marzen: Add slide switches").
As per [1], for GPIOs with interrupt-capability, IRQ controller needs to support both edges.
But TINT supports Rising or Falling edge, but not both. So, we cannot use this.
That is the reason using interrupt directly.
[1]
https://elixir.bootlin.com/linux/v6.16-rc4/source/drivers/input/keyboard/gpio_keys.c#L980
Cheers,
Biju
