Hi Chris,
On Wed, Mar 20, 2019 at 9:41 PM Chris Brandt <[email protected]> wrote:
> On Wed, Mar 20, 2019, Geert Uytterhoeven wrote:
> > This patch series adds support for devices on the I2C bus on the RSKRZA1
> > board, including the GPIO expander that drives 3 LEDs.
>
> Very cool.
>
> I figured there was a more graceful way of turning on/off those LEDs
> than what I was doing...which was just writing to the I2C bus in my LED
> heartbeat kernel thread.
> https://github.com/renesas-rz/rza_linux-4.19/blob/master/arch/arm/mach-shmobile/board-rskrza1.c#L145
Yeah, I've seen that code. Not fit for upstream ;-)
I also wanted to add support for the switches, as I prefer to have a
remote wake-up source before I move a board to my board farm (sh_eth in
RZ/A1 does not seem to support wake-on-LAN). However, that doesn't
work yet.
The usual approach would be:
#include <dt-bindings/input/input.h>
keyboard {
compatible = "gpio-keys";
key-1 {
gpios = <&port1 9 GPIO_ACTIVE_LOW>;
linux,code = <KEY_1>;
label = "SW1";
wakeup-source;
};
};
But that doesn't work, as RZ/A1 GPIO does not support interrupts.
The GPIOs connected to the switches can also be used as IRQ lines
with (pseudo patch)
keyboard {
+ pinctrl-names = "default";
+ pinctrl-0 = <&keyboard_pins>;
key-1 {
- gpios = <&port1 9 GPIO_ACTIVE_LOW>;
+ interrupt-parent = <&gic>;
+ interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_BOTH>;
}
}
+ keyboard_pins: keyboard {
+ pinmux = <RZA1_PINMUX(1, 9, 3)>; /* IRQ3 */
+ };
However, that also doesn't work, as the PL390 GIC supports rising edge
and high-level interrupts only. Falling edge and low-level interrupts
on the IRQ pins seem to be an RZ/A1-specific GIC extension, which
requires programming the non-standard registers (ICR0, ICR1, IRQRR).
Nevertheless, even with the plain supported interrupt modes I didn't
receive interrupts when using the switches.
I've just discovered commit 207c10b54ca81129 ("irq-gic: add support for
pins IRQ0-IRQ7") in rza_linux-4.14, but when using that, the system
locks up when pressing a switch :-(
Finally, I tried using the pin interrupts, which are the closest to GPIO
interrupts we seem to have. As these support high-level and rising-edge
interrupts only, while the switches are active-low, this means only
key-up events are detected:
interrupt-parent = <&gic>;
interrupts = <GIC_SPI 401 IRQ_TYPE_EDGE_RISING>;
What am I doing wrong?
Do you have a better solution?
The IRQx support looks most promising, but needs some work (separate
compatible value, small driver with a custom .irq_set_type, deferring
the rest to the normal GIC driver).
Thanks!
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
