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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Mon, 26 Sep 2022 09:38:32 +0200
Message-ID: <CAMRc=MeNJAgkaD6P4t6=0hy4F7Mkw_Jyg_X5QJ5C3em9cW4iOw@mail.gmail.com>
Subject: Re: [PATCH -next 0/2] allow gpio simulator be used as interrupt controller
To:     Wei Yongjun <weiyongjun1@huawei.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Linus Walleij <linus.walleij@linaro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Sep 26, 2022 at 8:57 AM Wei Yongjun <weiyongjun1@huawei.com> wrote:
>
>
>
> On 2022/9/1 0:08, Bartosz Golaszewski wrote:
> > On Fri, Aug 26, 2022 at 9:44 AM Wei Yongjun <weiyongjun1@huawei.com> wrote:
> >>
> >> This series allow gpio simulator be used as interrupt controller, the use
> >> case is mockup some device which using GPIO as interrupt controller, such
> >> as mcp2515 CAN device. With the dts [1], we can mockup a mcp2515 device,
> >> and trigger irq by following commands:
> >>
> >>  $ echo pull-down > /sys/bus/gpio/devices/gpiochip0/sim_gpio0/pull
> >>  $ echo pull-up > /sys/bus/gpio/devices/gpiochip0/sim_gpio0/pull
> >>
> >>
> >> --[1]---------------------------------------------------------
> >> /dts-v1/;
> >>
> >> #include <dt-bindings/interrupt-controller/irq.h>
> >>
> >> / {
> >>         clk24m: clk24m {
> >>                 compatible = "fixed-clock";
> >>                 clock-output-names = "clk24m";
> >>                 clock-frequency = <24000000>;
> >>                 #clock-cells = <0>;
> >>         };
> >>
> >>         gpio-sim {
> >>                 compatible = "gpio-simulator";
> >>
> >>                 bank0: bank0 {
> >>                         gpio-controller;
> >>                         #gpio-cells = <2>;
> >>                         ngpios = <16>;
> >>
> >>                         interrupt-controller;
> >>                         #interrupt-cells = <2>;
> >>
> >>                         line_b-hog {
> >>                                 gpio-hog;
> >>                                 gpios = <0 1>;
> >>                                 input;
> >>                                 line-name = "irq-sim";
> >>                         };
> >
> > Why do you need this hog? The GPIO will be marked as requested once
> > the interrupt is taken by the driver.
>
> Sorry for reply later.
>
> It seems that only if driver request gpio with fwnode_gpiod_get_index()
> marks GPIO as request one.
>
> If driver using request_threaded_irq() request one irq, the requested
> status will not be marked. We need to use hog or request by userspace
> to mark as requested.
>

Right, of course. Thanks.

> >
> >>                 };
> >>         };
> >>
> >>         spi: spi {
> >>                 compatible = "spi-mockup";
> >>
> >>                 #address-cells = <1>;
> >>                 #size-cells = <0>;
> >>
> >>                 can0: can@1 {
> >>                         compatible = "microchip,mcp2515";
> >>                         reg = <1>;
> >>                         clocks = <&clk24m>;
> >>                         interrupt-parent = <&bank0>;
> >>                         interrupts = <0 IRQ_TYPE_EDGE_BOTH>;
> >>                 };
> >>
> >>         };
> >> };
> >> ------------------------------><-----------------------------
> >>
> >> Wei Yongjun (2):
> >>   genirq/irq_sim: Allow both one and two cell bindings
> >>   gpio: sim: make gpio simulator can be used as interrupt controller
> >>
> >>  drivers/gpio/gpio-sim.c | 2 +-
> >>  kernel/irq/irq_sim.c    | 1 +
> >>  2 files changed, 2 insertions(+), 1 deletion(-)
> >>
> >> --
> >> 2.34.1
> >>
> >
> > Can you add some info about this to the documentation?
>

Ok, I'll wait for v2.

And you can drop the -next prefix too, it doesn't fix anything in next.

Bart

> Will do that
>
> Thanks,
> Wei Yongjun