RE: [PATCH v3 5/5] pinctrl: renesas: pinctrl-rzg2l: Add IRQ domain to handle GPIO interrupt

[Biju Das <biju.das.jz@bp.renesas.com>]

Hi Marc,

Thanks for the feedback.

> Subject: Re: [PATCH v3 5/5] pinctrl: renesas: pinctrl-rzg2l: Add IRQ domain
> to handle GPIO interrupt
> 
> On Sun, 15 May 2022 06:13:22 +0100,
> Biju Das <biju.das.jz@bp.renesas.com> wrote:
> >
> > Hi Prabhakar,
> >
> > Thanks for the example.
> >
> > > Subject: Re: [PATCH v3 5/5] pinctrl: renesas: pinctrl-rzg2l: Add IRQ
> > > domain to handle GPIO interrupt
> > >
> > > > But "offset" is a number from the GPIO offset space (0-122), while
> > >
> > > The "offset" reported by kernel is 120-511:
> > >
> > > root@smarc-rzg2l:~# cat /sys/kernel/debug/gpio
> > > gpiochip0: GPIOs 120-511, parent: platform/11030000.pinctrl,
> > > 11030000.pinctrl:
> > >  gpio-120 (P0_0                )
> > >  gpio-121 (P0_1                )
> > >  gpio-122 (P0_2                )
> > >  gpio-123 (P0_3                )
> > >  gpio-124 (P0_4                )
> > > .....
> > >  gpio-507 (P48_3               )
> > >  gpio-508 (P48_4               )
> > >  gpio-509 (P48_5               )
> > >  gpio-510 (P48_6               )
> > >  gpio-511 (P48_7               )
> > >
> > > > irq_find_mapping() expects a number from the domain's IRQ space,
> > > > which is only 0-31?
> > > >
> > > Nope, let me demonstrate with an example, I have configured the gpio
> > > pins as GPIO keys in DTS:
> > >
> > > +       keyboard {
> > > +               compatible = "gpio-keys";
> > > +               status = "okay";
> > > +
> > > +               key-1 {
> > > +                       gpios = <&pinctrl RZG2L_GPIO(43, 0)
> > > GPIO_ACTIVE_HIGH>;
> > > +                       linux,code = <KEY_1>;
> > > +                       linux,input-type = <EV_KEY>;
> > > +                       wakeup-source;
> > > +                       label = "SW1";
> > > +               };
> > > +
> > > +               key-2 {
> > > +                       gpios = <&pinctrl RZG2L_GPIO(41, 0)
> > > GPIO_ACTIVE_HIGH>;
> > > +                       linux,code = <KEY_2>;
> > > +                       linux,input-type = <EV_KEY>;
> > > +                       wakeup-source;
> > > +                       label = "SW2";
> > > +               };
> > > +
> > > +               key-3 {
> > > +                       gpios = <&pinctrl RZG2L_GPIO(43, 1)
> > > GPIO_ACTIVE_HIGH>;
> > > +                       linux,code = <KEY_3>;
> > > +                       linux,input-type = <EV_KEY>;
> > > +                       wakeup-source;
> > > +                       label = "SW3";
> > > +               };
> > > +       };
> > >
> > > root@smarc-rzg2l:~# cat /proc/interrupts | grep SW
> > > root@smarc-rzg2l:~# root@smarc-rzg2l:~# insmod gpio_keys.ko [
> > > 925.002720] input: keyboard as
> > > /devices/platform/keyboard/input/input3
> > > root@smarc-rzg2l:~# cat /proc/interrupts | grep SW
> > >  82:          0          0 11030000.pinctrl 344 Edge      SW1
> > >  83:          0          0 11030000.pinctrl 328 Edge      SW2
> > >  84:          0          0 11030000.pinctrl 345 Edge      SW3
> > > root@smarc-rzg2l:~#
> > >
> > > In here 82/83/84 are virq and 344/328/345 are hwirq, which can be
> > > confirmed from sysfs file:
> >
> > From your example, Looks like
> >
> > I believe from interrupt statistics point of view, cat
> > /proc/interrupts should report actual gpioint number (0->122)
> > corresponding to pin index for SW1, SW2 and SW3 ??
> 
> No. There is no need for such userspace-visible behaviour. Userspace has no
> business tracking those. The required information is in debugfs, and that
> more than enough.

Ok, So far I used cat /proc/interrupts for debugging, since I don't need to enable DEBUG config for
Enabling Debugfs for irq. This Debugfs irq is new info to me.

Our hardware manual has below info for usb-phy irq
2H0_OBINT	126(InterruptID)	SPI 94	IRQ 94	Level

cat /proc/interrupts matches with GICV3 Interrupt ID/ type in the HW manual
113:          0          0     GICv3 126 Level     11c50200.usb-phy

Debugfs is also showing similar info like hwirq and interrupt type. But I don't know which field corresponds to number
of interrupts? 

root@smarc-rzg2l:~# cat /sys/kernel/debug/irq/irqs/113
handler:  handle_fasteoi_irq
device:   (null)
status:   0x00000104
istate:   0x00000000
ddepth:   0
wdepth:   0
dstate:   0x13402204
            IRQ_TYPE_LEVEL_HIGH
            IRQD_LEVEL
            IRQD_ACTIVATED
            IRQD_IRQ_STARTED
            IRQD_SINGLE_TARGET
            IRQD_DEFAULT_TRIGGER_SET
            IRQD_HANDLE_ENFORCE_IRQCTX
node:     0
affinity: 0-1
effectiv: 0
domain:  :soc:interrupt-controller@11900000-1
 hwirq:   0x7e
 chip:    GICv3
  flags:   0x15
             IRQCHIP_SET_TYPE_MASKED
             IRQCHIP_MASK_ON_SUSPEND
             IRQCHIP_SKIP_SET_WAKE

Now coming to current case,

Currently GPIO INT 0-122(123 interrupts) corresponding to 120-511(291 interrupts) with same invalid lines.

From a debugging point, If user has put same irq name for gpioints(cat /proc/interrupts case), then how do we distinguish these interrupts??
(using hwirq??)

For using Debugfs, Do we need to first execute cat /proc/interrupts to get virq and from there we need to use virq to get statistics, right?

Cheers,
Biju