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

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 [off-list ref] wrote:

quoted

Hi Prabhakar,

Thanks for the example.

quoted

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

quoted

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               )

quoted

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