IRQ trigger rising edge doesnt work with 5.10.4

[Makurisan]

I called this function in the probe and the handler is immeadiately called and the value on the GPIO is 0. It seems the irq handler is configured with POLLing enabled but I want only rising edge.

rc = devm_request_irq(&vhub->spi->dev, vhub->irq, ast_vhub_irq, IRQF_TRIGGER_RISING | IRQF_SHARED,
					  KBUILD_MODNAME, vhub);

Under /proc/interrupts the interrupt appears with the "Edge" attribute
50: 3744 0 0 0 pinctrl-bcm2835 17 Edge v_hub

And the pin is defined:
GPIO 17: level=0 fsel=0 func=INPUT pull=DOWN

Is this a bug or what leads to this?

Tested with PI4 4GB and kernel
Linux pi 5.10.4-v8+ #1389 SMP PREEMPT Wed Jan 6 13:52:18 GMT 2021 aarch64 GNU/Linux

[pelwell]

How are you declaring the GPIO interrupt? It is normal (and perhaps necessary) to declare the trigger type using the IRQ flags in Device Tree, e.g. (from https://github.com/raspberrypi/linux/blob/rpi-5.10.y/arch/arm/boot/dts/overlays/sc16is750-i2c-overlay.dts):

			sc16is750: sc16is750@48 {
				compatible = "nxp,sc16is750";
				reg = <0x48>; /* i2c address */
				clocks = <&sc16is750_clk>;
				interrupt-parent = <&gpio>;
				interrupts = <24 2>; /* IRQ_TYPE_EDGE_FALLING */
				gpio-controller;
				#gpio-cells = <2>;
				i2c-max-frequency = <400000>;
			};

IRQ_TYPE_EDGE_RISING has the value 1, so your interrupts declaration would be:

				interrupt-parent = <&gpio>;
				interrupts = <0 1>; /* IRQ_TYPE_EDGE_RISING */

[Makurisan]

Ok, at the moment we use the config.txt with
dtoverlay=anyspi:spi0-0,dev="hubshield,v-hub",speed=1000000
In the linux documentation it is said that request_irq with parameter flag equal zero use the device tree otherwise the flags which are specified.

Is it possible to set the parameter in the config.txt?

[pelwell]

The anyspi overlay doesn't support interrupts. You will have to make a custom overlay to go along with your out-of-tree driver.

[Makurisan]

1. I set the gpio nbr already in code. Why is this not possible for request_irq. Can you explain the reason for that?
2. Can you give me an example which show this overlay stuff with spi. I tried the following without success. Do you see any problem because it is not loaded.

/dts-v1/;
/plugin/;

/*
#include <include/dt-bindings/interrupt-controller/irq.h>
 */

/ {
	compatible = "brcm,bcm2711";

	fragment@0 {
		target = <&spidev0>;
		__overlay__ {
			status = "disabled";
		};
	};

	fragment@1 {
		target = <&spi0>;
        __overlay__ {
			/* needed to avoid dtc warning */
    		#address-cells = <1>;
			#size-cells = <0>;
 			status = "okay";
            vhub: vhub@48 {
				compatible = "hubshield,v-hub";
				reg = <0x0>;
				interrupt-parent = <&gpio>;
				interrupts = <0 2>; /* IRQ_TYPE_EDGE_FALLING */
                reset-gpios = <&gpio 25 1>; // GPIO_ACTIVE_HIGH
				gpio-controller;
				#gpio-cells = <2>;
				spi-max-frequency = <4000000>;
			};
		};
	};

	__overrides__ {
		int_pin = <&vhub>,"interrupts:0";
        cs =  <&vhub>,"reg:0";
		speed =  <&vhub>,"spi-max-frequency:0";
    };

};

};

[pelwell]

Post the code you are using to configure the GPIO IRQ.

[Makurisan]

I have changed it to the above overlay and it is the same, means polling.

	vhub->irq = gpio_to_irq(vhub->gpio_irq);
	if (vhub->irq < 0) {
		dev_info(&vhub->spi->dev, "Failed to request spi irq:%d from device tree\n",
					vhub->irq);
	}
	else {
		dev_info(&vhub->spi->dev, "Succeeded to request gpio:%d with irq:%d\n", vhub->gpio_irq, vhub->irq);
	}
	// irq_set_irq_type(vhub->irq, IRQ_TYPE_LEVEL_HIGH);
	// irq_set_irq_type(vhub->irq, IRQ_TYPE_EDGE_FALLING );
	rc = devm_request_threaded_irq(&vhub->spi->dev, vhub->irq, NULL, ast_vhub_irq,
					IRQF_ONESHOT | IIRQF_TRIGGER_FALLING, KBUILD_MODNAME, vhub);
	if (rc)
	{
		dev_err(&vhub->spi->dev, "Failed to request interrupt\n");
		goto err;
	}

I also changed the interrupts to 0 in the overlay because the gpio irq comes from "gpio_to_irq(vhub->gpio_irq);".

interrupts = <0 2>; /* IRQ_TYPE_EDGE_FALLING */

[pelwell]

How can you tell that it is polling?

[Makurisan]

If I load the kernel driver the irq handler is called immeadiately again and again. (and btw I return IRQ_HANDLED which means the irq is cleared)

Inside the irq handler I print a debug message with the value from the gpio "gpio_get_value(g_gpio_ip_irq)". The function gets the value "1" if I set the gpio to "1". Do I set the gpio to low the gpio in the handler has the value "0".

You see it is polling regardless what I set in the request_irq function.

[pelwell]

There's a typo in your code (IIRQF_TRIGGER_FALLING) - are you sure you are building and running it?

Also, are you sure there is no glitching on the IRQ line?

Have a look at my gpio-fsm driver - drivers/gpio/gpio-fsm.c and arch/arm/boot/dts/overlays/fsm-demo-overlay.dts - for an example of code that uses edge triggering. In your situation I would add some debug code to that driver to confirm that the edge triggering is working as expected, then see how your code differs.

[Makurisan]

Yes, this was an copy,paste,rewrite problem.
I now changed to

rc = devm_request_irq(&vhub->spi->dev, vhub->irq, ast_vhub_irq, 0, KBUILD_MODNAME, vhub);
and in the overlay

interrupts = <17 2>; /* IRQ_TYPE_EDGE_FALLING */

The gpio is now from the overlay. The same result. always polling.

It is not the problem with device tree overlay. Any other idea?

[pelwell]

As I said above, start with the known-good gpio-fsm driver, perhaps changing the configuration to use GPIO 0, and add enough debug to prove to yourself that edge triggering works. If it doesn't, I can test that configuration here.

[Makurisan]

No, I dont do that. I have compiled our kernel with 5.4.83-v7+ on an rpi 3 and it works as expected.

It is a problem in your changes. Do it like I and you will see the problem.

[pelwell]

You are asking me to investigate a problem that so far only you are seeing, with a non-standard driver and overlay. I've requested that you test with an (RPi-)standard driver and overlay - is that too much to ask?

[Makurisan]

Ok, write exactly what I should do and I test it. This means write how to load the gpio-fsm driver with gpio 5 as INPUT irq.

I searched for the overlay and don*t know which one and how to use it.
Tried:
sudo modprobe gpio-fsm
sudo dtoverlay fsm-demo

The following error appears:
Of: /fsm-demo: could not get #gpio-cells' for /soc/interrupt controller...

on:
Linux pi 5.10.4-v8+ #1389 SMP PREEMPT Wed Jan 6 13:52:18 GMT 2021 aarch64 GNU/Linux