Issue using AON gpio as interrupt in device tree

Robotics & Edge Computing Jetson & Embedded Systems Jetson Xavier NX
1

Hi,

I’m currently trying to use GPIO04, aka TEGRA194_AON_GPIO(CC, 1) on the Xavier NX as the interrupt line for a PCA9534 I2C gpio expander.

I have set up the device tree as so:

    i2c@c240000 {
        gpio_i: gpio@20 {
            compatible = "nxp,pca9534";
            reg = <0x20>;
            interrupt-parent = <&tegra_aon_gpio>;
            interrupts = <TEGRA194_AON_GPIO(CC, 1) GPIO_ACTIVE_LOW>;
            interrupt-controller;
            #interrupt-cells = <2>;
            gpio-controller;
            #gpio-cells = <2>;

            status = "okay";
        };

I have also adjusted the pinmux as follows:

&tegra_pinctrl {
	pinctrl-names = "default", "drive", "unused";
	pinctrl-0 = <&pinmux_default>;
	status = "okay";
	pinmux_default: common {
		spi2_miso_pcc1 {
			nvidia,pins = "spi2_miso_pcc1";
			nvidia,function = "rsvd2";
			nvidia,pull = <TEGRA_PIN_PULL_UP>;
			nvidia,tristate = <TEGRA_PIN_ENABLE>;
			nvidia,enable-input = <TEGRA_PIN_ENABLE>;
			nvidia,io-high-voltage = <TEGRA_PIN_ENABLE>;
			nvidia,lpdr = <TEGRA_PIN_DISABLE>;
		};
	};
};

gpio@c2f0000 {
		gpio-init-names = "default";
		gpio-init-0 = <&gpio_default>;
		gpio_default: default {
			gpio-input = <
				TEGRA_GPIO(CC,1);
				>;
		};
	};

However I am seeing in dmesg that the driver fails to probe due to the IRQ not being able to be set up.

[    5.250949] irq: IRQ261: trimming hierarchy from :pmc@c360000
[    5.251140] pca953x 1-0020: supply vcc not found, using dummy regulator
[    5.256810] pca953x 1-0020: using no AI
[    5.262059] gpio gpiochip2: (tegra194-gpio-aon): gpiochip_lock_as_irq: tried to flag a GPIO set as output for IRQ
[    5.271058] gpio gpiochip2: (tegra194-gpio-aon): unable to lock HW IRQ 13 for IRQ
[    5.278578] genirq: Failed to request resources for 1-0020 (irq 261) on irqchip gpio
[    5.286475] pca953x 1-0020: failed to request irq 261
[    5.291449] pca953x: probe of 1-0020 failed with error -5

What is the issue with my current setup? Is it possible to configure AON gpio as hardware interrupts?

Thanks,
Akhil

3

Hi akhil.m.birlangi,

Are you using the devkit or custom board for Xavier NX?
What’s your Jetpack version in use?

It seems suspend_gpio also use this PIN as suspend-led-gpio in device tree by default.
Please confirm if you have this requirement, or you can remove it.

I would also suggest configuring pinmux through spreadsheet and generate .cfg file for Xavier NX.

4

We are using a custom board for Xavier NX.

I believe our current Jetpack version is fixed to 35.2.1

Is it possible to simply add a

/delete-node/ suspend_gpio;

to our dts to remove the pin allocation?

Also I am not sure how to generate a .cfg file from the dtsi provided from the pinmux spreadsheet. How do I go about making this .cfg and where should the file be placed during the build?

Thanks,
Akhil

5

Okay, you can add it to overlay dtbo to remove the usage of this pin.

Please refer to <Linux_for_Tegra>/kernel/pinmux/t19xREADME.txt for details.

7

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