Re: [PATCH] gpio: pca953x: Use irqchip template

[Linus Walleij <linus.walleij@linaro.org>]

On Wed, Sep 30, 2020 at 12:47 PM Nikhil Devshatwar <nikhil.nd@ti.com> wrote:

> I am getting a kernel crash on K3 j721e common processor board
> when HDMI is plugged in. Following is the full log with crash
> for NULL pointer derefence
>
> https://pastebin.ubuntu.com/p/wBPS2ymmqR/
>
> Upon inspection, I found that the "irq_find_mapping" call
> in the "pca953x_irq_handler" returns 0 and the same is passed
> to "handle_nested_irq"

This would typically happen if the driver using an IRQ
from the PCA953x does not properly request it.

Is this caused by this IRQ 504 from your /proc/interrupts:

504:          0          0    4-0021  10 Edge      HPD

This seems to be requested directly by the HDMI bridge
and not by the TI display controller.

I look in the k3-am654-base-board.dts in the upstream
kernel and I find this:

&main_i2c0 {
        pinctrl-names = "default";
        pinctrl-0 = <&main_i2c0_pins_default>;
        clock-frequency = <400000>;

        pca9555: gpio@21 {
                compatible = "nxp,pca9555";
                reg = <0x21>;
                gpio-controller;
                #gpio-cells = <2>;
        };
};

This is the GPIO controller used here, right?

I notice the following:
- There are no HDMI bridges using this GPIO controller in
  the upstream kernel.
- The PCA9555 here lacks necessary attributes such as
  parent IRQ (another GPIO) and the "interrupt-controller"
  and "#interrupt-cells".

So this can not be the device tree you are using.

Can you point us to:
- The actual device tree you are booting from?
- The actual bridge that is requesting the HPD IRQ?
- The upstream code for this bridge?

Yours,
Linus Walleij