Re: [PATCH 5/8] arm64: dts: ti: k3-am64: Enable IO expander interrupt

Hi all,

On 7/29/2026 3:09 PM, [email protected] wrote:
> Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
> - [High] The IO expander interrupt is incorrectly configured with IRQ_TYPE_LEVEL_HIGH polarity for an active-low open-drain output.
> - [Medium] The pad configuration for the SK board removes the internal pull-up, potentially leaving the open-drain interrupt line floating.
> --

This patch will be sent as a separate series, due to Vignesh's review, 
will test on am64x devices and fix before repining then.

~ Judith

> 
> --- Patch [5]: [PATCH 5/8] arm64: dts: ti: k3-am64: Enable IO expander interrupt ---
> commit 846c9ea4531cda7562459d539ef568783fb1e41c
> Author: Judith Mendez <[email protected]>
> 
> arm64: dts: ti: k3-am64: Enable IO expander interrupt
> 
> On AM64 EVM and SK boards, MMC1_SDWP is used for IO expander interrupt,
> remove from MMC1 pinmux node and setup as exp1 IO expander interrupt.
> 
>> diff --git a/arch/arm64/boot/dts/ti/k3-am642-evm.dts b/arch/arm64/boot/dts/ti/k3-am642-evm.dts
>> --- a/arch/arm64/boot/dts/ti/k3-am642-evm.dts
>> +++ b/arch/arm64/boot/dts/ti/k3-am642-evm.dts
> [ ... ]
>> @@ -481,6 +487,12 @@ exp1: gpio@22 {
>>   		bootph-all;
>>   		compatible = "ti,tca6424";
>>   		reg = <0x22>;
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&main_gpio1_ioexp_intr_pins_default>;
>> +		interrupt-parent = <&main_gpio1>;
>> +		interrupts = <78 IRQ_TYPE_LEVEL_HIGH>;
> 
> [Severity: High]
> Will setting this interrupt to IRQ_TYPE_LEVEL_HIGH cause an interrupt storm?
> 
> Since the TCA6424 IO expander has an active-low open-drain interrupt output,
> an active-high configuration might trigger continuously when the line is
> idle, eventually causing the kernel to disable the interrupt.
> 
>> +		interrupt-controller;
>> +		#interrupt-cells = <2>;
>>   		gpio-controller;
> 
>> diff --git a/arch/arm64/boot/dts/ti/k3-am642-sk.dts b/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> --- a/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> +++ b/arch/arm64/boot/dts/ti/k3-am642-sk.dts
>> @@ -198,7 +198,6 @@ &main_pmx0 {
>>   	main_mmc1_pins_default: main-mmc1-default-pins {
>>   		bootph-all;
>>   		pinctrl-single,pins = <
>> -			AM64X_IOPAD(0x029c, PIN_INPUT_PULLUP, 0) /* (C20) MMC1_SDWP */
>>   			AM64X_IOPAD(0x0298, PIN_INPUT_PULLUP, 0) /* (D19) MMC1_SDCD */
>>   			AM64X_IOPAD(0x0294, PIN_INPUT_PULLUP, 0) /* (J19) MMC1_CMD */
> [ ... ]
>> @@ -210,6 +209,13 @@ AM64X_IOPAD(0x027c, PIN_INPUT_PULLUP, 0) /* (K18) MMC1_DAT3 */
>>   		>;
>>   	};
>>   
>> +	main_gpio1_ioexp_intr_pins_default: main-gpio1-ioexp-intr-default-pins {
>> +		pinctrl-single,pins = <
>> +			AM64X_IOPAD(0x029c, PIN_INPUT, 7) /* (C20) MMC1_SDWP.GPIO1_78 */
> 
> [Severity: Medium]
> Does dropping the internal pull-up on this pad risk leaving the interrupt
> line floating?
> 
> The previous configuration for this pad on the SK board used
> PIN_INPUT_PULLUP. If the board lacks a dedicated external pull-up resistor
> for this open-drain interrupt, using PIN_INPUT might lead to spurious edge
> detections.
> 
>> +		>;
>> +		bootph-all;
>> +	};
> [ ... ]
>> @@ -383,6 +389,12 @@ exp1: gpio@70 {
>>   		bootph-all;
>>   		compatible = "nxp,pca9538";
>>   		reg = <0x70>;
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&main_gpio1_ioexp_intr_pins_default>;
>> +		interrupt-parent = <&main_gpio1>;
>> +		interrupts = <78 IRQ_TYPE_LEVEL_HIGH>;
> 
> [Severity: High]
> Could this also trigger an interrupt storm on the SK board?
> 
> Similar to the EVM board, the PCA9538 IO expander typically has an
> active-low open-drain interrupt. An active-high configuration will likely
> trigger unconditionally on boot.
> 
>> +		interrupt-controller;
>> +		#interrupt-cells = <2>;
>