gpio-sim as a Temporary GPIO Interrupt for PMIC - Configuration Help

elFunko — Fri, 11 Oct 2024 13:58:07 GMT

Hi everyone,

I'm currently working on getting a custom i.MX93 board up and running, and I'm facing an issue with the PMIC (the NXP PCA9451A). The problem is that the PMIC requires a GPIO interrupt to load its driver, but our board does not have any free GPIOs available.

To solve this, we came up with the idea of using a "fake" GPIO through gpio-sim or gpio-mockup, so that we can get the PMIC up and running for now. In a future revision of the board, we plan to replace this mockup GPIO with a real one. However, I'm struggling to get the PMIC driver to load, regardless of how I configure the gpio-sim node.

I've seen this patch from 2022, which seems to be attempting the same thing I'm trying to do. We're currently using Linux version 6.6.28-lf-6.6.y-lf-6.6.y-g81ea508ca4b7-dirty.

I've also made sure to add the necessary kernel configuration options, including:

CONFIG_GPIO_SIM=y
CONFIG_GPIOLIB=y
CONFIG_IRQ_SIM=y

Despite this, the PMIC driver does not load. Below is how I'd like the PMIC node to look in the device tree, using gpio-sim as the interrupt parent:

&lpi2c1 { #address-cells = <1>; #size-cells = <0>; clock-frequency = <400000>; pinctrl-names = "default", "sleep"; pinctrl-0 = <&pinctrl_lpi2c1>; pinctrl-1 = <&pinctrl_lpi2c1>; status = "okay"; pmic@25 { compatible = "nxp,pca9451a"; reg = <0x25>; interrupt-parent = <&gpio_sim>; interrupts = <0 IRQ_TYPE_EDGE_FALLING>;

Has anyone successfully used gpio-sim in a similar scenario, or can anyone suggest how the gpio-sim node should be configured to make this work?

Any help would be greatly appreciated!

Best regards,
Elia

i.MX Processorsのトピックgpio-sim as a Temporary GPIO Interrupt for PMIC - Configuration Help

gpio-sim as a Temporary GPIO Interrupt for PMIC - Configuration Help