MCUBOOT hold gpio on boot

[noy_e]

Hello,

I'm working with Zephyr and using MCUBOOT as bootloader.

Due to HW design I have to set and hold a gpio as fast as possible when the application boots (to prevent a reset)

What is the most effective way to do this ?

I tried to use SYS_INIT to write a function that will set the gpio, and it is called in POST_KERNEL init level to match the priority of the led gpio driver,

but it does not seem to be fast enough. I was wondering if you have any suggestions on how to optimize this process?

Thanks for your assistance,

Noy

[Håkon Alseth]

Hi,

 

You can use the regulators-fixed subsys to do this. Here's an example on how the DT will look:

https://github.com/nrfconnect/sdk-zephyr/blob/v3.7.99-ncs1-rc1/boards/nordic/thingy53/thingy53_nrf5340_common.dtsi#L110-L115

 

Remember to add this as a board overlay for mcuboot as well as setting CONFIG_REGULATOR=y

 

Kind regards,

Håkon

[noy_e]

Thanks!

I also found another option - to use gpio hogs

&gpio1 {

    power-hold {

        status = "okay";

        gpio-hog;

        gpios = <15 GPIO_ACTIVE_HIGH>;

        output-high;

    };

};

I'm using it on the mcuboot overlay + my application overlay since it's a multi image build.

Appreciate the help

Noy

[Håkon Alseth]

Hi Noy,

 

I am glad to hear that you found a solution to your issue!

Hope you have a wonderful day.

 

Cheers,

Håkon