Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => A20 => Topic started by: -peter- on June 10, 2022, 02:57:50 PM

Title: A20 Micro: u-boot and usb power
Post by: -peter- on June 10, 2022, 02:57:50 PM
Hello folks,

we are using a custom u-boot configuration: i've created a new defconfig based on micro file and changed some mostly cosmetic things in order to speed up the boot time.

We have a custom chip which is powered by a USB1 power, but this power it not being applied when loading u-boot. Later on, when Linux Kernel starts then the chip is powered properly, but the kernel uses a different device tree which is tied with kernlen in a blob.

Now i'd like to power this custom chip as soon as possible, so i need something which works in u-boot.

I tried some options e.g: "regulator-boot-on" (which i also used in the kernel's device tree)  but this seems to be ignored in u-boot.

Now i wonder how to do that in u-boot?
Any ideas?

with best regards,
Peter
Title: Re: A20 Micro: u-boot and usb power
Post by: LubOlimex on June 15, 2022, 09:37:15 AM
Can't say about the software solution, probably more experienced Linux guys would know but until you figure it out - maybe do the hardware solution - power the USB device from the same power supply as you use for the main board instead of using the USB supply. So once you apply power to the board it powers the device too.