topic Re: Poweroff USB port from userland in i.MX Processors

Poweroff USB port from userland

gnulux — Sun, 09 Oct 2022 18:16:26 GMT

Hi all ,

I'm working on development of a new board that will host IMXMP SOC.

I would like someway to poweroff usb port or usb devices from a program in linux userland.

Can i do this with the IMX processor ? does PMIC (regulator chip) can manage that ?

thks

Re: Poweroff USB port from userland

Zhiming_Liu — Tue, 11 Oct 2022 04:22:10 GMT

Hi @gnulux

PMIC can't do this, please refer kernel document:

https://www.kernel.org/doc/html/latest/driver-api/usb/power-management.html

Re: Poweroff USB port from userland

gnulux — Fri, 14 Oct 2022 09:46:49 GMT

Thks for your reply .
I'd already read and tested usbpower management , but it appears that usb devices still consume few watts in suspend.

I really need to cut the power to reduce power consumption.

Re: Poweroff USB port from userland

Zhiming_Liu — Mon, 17 Oct 2022 02:13:26 GMT

Can you share which usb port you need manage power, HOST port or TYPEC port?

Re: Poweroff USB port from userland

gnulux — Mon, 17 Oct 2022 15:23:28 GMT

Hi,

Mainly Host port.

On my final board ( which will have a little power rescue) i will have on USB port :

- a NFC reader

- backlight for touchscreen

- BLE

- Camera .

At the end, i would like to poweroff all usb port when main power supply is off except for the backlight.

I plan to use a SMARC 2.1 card with a IMX8MP this card has 6 USB ports + 1 OTG available.

I was wondering if if it was possible ?

Re: Poweroff USB port from userland

Zhiming_Liu — Tue, 18 Oct 2022 05:44:26 GMT

For HOST port, you can control USB2_PWR_EN to close USB2_HOST_VBUS if you reserve this part from EVK.