OSD3358-512M-BSM USB1 gadget problem, when I supply from VIN_USB

[jozsef.detari]

Dear Experts,

I would like to ask some help.

Our design is based on the OSD3358-512M-BSM SiP module. We stucked on a problem about USB1 bring-up as a device/gadget.

– Our device use USB1 for device, USB0 will be a host
– We use the OSD3358 VIN_USB port (this is the TPS65217 USB port) instead of VIN_AC (this is the TPS65217 AC port) for supplying our system (we will need limit our device to 500mA)
– We use Buildroot. U-boot ver is 2018.01 (Patched with eeprom check skip., octavosystems.com/…/ . Kernel is 5.4.28.

After several tests, here is our problem:

– USB1 seems initializing at boot, gadget is created, but the state is “not attached” all the time
– I tried OTG and device sets from kernel tree. Same result
– I tried my Linux firmware at a pocketbeagle board. If I use VIN_USB for supply (like on our board) on Pockebeagle , same problem, USB1 is not attached. If I supply my system over VIN_AC in pocketbeagle, the USB1 can enumerate and my gadget interface is shows up.

Some help for diagnostic

– USB0 is not used currently, it is in host mode
– We tried on 2 proto device at the same time to exclude asembly problems
– R83 (VBUS connect over a 0Ohm resistor, checked, mounted)
– R6 (USB1_ID is not mounted)
– VIN_USB measured, it is exactly 5V
– Our device contain a microSD card connector and an eMMC module. I tested the USb on our device when I just use eMMC. Same results, “not attached”.

Thank you.

• This topic was modified 3 years, 10 months ago by jozsef.detari.

Attachments:

1. 

   sbc.pdf
   

1. sbc.log_.txt

[Neeraj Dantu]

Jozsef,

A couple of things to note here:

1. Please verify the device tree initialization of USB1 as device: https://github.com/RobertCNelson/dtb-rebuilder/blob/4.14-ti/src/arm/am335x-pocketbeagle-common.dtsi#L981

2. The boot scripts in https://github.com/RobertCNelson/boot-scripts/tree/master/boot are responsible for starting the USB gadget on the interface.

The behavior you are describing with PocketBeagle is odd. For the USB interface to come up in device mode, USB1_VBUS needs to be set to >4.4V. So, powering the PocketBealge with AC input could not have activated the USB port.

On PocketBeagle, by default, USB0 is used in device mode and USB1 is used in host out of the box. If it is possible to change your usage of the ports, you will have support for device and host out of the box.

Best,

Neeraj

[Author]

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