IMX7 OTG1 port without PWR enable.

[davidsabalesky]

Our custom SOM module was ordered with -L, LVDS and hence pin 200 USB.OTG1_PWR pin is unavailable.

Can you always enable USB OTG1 port Vbus power and still have functionality with OTG?

Is there a work around to use another pin?

We cannot load our kernel via the USB OTG1 port yet.

In Addition, UBoot is not initializing the  RGMii ports, they are unavailable as well.

Does UBoot initialize these ports?

How can one change settings in UBoot to initialize Ethernet ports in RGMii mode?

Your assistance is greatly appreciated.

[CarlosCasillas · Accepted solution]

Hi David,

In order to meet USB OTG specification, the VBUS must be switched depending if the connected USB thing is Host or Device, to provide power only to Devices and avoid short-circuits with VBUS voltage of another Host. Thant’s why the ID pin should be polled and only providing the VBUS voltage when ID is grounded.

The i.MX7D processor includes two OTG controllers and one Host only. In case of requiring fixed VBUS on micro-USB connector the option would be configuring the module as Host only operation (also, configuring the Host mode on the USB OTG driver).

Hope this will be useful for you.
Best regards!
/Carlos
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[davidsabalesky]

Hi Carlos,

I greatly appreciate your response. Since OTG1 ports is only used in HOST mode, the solution is configuring the module as Host only operation and configuring the Host mode on the USB OTG driver. I am unfamiliar with how to do this and any direction to the process to configure the module and driver is appreciated. I do not have a kernel loaded as of yet. I do have full access the serial terminal and U-Boot. I read that only OTG1 ports is available to load the kernel from via USB. If other the other ports, OTG2 and USB Hub, can be configured to load the kernel from please let me know. I am in unfamiliar territory and will diligently research the path forward.

Sincerely,

David