66AK2G12: To swap data rolls on the USB1 side while receiving data on the USB0 side

O.H

Part Number: 66AK2G12

Hi expert,

My customer is using 66AK's USB 2port and is considering whether it is possible to configure it to support PD, with USB0 as Device and USB1 as Host, as shown in the diagram below.

Could you please tell me whether it is possible to swap data rolls on the USB1 side while playing the audio data on the USB0 side?
There is a possibility that a reset process will be necessary during the swap process, but I am concerned that it may affect audio data on the USB0 side to be interrupted.

Best regards,
O.H

6 months ago

0 Kallikuppa Sreenivasa 6 months ago

TI__Guru*** 148109 points

Hello O.H,

Thank you for the query.

I am trying to understand your query.

Are you checking if the USB1 role can be changed dynamically ?

Regards,

Sreenivasa

0 O.H 6 months ago in reply to Kallikuppa Sreenivasa

Genius 5665 points

Hello Sreenivasa,

Thank you for your repy.

Kallikuppa Sreenivasa said:
Are you checking if the USB1 role can be changed dynamically

Yes.
USB0 is used as a Device port and plays audio data from the PC, while USB1 is basically a HOST port, but there are use cases where only the data role is dynamically swapped depending on the type of peripheral equipment connected.

When using it like this,
Q1. Is it technically possible?
Q2. Is special processing required on the USB1 side?
Q3.When processing occurs on the USB1 side, does it affect the USB0 side (e.g. the sound stops when switching data rolls)?

Best regards,
O.H

0 Kallikuppa Sreenivasa 6 months ago in reply to O.H

TI__Guru*** 148109 points

Hello O.H,

Thank you for the query.

Let me check with the team internally if the use case you mentioned above is feasible.

Can you please confirm if this is a feasibility study or customer is facing some issues while implementing the functionality?

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa 6 months ago in reply to Kallikuppa Sreenivasa

TI__Guru*** 148109 points

Hello O.H,

Refer the below inputs i received

In general, the answer should be YES. The most important thing is we need to check Errata to ensure there is no any SoC bug which prevents usb role switching

Regards,

Sreenivasa

0 O.H 6 months ago in reply to Kallikuppa Sreenivasa

Genius 5665 points

Hello Sreenivasa,

Thank you for your support.

Kallikuppa Sreenivasa said:
Can you please confirm if this is a feasibility study or customer is facing some issues while implementing the functionality?

It is feasibility study.

I understand about Q1.We will check Errata.

We look forward to your additional comments regarding Q2 and Q3.

Best regards,
O.H

0 Kallikuppa Sreenivasa 6 months ago in reply to O.H

TI__Guru*** 148109 points

Hello O.H,

Thank you for the input.

The USB expert is looking into the queries and will update you.

Regards,

Sreenivasa

0 Bin Liu 6 months ago in reply to O.H

TI__Guru*** 141006 points

Hi O.H,

O.H said:
Q1. Is it technically possible?

The USB controller used on 66AK2G12 should support dual role switching. I don't find any reason why it shouldn't on 66AK2G12. The EVM is designed in the way that USB1 port supports dual role switching. However, the kernel device tree sets the EVM USB1 port to be device-only mode. I don't have the EVM to test if dual role works though. The software doesn't provide a reason why it is not dual role.

https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm/boot/dts/keystone-k2g-evm.dts?h=ti-linux-4.19.y#n368

O.H said:
Q2. Is special processing required on the USB1 side?

Nothing else, other than designing the USB1 connection in the same way as the EVM USB1 port, and set USB1 dr_mode = "otg" in kernel device tree.

O.H said:
Q3.When processing occurs on the USB1 side, does it affect the USB0 side (e.g. the sound stops when switching data rolls)?

it shouldn't not. The two USB modules on 66AK2G12 are independent.

0 O.H 6 months ago in reply to Bin Liu

Genius 5665 points

Hi Bin Liu,

Thank you for your support.

I understood. If I receive additional questions, I will contact you again.

Best regards,
O.H

0 Kallikuppa Sreenivasa 6 months ago in reply to O.H

TI__Guru*** 148109 points

hello O.H,

Thank you for the note.

Regards,

Sreenivasa

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66AK2G12: To swap data rolls on the USB1 side while receiving data on the USB0 side