DM814x USB host driver: How to modify the driver to ignore VBUSIN signal

Hi

since DM814X as USB host, hence the USBx_VBUS is driven from DM814X host and the same USBx_VBUS is given as input to USB_VBUSIN to DM814X, the DEVCTRL register (bit D4 and D3) reflect the status of VBUS  (00- below session, 01-above session below Avalid, 10- above Avalid below vbus valid, 11-above vbus valid refer to spec for more details ).

<from your mail>

As external usb device has feature to check VBUS voltage...hey didn't connect the VBUSIN pin with the VBUS signal on USB connector.

I did not understand above statement. what is this external device? Do you want to know how to get VBUS status at device side?

Regards

Ravi B

Ravi,

Customer used USB as host and let the VBUSIN pin open. But it seems that the USB driver will check the VBUSIN status. So we want to know how to modify the driver to ignore the VBUSIN status.

The USB device connected with DM814x USB port has the feature to detect the voltage of VBUS. 

Chris

When DM814X as USB Host, I did not understand what is the impact or issue you are observing when VBUSIN pin is not connected DM814x. Whether mentor controller will able to enter into host mode, whether is basic host functionality is working ? Can you confirm. 

<from previous mail>

The USB device connected with DM814x USB port has the feature to detect the voltage of VBUS

I did not understand the above statement, the device has feature to detect voltage of VBUS..ok..what you are looking for? what is the use case requirement. please explain.

Regards

Ravi B

Ravi,

If VBUSIN pin is open, the DM814x USB host can't detect the USB device, like Usb flash disk.

Based on the USB section of TRM, there will be an error interrupt when VBUSIN pin <4.4V. My customer just simply disabled vbus error interrupt in USBn_INTRUSBE, but the driver still doesn't work. Would you pls check what else we need to modify on the driver in this condition?

Exactly this is what i was expecting, that is why i was asking whether host mode is working or not.  The actual problem symtom is DM814X as host is not working, not detecting any device. The reason is USBx_VBUSIN is not connected to SoC.

I dont think there is any alternative to make it work, the only way is to connect the USBx_VBUSIN pin to DM814x.

But anyway i can confirm this IP team, is there any way to enter host controller with this configuration.

Regards

Ravi B

You mentioned everything but not actual problem.

Ravi,

Do you get any feedback from IP team?