External ULPI PHY extended register read

[alexfryer1]

On STM32F7 OTG_HS with an external ULPI PHY, is there a supported way for firmware to issue an ULPI Extended Register Read/Write transaction?

The required ULPI sequences are:

Extended read:

•     TX CMD 0xEF
•     extended address byte
•     read returned data

Extended write:

•     TX CMD 0xAF
•     extended address byte
•     data byte

The undocumented PHYCR viewport at USB_OTG_HS + 0x34 used by STM32CubeF7 only appears to support ordinary single register accesses. Can PHYCR issue an extended ULPI transaction?

Thanks,

Alex