[PATCH V10 3/4] power: supply: Add charger driver for Rockchip RK817

[Philip C]

> 
> In the Rockchip inno usb2 phy implementation, the extcon is an
> optional property that depends on your hardware design. If you have
> wired up the vbus det and id lines correctly and have a simple usb
> port, then you can leave this property out and the phy provides the
> state to itself. If you have a complicated design, such as a usb-c
> controller, or either the id or vbus det lines are broken, you'll need
> to provide the extcon with a pointer to the device that is providing
> this state.
> 
> The rk817 is not a valid extcon provider.
> 

Thank you for your reply Peter.  I have been thinking about this and 
looking at datasheets and schematics.  I think that the point is that 
the usb phy is inside the SoC, and not in the RK817 and so any logic 
concerning whether the port is in OTG mode or host mode must take place 
in the SoC, basically I guess in 
/drivers/phy/rockchip/phy-rockchip-inno-usb2.c

Given that I have a device that works in BSP but not in mainline I think 
that the secret of why may be somewhere in that c code, so that's where 
I need to look and play.

Your reply helped me to realise that.  Thanks, Philip