How do disable VBUS

[Sven Schwermer <sven@xxxxxxxxxxxxxxxx>]

Hi,

I have an embedded system built around an NXP i.MX6ULL SoC. Within that 
system, there is a USB device that's hooked up to USBOTG2 (chipidea 
driver) of the SoC. This USB OTG peripheral is statically set to host 
mode in the device tree. The USB device is powered by a separate supply 
in addition to the VBUS supply. Now I want to make sure that VBUS is 
switched off whenever I switch off the main power supply. I have started 
to write a little platform driver which will do the sequencing. However, 
I'm struggling to find a way to switch off the VBUS supply given a 
struct device* handle which I have managed to get. Is there an API that 
I can use? I have confirmed that unbinding the driver via sysfs does 
achieve this, however, how do I do this programmatically from kernel 
code, perhaps without unbinding the entire device?

Best regards,
Sven