Hi,
a customer is using the USB in host mode and needs to be able to programmatically control power on the USB host port and disconnect and re-enumarate a USB device, i.e. Once the device is powered off, that we are able to power it back on and successfully re-enumerate the device.
Could someone double-check the following steps using the sysfs for the USB driver and let us know whether this approach is good. The following commands do the job:
Un-bind the host controller
echo usb2 > /sys/bus/usb/drivers/usb/unbind
Output:
[ 15.569827] usb 2-1: USB disconnect, device number 2
[ 15.587779] musb_bus_suspend 2457: trying to suspend as a_host while active
At this point if I run the lsusb command I can see the two USB controllers but the device is no longer there.
root@muse-master:~# lsusb
Bus 002 Device 001: ID 1d6b:0002
Bus 001 Device 001: ID 1d6b:0002
Turn off the USB host power
echo 0 > /sys/class/leds/usb_host_power/brightness
Output:
[ 133.403930] musb-hdrc musb-hdrc.1.auto: VBUS_ERROR in a_wait_vrise (80, <SessEnd), retry #3, port1 0008050b
Turn on the USB host power
echo 1 > /sys/class/leds/usb_host_power/brightness
Re-bind the host controller
echo usb2 > /sys/bus/usb/drivers/usb/bind
At this point the device is recognized and drivers are loaded.
Please let us know if there are any gotchas.
Thanks!
--Gunter
