Thanks @Loic, Thanks for your suggestion.
My application is streaming the data from USB camera. During testing I noticed that the device is abruptly getting disconnected and reconnected (without any physical disruption). Sometimes after reconnection the device is not re-enumerated. It happens only once a while.
I have tried this but in case of error (as mentioned above) the device is not re-enumerated. The camera will be functional only after the physical USB disconnection and re-connection.
Is there some way by which I can power recycle the USB port.
Does this command
$ echo 78d9000.ehci > /sys/bus/platform/drivers/msm_hsusb_host/unbind
$ echo 78d9000.ehci > /sys/bus/platform/drivers/msm_hsusb_host/bind
actually triggers the gpio3(usb_hub_reset_N_pm) signal.