1==============================================
  2ChipIdea Highspeed Dual Role Controller Driver
  3==============================================
  4
  51. How to test OTG FSM(HNP and SRP)
  6-----------------------------------
  7
  8To show how to demo OTG HNP and SRP functions via sys input files
  9with 2 Freescale i.MX6Q sabre SD boards.
 10
 111.1 How to enable OTG FSM
 12-------------------------
 13
 141.1.1 Select CONFIG_USB_OTG_FSM in menuconfig, rebuild kernel
 15^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 16
 17Image and modules. If you want to check some internal
 18variables for otg fsm, mount debugfs, there are 2 files
 19which can show otg fsm variables and some controller registers value::
 20
 21	cat /sys/kernel/debug/ci_hdrc.0/otg
 22	cat /sys/kernel/debug/ci_hdrc.0/registers
 23
 241.1.2 Add below entries in your dts file for your controller node
 25^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 26
 27::
 28
 29	otg-rev = <0x0200>;
 30	adp-disable;
 31
 321.2 Test operations
 33-------------------
 34
 351) Power up 2 Freescale i.MX6Q sabre SD boards with gadget class driver loaded
 36   (e.g. g_mass_storage).
 37
 382) Connect 2 boards with usb cable: one end is micro A plug, the other end
 39   is micro B plug.
 40
 41   The A-device (with micro A plug inserted) should enumerate B-device.
 42
 433) Role switch
 44
 45   On B-device::
 46
 47	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 48
 49   B-device should take host role and enumerate A-device.
 50
 514) A-device switch back to host.
 52
 53   On B-device::
 54
 55	echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 56
 57   or, by introducing HNP polling, B-Host can know when A-peripheral wishes to
 58   be in the host role, so this role switch also can be triggered in
 59   A-peripheral side by answering the polling from B-Host. This can be done on
 60   A-device::
 61
 62	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
 63
 64   A-device should switch back to host and enumerate B-device.
 65
 665) Remove B-device (unplug micro B plug) and insert again in 10 seconds;
 67   A-device should enumerate B-device again.
 68
 696) Remove B-device (unplug micro B plug) and insert again after 10 seconds;
 70   A-device should NOT enumerate B-device.
 71
 72   if A-device wants to use bus:
 73
 74   On A-device::
 75
 76	echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop
 77	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req
 78
 79   if B-device wants to use bus:
 80
 81   On B-device::
 82
 83	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 84
 857) A-device power down the bus.
 86
 87   On A-device::
 88
 89	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop
 90
 91   A-device should disconnect with B-device and power down the bus.
 92
 938) B-device does data pulse for SRP.
 94
 95   On B-device::
 96
 97	echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req
 98
 99   A-device should resume usb bus and enumerate B-device.
100
1011.3 Reference document
102----------------------
103"On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification
104July 27, 2012 Revision 2.0 version 1.1a"
105
1062. How to enable USB as system wakeup source
107--------------------------------------------
108Below is the example for how to enable USB as system wakeup source
109on an imx6 platform.
110
1112.1 Enable core's wakeup::
112
113	echo enabled > /sys/bus/platform/devices/ci_hdrc.0/power/wakeup
114
1152.2 Enable glue layer's wakeup::
116
117	echo enabled > /sys/bus/platform/devices/2184000.usb/power/wakeup
118
1192.3 Enable PHY's wakeup (optional)::
120
121	echo enabled > /sys/bus/platform/devices/20c9000.usbphy/power/wakeup
122
1232.4 Enable roothub's wakeup::
124
125	echo enabled > /sys/bus/usb/devices/usb1/power/wakeup
126
1272.5 Enable related device's wakeup::
128
129	echo enabled > /sys/bus/usb/devices/1-1/power/wakeup
130
131If the system has only one usb port, and you want usb wakeup at this port, you
132can use the below script to enable usb wakeup::
133
134	for i in $(find /sys -name wakeup | grep usb);do echo enabled > $i;done;