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1==============================================2ChipIdea Highspeed Dual Role Controller Driver3==============================================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 files9with 2 Freescale i.MX6Q sabre SD boards.10 111.1 How to enable OTG FSM12-------------------------13 141.1.1 Select CONFIG_USB_OTG_FSM in menuconfig, rebuild kernel15^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^16 17Image and modules. If you want to check some internal18variables for otg fsm, mount debugfs, there are 2 files19which can show otg fsm variables and some controller registers value::20 21 cat /sys/kernel/debug/ci_hdrc.0/otg22 cat /sys/kernel/debug/ci_hdrc.0/registers23 241.1.2 Add below entries in your dts file for your controller node25^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^26 27::28 29 otg-rev = <0x0200>;30 adp-disable;31 321.2 Test operations33-------------------34 351) Power up 2 Freescale i.MX6Q sabre SD boards with gadget class driver loaded36 (e.g. g_mass_storage).37 382) Connect 2 boards with usb cable: one end is micro A plug, the other end39 is micro B plug.40 41 The A-device (with micro A plug inserted) should enumerate B-device.42 433) Role switch44 45 On B-device::46 47 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req48 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_req56 57 or, by introducing HNP polling, B-Host can know when A-peripheral wishes to58 be in the host role, so this role switch also can be triggered in59 A-peripheral side by answering the polling from B-Host. This can be done on60 A-device::61 62 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req63 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_drop77 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req78 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_req84 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_drop90 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_req98 99 A-device should resume usb bus and enumerate B-device.100 1011.3 Reference document102----------------------103"On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification104July 27, 2012 Revision 2.0 version 1.1a"105 1062. How to enable USB as system wakeup source107--------------------------------------------108Below is the example for how to enable USB as system wakeup source109on an imx6 platform.110 1112.1 Enable core's wakeup::112 113 echo enabled > /sys/bus/platform/devices/ci_hdrc.0/power/wakeup114 1152.2 Enable glue layer's wakeup::116 117 echo enabled > /sys/bus/platform/devices/2184000.usb/power/wakeup118 1192.3 Enable PHY's wakeup (optional)::120 121 echo enabled > /sys/bus/platform/devices/20c9000.usbphy/power/wakeup122 1232.4 Enable roothub's wakeup::124 125 echo enabled > /sys/bus/usb/devices/usb1/power/wakeup126 1272.5 Enable related device's wakeup::128 129 echo enabled > /sys/bus/usb/devices/1-1/power/wakeup130 131If the system has only one usb port, and you want usb wakeup at this port, you132can use the below script to enable usb wakeup::133 134 for i in $(find /sys -name wakeup | grep usb);do echo enabled > $i;done;135