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 with 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 wish 58 to be host role, so this role switch also can be trigged in A-peripheral 59 side by answering the polling from B-Host, this can be done on A-device:: 60 61 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req 62 63 A-device should switch back to host and enumerate B-device. 64 655) Remove B-device(unplug micro B plug) and insert again in 10 seconds, 66 A-device should enumerate B-device again. 67 686) Remove B-device(unplug micro B plug) and insert again after 10 seconds, 69 A-device should NOT enumerate B-device. 70 71 if A-device wants to use bus: 72 73 On A-device:: 74 75 echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop 76 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req 77 78 if B-device wants to use bus: 79 80 On B-device:: 81 82 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req 83 847) A-device power down the bus. 85 86 On A-device:: 87 88 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop 89 90 A-device should disconnect with B-device and power down the bus. 91 928) B-device does data pulse for SRP. 93 94 On B-device:: 95 96 echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req 97 98 A-device should resume usb bus and enumerate B-device. 99 1001.3 Reference document 101---------------------- 102"On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification 103July 27, 2012 Revision 2.0 version 1.1a" 104 1052. How to enable USB as system wakeup source 106-------------------------------------------- 107Below is the example for how to enable USB as system wakeup source 108at imx6 platform. 109 1102.1 Enable core's wakeup:: 111 112 echo enabled > /sys/bus/platform/devices/ci_hdrc.0/power/wakeup 113 1142.2 Enable glue layer's wakeup:: 115 116 echo enabled > /sys/bus/platform/devices/2184000.usb/power/wakeup 117 1182.3 Enable PHY's wakeup (optional):: 119 120 echo enabled > /sys/bus/platform/devices/20c9000.usbphy/power/wakeup 121 1222.4 Enable roothub's wakeup:: 123 124 echo enabled > /sys/bus/usb/devices/usb1/power/wakeup 125 1262.5 Enable related device's wakeup:: 127 128 echo enabled > /sys/bus/usb/devices/1-1/power/wakeup 129 130If the system has only one usb port, and you want usb wakeup at this port, you 131can use below script to enable usb wakeup:: 132 133 for i in $(find /sys -name wakeup | grep usb);do echo enabled > $i;done; 134