============================================== ChipIdea Highspeed Dual Role Controller Driver ============================================== 1. How to test OTG FSM(HNP and SRP) ----------------------------------- To show how to demo OTG HNP and SRP functions via sys input files with 2 Freescale i.MX6Q sabre SD boards. 1.1 How to enable OTG FSM ------------------------- 1.1.1 Select CONFIG_USB_OTG_FSM in menuconfig, rebuild kernel ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Image and modules. If you want to check some internal variables for otg fsm, mount debugfs, there are 2 files which can show otg fsm variables and some controller registers value:: cat /sys/kernel/debug/ci_hdrc.0/otg cat /sys/kernel/debug/ci_hdrc.0/registers 1.1.2 Add below entries in your dts file for your controller node ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ :: otg-rev = <0x0200>; adp-disable; 1.2 Test operations ------------------- 1) Power up 2 Freescale i.MX6Q sabre SD boards with gadget class driver loaded (e.g. g_mass_storage). 2) Connect 2 boards with usb cable with one end is micro A plug, the other end is micro B plug. The A-device(with micro A plug inserted) should enumerate B-device. 3) Role switch On B-device:: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req B-device should take host role and enumerate A-device. 4) A-device switch back to host. On B-device:: echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req or, by introducing HNP polling, B-Host can know when A-peripheral wish to be host role, so this role switch also can be trigged in A-peripheral side by answering the polling from B-Host, this can be done on A-device:: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req A-device should switch back to host and enumerate B-device. 5) Remove B-device(unplug micro B plug) and insert again in 10 seconds, A-device should enumerate B-device again. 6) Remove B-device(unplug micro B plug) and insert again after 10 seconds, A-device should NOT enumerate B-device. if A-device wants to use bus: On A-device:: echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req if B-device wants to use bus: On B-device:: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req 7) A-device power down the bus. On A-device:: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_drop A-device should disconnect with B-device and power down the bus. 8) B-device does data pulse for SRP. On B-device:: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req A-device should resume usb bus and enumerate B-device. 1.3 Reference document ---------------------- "On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification July 27, 2012 Revision 2.0 version 1.1a" 2. How to enable USB as system wakeup source -------------------------------------------- Below is the example for how to enable USB as system wakeup source at imx6 platform. 2.1 Enable core's wakeup:: echo enabled > /sys/bus/platform/devices/ci_hdrc.0/power/wakeup 2.2 Enable glue layer's wakeup:: echo enabled > /sys/bus/platform/devices/2184000.usb/power/wakeup 2.3 Enable PHY's wakeup (optional):: echo enabled > /sys/bus/platform/devices/20c9000.usbphy/power/wakeup 2.4 Enable roothub's wakeup:: echo enabled > /sys/bus/usb/devices/usb1/power/wakeup 2.5 Enable related device's wakeup:: echo enabled > /sys/bus/usb/devices/1-1/power/wakeup If the system has only one usb port, and you want usb wakeup at this port, you can use below script to enable usb wakeup:: for i in $(find /sys -name wakeup | grep usb);do echo enabled > $i;done;