| 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 HNP and SRP |
| --------------------------------------- |
| Pass otg-rev to be 0x0200, remove srp-disable and hnp-disable in dts like below: |
| dr_mode = "otg"; |
| otg-rev = <0x0200>; |
| adp-disable; |
| |
| 1.2 HNP and SRP 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 enumrate 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 enumrate A-device. |
| |
| 4) A-device switch back to host. |
| On A-device: |
| echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req |
| |
| or, on B-device: |
| echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req |
| |
| A-device should switch back to host and enumrate B-device. |
| |
| 5) Remove B-device(unplug micro B plug) and insert again in 10 seconds, |
| A-device should enumrate B-device again. |
| |
| 6) Remove B-device(unplug micro B plug) and insert again after 10 seconds, |
| A-device should NOT enumrate 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 enumrate B-device. |
| |
| 1.3 Enable and test USB OTG ADP |
| ---------------------- |
| Enable ADP in dts: |
| 1) Based on 1.2, remove adp-disable in dts. |
| |
| Test sequence: |
| 1) After A-device ends session(remove B-device and wait 10s, or a_bus_drop) |
| 2) Remove B-device, B-device will show "OTG device detached". |
| 3) Insert B-device, A-device will enumerate B-device. |
| |
| 1.4 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" |
| |
| 1.5 OTG compliance test |
| ---------------------- |
| Only below 3 popular gadget drivers are declared to be USB OTG and EH 2.0 |
| compliant(with otg descriptor comply with USB OTG and EH 2.0 as a peripheral): |
| - mass storage |
| - ether |
| - serial |
| |
| 1.6 Debug |
| If you want to check some internal variables for otg fsm, |
| Select CONFIG_USB_CHIPIDEA_DEBUG, 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 |
| |
| 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; |
| |