diff options
Diffstat (limited to 'Documentation/usb/chipidea.txt')
| -rw-r--r-- | Documentation/usb/chipidea.txt | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/Documentation/usb/chipidea.txt b/Documentation/usb/chipidea.txt index 05f735a1b..edf7cdfdd 100644 --- a/Documentation/usb/chipidea.txt +++ b/Documentation/usb/chipidea.txt @@ -3,14 +3,17 @@ 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 in menuconfig +1.1 How to enable OTG FSM --------------------------------------- -Select CONFIG_USB_OTG_FSM, 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: +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 ------------------- @@ -26,16 +29,17 @@ cat /sys/kernel/debug/ci_hdrc.0/registers On B-device: echo 1 > /sys/bus/platform/devices/ci_hdrc.0/inputs/b_bus_req - if HNP polling is not supported, also need: - On A-device: - echo 0 > /sys/bus/platform/devices/ci_hdrc.0/inputs/a_bus_req - B-device should take host role and enumrate 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 enumrate B-device. 5) Remove B-device(unplug micro B plug) and insert again in 10 seconds, |