Enable OTG gadget devices on Linux (OrangePI PC)

EduardMe1

Dear community,

Im trying to get an USB gadget via OTG running on Linux (OrangePI PC).
For example g_mass_storage or g_hid or g_serial is interesting.

What I want to achieve is, when I connect the OTG cable to OrangePI PC, it should be detected as a device on a PC. One of the above.
First challenge is to get it detected at all. Currently nothing happens, if I connect the cable.

I attempted the following:

I used loboris repo to re-build the kernel: https://github.com/loboris/OrangePI-Kernel
I changed the kernel config like this (described here):

1. Device Drivers  --->
   
2.              USB support  --->
   
3.                    <*>    NOP USB Transceiver Driver
   
4.                     [*]    SUNXI USB2.0 Dual Role Controller support --->
   
5.                              [*]    Sunxi USB2.0 Manager
   
6.                                   USB0 Controller support (otg support) --->
   
7.                                         (*) otg support

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Additionally I activated as <M> the OTG gadget drivers for g_mass_storage, g_hid and g_serial.
After the compilation, I have copied the uImage and the lib/modules folder onto the SD Card. The SD Card has a Linux image installed. In this case the Ubuntu_vivid_mini.img from loboris.

After replacing the above, the board is booting normally, but Im not able to activate the gadget drivers.
Im using following commands as root:

1. $ modprobe g_hid

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output is: insmod /lib/modules/3.4.39-02-lobo/kernel/drivers/usb/gadget/g_hid.komodrpobe: ERROR: could not insert g_hid: No such device

Although the module is there at the same location. I can modprobe the g_mass_storage, but still nothing shows up on the PC connected to OrangePI PC.

From my understanding, OrangePI PC should be detected as some device on a PC.
Any clues, tips or references how to setup OTG correctly?

Thanks!

EduardMe1

On Android I can activate the OTG (and adb) by following command:

1. echo 2 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role

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Is there a similar file or other way for linux to activate the device otg role?

EduardMe1

The same file, otg_role, is also there on Linux, but its not working as expected. I have loaded the android driver as build-in driver. On Android this gadget driver is configured after setting otg_role and plugging in a cable. Additionally bus 5 of the usb ports is deregistered on setting otg_role. I guess this port is the OTG port, which is configured as device. On Linux it stays in lsusb.

EduardMe1

Its actually working, except on loboris minimal images. If anyone is interested, these are the commands to enable the android composite driver under linux:

1. echo 1 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
   
2. echo 2 > /sys/bus/platform/devices/sunxi_usb_udc/otg_role
   
3. 
   
4. echo 0 > /sys/class/android_usb/android0/enable
   
5. echo 1d6b > /sys/class/android_usb/android0/idVendor
   
6. echo 0001 > /sys/class/android_usb/android0/idProduct
   
7. echo mtp > /sys/class/android_usb/android0/functions
   
8. echo 1 > /sys/class/android_usb/android0/enable

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Enables MTP for example. There is a list of other devices too.

boob

Thanks for the report!

All USB host working or just otg? Maybe it's possible to make an ethenet device g_ether module.
https://learn.adafruit.com/turni ... get/ethernet-gadget

EduardMe1

Not sure if the several gadgets work on its own. I was using successfully the android composite gadget to enable other gadgets and multiple in combination. HID, Mass Storage, MTP, ACM/Serial were working well. I think it also has RNDIS, which is basically the g_ether gadget. But I didnt test this one.

boob

Thanks a lot for your work, my goal is to make it work orange pi as OTG connected to an Openwrt device, OP for CPUing and display and openwrt as gateway (WT3020H have wireless 2T2R and 2 Ethernet port)!
I will try to compile kernel like you suggest and hope it's will work for RNIS ethernet device.
If all is right let 's go to buy one orange pi ;)

Many thanks

boob

I see "Ethernet Gadget (with CDC Ethernet support)" let 's go try compile

boob

It 's seem to be broken build on my 32bit linux machine :

1. arch/arm/mach-sunxi/power/brom/gen_check_code: 1: arch/arm/mach-sunxi/power/brom/gen_check_code: Syntax error: end of file unexpected (expecting ")")

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I try this  (http://www.orangepi.org/orangepi ... =viewthread&tid=436) but error on "usage" of gen_check_code.

I will try the kernel build of Jef Moine (http://moinejf.free.fr/opi2/index.html), with Orange PI PC support, but 1GB to download for lichee zip is long wait

Maybe an minimal mainline kernel support (HDMI, USB, ethernet) too.

boob

Here an ugly hack to compile with 32bit linux without gen_check_code problem :

edit the Makefile in OrangePI-Kernel-master/linux-3.4/arch/arm/mach-sunxi/power/brom for applying patch from JefMoine (http://moinejf.free.fr/opi2/kernel-3.4.patch).

New Makefile edited :

1. #makefile for resume.bin
   
2. 
   
3. always  := resumes.code
   
4. targets := resumes.elf
   
5. 
   
6. hostprogs-y        := mksunxichecksum
   
7. #always                += $(hostprogs-y)
   
8. 
   
9. #use "-Os" flags.
   
10. #Don't use "-O2" flags.
    
11. KBUILD_CFLAGS := -g -c -nostdlib -march=armv7-a -marm \
    
12.         -fno-unwind-tables -fno-asynchronous-unwind-tables -mlittle-endian -Os
    
13. #        --min_array_alignment=4 --no_unaligned_acces
    
14. 
    
15. KBUILD_CPPFLAGS += -I.
    
16. 
    
17. LD_FLAGS = -static
    
18. LIBS =
    
19. 
    
20. INCLUDE   = -I. \
    
21.        -I$(KDIR)/include \
    
22.        -I$(KDIR)/arch/arm/mach-sunxi/include
    
23. 
    
24. resumes-y :=   resumes.o        \
    
25.                resume_head.o
    
26. 
    
27. resumes-y := $(addprefix $(obj)/,$(resumes-y))
    
28. 
    
29. $(obj)/resumes.code: $(obj)/resumes.bin $(obj)/mksunxichecksum
    
30.         $(obj)/mksunxichecksum $(obj)/resumes.bin $(obj)/resumes.code
    
31. #        $(Q)$(obj)/gen_check_code $(obj)/resumes.bin $(obj)/resumes.code
    
32. $(obj)/resumes.bin: $(obj)/resumes.elf FORCE
    
33.         $(Q)$(CROSS_COMPILE)objcopy -O binary $(obj)/resumes.elf $(obj)/resumes.bin
    
34. 
    
35. ifneq ($(strip $(CONFIG_ARCH_SUN9I)),)
    
36. $(obj)/resumes.elf: $(srctree)/$(src)/sun9i_brom_scatter.scat $(resumes-y)
    
37.         $(Q)$(CROSS_COMPILE)ld -T $(srctree)/$(src)/sun9i_brom_scatter.scat -EL $(resumes-y) -o $(obj)/resumes.elf -Map $(obj)/resumes.map
    
38.         $(Q)$(CROSS_COMPILE)objdump -D $(obj)/resumes.elf > $(obj)/resumes.lst
    
39. endif
    
40. 
    
41. ifneq ($(strip $(CONFIG_ARCH_SUN8I)),)
    
42. $(obj)/resumes.elf: $(srctree)/$(src)/sun8i_brom_scatter.scat $(resumes-y)
    
43.         $(Q)$(CROSS_COMPILE)ld -T $(srctree)/$(src)/sun8i_brom_scatter.scat -EL $(resumes-y) -o $(obj)/resumes.elf -Map $(obj)/resumes.map
    
44.         $(Q)$(CROSS_COMPILE)objdump -D $(obj)/resumes.elf > $(obj)/resumes.lst
    
45. endif
    
46. 
    
47. clean-files += resumes.code resumes.elf

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add mksunxichecksum.c from https://gist.github.com/hno/dae626bc7765dcad2dae and change this line :

1. if (argc != 4) {
   
2.                 printf("Usage: %s file.bin file.code\n"
   
3.                        "calculates BROM checksum in boot header of given .bin file and writes to .code file\n"
   
4.                        "", argv[0]);
   
5.                 exit(1);
   
6.         }

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by :

1. if (argc != 3) {
   
2.                 printf("Usage: %s file.bin file.code\n"
   
3.                        "calculates BROM checksum in boot header of given .bin file and writes to .code file\n"
   
4.                        "", argv[0]);
   
5.                 exit(1);
   
6.         }

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It's compile now on 32bit linux system (I haven't board OP PC to test for now).