hello i just install the latest armbian on orange pi pc2 board, the kernal is already 4.14 therefore the OTG function should be there.

 

root@orangepipc2:~# dmesg |grep musb
[    1.323924] musb-hdrc musb-hdrc.1.auto: MUSB HDRC host driver
[    1.323939] musb-hdrc musb-hdrc.1.auto: new USB bus registered, assigned bus number 9
[    1.324416] usb usb9: Manufacturer: Linux 4.14.78-sunxi64 musb-hcd
[    1.324421] usb usb9: SerialNumber: musb-hdrc.1.auto
 

however, i cannot enable the usb serial over OTG. 

anyone can show me how to do it?

i tried it on debian and windows but both has nothing when i connect to the OTG port.

thanks very much!

 

does lsmod show g_serial as loaded?

did you connect the USB cable before booting?

I did read that some boards does activate the USB-serial only at boot time. so connecting later the cable doesnt work every time.

Hi,

thanks your reply.

it seems the g_serial is not loaded;

root@orangepipc2:~# lsmod
Module                  Size  Used by
rc_cec                 16384  0
ir_lirc_codec          16384  0
snd_soc_hdmi_codec     16384  1
lirc_dev               20480  1 ir_lirc_codec
dw_hdmi_i2s_audio      16384  0
dw_hdmi_cec            16384  0
snd_soc_simple_card    16384  0
sun8i_codec_analog     28672  1
snd_soc_simple_card_utils    16384  1 snd_soc_simple_card
sun4i_codec            49152  3
sun4i_i2s              20480  2
snd_soc_core          155648  6 sun4i_i2s,sun8i_codec_analog,snd_soc_hdmi_codec,sun4i_codec,snd_soc_simple_card_utils,snd_soc_simple_card
snd_pcm_dmaengine      16384  1 snd_soc_core
sunxi_cir              16384  0
snd_pcm               106496  4 sun4i_i2s,snd_soc_hdmi_codec,snd_soc_core,snd_pcm_dmaengine
sun8i_dw_hdmi          16384  0
snd_timer              32768  1 snd_pcm
dw_hdmi                28672  2 dw_hdmi_i2s_audio,sun8i_dw_hdmi
cec                    53248  2 dw_hdmi_cec,dw_hdmi
rc_core                32768  7 rc_cec,lirc_dev,ir_lirc_codec,sunxi_cir,cec
sun4i_gpadc_iio        16384  0
sun8i_mixer            16384  0
sun4i_tcon             28672  1 sun8i_dw_hdmi
iio_hwmon              16384  0
sun4i_drm              16384  0
industrialio           65536  2 sun4i_gpadc_iio,iio_hwmon
zram                   28672  5
sy8106a_regulator      16384  1
sunxi                  20480  0
musb_hdrc              98304  1 sunxi
 

i tried reboot the board with my USB connected to board microUSB OTG port, but still no g_serial loaded.

how can i configure it to load g_serial?

 

please check if the module is available with

modprobe g_serial

 

On a NanoPi Neo2 with Linux npi-neo2-23 4.14.89-sunxi64 is available:
 

root@npi-neo2-23(192.168.6.23):~# lsmod
Module                  Size  Used by
u_serial               24576  3 usb_f_acm
g_serial               16384  0
libcomposite           49152  2 g_serial,usb_f_acm

but on another Neo2 with Linux npi-neo2-27 4.19.4-sunxi64 it isnt available (to new?)
 

root@npi-neo2-27(192.168.6.27):~# modprobe g_serial
modprobe: FATAL: Module g_serial not found in directory /lib/modules/4.19.4-sunxi64

 

You can also check the following thread: