Elipsa USB OTG support on Elipsa

karnak · 06-07-2025, 03:40 AM

I was playing around with an Elipsa (SW 4.38.21908) and got OTG to work earlier today. I did not see a post so I'm adding it here.

To check the current USB mode:

Code:

# cat /sys/devices/platform/soc/usbc0/otg_role 
usb_device

To change it to host mode

Code:

# echo usb_host > /sys/devices/platform/soc/usbc0/otg_role
# cat /sys/devices/platform/soc/usbc0/otg_role 
usb_host

To change it back to device mode

Code:

# echo usb_device > /sys/devices/platform/soc/usbc0/otg_role

A few things I tried

- I was able to mount a usb pen and use a keyboard
- devices worked both with a regular usb to usb-c adaptor and with one of those OTG usb-c splitter cables (power of usb-c and device over usb-a)
- I was unable to use a USB Ethernet dongle though (not sure why, could be drivers)

I ran out of time for today. But maybe tomorrow or next week I'll have a deeper look.

lordeagle · 06-09-2025, 05:32 AM

Fantastic news, thanks a lot for sharing; indeed it would be great to get Ethernet going as well.

karnak · 07-03-2025, 07:03 AM

realtek 8153 usb ethernet adaptor works - interface was named eth0.

The default system runs dhcpcd 6.6 with an allow list for wlan0.
I was able to get an address for eth0 by running: dhcpcd -n eth0

But this clobbered the already running dhcpcd instance. Allowing the device to sleep seems to kill my running dhcpcd and restoring the old one, but this still leaves the IPs on both interfaces (which is weird but i'm not complaining).

There is a running dhcpd-dbus - so hopefully there is a better way to do this.

Also on the usb port I tried to connect a usb audio adaptor. aplay is installed and lists the device

[root@kobo onboard]# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Device [C-Media USB Audio Device], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

There are no default sound configs in the system, so playing a wav failed (probably missing channel alsa settings). But I was able to feed some random noise to the audio output. I did not check the mic.

Finally I tried to plug a couple USB hubs to add more devices. But results were mixed. First I saw some dmesg errors with devices failing to get address, but eventually was able to connect the ethernet adaptor and the audio card via a cheap 4-port USB hub.

06-07-2025, 03:40 AM	#1
karnak Junior Member Posts: 3 Karma: 10 Join Date: Jun 2025 Device: none	USB OTG support on Elipsa I was playing around with an Elipsa (SW 4.38.21908) and got OTG to work earlier today. I did not see a post so I'm adding it here. To check the current USB mode: Code: # cat /sys/devices/platform/soc/usbc0/otg_role usb_device To change it to host mode Code: # echo usb_host > /sys/devices/platform/soc/usbc0/otg_role # cat /sys/devices/platform/soc/usbc0/otg_role usb_host To change it back to device mode Code: # echo usb_device > /sys/devices/platform/soc/usbc0/otg_role A few things I tried - I was able to mount a usb pen and use a keyboard - devices worked both with a regular usb to usb-c adaptor and with one of those OTG usb-c splitter cables (power of usb-c and device over usb-a) - I was unable to use a USB Ethernet dongle though (not sure why, could be drivers) I ran out of time for today. But maybe tomorrow or next week I'll have a deeper look.

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06-09-2025, 05:32 AM	#2
lordeagle Enthusiast Posts: 49 Karma: 17448 Join Date: Jun 2020 Device: Kobo Elipsa2E & Libra H20, Kindle PW3 & PW2	Fantastic news, thanks a lot for sharing; indeed it would be great to get Ethernet going as well.

07-03-2025, 07:03 AM	#3
karnak Junior Member Posts: 3 Karma: 10 Join Date: Jun 2025 Device: none	realtek 8153 usb ethernet adaptor works - interface was named eth0. The default system runs dhcpcd 6.6 with an allow list for wlan0. I was able to get an address for eth0 by running: dhcpcd -n eth0 But this clobbered the already running dhcpcd instance. Allowing the device to sleep seems to kill my running dhcpcd and restoring the old one, but this still leaves the IPs on both interfaces (which is weird but i'm not complaining). There is a running dhcpd-dbus - so hopefully there is a better way to do this. Also on the usb port I tried to connect a usb audio adaptor. aplay is installed and lists the device [root@kobo onboard]# aplay -l ** List of PLAYBACK Hardware Devices ** card 0: Device [C-Media USB Audio Device], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 There are no default sound configs in the system, so playing a wav failed (probably missing channel alsa settings). But I was able to feed some random noise to the audio output. I did not check the mic. Finally I tried to plug a couple USB hubs to add more devices. But results were mixed. First I saw some dmesg errors with devices failing to get address, but eventually was able to connect the ethernet adaptor and the audio card via a cheap 4-port USB hub.