Insight into lan78xx driver support for Pi

RE: Insight into lan78xx driver support for Pi

colporteur — Sat, 26 Jun 2021 00:03:34 GMT

[View:/resized-image/__size/924x364/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-90981cf3-7015-4e48-b1c9-32f8247ca4a5/contentimage_5F00_208074.png:924:364]

Both Pi's support the OTG configuration (shown below) that enables IP over the USB connection.

filename: /boot/config.txt

add

dtoverlay=dwc2

filename:/boot/cmdline.txt

add after rootwait

modules-load=dwc2,g_ether

The PiZeroW doesn't appear to support the OTG configuration (shown below) that detected the Ethernet.

filename: /boot/config.txt

add

otg_mode=1

GL [mention:ef601b47037147bfb9b0b4a3ab63026a:e9ed411860ed4f2ba0265705b8793d05] do you have any insight you can share?

RE: Insight into lan78xx driver support for Pi

Gough Lui — Mon, 21 Jun 2021 08:55:27 GMT

I have the unit working on my Raspberry Pi 4 (but needing a USB-C to A OTG adapter + USB-A to USB-C cable because mine is the version with the CC pin issue, so using the included captive USB-C to USB-C results in no LED/no power).

In config.txt, I added otg_mode=1

This is mandatory to enable the USB 2.0 OTG controller that services the USB-C port's data pins. If you don't add this line, you will only get power and no USB-Ethernet detection.

On startup, it is automatically picked up on my installation of Raspberry Pi OS (Raspbian):

[embed:dc8ab71f-3b98-42d9-b0f6-e21e02a0f8e2:3ef06e6b-9b7d-4651-b12d-db8be7f5e991:type=text&text=%5B%0A0.000000%5D+Linux+version+5.10.17-v7l%2B+%28dom%40buildbot%29+%28arm-linux-gnueabihf-gcc-8+%28Ubuntu%2FLinaro+8.4.0-3ubuntu1%29+8.4.0%2C+GNU+ld+%28GNU+Binutils+for+Ubuntu%29+2.34%29+%231414+SMP+Fri+Apr+30+13%3A20%3A47+BST+2021%0A%5B%0A1.394777%5D+usbcore%3A+registered+new+interface+driver+lan78xx%0A%5B%0A1.984215%5D+usb+3-1%3A+New+USB+device+found%2C+idVendor%3D0424%2C+idProduct%3D7800%2C+bcdDevice%3D+3.00%0A%5B%0A1.984263%5D+usb+3-1%3A+New+USB+device+strings%3A+Mfr%3D1%2C+Product%3D2%2C+SerialNumber%3D3%0A%5B%0A1.984296%5D+usb+3-1%3A+Product%3A+LAN7800%0A%5B%0A1.984324%5D+usb+3-1%3A+Manufacturer%3A+Microchip%0A%5B%0A1.984353%5D+usb+3-1%3A+SerialNumber%3A+210460000404%0A%5B%0A2.271146%5D+libphy%3A+lan78xx-mdiobus%3A+probed%0A%5B%0A2.271192%5D+lan78xx+3-1%3A1.0+%28unnamed+net_device%29+%28uninitialized%29%3A+int+urb+period+64]

I did not need to install any drivers at all to get it working. I wasn't going to write about this until I delivered my RoadTest ... but seeing that you're rushing ahead into blogging, I thought I'd mention it.

Why does your kernel command line have initcall_blacklist=lan78xx_driver_init? That's perhaps not a good thing ... could stop a driver from loading. Perhaps start from a fresh Raspberry Pi OS (Raspbian) and add otg_mode=1 and it should just work.

- Gough

RE: Insight into lan78xx driver support for Pi

Jan Cumps — Mon, 21 Jun 2021 06:41:50 GMT

(On that page, under the Document tab, there is a driver section.

If you click the one for the kernel version of your OS, you get a link to the driver tarball.)

Edit: seems from your comments that you are on kernel 5.10. I didn't find a driver for it . But when I check linux git (and raspberry git), it seems to be part of the base code now. Odd.

RE: Insight into lan78xx driver support for Pi

skruglewicz — Sun, 20 Jun 2021 21:02:36 GMT

Doesn't the PI 4 have a type c power connector?