Kernel build for Silicon Labs CP210x UART Bridge

[rdelpellegrino]

I want to use some ESP32 boards that use the Silicon Labs CP210x UART Bridge in WSL2.
The Tested Devices list notes that the Silicon Labs CP210x UART Bridge requires a kernel build. I also see that a procedure for building a WSL kernel has kindly been provided. Before I embark on this exercise could anyone clarify whether I will need to obtain sources from FTDI for this, or is 'Silicon Labs CP210x UART Bridge' driver already selectable in the 'menuconfig' (perhaps under some other guise?)

[rdelpellegrino]

Looks like I found the answer to my own question here.

https://github.com/microsoft/WSL2-Linux-Kernel/blob/linux-msft-wsl-5.10.y/drivers/usb/serial/Kconfig

`config USB_SERIAL_CP210X
	tristate "USB CP210x family of UART Bridge Controllers"
	help
	  Say Y here if you want to use a CP2101/CP2102/CP2103 based USB
	  to RS232 converters.

	  To compile this driver as a module, choose M here: the
	  module will be called cp210x.

Perhaps it will help someone else...
`

[rdelpellegrino]

I may as well confirm that I was able to successfully get the Silicon Labs CP210x UART Bridge in WSL2. This was done by simply blindly following the instructions on WSL-support and selecting the USB CP210x family of UART Bridge Controllers in menuconfig.

WSL2:

>  uname -r
5.10.60.1-microsoft-standard-WSL2+
>  usbip version
usbip (usbip-utils 2.0)
>  sudo usbip port
Imported USB devices
====================
Port 00: <Port in Use> at Full Speed(12Mbps)
       Silicon Labs : CP210x UART Bridge (10c4:ea60)
       1-1 -> usbip://172.30.112.1:3240/2-4
           -> remote bus/dev 002/004
>  sudo cat /dev/ttyUSB0
Restarting in 1 seconds...
Restarting in 0 seconds...
Restarting now.
I (13) boot: ESP-IDF v4.3.2 2nd stage bootloader
I (13) boot: compile time 21:00:02
I (13) boot: chip revision: 1
I (14) boot_comm: chip revision: 1, min. bootloader chip revision: 0
I (21) boot.esp32: SPI Speed      : 40MHz
I (26) boot.esp32: SPI Mode       : DIO
I (31) boot.esp32: SPI Flash Size : 4MB
I (35) boot: Enabling RNG early entropy source...
I (41) boot: Partition Table:
I (44) boot: ## Label            Usage          Type ST Offset   Length
I (51) boot:  0 nvs              WiFi data        01 02 00009000 00006000
I (59) boot:  1 phy_init         RF data          01 01 0000f000 00001000
I (66) boot:  2 factory          factory app      00 00 00010000 00100000
I (74) boot: End of partition table
I (78) boot_comm: chip revision: 1, min. application chip revision: 0
I (85) esp_image: segment 0: paddr=00010020 vaddr=3f400020 size=06de0h ( 28128) map
I (104) esp_image: segment 1: paddr=00016e08 vaddr=3ffb0000 size=02934h ( 10548) load
I (108) esp_image: segment 2: paddr=00019744 vaddr=40080000 size=068d4h ( 26836) load
I (122) esp_image: segment 3: paddr=00020020 vaddr=400d0020 size=13a74h ( 80500) map
I (151) esp_image: segment 4: paddr=00033a9c vaddr=400868d4 size=049f8h ( 18936) load
I (159) esp_image: segment 5: paddr=0003849c vaddr=50000000 size=00010h (    16) load
I (165) boot: Loaded app from partition at offset 0x10000
I (165) boot: Disabling RNG early entropy source...
I (179) cpu_start: Pro cpu up.
I (180) cpu_start: Starting app cpu, entry point is 0x40081044
I (174) cpu_start: App cpu up.
I (194) cpu_start: Pro cpu start user code
I (194) cpu_start: cpu freq: 160000000
I (194) cpu_start: Application information:
I (199) cpu_start: Project name:     hello-world
I (204) cpu_start: App version:      1
I (208) cpu_start: Compile time:     Jan 24 2022 20:59:33
I (214) cpu_start: ELF file SHA256:  a47897bfb46a08ea...
I (220) cpu_start: ESP-IDF:          v4.3.2
I (226) heap_init: Initializing. RAM available for dynamic allocation:
I (233) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM
I (239) heap_init: At 3FFB3210 len 0002CDF0 (179 KiB): DRAM
I (245) heap_init: At 3FFE0440 len 00003AE0 (14 KiB): D/IRAM
I (251) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (258) heap_init: At 4008B2CC len 00014D34 (83 KiB): IRAM
I (265) spi_flash: detected chip: winbond
I (268) spi_flash: flash io: dio
I (273) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
Hello world!
This is esp32 chip with 2 CPU core(s), WiFi/BT/BLE, silicon revision 1, 4MB external flash
Minimum free heap size: 291312 bytes

Windows:

C:\WINDOWS\system32>ver
Microsoft Windows [Version 10.0.19044.1469]

C:\WINDOWS\system32>usbipd wsl list
BUSID  DEVICE                                                        STATE
2-4    Silicon Labs CP210x USB to UART Bridge (COM3)                 Attached - wsl2-usbip
4-3    Logitech USB Input Device, USB Input Device                   Not attached

So happy days for esp32 developers...

[elasticdotventures]

I've spent a few hours already before finding your post.
Also looks like CP210x will be standard in 5.10.93.2 (no custom kernel required)
https://github.com/microsoft/WSL2-Linux-Kernel/releases/tag/linux-msft-wsl-5.10.93.2