Wiznet makers

What This PR Does

This is an Ethernet driver PR that enables WIZnet W6300 support on Zephyr RTOS.

It brings the W6300-EVB-Pico2 board (RP2350 + W6300) into the Zephyr ecosystem — adding the driver code, Devicetree binding, board definition files, and documentation all in one go.

Authored by WIZnet engineer Ethan-cho (Manjae Cho), the PR is currently going through community review with the goal of merging into the Zephyr mainline repository.

Background: W6300 on Zephyr

Zephyr RTOS is an open-source real-time operating system used across a wide range of domains — industrial IoT, wearables, automotive embedded systems, and more. Managed by the Linux Foundation with over 14,000 GitHub stars, getting a driver merged here means the chip becomes immediately usable across countless Zephyr-based projects.

The W6300 is WIZnet's latest Ethernet controller, supporting up to 90Mbps throughput via a hardwired TCP/IP stack and QSPI interface. Until now, no official Zephyr driver existed for the W6300. This PR is the first attempt to fill that gap.

The Role of WIZnet W6300

In this driver, the W6300 handles Ethernet MAC/PHY and packet I/O. It operates in MACRAW mode, passing raw Ethernet frames directly to the host (RP2350), with TCP/IP processing handled by the Zephyr network stack.

⚠️ What's Not Implemented Yet

Two of the W6300's headline features are not yet implemented in this PR.

In short, this is a baseline implementation that drives the W6300 via bit-bang SPI (500kHz) in MACRAW mode. The chip's performance advantages — QSPI throughput and TOE offloading — are not utilized at this stage.

The approach follows Zephyr's established driver patterns: MACRAW is the standard integration method for Ethernet controllers in Zephyr, and the existing W5500 driver uses the same approach.

How It Works

Bit-bang SPI Layer

The W6300 and RP2350 communicate via the zephyr,spi-bitbang driver, which software-toggles GPIO17 (CLK), GPIO18 (MOSI), GPIO19 (MISO), and GPIO16 (CS) directly. The maximum clock is set to 500kHz. The driver uses W6300's binary register protocol — selecting a register block via BSB (Block Select Bit), then exchanging a 16-bit address and data.

// W6300 SPI frame structure (from driver code)
uint8_t header[3] = {
    w6300_spi_instr(W6300_SPI_RWB_READ, bsb),
    (uint8_t)(addr >> 8),
    (uint8_t)addr,
};

MACRAW RX Loop

A dedicated Zephyr thread (eth_w6300) polls the W6300's receive buffer on interrupt, then passes Ethernet frames up to the Zephyr network stack via net_recv_data.

Devicetree Configuration

All hardware configuration — pin assignments, SPI bus, interrupt, and MAC address — is declared in Devicetree. The zephyr,random-mac-address property enables dynamic MAC address assignment.

/* W6300-EVB-Pico2 Devicetree (actual) */
spi_w6300: spi-bitbang {
    compatible = "zephyr,spi-bitbang";
    clk-gpios  = <&gpio0 17 GPIO_ACTIVE_HIGH>;
    mosi-gpios = <&gpio0 18 GPIO_ACTIVE_HIGH>;
    miso-gpios = <&gpio0 19 GPIO_ACTIVE_HIGH>;
    cs-gpios   = <&gpio0 16 GPIO_ACTIVE_LOW>;
    ethernet: w6300@0 {
        compatible = "wiznet,w6300";
        spi-max-frequency = <500000>;
        int-gpios = <&gpio0 15 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
        reset-gpios = <&gpio0 22 GPIO_ACTIVE_LOW>;
        zephyr,random-mac-address;
    };
};

Zephyr Network Stack Integration

By implementing Zephyr's ethernet.h API, the driver abstracts the W6300 entirely from the application layer. Any network feature Zephyr supports — DHCP, TCP/UDP, IPv4/IPv6 — works out of the box.

Hardware Overview

What This Driver Opens Up

Once merged into the Zephyr mainline, the W6300 becomes an immediately usable component across any Zephyr-based platform or application.

The current lack of QSPI support also means there is room for the driver to grow — the W6300's hardware is capable of far more than what this initial implementation uses.

Tech Stack Summary

Closing

This PR is the first step toward W6300 becoming an officially supported part in the Zephyr RTOS ecosystem. The current implementation is minimal — bit-bang SPI at 500kHz with MACRAW — but establishing W6300 within Zephyr's driver framework is itself significant. Once a WIZnet chip is registered as an officially supported component in one of the world's largest embedded RTOS projects, industrial and commercial adoption naturally follows.

Project Link

• Zephyr PR: https://github.com/zephyrproject-rtos/zephyr/pull/102727