ESP_ETH_PHY_ADDR_AUTO not supported by arduino-esp32 - signedness problem

[sauttefk]

Board

Any board with Ethernet

Device Description

Any board with Ethernet

Hardware Configuration

Any board with Ethernet

Version

latest master (checkout manually)

IDE Name

not relevant

Operating System

not relevant

Flash frequency

not relevant

PSRAM enabled

yes

Upload speed

not relevant

Description

ETHClass::begin accepts phy_addr as uint8_t introduced in IDF 5.x the new mode ESP_ETH_PHY_ADDR_AUTO (defined as -1) to automatically detect the Ethernet PHY address.

The problem arises from a mismatch in signedness between the parameter phy_addr of ETHClass::begin and its counterpart in the eth_phy_config_t struct, where phy_addr is defined as int32_t. This discrepancy leads to unintended behavior: the value -1, when interpreted as an unsigned uint8_t, becomes 255, resulting in a failed PHY detection process.

Additionally, the error message "SPI Ethernet driver install failed" is inaccurately displayed for all Ethernet drivers, not just SPI.

Sketch

/*
    This sketch shows the Ethernet event usage

*/

// Important to be defined BEFORE including ETH.h for ETH.begin() to work.
// Example RMII LAN8720 (Olimex, etc.)
#ifndef ETH_PHY_TYPE
#define ETH_PHY_TYPE        ETH_PHY_LAN8720
#define ETH_PHY_ADDR        ESP_ETH_PHY_ADDR_AUTO
#define ETH_PHY_MDC         23
#define ETH_PHY_MDIO        18
#define ETH_PHY_POWER       -1
#define ETH_CLK_MODE        ETH_CLOCK_GPIO0_IN
#endif

#include <ETH.h>

static bool eth_connected = false;

// WARNING: WiFiEvent is called from a separate FreeRTOS task (thread)!
void WiFiEvent(WiFiEvent_t event)
{
  switch (event) {
    case ARDUINO_EVENT_ETH_START:
      Serial.println("ETH Started");
      // The hostname must be set after the interface is started, but needs
      // to be set before DHCP, so set it from the event handler thread.
      ETH.setHostname("esp32-ethernet");
      break;
    case ARDUINO_EVENT_ETH_CONNECTED:
      Serial.println("ETH Connected");
      break;
    case ARDUINO_EVENT_ETH_GOT_IP:
      Serial.println("ETH Got IP");
      ETH.printInfo(Serial);
      eth_connected = true;
      break;
    case ARDUINO_EVENT_ETH_LOST_IP:
      Serial.println("ETH Lost IP");
      eth_connected = false;
      break;
    case ARDUINO_EVENT_ETH_DISCONNECTED:
      Serial.println("ETH Disconnected");
      eth_connected = false;
      break;
    case ARDUINO_EVENT_ETH_STOP:
      Serial.println("ETH Stopped");
      eth_connected = false;
      break;
    default:
      break;
  }
}

void testClient(const char * host, uint16_t port)
{
  Serial.print("\nconnecting to ");
  Serial.println(host);

  WiFiClient client;
  if (!client.connect(host, port)) {
    Serial.println("connection failed");
    return;
  }
  client.printf("GET / HTTP/1.1\r\nHost: %s\r\n\r\n", host);
  while (client.connected() && !client.available());
  while (client.available()) {
    Serial.write(client.read());
  }

  Serial.println("closing connection\n");
  client.stop();
}

void setup()
{
  Serial.begin(115200);
  WiFi.onEvent(WiFiEvent);  // Will call WiFiEvent() from another thread.
  ETH.begin();
}

void loop()
{
  if (eth_connected) {
    testClient("google.com", 80);
  }
  delay(10000);
}

Debug Message

[  4152][E][eth_phy_802_3]: esp_eth_phy_802_3_pwrctl(244): power up timeout
[  4160][E][eth_phy_802_3]: esp_eth_phy_802_3_basic_phy_init(410): power control failed
[  4169][E][lan87xx]: lan87xx_init(341): failed to init PHY
[  4175][E][esp_eth]: esp_eth_driver_install(229): init phy failed
[  2188][E][ETH.cpp:171] begin(): SPI Ethernet driver install failed: -1

Other Steps to Reproduce

1. Call ETHClass::begin with phy_addr set to ESP_ETH_PHY_ADDR_AUTO.
2. Observe the value of phy_addr within the eth_phy_config_t struct.
3. Notice the discrepancy between the expected and actual values, leading to failed PHY detection.

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[P-R-O-C-H-Y]

Thanks @sauttefk for reporting the issue. I have opened a PR #9313, please if you have spare time, give it a try if everything works now :)