Rebase PoE delta onto merged PR #1983 Ethernet foundation

#1983 landed a generic RAK4631 Ethernet base (repeater/room_server/companion
envs, single-client SerialEthernetInterface, EthernetCLI telnet CLI) and
independently added the same WB_IO2 rail-power fix we found for PoE boot.
Layer the remaining PoE-specific delta on top of it instead of duplicating:

- W5100SPoE: drop the now-redundant WB_IO2 early-ctor code (covered by
  #1983's own constructor), keep only the early W5100S RST release and the
  bit-bang activation/VERSIONR check.
- SerialEthernetInterface: add PoE-safe deferred bring-up (Ethernet.init/
  begin() moved out of begin() into loop(), gated by an _hwReady flag, so
  the disruptive PHY soft-reset + DHCP can't collapse the marginal PoE
  supply at cold start) and bounded DHCP with a static-IP fallback.
- EthernetCLI: same deferral (vTaskDelay before hardware bring-up) and
  bounded DHCP + static fallback for the repeater/room_server telnet path.
- platformio.ini: add RAK_4631_{repeater,room_server,companion_radio}
  _ethernet_poe envs extending #1983's _ethernet envs with WITH_W5100S_POE.

Verified: all three new _poe envs build, plus the plain _ethernet envs and
non-Ethernet variants (no cross-variant breakage).

Co-Authored-By: Claude Sonnet 5 <[email protected]>

src/helpers/nrf52/EthernetCLI.h

@@ -27,6 +27,26 @@ static SPIClass ETHERNET_SPI_PORT(NRF_SPIM1, PIN_SPI1_MISO, PIN_SPI1_SCK, PIN_SP
 
 #define ETHERNET_RETRY_INTERVAL_MS 30000
 
+#ifdef WITH_W5100S_POE
+  // Give the RAK19018 (Silvertel) PoE converter time to latch on the current
+  // the W5100S is already drawing (board.begin()'s early RST release +
+  // bit-bang soft-reset) before doing the *disruptive* Ethernet-library
+  // bring-up (another PHY soft-reset + blocking DHCP) — doing that
+  // immediately reliably collapsed the marginal PoE supply.
+  #ifndef ETH_POE_DEFER_MS
+    #define ETH_POE_DEFER_MS 6000
+  #endif
+  #ifndef ETH_STATIC_IP
+    #define ETH_STATIC_IP  192,168,1,50
+  #endif
+  #ifndef ETH_GATEWAY
+    #define ETH_GATEWAY    192,168,1,1
+  #endif
+  #ifndef ETH_SUBNET
+    #define ETH_SUBNET     255,255,255,0
+  #endif
+#endif
+
 static EthernetServer ethernet_server(ETHERNET_TCP_PORT);
 static EthernetClient ethernet_client;
 static volatile bool ethernet_running = false;
@@ -35,6 +55,10 @@ static volatile bool ethernet_running = false;
 static void ethernet_task(void* param) {
   (void)param;
 
+#ifdef WITH_W5100S_POE
+  vTaskDelay(pdMS_TO_TICKS(ETH_POE_DEFER_MS));
+#endif
+
   Serial.println("ETH: Initializing hardware");
   // WB_IO2 (power enable) is already driven HIGH by early constructor
   // in RAK4631Board.cpp to support POE boot.
@@ -51,6 +75,22 @@ static void ethernet_task(void* param) {
   Serial.printf("ETH: MAC: %02X:%02X:%02X:%02X:%02X:%02X\n",
       mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
 
+#ifdef WITH_W5100S_POE
+  // Bounded DHCP with a static-IP fallback, so the node stays reachable even
+  // without a DHCP server (no infinite retry — this build has no battery and
+  // must always come up somewhere).
+  Serial.println("ETH: Attempting DHCP...");
+  if (Ethernet.begin(mac, 10000, 2000) == 0) {
+    Serial.println("ETH: DHCP failed -> static IP fallback");
+    IPAddress ip(ETH_STATIC_IP), gw(ETH_GATEWAY), sn(ETH_SUBNET);
+    Ethernet.begin(mac, ip, gw, gw, sn);
+  }
+  IPAddress ip = Ethernet.localIP();
+  Serial.printf("ETH: IP: %u.%u.%u.%u\n", ip[0], ip[1], ip[2], ip[3]);
+  Serial.printf("ETH: Listening on TCP port %d\n", ETHERNET_TCP_PORT);
+  ethernet_server.begin();
+  ethernet_running = true;
+#else
   // Retry loop: keep trying until we get an IP
   while (!ethernet_running) {
     Serial.println("ETH: Attempting DHCP...");
@@ -75,8 +115,9 @@ static void ethernet_task(void* param) {
     ethernet_server.begin();
     ethernet_running = true;
   }
+#endif
 
-  // DHCP succeeded, task is done
+  // DHCP succeeded (or static fallback applied), task is done
   vTaskDelete(NULL);
 }
 

src/helpers/nrf52/SerialEthernetInterface.cpp

@@ -48,7 +48,7 @@ static void eth_init_spi_and_pins() {
 }
 
 // Bring up the DHCP/static IP + start listening. Returns true on success.
-static bool eth_bring_up(const uint8_t mac[6]) {
+static bool eth_bring_up(uint8_t mac[6]) {
 #ifdef WITH_W5100S_POE
   // Bounded DHCP with a static-IP fallback, so the node stays reachable even
   // without a DHCP server and never blocks indefinitely at cold start.

variants/rak4631/W5100SPoE.cpp

@@ -4,29 +4,15 @@
 #include <nrf.h>
 #include "W5100SPoE.h"
 
-// ── Early power-rail + RST release (constructor priority 200) ────────────────
-// Runs before setup(), right after SystemInit. Two jobs, as early as possible
-// so the W5100S draws its full operating current before the RAK19018
-// (Silvertel) converter folds back during PoE cold-start:
-//
-//   1. Drive PIN_3V3_EN (P1.02 / WB_IO2 / Arduino 34) HIGH — this is the
-//      RAK19007 3.3 V PERIPHERAL POWER ENABLE that feeds the RAK13800/W5100S.
-//      Meshtastic does this in initVariant(); stock MeshCore never did, so our
-//      W5100S was only weakly powered via a default path (responds on USB but
-//      can't pull its full ~130 mA on the marginal PoE rail).
-//   2. Drive W5100S RST (P0.21 / WB_IO3 / Arduino 21) HIGH — out of reset.
+// ── Early RST release (constructor priority 200) ─────────────────────────────
+// Runs before setup(), right after SystemInit — earlier than the ETHERNET_ENABLED
+// constructor in RAK4631Board.cpp that powers the peripheral rail (WB_IO2,
+// priority 102 runs first) but well before setup()/board.begin(), so the
+// W5100S starts drawing its full operating current as early as possible,
+// before the RAK19018 (Silvertel) converter's foldback timer expires.
 //
 // Raw registers because the Arduino GPIO layer isn't up this early.
-static void __attribute__((constructor(200))) w5100s_early_power_init() {
-    // P1.02 = 3V3_EN → HIGH (power the peripheral rail FIRST)
-    NRF_P1->PIN_CNF[2] =
-        (GPIO_PIN_CNF_DIR_Output       << GPIO_PIN_CNF_DIR_Pos) |
-        (GPIO_PIN_CNF_INPUT_Disconnect << GPIO_PIN_CNF_INPUT_Pos) |
-        (GPIO_PIN_CNF_PULL_Disabled    << GPIO_PIN_CNF_PULL_Pos) |
-        (GPIO_PIN_CNF_DRIVE_S0S1       << GPIO_PIN_CNF_DRIVE_Pos) |
-        (GPIO_PIN_CNF_SENSE_Disabled   << GPIO_PIN_CNF_SENSE_Pos);
-    NRF_P1->OUTSET = (1UL << 2);
-
+static void __attribute__((constructor(200))) w5100s_early_rst_release() {
     // P0.21 = W5100S RST → HIGH (release from reset)
     NRF_P0->PIN_CNF[21] =
         (GPIO_PIN_CNF_DIR_Output       << GPIO_PIN_CNF_DIR_Pos) |
@@ -83,13 +69,11 @@ static uint8_t bb_read_reg(uint16_t addr) {
 }
 
 // ── Full W5100S bring-up ────────────────────────────────────────────────────
-// Called from RAK4631Board::begin(). Confirms the 3V3 rail + RST are driven
-// (Arduino API, in case the core re-init touched them), then soft-resets and
-// reads VERSIONR. Returns VERSIONR (0x51 = healthy W5100S).
+// Called from RAK4631Board::begin(). Confirms RST is driven (Arduino API, in
+// case the core re-init touched it), then soft-resets and reads VERSIONR.
+// Returns VERSIONR (0x51 = healthy W5100S).
 uint8_t w5100s_poe_init() {
-    // Make sure the peripheral power rail stays driven HIGH.
-    pinMode(W5100S_3V3_EN_PIN, OUTPUT); digitalWrite(W5100S_3V3_EN_PIN, HIGH);
-    delay(20);  // let the rail/W5100S settle after enable
+    delay(20);  // let the rail/W5100S settle after the ETHERNET_ENABLED ctor's WB_IO2 enable
 
     // Park both chip-selects HIGH on the shared bus, RST released.
     pinMode(LORA_NSS_PIN,   OUTPUT); digitalWrite(LORA_NSS_PIN,   HIGH);

variants/rak4631/W5100SPoE.h

@@ -1,6 +1,7 @@
 #pragma once
 
-// W5100S activation for PoE operation on RAK10720 (RAK4631 + RAK13800 + RAK19018).
+// W5100S early activation for PoE operation on RAK10720 (RAK4631 + RAK13800 +
+// RAK19018).
 //
 // ROOT CAUSE (confirmed via RAK forum + Meshtastic rak4631_eth_gw variant):
 // The RAK19018 PoE module (Silvertel Ag9905MT) enters a non-continuous
@@ -8,14 +9,14 @@
 // repeater draws only a few mA, so the converter never latches → the supply
 // pulses and the device never boots (fade-in / brighten / die / repeat LED).
 //
-// The fix that lets Meshtastic boot on PoE without a battery: bring the
-// W5100S PHY into its active state. An active W5100S draws ~120 mA — enough
-// to keep the Silvertel converter latched in continuous mode.
-//
-// The W5100S has no power-enable pin on this board (always powered), but its
-// RST must be HIGH for the PHY to run. We release RST as early as possible
-// (before setup(), via a constructor) so the PHY draws current and latches
-// the converter before its foldback timer expires.
+// The fix: bring the W5100S PHY into its active state as early as possible.
+// An active W5100S draws ~120 mA — enough to keep the Silvertel converter
+// latched in continuous mode. The peripheral power rail (WB_IO2 / P1.02) is
+// already driven HIGH by an early constructor in RAK4631Board.cpp whenever
+// ETHERNET_ENABLED is set; this file only handles releasing RST (the rail
+// alone isn't enough — the chip must actually be brought out of reset and
+// made to draw its full current well before the Ethernet library's own
+// (later, disruptive) bring-up runs).
 //
 // Pin mapping (from Meshtastic rak4631_eth_gw variant.h):
 //   RST → PIN_ETHERNET_RESET = 21 (P0.21 / WB_IO3)
@@ -30,13 +31,6 @@
   #define W5100S_CS_PIN   26   // WB_SPI_CS
 #endif
 
-// RAK19007 3.3 V peripheral power enable (feeds the RAK13800/W5100S).
-// Must be driven HIGH or the W5100S is only weakly powered — exactly what
-// Meshtastic's initVariant() does and stock MeshCore omits.
-#ifndef W5100S_3V3_EN_PIN
-  #define W5100S_3V3_EN_PIN  34   // P1.02 / WB_IO2
-#endif
-
 // Called from RAK4631Board::begin(); fully brings up the W5100S (soft reset +
 // activation) so it draws full operating current. Returns VERSIONR (0x51 = ok).
 uint8_t w5100s_poe_init();

variants/rak4631/platformio.ini

@@ -267,3 +267,27 @@ build_src_filter = ${rak4631.build_src_filter}
   +<../examples/kiss_modem/>
 lib_deps =
   ${rak4631.lib_deps}
+
+; RAK10720 (RAK4631 + RAK13800/W5100S + RAK19018 PoE) variants.
+; WITH_W5100S_POE adds: early W5100S RST release + activation (so the
+; RAK19018/Silvertel converter latches on PoE with no battery), the
+; no-battery boot-voltage bypass, and PoE-safe deferred Ethernet bring-up
+; (DHCP with a bounded timeout + static-IP fallback, after the converter
+; is solidly latched).
+[env:RAK_4631_repeater_ethernet_poe]
+extends = env:RAK_4631_repeater_ethernet
+build_flags =
+  ${env:RAK_4631_repeater_ethernet.build_flags}
+  -D WITH_W5100S_POE=1
+
+[env:RAK_4631_room_server_ethernet_poe]
+extends = env:RAK_4631_room_server_ethernet
+build_flags =
+  ${env:RAK_4631_room_server_ethernet.build_flags}
+  -D WITH_W5100S_POE=1
+
+[env:RAK_4631_companion_radio_ethernet_poe]
+extends = env:RAK_4631_companion_radio_ethernet
+build_flags =
+  ${env:RAK_4631_companion_radio_ethernet.build_flags}
+  -D WITH_W5100S_POE=1