From edc3f380dcd722281bcadbbe530726f7bc03e972 Mon Sep 17 00:00:00 2001
From: Nate Clark <nate@nateclark.com>
Date: Mon, 13 May 2024 14:29:53 -0400
Subject: [PATCH] Adds fix for RMII Mode Register setting in eth config

---
 components/modules/eth.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/components/modules/eth.c b/components/modules/eth.c
index 253935b1b..c1976c064 100644
--- a/components/modules/eth.c
+++ b/components/modules/eth.c
@@ -300,6 +300,45 @@ static int leth_init( lua_State *L )
   if (err != ESP_OK)
     goto cleanup_mac_phy;
 
+  // set RMII Mode Register on RTL8201
+  if (phy_type == ETH_PHY_RTL8201 && CONFIG_ETH_RMII_CLK_INPUT) {
+    esp_err_t err;
+    uint32_t phy_rmii_mode;
+    err = mac->write_phy_reg(mac, phy_cfg.phy_addr, 0x1f, 0x07);
+    if (err != ESP_OK)
+      return luaL_error (L, "Setting Page 7 failed");
+
+    /*
+    * RTL8201 RMII Mode Setting Register (RMSR)
+    * Page 7 Register 16
+    *
+    * bit 0      Reserved            0
+    * bit 1      Rg_rmii_rxdsel      1 (default)
+    * bit 2      Rg_rmii_rxdv_sel:   0 (default)
+    * bit 3      RMII Mode:          1 (RMII Mode)
+    * bit 4~7    Rg_rmii_rx_offset:  1111 (default)
+    * bit 8~11   Rg_rmii_tx_offset:  1111 (default)
+    * bit 12     Rg_rmii_clkdir:     1 (Input)
+    * bit 13~15  Reserved            000
+    *
+    * Binary: 0001 1111 1111 1010
+    * Hex: 0x1FFA
+    *
+    */
+
+    err = mac->read_phy_reg(mac, phy_cfg.phy_addr, 0x10, &(phy_rmii_mode));
+    if (err != ESP_OK)
+      return luaL_error (L, "Read PHY RMSR Register failed");
+
+    err = mac->write_phy_reg(mac, phy_cfg.phy_addr, RTL8201_RMSR_REG_ADDR, 0x1FFA);
+    if (err != ESP_OK)
+      return luaL_error (L, "Setting Register 16 RMII Mode Setting failed");
+
+    err = mac->write_phy_reg(mac, phy_cfg.phy_addr, 0x1f, 0x0);
+    if (err != ESP_OK)
+      return luaL_error (L, "Setting Page 0 failed");
+  }
+
   esp_netif_config_t netif_cfg = ESP_NETIF_DEFAULT_ETH();
   esp_netif_t *new_eth = esp_netif_new(&netif_cfg);