esp_eth: Add ioctl command for getting duplex mode

Similar to ETH_CMD_G_SPEED, add ETH_CMD_G_DUPLEX_MODE for getting duplex mode.

Merges https://github.com/espressif/esp-idf/pull/6436

components/esp_eth/include/esp_eth_com.h

@@ -93,6 +93,7 @@ typedef enum {
     ETH_CMD_G_SPEED,       /*!< Get Speed */
     ETH_CMD_S_PROMISCUOUS, /*!< Set promiscuous mode */
     ETH_CMD_S_FLOW_CTRL,   /*!< Set flow control */
+    ETH_CMD_G_DUPLEX_MODE, /*!< Get Duplex mode */
 } esp_eth_io_cmd_t;
 
 /**

components/esp_eth/src/esp_eth.c

@@ -379,6 +379,10 @@ esp_err_t esp_eth_ioctl(esp_eth_handle_t hdl, esp_eth_io_cmd_t cmd, void *data)
         ETH_CHECK(mac->enable_flow_ctrl(mac, (bool)data) == ESP_OK, "enable mac flow control failed", err, ESP_FAIL);
         ETH_CHECK(phy->advertise_pause_ability(phy, (uint32_t)data) == ESP_OK, "phy advertise pause ability failed", err, ESP_FAIL);
         break;
+    case ETH_CMD_G_DUPLEX_MODE:
+        ETH_CHECK(data, "no mem to store duplex value", err, ESP_ERR_INVALID_ARG);
+        *(eth_duplex_t *)data = eth_driver->duplex;
+        break;
     default:
         ETH_CHECK(false, "unknown io command: %d", err, ESP_ERR_INVALID_ARG, cmd);
         break;