usb_host: Unify CDC event callbacks

And return error code from C++ close method.

examples/peripherals/usb/host/cdc/common/cdc_acm_host/cdc_acm_host.c

@@ -946,7 +946,7 @@ static bool cdc_acm_is_transfer_completed(usb_transfer_t *transfer)
                 .type = CDC_ACM_HOST_ERROR,
                 .data.error = (int) transfer->status
             };
-            cdc_dev->notif.cb((cdc_acm_dev_hdl_t) cdc_dev, &error_event, cdc_dev->cb_arg);
+            cdc_dev->notif.cb(&error_event, cdc_dev->cb_arg);
         }
     }
     return completed;
@@ -981,7 +981,7 @@ static void notif_xfer_cb(usb_transfer_t *transfer)
                     .type = CDC_ACM_HOST_NETWORK_CONNECTION,
                     .data.network_connected = (bool) notif->wValue
                 };
-                cdc_dev->notif.cb((cdc_acm_dev_hdl_t) cdc_dev, &net_conn_event, cdc_dev->cb_arg);
+                cdc_dev->notif.cb(&net_conn_event, cdc_dev->cb_arg);
             }
             break;
         }
@@ -992,7 +992,7 @@ static void notif_xfer_cb(usb_transfer_t *transfer)
                     .type = CDC_ACM_HOST_SERIAL_STATE,
                     .data.serial_state = cdc_dev->serial_state
                 };
-                cdc_dev->notif.cb((cdc_acm_dev_hdl_t) cdc_dev, &serial_state_event, cdc_dev->cb_arg);
+                cdc_dev->notif.cb(&serial_state_event, cdc_dev->cb_arg);
             }
             break;
         }
@@ -1043,8 +1043,9 @@ static void usb_event_cb(const usb_host_client_event_msg_t *event_msg, void *arg
                 // The suddenly disconnected device was opened by this driver: inform user about this
                 const cdc_acm_host_dev_event_data_t disconn_event = {
                     .type = CDC_ACM_HOST_DEVICE_DISCONNECTED,
+                    .data.cdc_hdl = (cdc_acm_dev_hdl_t) cdc_dev,
                 };
-                cdc_dev->notif.cb((cdc_acm_dev_hdl_t) cdc_dev, &disconn_event, cdc_dev->cb_arg);
+                cdc_dev->notif.cb(&disconn_event, cdc_dev->cb_arg);
             }
         }
         break;

examples/peripherals/usb/host/cdc/common/cdc_acm_host/include/usb/cdc_acm_host.h

@@ -64,9 +64,10 @@ typedef enum {
 typedef struct {
     cdc_acm_host_dev_event_t type;
     union {
-        int error;                         // Error code from USB Host
-        cdc_acm_uart_state_t serial_state; // Serial (UART) state
-        bool network_connected;            // Network connection event
+        int error;                         //!< Error code from USB Host
+        cdc_acm_uart_state_t serial_state; //!< Serial (UART) state
+        bool network_connected;            //!< Network connection event
+        cdc_acm_dev_hdl_t cdc_hdl;         //!< Disconnection event
     } data;
 } cdc_acm_host_dev_event_data_t;
 
@@ -87,9 +88,9 @@ typedef void (*cdc_acm_data_callback_t)(uint8_t* data, size_t data_len, void *us
 
 /**
  * @brief Device event callback type
- * @see cdc_acm_host_dev_event_t
+ * @see cdc_acm_host_dev_event_data_t
  */
-typedef void (*cdc_acm_host_dev_callback_t)(cdc_acm_dev_hdl_t cdc_hdl, const cdc_acm_host_dev_event_data_t *event, void *user_ctx);
+typedef void (*cdc_acm_host_dev_callback_t)(const cdc_acm_host_dev_event_data_t *event, void *user_ctx);
 
 /**
  * @brief Configuration structure of USB Host CDC-ACM driver
@@ -298,10 +299,13 @@ public:
         return cdc_acm_host_open_vendor_specific(vid, pid, interface_idx, dev_config, &this->cdc_hdl);
     }
 
-    inline void close()
+    inline esp_err_t close()
     {
-        cdc_acm_host_close(this->cdc_hdl);
-        this->cdc_hdl = NULL;
+        esp_err_t err = cdc_acm_host_close(this->cdc_hdl);
+        if (err == ESP_OK) {
+            this->cdc_hdl = NULL;
+        }
+        return err;
     }
 
     inline esp_err_t line_coding_get(cdc_acm_line_coding_t *line_coding)

examples/peripherals/usb/host/cdc/common/cdc_acm_host/test/test_cdc_acm_host.c

@@ -110,7 +110,7 @@ static void handle_rx2(uint8_t *data, size_t data_len, void *arg)
     TEST_ASSERT_EQUAL_STRING_LEN(data, arg, data_len);
 }
 
-static void notif_cb(cdc_acm_dev_hdl_t cdc_hdl, const cdc_acm_host_dev_event_data_t *event, void *user_ctx)
+static void notif_cb(const cdc_acm_host_dev_event_data_t *event, void *user_ctx)
 {
     switch (event->type) {
     case CDC_ACM_HOST_ERROR:
@@ -122,7 +122,7 @@ static void notif_cb(cdc_acm_dev_hdl_t cdc_hdl, const cdc_acm_host_dev_event_dat
         break;
     case CDC_ACM_HOST_DEVICE_DISCONNECTED:
         printf("Disconnection event\n");
-        TEST_ASSERT_EQUAL(ESP_OK, cdc_acm_host_close(cdc_hdl));
+        TEST_ASSERT_EQUAL(ESP_OK, cdc_acm_host_close(event->data.cdc_hdl));
         xTaskNotifyGive(user_ctx);
         break;
     default: