feat(esp_stdio): Revert breaking change

- also revert the modification in the singature of uninstall function
in all the concerned esp_driver* components and esp_stdio.
- added proper documentation of the feature in the programming guide

components/esp_stdio/include/esp_stdio.h

@@ -14,6 +14,18 @@ extern "C" {
 
 #define ESP_VFS_DEV_CONSOLE "/dev/console"
 
+/**
+ * @brief Register the default console VFS backend(s) selected in Kconfig.
+ *
+ * Sets up the primary (and any Kconfig-selected secondary) console sink and
+ * mounts them under /dev/console. This function is automatically called from
+ * startup code to enable serial output; applications normally do not need to
+ * call it themselves.
+ *
+ * @return ESP_OK on success, or an error code from the underlying VFS registration.
+ */
+esp_err_t esp_stdio_register(void);
+
 #if CONFIG_VFS_SUPPORT_IO
 
 #include "esp_vfs_common.h"
@@ -134,7 +146,7 @@ esp_err_t esp_stdio_install_io_driver(void);
  * If a user has taken over the primary console with esp_stdio_push_primary(),
  * this function is a no-op.
  */
-esp_err_t esp_stdio_uninstall_io_driver(void);
+void esp_stdio_uninstall_io_driver(void);
 
 #ifdef __cplusplus
 }

components/esp_stdio/linux/esp_stdio_linux.c

@@ -21,10 +21,9 @@ static void disable_raw_mode(void)
     assert(tcsetattr(STDIN_FILENO, TCSAFLUSH, &s_orig_termios) == 0);
 }
 
-esp_err_t linux_vfs_dev_port_deinit(linux_port_config_t *config)
+void linux_vfs_dev_port_deinit(linux_port_config_t *config)
 {
     (void)config;
-    return ESP_OK;
 }
 
 esp_err_t linux_vfs_dev_port_init(linux_port_config_t *config)

components/esp_stdio/linux/include/esp_stdio_linux.h

@@ -43,9 +43,8 @@ esp_err_t linux_vfs_dev_port_init(linux_port_config_t *config);
  * switching to another console interface.
  *
  * @param config Pointer to the Linux console port configuration.
- * @return ESP_OK if the driver was successfully uninstalled, or an error otherwise.
  */
-esp_err_t linux_vfs_dev_port_deinit(linux_port_config_t *config);
+void linux_vfs_dev_port_deinit(linux_port_config_t *config);
 
 #ifdef __cplusplus
 }

components/esp_stdio/stdio_port.c

@@ -73,30 +73,28 @@ esp_err_t esp_stdio_install_io_driver(void)
     return ret;
 }
 
-esp_err_t esp_stdio_uninstall_io_driver(void)
+void esp_stdio_uninstall_io_driver(void)
 {
 #if CONFIG_VFS_SUPPORT_IO
     /* If a user primary is registered, deinit is the caller's responsibility. */
     if (esp_stdio_has_user_primary()) {
-        return ESP_OK;
+        return;
     }
 #endif // CONFIG_VFS_SUPPORT_IO
 
-    esp_err_t ret = ESP_FAIL;
 #if CONFIG_IDF_TARGET_LINUX
     linux_port_config_t config = ESP_CONSOLE_DEV_LINUX_CONFIG_DEFAULT();
-    ret = linux_vfs_dev_port_deinit(&config);
+    linux_vfs_dev_port_deinit(&config);
 #elif CONFIG_VFS_SUPPORT_IO
 #if CONFIG_ESP_CONSOLE_UART
     esp_console_dev_uart_config_t config = ESP_CONSOLE_DEV_UART_CONFIG_DEFAULT();
-    ret = uart_vfs_dev_port_deinit(&config);
+    uart_vfs_dev_port_deinit(&config);
 #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     esp_console_dev_usb_serial_jtag_config_t config = ESP_CONSOLE_DEV_USB_SERIAL_JTAG_CONFIG_DEFAULT();
-    ret = usb_serial_jtag_vfs_dev_port_deinit(&config);
+    usb_serial_jtag_vfs_dev_port_deinit(&config);
 #elif CONFIG_ESP_CONSOLE_USB_CDC
     esp_console_dev_usb_cdc_config_t config = ESP_CONSOLE_DEV_CDC_CONFIG_DEFAULT();
-    ret = cdcacm_vfs_dev_port_deinit(&config);
+    cdcacm_vfs_dev_port_deinit(&config);
 #endif
 #endif
-    return ret;
 }

components/esp_stdio/stdio_vfs.c

@@ -358,7 +358,7 @@ static const esp_vfs_fs_ops_t s_vfs_console = {
 #endif
 };
 
-static esp_err_t esp_stdio_register(void)
+esp_err_t esp_stdio_register(void)
 {
     _lock_init(&s_lock);
 

components/esp_stdio/test_apps/custom_io/main/test_custom_io.c

@@ -205,7 +205,7 @@ TEST_CASE("install/uninstall are no-ops with user primary", "[esp_stdio]")
     TEST_ASSERT_EQUAL(ESP_OK, esp_stdio_push_primary(h));
 
     TEST_ASSERT_EQUAL(ESP_OK, esp_stdio_install_io_driver());
-    TEST_ASSERT_EQUAL(ESP_OK, esp_stdio_uninstall_io_driver());
+    esp_stdio_uninstall_io_driver();
     TEST_ASSERT_EQUAL(0, mock_a.open_count);  /* driver not initialised by install */
 
     TEST_ASSERT_EQUAL(ESP_OK, esp_stdio_pop_primary(NULL));