rgb_lcd: added API to manually refresh the LCD

components/esp_lcd/include/esp_lcd_panel_rgb.h

@@ -181,12 +181,19 @@ esp_err_t esp_lcd_rgb_panel_register_event_callbacks(esp_lcd_panel_handle_t pane
  *      - ESP_OK: Get frame buffer address successfully
  */
 esp_err_t esp_lcd_rgb_panel_get_frame_buffer(esp_lcd_panel_handle_t panel, uint32_t fb_num, void **fb0, ...);
+
+/**
+ * @brief Manually trigger once transmission of the frame buffer to the LCD panel
+ *
+ * @note This function should only be called when the RGB panel is working under the `refresh_on_demand` mode.
+ *
+ * @param[in] panel LCD panel handle, returned from `esp_lcd_new_rgb_panel()`
  * @return
- *          - ESP_ERR_NOT_SUPPORTED   if frequency is unreachable
- *          - ESP_ERR_INVALID_ARG     if parameter panel is invalid
- *          - ESP_OK                  on success
+ *      - ESP_ERR_INVALID_ARG: Start a refresh failed because of invalid argument
+ *      - ESP_ERR_INVALID_STATE: Start a refresh failed because the LCD panel is not created with the `refresh_on_demand` flag enabled.
+ *      - ESP_OK: Start a refresh successfully
  */
-esp_err_t esp_rgb_panel_set_pclk(esp_lcd_panel_handle_t panel, uint32_t freq_hz);
+esp_err_t esp_lcd_rgb_panel_refresh(esp_lcd_panel_handle_t panel);
 
 #endif // SOC_LCD_RGB_SUPPORTED
 

components/esp_lcd/src/esp_lcd_rgb_panel.c

@@ -338,6 +338,15 @@ esp_err_t esp_lcd_rgb_panel_get_frame_buffer(esp_lcd_panel_handle_t panel, uint3
     return ESP_OK;
 }
 
+esp_err_t esp_lcd_rgb_panel_refresh(esp_lcd_panel_handle_t panel)
+{
+    ESP_RETURN_ON_FALSE(panel, ESP_ERR_INVALID_ARG, TAG, "invalid argument");
+    esp_rgb_panel_t *rgb_panel = __containerof(panel, esp_rgb_panel_t, base);
+    ESP_RETURN_ON_FALSE(!rgb_panel->flags.stream_mode, ESP_ERR_INVALID_STATE, TAG, "refresh on demand is not enabled");
+    lcd_rgb_panel_start_transmission(rgb_panel);
+    return ESP_OK;
+}
+
 static esp_err_t rgb_panel_del(esp_lcd_panel_t *panel)
 {
     esp_rgb_panel_t *rgb_panel = __containerof(panel, esp_rgb_panel_t, base);

docs/en/migration-guides/peripherals.rst

@@ -268,6 +268,7 @@ LCD
 - :cpp:func:`esp_lcd_panel_disp_off` is deprecated, please use :cpp:func:`esp_lcd_panel_disp_on_off` instead.
 - ``dc_as_cmd_phase`` is removed. The SPI LCD driver currently doesn't support a 9bit SPI LCD. Please always use a dedicated GPIO to control the LCD D/C line.
 - The way to register RGB panel event callbacks has been moved from the :cpp:type:`esp_lcd_rgb_panel_config_t` into a separate API :cpp:func:`esp_lcd_rgb_panel_register_event_callbacks`. However, the event callback signature is not changed.
+- If the RGB LCD is created with the ``refresh_on_demand`` flag enabled, the driver won't start a refresh in the :cpp:func:`esp_lcd_panel_draw_bitmap`. Now you have to call :cpp:func:`esp_lcd_rgb_panel_refresh` to refresh the screen by yourself.
 
 .. only:: SOC_MCPWM_SUPPORTED