perf: optimize ST7789 LVGL touch responsiveness

main/spi_lcd_touch_example_main.c

@@ -30,13 +30,13 @@
 static const char *TAG = "lvgl_touch";
 
 #define LCD_SPI_HOST                     SPI2_HOST
-#define EXAMPLE_LCD_PIXEL_CLOCK_HZ       (10 * 1000 * 1000)
+#define EXAMPLE_LCD_PIXEL_CLOCK_HZ       (40 * 1000 * 1000)
 #define EXAMPLE_LCD_CMD_BITS             8
 #define EXAMPLE_LCD_PARAM_BITS           8
 #define EXAMPLE_LVGL_TICK_PERIOD_MS      2
-#define EXAMPLE_LVGL_BUFFER_LINES        80
+#define EXAMPLE_LVGL_BUFFER_LINES        120
-#define EXAMPLE_TOUCH_I2C_FREQ_HZ        (100 * 1000)
+#define EXAMPLE_TOUCH_I2C_FREQ_HZ        (400 * 1000)
-#define EXAMPLE_TOUCH_LOG_PERIOD_MS      120
+#define EXAMPLE_TOUCH_LOG_PERIOD_MS      500
 #define EXAMPLE_TOUCH_PROBE_TIMEOUT_MS   30
 
 // Current adapter wiring:
@@ -85,6 +85,12 @@ static bool notify_lvgl_flush_ready(esp_lcd_panel_io_handle_t panel_io, esp_lcd_
 
 static void lvgl_flush_cb(lv_display_t *disp, const lv_area_t *area, uint8_t *px_map)
 {
+    size_t pixel_count = (size_t)(area->x2 - area->x1 + 1) * (area->y2 - area->y1 + 1);
+
+    // LVGL stores RGB565 pixels in the ESP32's native little-endian byte order,
+    // while this ST7789 panel expects the high byte on the SPI bus first.
+    lv_draw_sw_rgb565_swap(px_map, pixel_count);
+
     esp_err_t ret = esp_lcd_panel_draw_bitmap(s_panel, area->x1, area->y1, area->x2 + 1, area->y2 + 1, px_map);
     if (ret != ESP_OK) {
         ESP_LOGE(TAG, "LCD flush failed: %s", esp_err_to_name(ret));
@@ -159,10 +165,10 @@ static void lvgl_task(void *arg)
     (void)arg;
     while (1) {
         uint32_t delay_ms = lv_timer_handler();
-        if (delay_ms < 2) {
+        if (delay_ms < 1) {
-            delay_ms = 2;
+            delay_ms = 1;
-        } else if (delay_ms > 8) {
+        } else if (delay_ms > 5) {
-            delay_ms = 8;
+            delay_ms = 5;
         }
         vTaskDelay(pdMS_TO_TICKS(delay_ms));
     }
@@ -396,60 +402,11 @@ static esp_err_t init_i2c_bus(void)
     return ESP_OK;
 }
 
-static esp_err_t release_touch_reset_before_i2c(void)
+static void log_gt911_i2c_idle_levels(void)
 {
-    gpio_config_t rst_gpio_config = {
+    ESP_LOGI(TAG, "GT911 I2C idle levels: SCL(IO%d)=%d SDA(IO%d)=%d",
-        .mode = GPIO_MODE_OUTPUT,
+             EXAMPLE_PIN_NUM_TOUCH_SCL, gpio_get_level(EXAMPLE_PIN_NUM_TOUCH_SCL),
-        .pin_bit_mask = 1ULL << EXAMPLE_PIN_NUM_TOUCH_RST,
+             EXAMPLE_PIN_NUM_TOUCH_SDA, gpio_get_level(EXAMPLE_PIN_NUM_TOUCH_SDA));
-    };
-
-    ESP_LOGI(TAG, "Release GT911 reset on IO%d before I2C bus init", EXAMPLE_PIN_NUM_TOUCH_RST);
-    esp_err_t ret = gpio_config(&rst_gpio_config);
-    if (ret != ESP_OK) {
-        ESP_LOGE(TAG, "GPIO%d configuration failed: %s (0x%x)", EXAMPLE_PIN_NUM_TOUCH_RST,
-                 esp_err_to_name(ret), ret);
-        return ret;
-    }
-
-    ret = gpio_set_level(EXAMPLE_PIN_NUM_TOUCH_RST, 1);
-    if (ret != ESP_OK) {
-        ESP_LOGE(TAG, "GPIO%d release failed: %s (0x%x)", EXAMPLE_PIN_NUM_TOUCH_RST,
-                 esp_err_to_name(ret), ret);
-        return ret;
-    }
-
-    vTaskDelay(pdMS_TO_TICKS(120));
-    return ESP_OK;
-}
-
-static bool scan_i2c_bus_handle(i2c_master_bus_handle_t bus, const char *label, int scl, int sda)
-{
-    bool found = false;
-
-    ESP_LOGI(TAG, "Scan I2C devices on %s: SCL=IO%d SDA=IO%d", label, scl, sda);
-    for (uint8_t addr = 0x08; addr < 0x78; addr++) {
-        esp_err_t ret = i2c_master_probe(bus, addr, 10);
-        if (ret == ESP_OK) {
-            ESP_LOGI(TAG, "I2C device found on %s at 0x%02x", label, addr);
-            found = true;
-        }
-    }
-
-    if (!found) {
-        ESP_LOGW(TAG, "No I2C device found on %s: SCL=IO%d SDA=IO%d", label, scl, sda);
-    }
-
-    return found;
-}
-
-static bool scan_i2c_bus(void)
-{
-    bool found = scan_i2c_bus_handle(s_i2c_bus, "configured GT911 bus", EXAMPLE_PIN_NUM_TOUCH_SCL,
-                                     EXAMPLE_PIN_NUM_TOUCH_SDA);
-    if (!found) {
-        ESP_LOGW(TAG, "Check T_SCL/T_SDA wiring, touch power, common GND, and I2C pull-ups");
-    }
-    return found;
 }
 
 static esp_err_t select_gt911_address(uint8_t dev_addr)
@@ -473,16 +430,23 @@ static esp_err_t select_gt911_address(uint8_t dev_addr)
     ESP_RETURN_ON_ERROR(gpio_set_level(EXAMPLE_PIN_NUM_TOUCH_IRQ, 0), TAG, "drive GT911 INT low failed");
     vTaskDelay(pdMS_TO_TICKS(10));
     ESP_RETURN_ON_ERROR(gpio_set_level(EXAMPLE_PIN_NUM_TOUCH_IRQ, int_level), TAG, "set GT911 address level failed");
-    vTaskDelay(pdMS_TO_TICKS(2));
+    vTaskDelay(pdMS_TO_TICKS(1));
     ESP_RETURN_ON_ERROR(gpio_set_level(EXAMPLE_PIN_NUM_TOUCH_RST, 1), TAG, "release GT911 reset failed");
-    vTaskDelay(pdMS_TO_TICKS(80));
+    vTaskDelay(pdMS_TO_TICKS(10));
+    ESP_RETURN_ON_ERROR(gpio_set_direction(EXAMPLE_PIN_NUM_TOUCH_IRQ, GPIO_MODE_INPUT), TAG,
+                        "release GT911 INT failed");
+    ESP_RETURN_ON_ERROR(gpio_set_pull_mode(EXAMPLE_PIN_NUM_TOUCH_IRQ, GPIO_PULLUP_ONLY), TAG,
+                        "enable GT911 INT pull-up failed");
+    vTaskDelay(pdMS_TO_TICKS(50));
     return ESP_OK;
 }
 
 static esp_err_t try_init_gt911_touch(uint8_t dev_addr)
 {
-    ESP_LOGI(TAG, "Initialize GT911 touch at I2C address 0x%02x", dev_addr);
+    ESP_LOGI(TAG, "Initialize GT911 at 0x%02x with RST=IO%d INT=IO%d",
+             dev_addr, EXAMPLE_PIN_NUM_TOUCH_RST, EXAMPLE_PIN_NUM_TOUCH_IRQ);
     ESP_RETURN_ON_ERROR(select_gt911_address(dev_addr), TAG, "select GT911 address failed");
+    log_gt911_i2c_idle_levels();
 
     esp_err_t ret = i2c_master_probe(s_i2c_bus, dev_addr, EXAMPLE_TOUCH_PROBE_TIMEOUT_MS);
     if (ret != ESP_OK) {
@@ -540,11 +504,13 @@ static esp_err_t init_gt911_touch(void)
 
 static void init_touch_optional(void)
 {
-    esp_err_t ret = release_touch_reset_before_i2c();
+    esp_err_t ret = init_i2c_bus();
-    if (ret == ESP_OK) {
-        ret = init_i2c_bus();
-    }
     if (ret == ESP_OK) {
+        esp_err_t reset_ret = i2c_master_bus_reset(s_i2c_bus);
+        if (reset_ret != ESP_OK) {
+            ESP_LOGW(TAG, "GT911 I2C bus recovery failed: %s", esp_err_to_name(reset_ret));
+            log_gt911_i2c_idle_levels();
+        }
         ret = init_gt911_touch();
     }
 
@@ -556,7 +522,8 @@ static void init_touch_optional(void)
     ESP_LOGE(TAG, "GT911 is unavailable: %s. Continue with LCD only", esp_err_to_name(ret));
     s_touch = NULL;
     if (s_i2c_bus != NULL) {
-        scan_i2c_bus();
+        log_gt911_i2c_idle_levels();
+        ESP_LOGW(TAG, "Check T_SCL/T_SDA wiring, touch power, common GND, and I2C pull-ups");
     }
 }
 
@@ -613,6 +580,6 @@ void app_main(void)
 
     ESP_ERROR_CHECK(init_spi_bus());
     ESP_ERROR_CHECK(init_st7789_panel(&panel_io));
-    ESP_ERROR_CHECK(init_display_buffer());
+    init_touch_optional();
-    ESP_ERROR_CHECK(display_standard_diagnostic());
+    ESP_ERROR_CHECK(init_lvgl(panel_io));
 }

sdkconfig.defaults

@@ -8,6 +8,8 @@ CONFIG_LV_FONT_MONTSERRAT_18=y
 CONFIG_ESP_LCD_TOUCH_MAX_POINTS=5
 CONFIG_ESP_LCD_TOUCH_MAX_BUTTONS=0
 CONFIG_FREERTOS_HZ=1000
+CONFIG_ESP_DEFAULT_CPU_FREQ_MHZ_240=y
+CONFIG_COMPILER_OPTIMIZATION_PERF=y
 CONFIG_IDF_TARGET="esp32s3"
 CONFIG_EXAMPLE_LCD_CONTROLLER_ST7789=y
 CONFIG_EXAMPLE_LCD_ST7735_H_RES=240