Support IDF version < v4.3

Author: tore-espressif

lvgl_tft/esp_lcd_backlight.c

@@ -10,7 +10,8 @@
 #include "driver/ledc.h"
 #include "driver/gpio.h"
 #include "esp_log.h"
-#include "esp_rom_gpio.h" // for output signal inversion
+#include "esp_rom_gpio.h"    // for output signal inversion
+#include "soc/ledc_periph.h" // to invert LEDC output on IDF version < v4.3
 
 typedef struct {
     bool pwm_control; // true: LEDC is used, false: GPIO is used
@@ -40,8 +41,7 @@ disp_backlight_h disp_backlight_new(const disp_backlight_config_t *config)
             .intr_type = LEDC_INTR_DISABLE,
             .timer_sel = config->timer_idx,
             .duty = 0,
-            .hpoint = 0,
-            .flags.output_invert = config->output_invert //@todo added only in recent IDF versions
+            .hpoint = 0
         };
         const ledc_timer_config_t LCD_backlight_timer = {
             .speed_mode = LEDC_LOW_SPEED_MODE,
@@ -52,6 +52,7 @@ disp_backlight_h disp_backlight_new(const disp_backlight_config_t *config)
 
         ESP_ERROR_CHECK(ledc_timer_config(&LCD_backlight_timer));
         ESP_ERROR_CHECK(ledc_channel_config(&LCD_backlight_channel));
+        esp_rom_gpio_connect_out_signal(config->gpio_num, ledc_periph_signal[LEDC_LOW_SPEED_MODE].sig_out0_idx + config->channel_idx, config->output_invert, 0);
     }
     else
     {