Fix: change LCD backlight to use ledc pwm driver instead of gpio. Fixes #13

Refs: #13

main/esp32-sequencer.c

@@ -298,10 +298,18 @@ static void lvgl_increase_tick(void *arg) {
 /* Setup for TFT LCD Display and LVGL GUI */
 static void display_init(void) {
   ESP_LOGI(TAG, "Initialing LCD");
+
   // Configure backlight
-  gpio_reset_pin(LCD_BK_LIGHT_PIN);
-  gpio_set_direction(LCD_BK_LIGHT_PIN, GPIO_MODE_OUTPUT);
-  gpio_set_level(LCD_BK_LIGHT_PIN, 1);
+  ledc_channel_config_t ledc_lcd_bk_light_channel = {
+    .channel = LEDC_CHANNEL_2,
+    .gpio_num = LCD_BK_LIGHT_PIN,
+    .speed_mode = LEDC_LOW_SPEED_MODE,
+    .timer_sel = LEDC_TIMER_0,
+    .intr_type = LEDC_INTR_DISABLE,
+    .duty = 3000,
+    .hpoint = 0
+  };
+  ESP_ERROR_CHECK(ledc_channel_config(&ledc_lcd_bk_light_channel));
 
   // Setup SPI Bus
   spi_bus_config_t spi_cfg = {