set backlight, dont disable on shutdown

include/lcd.h

@@ -22,6 +22,7 @@ void lcd_close(struct lcd_t *lcd);
 void lcd_clear(struct lcd_t *lcd);
 void lcd_set_contrast(struct lcd_t *lcd, uint8_t contrast);
 void lcd_set_backlight(struct lcd_t *lcd, bool enabled);
+void lcd_set_brightness(struct lcd_t *lcd, uint8_t brightness);
 void lcd_set_cursor(struct lcd_t *lcd, uint8_t row, uint8_t col);
 void lcd_set_custom_char(struct lcd_t *lcd, uint8_t index, const lcd_glyph_t *glyph);
 void lcd_write_buf(struct lcd_t *lcd, uint8_t row, uint8_t col, const char *str);
@@ -31,4 +32,4 @@ void lcd_flush_buf(struct lcd_t *lcd);
 char lcd_bar(struct lcd_t *lcd, uint8_t char_id, double value);
 int lcd_init(struct lcd_t *lcd);
 
-#endif
+#endif

src/lcd.c

@@ -2,6 +2,7 @@
 #include "log.h"
 #include <fcntl.h>
 #include <stdarg.h>
+#include <stdint.h>
 #include <string.h>
 #include <termios.h>
 #include <unistd.h>
@@ -58,6 +59,12 @@ void lcd_set_backlight(struct lcd_t *lcd, const bool enabled) {
 	lcd_write(lcd, cmdbuf, enabled ? 3 : 2);
 }
 
+void lcd_set_brightness(struct lcd_t *lcd, const uint8_t brightness) {
+    applog(LOG_INF, "Set backlight brightness to %d", brightness);
+    const uint8_t cmdbuf[] = {0xFE, 152, brightness};
+    lcd_write(lcd, cmdbuf, 3);
+}
+
 void lcd_set_cursor(struct lcd_t *lcd, const uint8_t row, const uint8_t col) {
 	const uint8_t cmdbuf[] = {0xFE, 71, col + 1, row + 1};
 	lcd_write(lcd, cmdbuf, sizeof(cmdbuf));
@@ -138,4 +145,4 @@ int lcd_init(struct lcd_t *lcd) {
 
 	lcd_clear(lcd);
 	return 0;
-}
+}

src/main.c

@@ -99,6 +99,7 @@ static void *display_thread(void *arg) {
 		.baud = 0010002, // from termios-baud.h, B115200
 	};
 	lcd_init(&lcd);
+	lcd_set_brightness(&lcd, 255);
 	lcd_set_backlight(&lcd, true);
 	lcd_set_contrast(&lcd, lcd_contrast);
 
@@ -175,7 +176,6 @@ static void *display_thread(void *arg) {
 	}
 
 	lcd_write_buf(&lcd, 2, 16, "Goodbye"); // center
-	lcd_set_backlight(&lcd, false);
 	lcd_flush_buf(&lcd);
 	lcd_close(&lcd);
 	applog(LOG_WRN, "display thread stopped");