auxdisplay: charlcd: make backlight initial state configurable

mansr · ojeda · commit cc5d04d840d6 · 2019-03-17T08:48:45.000+01:00
The charlcd driver currently flashes the backlight once on init.
This may not be desirable.  Thus, add options for turning the
backlight off or on as well.

Signed-off-by: Mans Rullgard &lt;mans@mansr.com&gt;
Signed-off-by: Miguel Ojeda &lt;miguel.ojeda.sandonis@gmail.com&gt;
diff --git a/drivers/auxdisplay/Kconfig b/drivers/auxdisplay/Kconfig
@@ -445,6 +445,27 @@ config PANEL_BOOT_MESSAGE
 	  An empty message will only clear the display at driver init time. Any other
 	  printf()-formatted message is valid with newline and escape codes.
 
+choice
+	prompt "Backlight initial state"
+	default CHARLCD_BL_FLASH
+
+	config CHARLCD_BL_OFF
+		bool "Off"
+		help
+		  Backlight is initially turned off
+
+	config CHARLCD_BL_ON
+		bool "On"
+		help
+		  Backlight is initially turned on
+
+	config CHARLCD_BL_FLASH
+		bool "Flash"
+		help
+		  Backlight is flashed briefly on init
+
+endchoice
+
 endif # AUXDISPLAY
 
 config PANEL
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
@@ -769,6 +769,14 @@ static void charlcd_puts(struct charlcd *lcd, const char *s)
 #define LCD_INIT_TEXT "Linux-" UTS_RELEASE "\n"
 #endif
 
+#ifdef CONFIG_CHARLCD_BL_ON
+#define LCD_INIT_BL "\x1b[L+"
+#elif defined(CONFIG_CHARLCD_BL_FLASH)
+#define LCD_INIT_BL "\x1b[L*"
+#else
+#define LCD_INIT_BL "\x1b[L-"
+#endif
+
 /* initialize the LCD driver */
 static int charlcd_init(struct charlcd *lcd)
 {
@@ -790,7 +798,7 @@ static int charlcd_init(struct charlcd *lcd)
 		return ret;
 
 	/* display a short message */
-	charlcd_puts(lcd, "\x1b[Lc\x1b[Lb\x1b[L*" LCD_INIT_TEXT);
+	charlcd_puts(lcd, "\x1b[Lc\x1b[Lb" LCD_INIT_BL LCD_INIT_TEXT);
 
 	/* clear the display on the next device opening */
 	priv->must_clear = true;
