The NEC µPD16314 can alter the the brightness of the LCD. Make it possible
to set this via escape sequence Y0 - Y3. B and R were already taken, so
I picked Y for luminance.
Signed-off-by: Sean Young <s...@mess.org>
---
drivers/auxdisplay/charlcd.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c
index a16c72779722..7a671ad959d1 100644
--- a/drivers/auxdisplay/charlcd.c
+++ b/drivers/auxdisplay/charlcd.c
@@ -39,6 +39,8 @@
#define LCD_FLAG_F 0x0020 /* Large font mode */
#define LCD_FLAG_N 0x0040 /* 2-rows mode */
#define LCD_FLAG_L 0x0080 /* Backlight enabled */
+#define LCD_BRIGHTNESS_MASK 0x0300 /* Brightness */
+#define LCD_BRIGHTNESS_SHIFT 8
/* LCD commands */
#define LCD_CMD_DISPLAY_CLEAR 0x01 /* Clear entire display */
@@ -490,6 +492,17 @@ static inline int handle_lcd_special_code(struct charlcd
*lcd)
charlcd_gotoxy(lcd);
processed = 1;
break;
+ case 'Y': /* brightness (luma) */
+ switch (esc[1]) {
+ case '0': /* 25% */
+ case '1': /* 50% */
+ case '2': /* 75% */
+ case '3': /* 100% */
+ priv->flags = (priv->flags & ~(LCD_BRIGHTNESS_MASK)) |
+ (('3' - esc[1]) << LCD_BRIGHTNESS_SHIFT);
+ processed = 1;
+ break;
+ }
}
/* TODO: This indent party here got ugly, clean it! */
@@ -507,12 +520,15 @@ static inline int handle_lcd_special_code(struct charlcd
*lcd)
((priv->flags & LCD_FLAG_C) ? LCD_CMD_CURSOR_ON : 0) |
((priv->flags & LCD_FLAG_B) ? LCD_CMD_BLINK_ON : 0));
/* check whether one of F,N flags was changed */
- else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N))
+ else if ((oldflags ^ priv->flags) & (LCD_FLAG_F | LCD_FLAG_N |
+ LCD_BRIGHTNESS_MASK))
lcd->ops->write_cmd(lcd,
LCD_CMD_FUNCTION_SET |
((lcd->ifwidth == 8) ? LCD_CMD_DATA_LEN_8BITS : 0) |
((priv->flags & LCD_FLAG_F) ? LCD_CMD_FONT_5X10_DOTS :
0) |
- ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0));
+ ((priv->flags & LCD_FLAG_N) ? LCD_CMD_TWO_LINES : 0) |
+ ((priv->flags & LCD_BRIGHTNESS_MASK) >>
+ LCD_BRIGHTNESS_SHIFT));
/* check whether L flag was changed */
else if ((oldflags ^ priv->flags) & LCD_FLAG_L)
charlcd_backlight(lcd, !!(priv->flags & LCD_FLAG_L));
--
2.14.3
