drivers: video: fbdev: atmel_lcdfb.c: Add ability to inverted backlight PWM.

The code has a variable to change the polarity of the PWM backlight control but
it was not being initialized. This patch adds a devicetree entry to set the
variable if required.
Signed-off-by: Michael Welling <mwelling@ieee.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Documentation/devicetree/bindings/video/atmel,lcdc.txt

@@ -46,6 +46,7 @@ Required properties (as per of_videomode_helper):
 
 Optional properties (as per of_videomode_helper):
  - atmel,lcdcon-backlight: enable backlight
+ - atmel,lcdcon-backlight-inverted: invert backlight PWM polarity
  - atmel,lcd-wiring-mode: lcd wiring mode "RGB" or "BRG"
  - atmel,power-control-gpio: gpio to power on or off the LCD (as many as needed)
 

drivers/video/fbdev/atmel_lcdfb.c

@@ -290,7 +290,7 @@ static void init_contrast(struct atmel_lcdfb_info *sinfo)
 
 	/* contrast pwm can be 'inverted' */
 	if (pdata->lcdcon_pol_negative)
-			contrast_ctr &= ~(ATMEL_LCDC_POL_POSITIVE);
+		contrast_ctr &= ~(ATMEL_LCDC_POL_POSITIVE);
 
 	/* have some default contrast/backlight settings */
 	lcdc_writel(sinfo, ATMEL_LCDC_CONTRAST_CTR, contrast_ctr);
@@ -1095,6 +1095,7 @@ static int atmel_lcdfb_of_init(struct atmel_lcdfb_info *sinfo)
 	pdata->lcd_wiring_mode = ret;
 
 	pdata->lcdcon_is_backlight = of_property_read_bool(display_np, "atmel,lcdcon-backlight");
+	pdata->lcdcon_pol_negative = of_property_read_bool(display_np, "atmel,lcdcon-backlight-inverted");
 
 	timings = of_get_display_timings(display_np);
 	if (!timings) {