staging: ftbft: Use backlight helper

backlight_properties.fb_blank is deprecated. The states it represents
are handled by other properties; but instead of accessing those
properties directly, drivers should use the helpers provided by
backlight.h.

Instead of manually checking the power state in struct
backlight_properties, use backlight_is_blank().

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Len Baker <len.baker@gmx.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-staging@lists.linux.dev
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Stephen Kitt <steve@sk2.org>
Link: https://lore.kernel.org/r/20220607185516.1129900-1-steve@sk2.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fbtft/fb_ssd1351.c

@@ -196,8 +196,7 @@ static int update_onboard_backlight(struct backlight_device *bd)
 		      "%s: power=%d, fb_blank=%d\n",
 		      __func__, bd->props.power, bd->props.fb_blank);
 
-	on = (bd->props.power == FB_BLANK_UNBLANK) &&
-	     (bd->props.fb_blank == FB_BLANK_UNBLANK);
+	on = !backlight_is_blank(bd);
 	/* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
 	write_reg(par, 0xB5, on ? 0x03 : 0x02);
 

drivers/staging/fbtft/fbtft-core.c

@@ -137,8 +137,7 @@ static int fbtft_backlight_update_status(struct backlight_device *bd)
 		      "%s: polarity=%d, power=%d, fb_blank=%d\n",
 		      __func__, polarity, bd->props.power, bd->props.fb_blank);
 
-	if ((bd->props.power == FB_BLANK_UNBLANK) &&
-	    (bd->props.fb_blank == FB_BLANK_UNBLANK))
+	if (!backlight_is_blank(bd))
 		gpiod_set_value(par->gpio.led[0], polarity);
 	else
 		gpiod_set_value(par->gpio.led[0], !polarity);