drivers/video/backlight/platform_lcd.c: introduce probe callback

Platform LCD devices may need to do some device-specific initialization
before they can be used (regulator or GPIO setup, for example), but
currently the driver does not support any way of doing this.  This patch
adds a probe() callback to plat_lcd_data which platform LCD devices can
set to indicate that device-specific initialization is needed.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/backlight/platform_lcd.c

@@ -86,6 +86,12 @@ static int platform_lcd_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	if (pdata->probe) {
+		err = pdata->probe(pdata);
+		if (err)
+			return err;
+	}
+
 	plcd = devm_kzalloc(&pdev->dev, sizeof(struct platform_lcd),
 			    GFP_KERNEL);
 	if (!plcd) {

include/video/platform_lcd.h

@@ -15,6 +15,7 @@ struct plat_lcd_data;
 struct fb_info;
 
 struct plat_lcd_data {
+	int	(*probe)(struct plat_lcd_data *);
 	void	(*set_power)(struct plat_lcd_data *, unsigned int power);
 	int	(*match_fb)(struct plat_lcd_data *, struct fb_info *);
 };