auxdisplay: ht16k33: Fix frame buffer device blanking

As the ht16k33 frame buffer sub-driver does not register an fb_ops.fb_blank() handler, blanking does not work: $ echo 1 > /sys/class/graphics/fb0/blank sh: write error: Invalid argument Fix this by providing a handler that always returns zero, to make sure blank events will be sent to the actual device handling the backlight. Reported-by: Robin van der Gracht <[email protected]> Suggested-by: Robin van der Gracht <[email protected]> Fixes: 8992da4 ("auxdisplay: ht16k33: Driver for LED controller") Signed-off-by: Geert Uytterhoeven <[email protected]> Signed-off-by: Miguel Ojeda <[email protected]>
chewitt · Oct 21, 2021 · 840fe25 · 840fe25
1 parent 80f9eb7
commit 840fe25
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
@@ -219,6 +219,15 @@ static const struct backlight_ops ht16k33_bl_ops = {
 	.check_fb	= ht16k33_bl_check_fb,
 };
 
+/*
+ * Blank events will be passed to the actual device handling the backlight when
+ * we return zero here.
+ */
+static int ht16k33_blank(int blank, struct fb_info *info)
+{
+	return 0;
+}
+
 static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	struct ht16k33_priv *priv = info->par;
@@ -231,6 +240,7 @@ static const struct fb_ops ht16k33_fb_ops = {
 	.owner = THIS_MODULE,
 	.fb_read = fb_sys_read,
 	.fb_write = fb_sys_write,
+	.fb_blank = ht16k33_blank,
 	.fb_fillrect = sys_fillrect,
 	.fb_copyarea = sys_copyarea,
 	.fb_imageblit = sys_imageblit,