hid/picolcd: Use fb_ops helpers for deferred I/O

Generate callback functions for struct fb_ops with the fbdev macro
FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(). Initialize struct fb_ops to
the generated functions with an fbdev initializer macro.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: "Bruno Prémont" <bonbons@linux-vserver.org>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230828132131.29295-7-tzimmermann@suse.de

drivers/hid/Kconfig

@@ -871,11 +871,7 @@ config HID_PICOLCD_FB
 	default !EXPERT
 	depends on HID_PICOLCD
 	depends on HID_PICOLCD=FB || FB=y
-	select FB_DEFERRED_IO
-	select FB_SYS_FILLRECT
-	select FB_SYS_COPYAREA
-	select FB_SYS_IMAGEBLIT
-	select FB_SYS_FOPS
+	select FB_SYSMEM_HELPERS_DEFERRED
 	help
 	  Provide access to PicoLCD's 256x64 monochrome display via a
 	  framebuffer device.

drivers/hid/hid-picolcd_fb.c

@@ -283,54 +283,6 @@ static void picolcd_fb_update(struct fb_info *info)
 	mutex_unlock(&info->lock);
 }
 
-/* Stub to call the system default and update the image on the picoLCD */
-static void picolcd_fb_fillrect(struct fb_info *info,
-		const struct fb_fillrect *rect)
-{
-	if (!info->par)
-		return;
-	sys_fillrect(info, rect);
-
-	schedule_delayed_work(&info->deferred_work, 0);
-}
-
-/* Stub to call the system default and update the image on the picoLCD */
-static void picolcd_fb_copyarea(struct fb_info *info,
-		const struct fb_copyarea *area)
-{
-	if (!info->par)
-		return;
-	sys_copyarea(info, area);
-
-	schedule_delayed_work(&info->deferred_work, 0);
-}
-
-/* Stub to call the system default and update the image on the picoLCD */
-static void picolcd_fb_imageblit(struct fb_info *info, const struct fb_image *image)
-{
-	if (!info->par)
-		return;
-	sys_imageblit(info, image);
-
-	schedule_delayed_work(&info->deferred_work, 0);
-}
-
-/*
- * this is the slow path from userspace. they can seek and write to
- * the fb. it's inefficient to do anything less than a full screen draw
- */
-static ssize_t picolcd_fb_write(struct fb_info *info, const char __user *buf,
-		size_t count, loff_t *ppos)
-{
-	ssize_t ret;
-	if (!info->par)
-		return -ENODEV;
-	ret = fb_sys_write(info, buf, count, ppos);
-	if (ret >= 0)
-		schedule_delayed_work(&info->deferred_work, 0);
-	return ret;
-}
-
 static int picolcd_fb_blank(int blank, struct fb_info *info)
 {
 	/* We let fb notification do this for us via lcd/backlight device */
@@ -417,18 +369,31 @@ static int picolcd_set_par(struct fb_info *info)
 	return 0;
 }
 
+static void picolcdfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
+{
+	if (!info->par)
+		return;
+	schedule_delayed_work(&info->deferred_work, 0);
+}
+
+static void picolcdfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
+{
+	if (!info->par)
+		return;
+	schedule_delayed_work(&info->deferred_work, 0);
+}
+
+FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(picolcdfb_ops,
+				   picolcdfb_ops_damage_range,
+				   picolcdfb_ops_damage_area)
+
 static const struct fb_ops picolcdfb_ops = {
 	.owner        = THIS_MODULE,
+	FB_DEFAULT_DEFERRED_OPS(picolcdfb_ops),
 	.fb_destroy   = picolcd_fb_destroy,
-	.fb_read      = fb_sys_read,
-	.fb_write     = picolcd_fb_write,
 	.fb_blank     = picolcd_fb_blank,
-	.fb_fillrect  = picolcd_fb_fillrect,
-	.fb_copyarea  = picolcd_fb_copyarea,
-	.fb_imageblit = picolcd_fb_imageblit,
 	.fb_check_var = picolcd_fb_check_var,
 	.fb_set_par   = picolcd_set_par,
-	.fb_mmap      = fb_deferred_io_mmap,
 };