fbdev/pvr2fb: Initialize fb_ops to fbdev I/O-memory helpers

Initialize the instance of struct fb_ops with fbdev initializer
macros for framebuffers in I/O address space. Set the read/write,
draw and mmap callbacks to the correct implementation and avoid
implicit defaults. Also select the necessary I/O helpers in Kconfig.

Fbdev drivers sometimes rely on the callbacks being NULL for a
default implementation to be invoked; hence requiring the I/O
helpers to be built in any case. Setting all callbacks in all
drivers explicitly will allow to make the I/O helpers optional.
This benefits systems that do not use these functions.

No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230927074722.6197-29-tzimmermann@suse.de

drivers/video/fbdev/Kconfig

@@ -634,6 +634,7 @@ config FB_PVR2
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
+	select FB_IOMEM_FOPS
 	select VIDEO_NOMODESET
 	help
 	  Say Y here if you have a PowerVR 2 card in your box.  If you plan to

drivers/video/fbdev/pvr2fb.c

@@ -725,16 +725,18 @@ static ssize_t pvr2fb_write(struct fb_info *info, const char *buf,
 
 static const struct fb_ops pvr2fb_ops = {
 	.owner		= THIS_MODULE,
+#ifdef CONFIG_PVR2_DMA
+	.fb_read	= fb_io_read,
+	.fb_write	= pvr2fb_write,
+#else
+	__FB_DEFAULT_IOMEM_OPS_RDWR,
+#endif
 	.fb_setcolreg	= pvr2fb_setcolreg,
 	.fb_blank	= pvr2fb_blank,
+	__FB_DEFAULT_IOMEM_OPS_DRAW,
 	.fb_check_var	= pvr2fb_check_var,
 	.fb_set_par	= pvr2fb_set_par,
-#ifdef CONFIG_PVR2_DMA
-	.fb_write	= pvr2fb_write,
-#endif
-	.fb_fillrect	= cfb_fillrect,
-	.fb_copyarea	= cfb_copyarea,
-	.fb_imageblit	= cfb_imageblit,
+	__FB_DEFAULT_IOMEM_OPS_MMAP,
 };
 
 #ifndef MODULE