fbdev/atyfb: 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/20230927074722.6197-8-tzimmermann@suse.de

drivers/video/fbdev/Kconfig

@@ -1086,6 +1086,7 @@ config FB_ATY
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT
 	select FB_BACKLIGHT if FB_ATY_BACKLIGHT
+	select FB_IOMEM_FOPS
 	select FB_MACMODES if PPC
 	select FB_ATY_CT if SPARC64 && PCI
 	select VIDEO_NOMODESET

drivers/video/fbdev/aty/atyfb_base.c

@@ -301,6 +301,7 @@ static struct fb_ops atyfb_ops = {
 	.owner		= THIS_MODULE,
 	.fb_open	= atyfb_open,
 	.fb_release	= atyfb_release,
+	__FB_DEFAULT_IOMEM_OPS_RDWR,
 	.fb_check_var	= atyfb_check_var,
 	.fb_set_par	= atyfb_set_par,
 	.fb_setcolreg	= atyfb_setcolreg,
@@ -315,6 +316,8 @@ static struct fb_ops atyfb_ops = {
 	.fb_imageblit	= atyfb_imageblit,
 #ifdef __sparc__
 	.fb_mmap	= atyfb_mmap,
+#else
+	__FB_DEFAULT_IOMEM_OPS_MMAP,
 #endif
 	.fb_sync	= atyfb_sync,
 };