[PATCH 3/4] fbdev: atafb: Fix broken frame buffer after kexec

[Geert Uytterhoeven]

On Falcon, Atari frame buffer initialization relies on preprogrammed
register values.  These register values are changed to blank the
console.

Hence when using kexec to boot into a new kernel while the console is
blanked, the new kernel cannot determine the current video
configuration, and the Atari frame buffer driver fails to initialize:

    atafb: phys_screen_base 6ce000 screen_len 4096

Fix this by doing a straight-forward conversion of the driver to a
platform device driver, and adding a shutdown handler that unblanks the
display.

Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org>
---
 drivers/video/fbdev/atafb.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/atafb.c b/drivers/video/fbdev/atafb.c
index d82007c113e6303c..4db8166d11b30409 100644
--- a/drivers/video/fbdev/atafb.c
+++ b/drivers/video/fbdev/atafb.c
@@ -54,6 +54,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/platform_device.h>
 
 #include <asm/setup.h>
 #include <linux/uaccess.h>
@@ -3072,7 +3073,7 @@ int __init atafb_setup(char *options)
        return 0;
 }
 
-int __init atafb_init(void)
+static int __init atafb_probe(struct platform_device *pdev)
 {
        int pad, detected_mode, error;
        unsigned int defmode = 0;
@@ -3084,9 +3085,6 @@ int __init atafb_init(void)
        atafb_setup(option);
        printk("atafb_init: start\n");
 
-       if (!MACH_IS_ATARI)
-               return -ENODEV;
-
        do {
 #ifdef ATAFB_EXT
                if (external_addr) {
@@ -3247,4 +3245,32 @@ int __init atafb_init(void)
        return 0;
 }
 
+static void atafb_shutdown(struct platform_device *pdev)
+{
+       /* Unblank before kexec */
+       if (fbhw->blank)
+               fbhw->blank(0);
+}
+
+static struct platform_driver atafb_driver = {
+       .shutdown       = atafb_shutdown,
+       .driver = {
+               .name   = "atafb",
+       },
+};
+
+static int __init atafb_init(void)
+{
+       struct platform_device *pdev;
+
+       if (!MACH_IS_ATARI)
+               return -ENODEV;
+
+       pdev = platform_device_register_simple("atafb", -1, NULL, 0);
+       if (IS_ERR(pdev))
+               return PTR_ERR(pdev);
+
+       return platform_driver_probe(&atafb_driver, atafb_probe);
+}
+
 device_initcall(atafb_init);
-- 
2.17.1