tty: vt, cleanup and document con_scroll

Scrolling helpers scrup and scrdown both accept 'top' and 'bottom' as
unsigned int. Number of lines 'nr' is accepted as int, but all callers
pass down unsigned too. So change the type of 'nr' to unsigned too.
Now, promote unsigned int from the helpers up to the con_scroll
hook which actually accepted all those as signed int.

Next, the 'dir' parameter can have only two values and we define
constants for that: SM_UP and SM_DOWN. Switch them to enum and do
proper type checking on 'dir' too.

Finally, document the behaviour of the hook.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
Cc: <linux-parisc@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index 3a10ac19598f..79c9bd8d3025 100644
--- a/drivers/video/console/sticon.c
+++ b/drivers/video/console/sticon.c
@@ -153,12 +153,13 @@ static void sticon_cursor(struct vc_data *conp, int mode)
     }
 }
 
-static int sticon_scroll(struct vc_data *conp, int t, int b, int dir, int count)
+static bool sticon_scroll(struct vc_data *conp, unsigned int t,
+		unsigned int b, enum con_scroll dir, unsigned int count)
 {
     struct sti_struct *sti = sticon_sti;
 
     if (vga_is_gfx)
-        return 0;
+        return false;
 
     sticon_cursor(conp, CM_ERASE);
 
@@ -174,7 +175,7 @@ static int sticon_scroll(struct vc_data *conp, int t, int b, int dir, int count)
 	break;
     }
 
-    return 0;
+    return false;
 }
 
 static void sticon_init(struct vc_data *c, int init)