[ARM] amba-clcd: Allow RGB555 and RGB565 with 16bpp

Some folk want to use RGB555 rather tahn RGB565 with amba-clcd.
Allow amba-clcd to accept either pixel format.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 29 insertions, 25 deletions

diff --git a/drivers/video/amba-clcd.c b/drivers/video/amba-clcd.c
index b2187175d03f..6761b68c35e9 100644
--- a/drivers/video/amba-clcd.c
+++ b/drivers/video/amba-clcd.c
@@ -116,9 +116,10 @@ clcdfb_set_bitfields(struct clcd_fb *fb, struct fb_var_screeninfo *var)
         int ret = 0;
 
         memset(&var->transp, 0, sizeof(var->transp));
-        memset(&var->red, 0, sizeof(var->red));
-        memset(&var->green, 0, sizeof(var->green));
-        memset(&var->blue, 0, sizeof(var->blue));
+
+        var->red.msb_right = 0;
+        var->green.msb_right = 0;
+        var->blue.msb_right = 0;
 
         switch (var->bits_per_pixel) {
         case 1:
@@ -133,34 +134,20 @@ clcdfb_set_bitfields(struct clcd_fb *fb, struct fb_var_screeninfo *var)
                 var->blue.offset        = 0;
                 break;
         case 16:
-                var->red.length         = 5;
-                var->green.length       = 6;
-                var->blue.length        = 5;
-                if (fb->panel->cntl & CNTL_BGR) {
-                        var->red.offset         = 11;
-                        var->green.offset       = 5;
-                        var->blue.offset        = 0;
-                } else {
-                        var->red.offset         = 0;
-                        var->green.offset       = 5;
-                        var->blue.offset        = 11;
-                }
+                var->red.length = 5;
+                var->blue.length = 5;
+                /*
+                 * Green length can be 5 or 6 depending whether
+                 * we're operating in RGB555 or RGB565 mode.
+                 */
+                if (var->green.length != 5 && var->green.length != 6)
+                        var->green.length = 6;
                 break;
         case 32:
                 if (fb->panel->cntl & CNTL_LCDTFT) {
                         var->red.length         = 8;
                         var->green.length       = 8;
                         var->blue.length        = 8;
-
-                        if (fb->panel->cntl & CNTL_BGR) {
-                                var->red.offset         = 16;
-                                var->green.offset       = 8;
-                                var->blue.offset        = 0;
-                        } else {
-                                var->red.offset         = 0;
-                                var->green.offset       = 8;
-                                var->blue.offset        = 16;
-                        }
                         break;
                 }
         default:
@@ -168,6 +155,23 @@ clcdfb_set_bitfields(struct clcd_fb *fb, struct fb_var_screeninfo *var)
                 break;
         }
 
+        /*
+         * >= 16bpp displays have separate colour component bitfields
+         * encoded in the pixel data.  Calculate their position from
+         * the bitfield length defined above.
+         */
+        if (ret == 0 && var->bits_per_pixel >= 16) {
+                if (fb->panel->cntl & CNTL_BGR) {
+                        var->blue.offset = 0;
+                        var->green.offset = var->blue.offset + var->blue.length;
+                        var->red.offset = var->green.offset + var->green.length;
+                } else {
+                        var->red.offset = 0;
+                        var->green.offset = var->red.offset + var->red.length;
+                        var->blue.offset = var->green.offset + var->green.length;
+                }
+        }
+
         return ret;
 }