Re: [PATCH] video: ARM CLCD: runtime check for Versatile

On Wednesday 03 February 2016 00:41:54 Russell King - ARM Linux wrote:

On Tue, Feb 02, 2016 at 10:10:49PM +0100, Arnd Bergmann wrote:

quoted

On Tuesday 02 February 2016 21:47:39 Linus Walleij wrote:

quoted

        } else {
-#ifdef CONFIG_ARCH_VERSATILE
-               fb->off_ienb = CLCD_PL111_IENB;
-               fb->off_cntl = CLCD_PL111_CNTL;
-#else
-               fb->off_ienb = CLCD_PL110_IENB;
-               fb->off_cntl = CLCD_PL110_CNTL;
-#endif
+               if (of_machine_is_compatible("arm,versatile-ab") ||
+                   of_machine_is_compatible("arm,versatile-pb")) {
+                       fb->off_ienb = CLCD_PL111_IENB;
+                       fb->off_cntl = CLCD_PL111_CNTL;
+               } else {
+                       fb->off_ienb = CLCD_PL110_IENB;
+                       fb->off_cntl = CLCD_PL110_CNTL;
+               }
        }

Could that be done based on the AMBA device ID instead?

Unfortunately not.  It's a mistake made on one Versatile board
which reverses the registers.  There's nothing to distinguish it
in the primecell itself.

Ok, I see. It would be nice to have this knowledge locally in
the driver, e.g. through a special compatible string for the
variant on the versatile, or a bool property, but this way seems
good enough as we can be reasonably sure that nobody else made the
same mistake.

	Arnd