asm-generic: delay.h fix udelay and ndelay for 8 bit args
With a non-constant 8-bit argument, a call to udelay() generates a warning:
drivers/gpu/drm/radeon/atom.c: In function 'atom_op_delay':
drivers/gpu/drm/radeon/atom.c:654: warning: comparison is always false due to limited range of data type
The code looks like it works OK with an 8-bit arg, and the calling code is
doing nothing wrong, so udelay() needs fixing.
Fixing it was rather tricky. Simply typecasting `n' in the comparison with
20000 didn't change anything. Hence the divide-by-20000 trick.
Using a do{}while loop didn't work because udelay() is used in ?: statements,
hence the ({...}) construct.
While I was there I replaced the brain-bending ?:?:?: mess with nice if/else
code.
Probably other architectures are generating the same warning and can use a
similar change.
[Taken from the x86 tree and moved to asm-generic by Jonas Bonn]
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
1 file changed