[PATCH] m68k: atari: Make Atari ROM port I/O write macros return void

From: Geert Uytterhoeven
Date: Fri May 20 2022 - 10:32:49 EST


The macros implementing Atari ROM port I/O writes do not cast away their
output, unlike similar implementations for other I/O buses.
When they are combined using conditional expressions in the definitions of
outb() and friends, this triggers sparse warnings like:

drivers/net/appletalk/cops.c:382:17: error: incompatible types in conditional expression (different base types):
drivers/net/appletalk/cops.c:382:17: unsigned char
drivers/net/appletalk/cops.c:382:17: void

Fix this by adding casts to "void".

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
Survived m68k/allmodconfig.
To be queued in the m68k tree for v5.19.

Removing the casts instead causes issues with functions propagating void
return values (return expression in void function), which BTW sparse
complains about, too.
---
arch/m68k/include/asm/raw_io.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/m68k/include/asm/raw_io.h b/arch/m68k/include/asm/raw_io.h
index 80eb2396d01ebf61..3ba40bc1dfaa9471 100644
--- a/arch/m68k/include/asm/raw_io.h
+++ b/arch/m68k/include/asm/raw_io.h
@@ -80,14 +80,14 @@
({ u16 __v = le16_to_cpu(*(__force volatile u16 *) (addr)); __v; })

#define rom_out_8(addr, b) \
- ({u8 __maybe_unused __w, __v = (b); u32 _addr = ((u32) (addr)); \
+ (void)({u8 __maybe_unused __w, __v = (b); u32 _addr = ((u32) (addr)); \
__w = ((*(__force volatile u8 *) ((_addr | 0x10000) + (__v<<1)))); })
#define rom_out_be16(addr, w) \
- ({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
+ (void)({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
__w = ((*(__force volatile u16 *) ((_addr & 0xFFFF0000UL) + ((__v & 0xFF)<<1)))); \
__w = ((*(__force volatile u16 *) ((_addr | 0x10000) + ((__v >> 8)<<1)))); })
#define rom_out_le16(addr, w) \
- ({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
+ (void)({u16 __maybe_unused __w, __v = (w); u32 _addr = ((u32) (addr)); \
__w = ((*(__force volatile u16 *) ((_addr & 0xFFFF0000UL) + ((__v >> 8)<<1)))); \
__w = ((*(__force volatile u16 *) ((_addr | 0x10000) + ((__v & 0xFF)<<1)))); })

--
2.25.1