Re: [PATCH] spi/xilinx: Cast ioread32/iowrite32 function pointers

[Ricardo Ribalda Delgado]

Hello Arnd

On Thu, Jan 29, 2015 at 11:11 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>> > I think the definitions in include/asm-generic/iomap.h are actually wrong,
>> > as they lack a const:
>> >
>> >     extern unsigned int ioread8(void __iomem *);
>> >     extern unsigned int ioread16(void __iomem *);
>> >     extern unsigned int ioread16be(void __iomem *);
>> >     extern unsigned int ioread32(void __iomem *);
>> >     extern unsigned int ioread32be(void __iomem *);
>> >
>> > Note that the definitions in include/asm-generic/io.h do have the const:
>> >
>> >     static inline u8 ioread8(const volatile void __iomem *addr)
>> >     static inline u16 ioread16(const volatile void __iomem *addr)
>> >     static inline u32 ioread32(const volatile void __iomem *addr)
>> >     static inline u16 ioread16be(const volatile void __iomem *addr)
>> >     static inline u32 ioread32be(const volatile void __iomem *addr)
>>
> I think we don't need the 'volatile' keyword here. The main reason
> we have it on readl() is to shut up the compiler when dealing with
> ancient driver code that annotates iomem pointers as volatile.
>
> This is generally considered a (minor) driver mistake though, and
> modern drivers that for some reason use ioread*() typically don't
> do that (or they get a warning).

What about the different return type? u8 vs int
Thanks

-- 
Ricardo Ribalda
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/