Re: Coding style details (checkpatch)

Joe Perches
2015-06-22T06:12:40Z

On Mon, 2015-06-22 at 07:33 +0200, Krzysztof Hałasa wrote:
> Joe Perches <joe@perches.com> writes:
>
> > How is the macro used?
> > #define REG8_1(a0) ((const u16[8]){a0, a0 + 1, a0 + 2, a0 + 3})
>
> #define REG8_1(a0) ((const u16[8]){a0, a0 + 1, a0 + 2, a0 + 3, a0 + 4, a0 + 5, a0 + 6, a0 + 7})
[]
> #define VDMA_CHANNEL_CONFIG REG8_1(0x10)
[]
> reg_write(vc->dev, VDMA_CHANNEL_CONFIG[vc->ch], dma_cfg);
[]
> ERROR: space required before the open brace '{'
> +#define REG8_1(a0) ((const u16[8]){a0, a0 + 1, a0 + 2, a0 + 3})
>
> Does this qualify as the "false positive"?

Probably, yes. Is it worth fixing? Probably not.

It might be better to use some base + index macro
as it could be smaller object code.

Something like:

#define REG_NO(base, multiplier, index) (base + (multiplier * index))

reg_write(vc->dev, REG_NO(0x10, 1, vc->ch), dma_cfg);
or

#define VDMA_CHANNEL_CONFIG 0x10

reg_write(vc->dev, REG_NO(VDMA_CHANNEL_CONFIG, 1, vc->ch), dma_cfg);

etc...