Re: Coding style details (checkpatch)

From	Joe Perches <joe@perches.com>
Newsgroups	linux.kernel
Subject	Re: Coding style details (checkpatch)
Date	2015-06-22 08:20 +0200
Message-ID	<pE3fj-3OG-5@gated-at.bofh.it> (permalink)
References	(2 earlier) <pD1Sh-4Mq-9@gated-at.bofh.it> <pD1Si-4Mq-25@gated-at.bofh.it> <pD2bE-59i-17@gated-at.bofh.it> <pD5VU-26b-9@gated-at.bofh.it> <pE2CC-2QP-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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...


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Thread

Coding style details khalasa@piap.pl (Krzysztof Hałasa) - 2015-06-19 10:40 +0200
  Re: Coding style details Frans Klaver <fransklaver@gmail.com> - 2015-06-19 11:10 +0200
    Re: Coding style details (checkpatch) khalasa@piap.pl (Krzysztof Hałasa) - 2015-06-22 07:40 +0200
      Re: Coding style details (checkpatch) Joe Perches <joe@perches.com> - 2015-06-22 08:20 +0200
        Re: Coding style details (checkpatch) khalasa@piap.pl (Krzysztof Hałasa) - 2015-06-22 08:40 +0200
          Re: Coding style details (checkpatch) Joe Perches <joe@perches.com> - 2015-06-22 08:50 +0200

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