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SubjectRe: [PATCH v2] spi: core: Validate lenght of the transfers in message
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Hi,

On Sun, 2014-02-16 at 15:25 +0100, Gerhard Sittig wrote:
> On Sat, Feb 15, 2014 at 08:09 +0200, Ivan T. Ivanov wrote:
> >
> > From: "Ivan T. Ivanov" <iivanov@mm-sol.com>
> >
> > SPI transfer lenght should be a power-of-two multiple
> > of eight bits.
>
> Please re-check for "lenght" typos in subjects and commit logs
> (code comments appear to be correct already).

Thanks, will correct them.

>
>
> The commit message still confuses me. You don't check that the
> length of an SPI transfer has a power-of-two length in bytes.
>
> Instead what the check implements is IIUC
> - pad "odd" bits-per-word settings before the check to full 1/2/4
> byte length specs (this is the power-of-two thing)
> - the total length of the SPI transfer cannot be empty (which I'd
> consider an optimization, not a violation, and may need a
> separate discussion)

I am not sure that I understand this one. I will say "the total
length of the SPI transfer _should not_ be empty". There is no
check for this currently.

> - the total length of the SPI transfer must be such that each
> "word" must be provided within a full 1/2/4 byte entity, with
> padding bits if the bits-per-word is "odd"
>
> Is this a misunderstanding on my side? A terminology thing? To
> me, the "SPI transfer" is the total payload and may have any
> arbitrary length. What you check for is a constraint on the
> transfer's length derived from or based on the "word length"
> ('word' in SPI context).
>
> So the code may be appropriate, yet the description may need an
> update, to not have the next person ask the same questions again.
>

I just forgot to update commit message. Will try to be more
careful next time.

Regards,
Ivan

>
> virtually yours
> Gerhard Sittig




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