Messages in this thread | | | Date | Tue, 1 May 2018 14:22:11 +0100 | From | Lee Jones <> | Subject | Re: [PATCH 1/1] mfd: tps65911-comparator: Fix an off by one bug |
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On Tue, 01 May 2018, Robin Murphy wrote:
> On 01/05/18 10:45, Lee Jones wrote: > > The COMP1 and COMP2 elements are in 0 and 1 respectively so this code is > > accessing the wrong elements and one space beyond the end of the array. > > > > The "id" variable is never COMP (0) so that code can be removed. > > > > Fixes: 6851ad3ab346 ("TPS65911: Comparator: Add comparator driver") > > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > --- > > > > History: > > > > Dan was the originator of this patch and the author of the commit log, > > but produced 2 code solutions which I wasn't happy with. The first > > submission [0] introduced a COMP device, which after a quick check of > > the datasheet [1] appeared to be fictitious. A subsequent submission > > [2] conducted arithmetic in array indexes. > > > > It is my belief that the correct solution is to roll which the > > situation the hardware engineers presented us with and define COMP1 > > at position 0 and COMP2 at position 1 such that we can use the > > simplest code possible to select them. > > > > Dan wasn't happy to put his name to this, which I completely > > understand. Calling SOMETHING1 0 (zero) is a little unnatural. > > > > However, since I have no shame, I offered to submit it. > > As an idly-curious passer-by, this looks perfectly reasonable to me - I > don't see why a mapping between names and indices should have to be > artificially constrained just because the names happen to contain numerals.
Right. This was my thinking too.
> If it's really that abhorrent, then I guess they could be named something > like COMPn_ID for even more clarity. > > That said, now that I've gone and looked, the whole business seems > ridiculously over-engineered. AFAICS it would be infinitely simpler to just > pass the register address directly where id is currently passed, statically > define UV_MAX, and get rid of the otherwise-pointless struct comparator > entirely. The current abstraction doesn't look like it could actually scale > to support different chips without major surgery anyway.
Sounds good. Patches always welcome. ;)
-- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog
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