Re: [PATCH v3] mfd: syscon: Add non-DT support
From: Alexander Shiyan
Date: Thu Feb 21 2013 - 10:27:35 EST
> > > > > treat the absence of DT information as an error, and a call to
> > > > > syscon_regmap_lookup_by_compatible or syscon_regmap_lookup_by_phandle
> > > > > will always return the syscon device that was registered first, or
> > > > > -EPROBE_DEFER for any error.
> > > >
> > > > The initial idea is search desired syscon device from drivers only by one function
> > > > (i.e. search syscon device by compatible string or by specific alias) and no depend
> > > > on DT or non-DT. I.e. define syscon device always at machine start (even if we run
> > > > machine from DTS), because device should be always present in system.
> > >
> > > I don't understand yet what the advantage for clps711x is over just a single
> > > register area that would get registered at boot time and replace all the
> > > clps_readl/clps_writel calls.
> > This cause a serious perfomance impact. Only SYSCON and SYSFLG is used
> > in several places and should be protected by spinlocks. Other registers
> > can be used without locks. And, as say before, clps_read/write will be replaced with
> > read/write when registers will passed as resource. First example of this change I
> > sent to you before (patchset for serial driver).
> Yes, that makes sense. I have no fundamental objections then. I'll wait
> for the next version of your patch and then comment on any details I still
> find sticking out.
OK. Next version will be sent in few minutes.
I am leave search by id_entry and extend it with variant from first patch version.
This will allow to search syscon device with id_entry record in the driver, and
without last one by specifying generic name with id (for example "syscon.0").