Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: Re[14]: [PATCH v3] mfd: syscon: Add non-DT support | Date | Wed, 20 Feb 2013 21:27:09 +0000 |
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On Wednesday 20 February 2013, Alexander Shiyan wrote: > > On Wednesday 20 February 2013, Alexander Shiyan wrote: > > > No. Target have a three SYSCON registers and two SYSFLG. All these registers > > > can be combined into three syscon devices. > > > Only these registers will be handled via syscon device, so it is not only one. > > > Or you mean about handle all register via syscon? It is not it. > > > > Yes, I was expecting that you would list all three pages in the resource > > for the syscon device, basically making all of the core clps711x > > registers available this way. > > All other will be passed as resource to drivers, as for other drivers. > And this change replaces clps_read/write.
Ok, I see.
> > > > 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.
Arnd
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