Re[14]: [PATCH v3] mfd: syscon: Add non-DT support

["Alexander Shiyan" <shc_work@mail.ru>]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=utf-8, Size: 1936 bytes --]

> 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.

> > > 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).

---
ÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥