> -----Original Message-----
> From: Yangbo Lu
> Sent: Wednesday, January 06, 2016 2:58 PM
> To: Scott Wood; Ulf Hansson
> Cc: Lu Yangbo-B47093; linux-mmc; Xie Xiaobo-R63061; Leo li
> Subject: RE: [v4, 5/6] mmc: kconfig: select FSL_GUTS for
> MMC_SDHCI_OF_ESDHC
> 
> > -----Original Message-----
> > From: Scott Wood [mailto:scottw...@freescale.com]
> > Sent: Tuesday, December 29, 2015 3:10 AM
> > To: Ulf Hansson; Yangbo Lu
> > Cc: Lu Yangbo-B47093; linux-mmc; Xie Xiaobo-R63061; Leo li
> > Subject: Re: [v4, 5/6] mmc: kconfig: select FSL_GUTS for
> > MMC_SDHCI_OF_ESDHC
> >
> > On Mon, 2015-12-28 at 13:10 +0100, Ulf Hansson wrote:
> > > On 28 December 2015 at 11:26, Yangbo Lu <yangbo...@nxp.com> wrote:
> > > > > -----Original Message-----
> > > > > From: Ulf Hansson [mailto:ulf.hans...@linaro.org]
> > > > > Sent: Thursday, December 17, 2015 7:31 PM
> > > > > To: Scott Wood
> > > > > Cc: Lu Yangbo-B47093; linux-mmc; Xie Xiaobo-R63061; Leo li
> > > > > Subject: Re: [v4, 5/6] mmc: kconfig: select FSL_GUTS for
> > > > > MMC_SDHCI_OF_ESDHC
> > > > >
> > > > > [...]
> > > > >
> > > > > > >
> > > > > > > And I think stubs for reading SVR is quite a bad idea.
> > > > > > > It'll make the driver build but it will silently not be able
> > > > > > > to apply SVR-based
> > > > > workarounds.
> > > > > >
> > > > > > It doesn't have to be "silent", the driver can return an error
> > > > > > (and print error messages) from its ->probe() method, if the
> > > > > > calls to the GUTS driver fails.
> > > > > >
> > > > > > Anyway, I mentioned this idea only to understand the need for
> > > > > > *optional* GUTS supports. Perhaps there is a cross SOC drivers
> > > > > > that for some platforms depends on GUTS but on others it
> doesn't.
> > > > > >
> > > > > > Maybe that isn't case then!?
> > > > >
> > > > > Can you please answer this question!?
> > > > >
> > > > > According to the earlier versions of this patchset and from your
> > > > > comments [1], it *do* seems like the GUTS driver may be optional
> > > > > and thus stubs could address this.
> > > > >
> > > > > Kind regards
> > > > > Uffe
> > > > >
> > > > > [1]
> > > > > http://www.spinics.net/lists/linux-mmc/msg34412.html
> > > >
> > > > [Lu Yangbo-B47093] Hi Scott and Uffe, In the earlier version, I'd
> > > > like to use syscon support and only add 'syscon' compatible in the
> > > > dts whose eSDHC needs to use it to get SVR.
> > > > But I never thought this had caused so much discussion... :(
> > >
> > > Sorry, I understand your frustration but that's life sometimes. :-)
> > >
> > > To me, the syscon solution is more elegant...
> >
> > The syscon patch was terrible.  It would have accessed a certain
> > location in any node labelled "syscon" whether it was guts or not, in
> > addition to the other complaints.
> >
> > -Scott
> 
> [Lu Yangbo-B47093] As my understand, the syscon APIs would just check
> whether there is a 'syscon' compatible.
> If no, the APIs return. We still could maintain a list of compatibles for
> guts if using syscon.

[Lu Yangbo-B47093] It's ok to use a compatible name that is not 'syscon' as the 
parameter of the APIs.
The node needs just to contain 'syscon'. 

> In my opinion, syscon and guts driver are just two method to get SVR.
> 
> I agree with Uffe, because I think syscon is really designed for this
> situation and many arm platforms are using it.
> Of course, I still would like to try guts driver if you insist on it.
> 
> 
> 
> 
> 

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