Re: [v4, 5/6] mmc: kconfig: select FSL_GUTS for MMC_SDHCI_OF_ESDHC

[Scott Wood <scottwood@freescale.com>]

On Mon, 2015-12-28 at 13:10 +0100, Ulf Hansson wrote:
> On 28 December 2015 at 11:26, Yangbo Lu <yangbo.lu@nxp.com> wrote:
> > > -----Original Message-----
> > > From: Ulf Hansson [mailto:ulf.hansson@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