[U-Boot] [PATCH v4] mmc: socfpga_dw_mmc: Enable calibration for drvsel and smplsel

[Pavel Machek]

Hi!
> > > OK, this is bad. Originally, if we didn't specify these in the DT, we
> > > would
> > > use the default values of 0x3 and 0x0 , but now we do the
> > > calibration. I wonder,
> > > do we care about DT ABI compatibility on the U-Boot level or not ?
> > 
> > If the compatibility failed, it will still invoke the calibration to
> > get the correct value. Just that its in the cost of boot time.
> 
> Hopefully the calibration does it's job then.
> 
> > At same time, I am rethinking another email thread on suggesting to put
> > this into common dw_mmc code. Here are my proposal
> 
> Having this in common code would make sense.
> 
> > 1. Put back the correct default value for DT ABI compatiblity
> > 2. Adding a node to enable calibration. If node not exist, calibration
> > will disabled as default.
> 
> But "enable calibration" is not really a hardware property, so it shouldn't
> be in the DT. The DT is purely a hardware description and only the smplsel
> and drvsel fit into this, some "enable-calibration" does not.

Well... "enable calibration" is not hardware property, but "well-known
autocalibration works on this hardware" is.. Anyway, config option is
probably fine, too.

How does Linux solve this? It needs to do some calibration, too, no?
We should use whatever dts Linux uses...
									Pavel
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