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

[Marek Vasut]

On Wednesday, December 02, 2015 at 04:10:19 PM, Chin Liang See wrote:
> On Wed, 2015-12-02 at 15:39 +0100, Marek Vasut wrote:
> > On Wednesday, December 02, 2015 at 06:52:17 AM, Chin Liang See wrote:
> > 
> > [...]
> > 
> > > > 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.
> 
> Sound reasonable. In this case, I can put this into KConfig where user
> can configure this easily through menuconfig.

OK, this would be much better.

Best regards,
Marek Vasut