Re: [PATCH 2/2] spi: Add Qualcomm QUP SPI controller support

[Courtney Cavin <courtney.cavin@sonymobile.com>]

On Mon, Feb 10, 2014 at 08:41:44PM +0100, Ivan T. Ivanov wrote:
> 
> Hi,
> 
> On Mon, 2014-02-10 at 11:47 -0600, Andy Gross wrote:
> > On Mon, Feb 10, 2014 at 06:55:02PM +0200, Ivan T. Ivanov wrote:
> > 
> > [....]
> > 
> > > > > > Bail here?
> > > > > 
> > > > > I don't know. What will be the consequences if controller continue to
> > > > > operate on its default rate?
> > > > > 
> > > > 
> > > > It is unclear.  But if you can't set the rate that is configured or if there is
> > > > a misconfiguration, it's probably better to exit the probe and catch it here.
> > > 
> > > 
> > > My preference is to delay clock speed change till first
> > > SPI transfer. And use wherever transfer itself mandate.
> > > 
> > 
> > That works.  My only concern is that it might be nice to catch a configuration
> > problem early rather than wait for the SPI transfer to fail continuously.
> 
> If developer is skilled enough to know which version controller is,
> (s)he will be able to put the right frequency constrain here :-)

A developer doesn't have to have much skill at all to copy-paste DT
configurations around and muck with numbers....  I agree with Andy here,
early validation is a good idea here, at the very least, some sanity
checks.

-Courtney