Re: [RFC PATCH 3/5] pxa: clean up the legacy SSP API

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Tue, Apr 28, 2009 at 08:06:08PM -0300, Daniel Ribeiro wrote:
> Em Ter, 2009-04-28 às 23:20 +0100, Russell King - ARM Linux escreveu:
> > On Thu, Apr 23, 2009 at 01:06:12PM +0800, Eric Miao wrote:
> > > Actually, due to the number of possible SSP configurations, it's quite a
> > > difficult job to maintain an API that can be well re-used. The guideline
> > > here is to keep only a list of SSP devices and their basic information,
> > > and it's up to the user driver (like SPI or Audio SSP) to configure the
> > > SSP in a desired way.
> > 
> > Hmm, the LX battery driver uses this API for its rudimentary battery
> > communication channel with the PCON.
> > 
> > What are you suggesting as the replacement API?  Direct register access?
> 
> The SPI subsystem?

Can the SPI system cope with the other chip being the master of the
interface.  In other words, can SPI sit around primed for a transfer,
and notify the user of SPI that new data has arrived?

If not, the SPI subsystem is totally unsuitable for this.