[PATCH 2/3] mach-ux500: export System-on-Chip information via sysfs

[arnd@arndb.de (Arnd Bergmann)]

On Wednesday 13 July 2011 22:32:26 Greg KH wrote:
> On Wed, Jul 13, 2011 at 09:40:35AM -0700, Saravana Kannan wrote:
> > On 07/13/2011 12:55 AM, Lee Jones wrote:
> > >On 12/07/11 17:29, Saravana Kannan wrote:
> > >I initially had it all as part of soc_device_register, but Arnd told me
> > >to remove it in this patch-set.
> > >
> > >See here:
> > >
> > >On 17/04/11 19:36, Arnd Bergmann wrote:
> > >>For the nonstandard attributes, I would recommend having the individual
> > >>drivers call device_create_file, in order to discourage the use of
> > >>device specific attribute names.
> > 
> > Arnd,
> > 
> > I don't think forcing individual driver to call device_create_file()
> > is really going to be much of a discouragement.
> 
> Yes it is as calling that is broken and wrong and userspace will race
> with the kernel and bad things will happen on the wrong phase of the
> moon.
> 
> But again, I never saw the original series to explain why...

This is about attributes to the main device that acts as a parent for all
devices on the SoC, so there is no user space at the time.

IIRC, the original patch was documenting a set of standard attributes and
letting the SoC specific driver pass a set of static attributes in the
hope that they do whatever is documented.

In one of my review comments, I asked this to be changed to pass a data
structure with the actual contents of those attributes and to make
the implementation common to the soc independent code, in order to
reduce the amount of code needed in each soc implementation, to enforce
consistent behavior, and to make it more obvious (and painful) when an
soc implementation adds a nonstandard attribute.

It seems the final outcome was to have a data structure of function
pointers to get the attribute contents, which is less nice but still
acceptable IMHO.

	Arnd