RE: [PATCH 08/20] pinctrl: Assume map table entries can't have aNULL name field

[Stephen Warren]

Dong Aisheng wrote at Wednesday, February 22, 2012 9:48 PM:
> On Wed, Feb 22, 2012 at 07:53:44PM -0800, Stephen Warren wrote:
...
> > I'm hoping that we don't do this internal conversion. The rules I'd like are:
...
> > * Every mapping table entry must include a non-NULL name field.
> >
> > * Every call to pinctrl_get()/pinctrl_lookup_state() must pass a non-NULL name
>
> This is a way.
> 
> Before using this, i'm  still wondering what big problems do you think for us to support
> a NULL map name?
> Because the name for devices do not have different state really does not make too much
> sense but extra overhead.

If we disallow NULL names, it simplifies the code in the pinctrl core;
when registering mappings or right at the start of pinctrl_get() or
pinctrl_lookup_state(), we check if the name is NULL and if so error out.
Everywhere else can then assume name!=NULL, and hence not have special-
cases for name==NULL, e.g.:

In debug code:
name ? name : "(unnamed)"
vs.:
name

When matching mapping table entries:
match = !name ? !map->name : !strcmp(name, map->name)
vs.:
match = !strcmp(name, map->name)

Similar for the body of pinctrl_lookup_state().

Equally, it's not possible to generate a mapping table entry with a NULL
name from device tree given the bindings we discussed, so disallowing them
everywhere keeps things consistent.

-- 
nvpublic

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