[PATCH 6/6] ARM: dts: add pinctrl in PXA DT files

On 10.08.2012 12:56, Linus Walleij wrote:

On Thu, Aug 9, 2012 at 4:28 PM, Daniel Mack [off-list ref] wrote:

quoted

I am looking at the generic pinctrl code right now

Sweet!

quoted

and I wonder if the following approach would be ok:

- each driver that calls pinctrl_register() has its own dt_match_table
entry, so the 'compatible' part of the bindings is specific to a pin
controller chip.

Yep.

quoted

- introduce a pinctrl_parse_of(struct of_node *) and call that after the
driver has added all its pins. That function walks all the children of
the given node and uses the callbacks provided by the driver to do the
actual work.

Isn't that already how it works? Maybe I misunderstand, do you mean
that you want to pass the DT node to pinctrl_register()?

To parse the generic bits, yes. But I realized only now that we already
have dt_to_map_one_config()

Are you talking about using pinctrl hogs to set up the default
configuration and muxing? That can already be done today,
and has nothing to do with whether you use generic pin config
or not.

This uses the .dt_node_to_map() and .dt_free_map() callbacks
in the pinctrl_ops vtable to generate a map from the device tree,
in any way you want.

Yes, I see. And this is where duplication emerges, or, where
consolidation would need to be done. If we want to standardize the way
pins are set up in terms of bias, pullup/pulldown and all that, we would
just need to map generic DT entries to PIN_CONFIG_* and call the pin
controllers specific functions.

So the infrastructure I think already exists, but whereas all
current driver have their own config and mux (etc) parsing
code, pinconf-generic could provide something that would
be common for all driver using generic pin config.

Exactly. And then the question is whether we want implicit behaviour.
IOW - let dt_to_map_one_config() parse the generic bits and then call
the driver specific augmentation code, if any.


Daniel