On Thu, Jan 12, 2012 at 12:56:52PM -0800, Stephen Warren wrote:

Dong Aisheng wrote at Thursday, January 12, 2012 1:36 AM:

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Stephen Warren wrote at Thursday, January 12, 2012 4:18 AM:

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Dong Aisheng wrote at Tuesday, January 10, 2012 1:21 AM:

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Stephen Warren wrote at Saturday, January 07, 2012 2:03 AM:

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Personally, I think I'd be OK with the sysfs pinctrl map file only containing
the map entries for devices that had used the pinctrl API, and hence only
parsing the pinmux properties in pinmux_get().

Actually I already did it like that in the patch I sent:
https://lkml.org/lkml/2012/1/5/153

Originally I'd like to do like that but I found an inconsistent issue that
the sysfs pinctrl map file will behave differently between dt and non-dt
Platform. For non-dt, it means showing all exist map entries. For dt, it means
Only used pinmux map entries.

And in current design when device calls pinmux_get, it will search a predefined
pinmux_maps array to find which function and group it is binded to.
If switch to the new way, we only dynamically create pinmux map and dynamically
register it when pinmux_get is called, first we need to change the code path in
pinmux_get in a totally different way, second for support that we may also better
to change pinmux_maps array to a list.
But after changing the pinmux_maps to a list, what about using in non-dt?

So without any strong reason i still think it would be better to keep consistency
With the non-dt pinctrl subsystem.
And the effort would be minimum since besides constructing the map by parsing
Device tree, everyting is the same as before in pinmux map and we could re-use
the current code.

OK. I think this can work out pretty easily with a bus notifier as I
mentioned before.

But, one thought on doing this in pinmux_get(). I'd simply implement a
Function that read a DT node's pinmux property/node, converted it to a
pinmux mapping table, and registered it with the pinctrl core. Then,
pinmux_get() could simply call this before doing anything else at all.
I don't think you'd need to modify how pinmux_get() worked at all.

This sounds like a pretty good idea to me.

-- 
Regards,
Shawn