[RFC 2/2] ARM:Tegra: Device Tree Support: Initialize audio card gpio's from the device tree.
Segher Boessenkool
segher at kernel.crashing.org
Tue May 31 10:58:46 EST 2011
> The producer side works fine as-is, agreed.
+1
> What I was not sure about was the use of having an array of unnamed
> gpios as part of the consumer-side binding, where there's no logical
> ordering between these entries.
>
> In the sdhci case, there are three gpios; one to supply power to the
> slot;
> one for card detect and one for write protect sense.
>
> In that case, it would make a whole lot more sense to have three
> separate
> properties, say "power-gpio", "cd-gpio" and "wp-gpio", than an opaque
> array of
> entries without description besides what comments are used in the dts
> file.
Yes. And this way you can also show a specific board doesn't have a
specific function GPIO wired up by simply not having the property for
it, instead of that ugly 0 phandle business.
> That these in turn point just to gpio number <x> at controller <y> is
> OK with
> me.
Controller <y> GPIO # <x> with flags <w>, yes. A generic "GPIO
specifier".
> Also, I can see cases where it makes sense to have more than one gpio
> references in a property (i.e. busses), but only where there's either
> internal
> ordering to them, or where ordering doesn't matter at all.
That's up to the device binding, let's hope the people who write those
show good judgement :-)
Segher
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