Re: [PATCH v2 5/9] document: devicetree: bind pinconf with pin-single
From: Haojian Zhuang <hidden>
Date: 2012-10-31 22:51:33
Also in:
linux-arm-kernel
On Wed, Oct 31, 2012 at 11:26 PM, Stephen Warren [off-list ref] wrote:
On 10/31/2012 10:58 AM, Haojian Zhuang wrote:quoted
On Tue, Oct 23, 2012 at 6:44 AM, Stephen Warren [off-list ref] wrote:quoted
3) Why is pinctrl-single,gpio-func optional? Presumably you always need to program the pinmux HW to select the GPIO function. Yet, the driver code in an earlier patch seems to deliberately do nothing if this property is missing. Shouldn't the DT parsing return an error instead?pinctrl-single,gpio-func is optional for above reason.Presumably the node that contains the pinctrl-single,gpio-func property is optional, but once you have such a node, pinctrl-single,gpio-func is required?
Yes, gpio-func is must required if the phandle of gpio range is defined. I'll add such comments in document.
quoted
quoted
I suppose it's OK that a generic pin controller binding would use the generic pin configuration config options. I'm still not convinced that the semantics of generic pin control make sense. Maybe if they're just arbitrary names for SoC-specific things it's fine though. Do these patches expose /all/ generic pin configuration options? It doesn't seem worth exposing only some of them and ignoring others.I believe general pinconf can't support all cases in different silicons.I tend to agree.quoted
And we still have some common features that could be covered in general pinconf. So we need a structure to support both pinconf & specific pinconf.But that tends to imply that adding support for generic pinconf into the pinctrl-simple driver isnt' actually going to be useful for anyone. If pinctrl-single only supports some part of your HW, how can you use it? Or, do you intend to somehow make pinctrl-single support both the common generic pinconf stuff, and somehow be extensible to support any SoC-specific pin config fields?
I'm intend to make pinctrl-single to support both the common generic pinconf stuff and any SoC-specific pinconf. I'll try to handle it. But they won't be included in V3.