Messages in this thread | | | Date | Mon, 15 Jun 2015 09:58:05 -0600 | From | Stephen Warren <> | Subject | Re: [RESEND PATCH 1/2] pinctrl: change function behavior for per pin muxing controllers |
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On 06/10/2015 09:04 AM, Ludovic Desroches wrote: > When having a controller which allows per pin muxing, declaring with > which groups a function can be used is a useless constraint since groups > are something virtual.
This isn't true.
Irrespective of whether a particular piece of pinmux HW can control the mux function for each pin individually, or only in groups, it's quite likely that each function can only be selected onto a subset of those pins or groups. Requiring the pinctrl driver to inform the core which set of pins/groups particular functions can be selected onto seems quite reasonable.
In my opinion at least, for HW that can select the mux function at the per-pin level, the only sensible set of groups is one group per pin with each group containing a single pin. Any other use of groups is a SW/user-level construct, and is something unrelated to why the pinctrl subsystem supports groups. If we want to represent those groups in pinctrl, there should be two separate sets of groups; one to represent the actual HW capabilities, and one to represent the SW/user-level convenience abstractions.
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