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SubjectRe: [PATCH 1/2] User access to internal clocks
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> You're not understanding the issue(s).
>
> 1. there is no 1:1 mapping between the identifiers (struct device +
> connection ID) and the struct clk. It's actually a many-to-one
> mapping.
>
> That means there is _no_ name associated with a struct clk.
>
> Conceptually, clk_get() gives you a struct clk for the struct device
> and a connection ID. How that mapping is achieved isn't specified
> in the API, all that's required is that such a mapping is performed.
> It is _specifically_ intended that more than one set of {device,id}
> pairs will map to the same clk.
>
> So, now to insist that you can go from a struct clk to some kind of
> string identifier for it is changing this - you're now requiring
> that every struct clk has a unique name. This is not the case.
> PXA, for instance, struct clk's are now completely nameless. They
> have no identifier.
>
> If you want to have a string identifier which works in every case,
> this will:
>
> sprintf(identifer, "%p", clk);
>
> Or, I guess you could force every struct clk to have a 'sysfs_name'
> field just to export them out via sysfs - and that'll be all that
> it's used for.
>
> 2. there is no generic way to walk a set of struct clk's - indeed, there
> may be no list of them (and there exists implmentations where that is
> true) and the only list which does exist is a set ID to clk mapping
> structures.
>
>> Otherwise, what do you suggest to enumerate and distinguish all system
>> clocks ?
>
> There exists no such concept in the API, what you're asking for is
> implementation specific.
>

Thank you for this explanation, now it's much more clear to me.

What about adding a dedicated function to clk api that registers a struct clk
in a linked list and associates it with a name, with the only specific purpose
to enumerate and list (and possibly change rate and parents) all
clocks in sysfs ?
Obviously only specifically registered clocks will be visible in sysfs...


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