Messages in this thread | | | Date | Wed, 24 Sep 2014 10:27:19 +0200 | From | Tomeu Vizoso <> | Subject | Re: [PATCH v13 0/9] Per-user clock constraints |
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On 09/23/2014 10:59 PM, Stephen Boyd wrote: > On 09/23/14 11:40, Tomeu Vizoso wrote: >> Hello, >> >> this version of the patchset addresses some issues that Russell pointed out >> yesterday: >> >> * Refactor the changes to clkdev.c to reduce the amount of ifdefs. >> >> * Properly release clocks when there isn't enough memory to create the per-user >> wrapper. >> >> * Add clk_provider_put(struct clk_core*) for clock implementations to call >> instead of clk_put(struct clk*) (instead of exposing __clk_put). >> >> As the previous versions, this is based on top of 3.17-rc4 and Mike's patch at >> [0]. > > Any thoughts on my comments on patch set #10[1]? It seems like we can > avoid having a flag day to support this.
I cannot say that I fully understand your proposal, but IMO the most valuable thing in this patchset is precisely the API split (and thus, the flag day is inherent to it).
I see a lot of value in clk consumers to use a defined set of functions that all take and/or return struct clk, and for providers to use the functions that take and/or return struct clk_core. Makes the API clearer and allows it to have a more scalable growth in the future.
A less important feature of the patchset are per-user clocks, which (if I understand correctly) your proposal would address without requiring a flag day.
And then we have clock constraints, which is probably the least important feature in the grand scheme of things, but it's actually what I personally care about.
If we wanted to add a way for clk users to specify clock constraints without any refactoring, we could easily do so by reusing the request pattern that pm_qos uses:
void clk_add_constraint(struct clk_request *req, int constraint_type, unsigned long value);
void clk_update_constraint(struct clk_request *req, unsigned long new_value);
void clk_remove_constraint(struct clk_request *req);
It wouldn't be that bad IMO, but the API refactoring was something that was long desired and this was seen as a good opportunity to tackle it before it gets worst.
Cheers,
Tomeu
> [1] https://lkml.org/lkml/2014/9/9/960 >
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