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SubjectRe: [PATCH] clk: Only recalculate the rate if needed
Date
Quoting Tomeu Vizoso (2015-02-06 06:13:01)
> We don't really need to recalculate the effective rate of a clock when a
> per-user clock is removed, if the constraints of the later aren't
> limiting the requested rate.
>
> This was causing problems with clocks that never had a rate set before,
> as rate_req would be zero. Though this could be considered a bug in the
> implementation of those clocks, this should be checked somewhere else.
>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>

Fixes: 1c8e600440c7 ("clk: Add rate constraints to clocks")

Applied to clk-next. With this fix sunxi no longer vomits WARNs
everywhere due to divide-by-zero in the following path:

of_clk_init -> parent_ready -> __clk_put

Thanks,
Mike

>
> ---
>
> This applies on top of https://lkml.org/lkml/2015/2/5/769
> ---
> drivers/clk/clk.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index a7d37c3..4ea2d53 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -2664,7 +2664,11 @@ void __clk_put(struct clk *clk)
> clk_prepare_lock();
>
> hlist_del(&clk->clks_node);
> - clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
> +
> + if (clk->min_rate > clk->core->req_rate ||
> + clk->max_rate < clk->core->req_rate)
> + clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
> +
> owner = clk->core->owner;
> kref_put(&clk->core->ref, __clk_release);
>
> --
> 1.9.3
>


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