Re: [PATCH v5] clk: change clk_ops' ->determine_rate() prototype
From: Tero Kristo
Date: Mon Jul 13 2015 - 05:01:32 EST
On 07/08/2015 03:57 AM, Stephen Boyd wrote:
On 07/07, Boris Brezillon wrote:
Clock rates are stored in an unsigned long field, but ->determine_rate()
(which returns a rounded rate from a requested one) returns a long
value (errors are reported using negative error codes), which can lead
to long overflow if the clock rate exceed 2Ghz.
Change ->determine_rate() prototype to return 0 or an error code, and pass
a pointer to a clk_rate_request structure containing the expected target
rate and the rate constraints imposed by clk users.
The clk_rate_request structure might be extended in the future to contain
other kind of constraints like the rounding policy, the maximum clock
inaccuracy or other things that are not yet supported by the CCF
(power consumption constraints ?).
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
CC: Jonathan Corbet <corbet@xxxxxxx>
CC: Tony Lindgren <tony@xxxxxxxxxxx>
CC: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
CC: "Emilio López" <emilio@xxxxxxxxxxxxx>
CC: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
CC: Tero Kristo <t-kristo@xxxxxx>
CC: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
CC: Prashant Gaikwad <pgaikwad@xxxxxxxxxx>
CC: Stephen Warren <swarren@xxxxxxxxxxxxx>
CC: Thierry Reding <thierry.reding@xxxxxxxxx>
CC: Alexandre Courbot <gnurou@xxxxxxxxx>
CC: linux-doc@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx
CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
CC: linux-omap@xxxxxxxxxxxxxxx
CC: linux-mips@xxxxxxxxxxxxxx
CC: linux-tegra@xxxxxxxxxxxxxxx
---
I'll throw this patch into -next now to see if any other problems
shake out. I'm hoping we get some more acks though, so it'll be
on it's own branch and become immutable in a week or so. One
question below.
Gave this patch a quick test on the boards I have access to, and didn't
notice any obvious problems.
So, for the TI parts:
Acked-by: Tero Kristo <t-kristo@xxxxxx>
diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
index 616f5ae..9e69f34 100644
--- a/drivers/clk/clk-composite.c
+++ b/drivers/clk/clk-composite.c
@@ -99,33 +99,33 @@ static long clk_composite_determine_rate(struct clk_hw *hw, unsigned long rate,
parent_rate = __clk_get_rate(parent);
- tmp_rate = rate_ops->round_rate(rate_hw, rate,
+ tmp_rate = rate_ops->round_rate(rate_hw, req->rate,
&parent_rate);
if (tmp_rate < 0)
continue;
- rate_diff = abs(rate - tmp_rate);
+ rate_diff = abs(req->rate - tmp_rate);
- if (!rate_diff || !*best_parent_p
+ if (!rate_diff || !req->best_parent_hw
|| best_rate_diff > rate_diff) {
- *best_parent_p = __clk_get_hw(parent);
- *best_parent_rate = parent_rate;
+ req->best_parent_hw = __clk_get_hw(parent);
+ req->best_parent_rate = parent_rate;
best_rate_diff = rate_diff;
best_rate = tmp_rate;
}
if (!rate_diff)
- return rate;
+ return 0;
}
- return best_rate;
+ req->rate = best_rate;
+ return 0;
} else if (mux_hw && mux_ops && mux_ops->determine_rate) {
__clk_hw_set_clk(mux_hw, hw);
- return mux_ops->determine_rate(mux_hw, rate, min_rate,
- max_rate, best_parent_rate,
- best_parent_p);
+ return mux_ops->determine_rate(mux_hw, req);
} else {
pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n");
+ req->rate = 0;
return 0;
Shouldn't this return an error now? And then assigning req->rate
wouldn't be necessary. Sorry I must have missed this last round.
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