linux-kernel - [PATCH] clk: Only recalculate the rate if needed

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Date:	Fri,  6 Feb 2015 15:13:01 +0100
From:	Tomeu Vizoso <tomeu.vizoso@...labora.com>
To:	linux-kernel@...r.kernel.org
Cc:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>,
	Thierry Reding <thierry.reding@...il.com>,
	Peter De Schrijver <pdeschrijver@...dia.com>,
	Mike Turquette <mturquette@...aro.org>,
	Stephen Boyd <sboyd@...eaurora.org>
Subject: [PATCH] clk: Only recalculate the rate if needed

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@...il.com>
Cc: Peter De Schrijver <pdeschrijver@...dia.com>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@...labora.com>

---

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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