On 01/29, Stephen Boyd wrote:

On 01/29/15 05:31, Geert Uytterhoeven wrote:

quoted

Hi Tomeu, Mike,

On Fri, Jan 23, 2015 at 12:03 PM, Tomeu Vizoso
[off-list ref] wrote:

quoted

--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c

@@ -2391,25 +2543,24 @@ int __clk_get(struct clk *clk)
        return 1;
 }

-static void clk_core_put(struct clk_core *core)
+void __clk_put(struct clk *clk)
 {
        struct module *owner;

-       owner = core->owner;
+       if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
+               return;

        clk_prepare_lock();
-       kref_put(&core->ref, __clk_release);
+
+       hlist_del(&clk->child_node);
+       clk_core_set_rate_nolock(clk->core, clk->core->req_rate);

At this point, clk->core->req_rate is still zero, causing
cpg_div6_clock_round_rate() to be called with a zero "rate" parameter,
e.g. on r8a7791:

Hmm.. I wonder if we should assign core->req_rate to be the same as
core->rate during __clk_init()? That would make this call to
clk_core_set_rate_nolock() a nop in this case.

Here's a patch to do this

---8<----
From: Stephen Boyd <redacted>
Subject: [PATCH] clk: Assign a requested rate by default

We need to assign a requested rate here so that we avoid
requesting a rate of 0 on clocks when we remove clock consumers.

Signed-off-by: Stephen Boyd <redacted>
---
 drivers/clk/clk.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index a29daf9edea4..8416ed1c40be 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c

@@ -2142,6 +2142,7 @@ int __clk_init(struct device *dev, struct clk *clk_user)
 	struct clk_core *orphan;
 	struct hlist_node *tmp2;
 	struct clk_core *clk;
+	unsigned long rate;
 
 	if (!clk_user)
 		return -EINVAL;

@@ -2266,12 +2267,13 @@ int __clk_init(struct device *dev, struct clk *clk_user)
 	 * then rate is set to zero.
 	 */
 	if (clk->ops->recalc_rate)
-		clk->rate = clk->ops->recalc_rate(clk->hw,
+		rate = clk->ops->recalc_rate(clk->hw,
 				clk_core_get_rate_nolock(clk->parent));
 	else if (clk->parent)
-		clk->rate = clk->parent->rate;
+		rate = clk->parent->rate;
 	else
-		clk->rate = 0;
+		rate = 0;
+	clk->rate = clk->req_rate = rate;
 
 	/*
 	 * walk the list of orphan clocks and reparent any that are children of

-- 
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