[RFC PATCH 1/3] clk: fix inconsistent use of req_rate

Heiko Stuebner
2016-05-02T16:36:20Z

The req_rate property seems to be made to hold the rate requested through
clk_set_rate. Currently it gets initialized in clk_init to the clocks
current rate and then adapted in clk_set_rate calls. Orphan clocks and
their children get initialized to a rate of 0 and req_rate never gets
re-set when these lose their orphan-status.

Initializing req_rate to the clocks rate also is unintuitive as it just
copies the value that is already in the rate property and also looses the
information if a component actually requested a specific rate.

So separate the requested rate and only set it in clk_core_set_rate_nolock
when a real rate gets requested. The users of the req_rate __clk_put and
clk_set_rate_range that adjust a clock based on that value use req_rate
at first and fall back to rate if no rate had been requested now.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
drivers/clk/clk.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f079ea4..65e0aad 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1507,8 +1507,10 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
return 0;

/* bail early if nothing to do */
- if (rate == clk_core_get_rate_nolock(core))
+ if (rate == clk_core_get_rate_nolock(core)) {
+ core->req_rate = req_rate;
return 0;
+ }

if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
return -EBUSY;
@@ -1599,9 +1601,14 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
clk_prepare_lock();

if (min != clk->min_rate || max != clk->max_rate) {
+ unsigned long rate = clk->core->req_rate;
+
+ if (!rate)
+ rate = clk->core->rate;
+
clk->min_rate = min;
clk->max_rate = max;
- ret = clk_core_set_rate_nolock(clk->core, clk->core->req_rate);
+ ret = clk_core_set_rate_nolock(clk->core, rate);
}

clk_prepare_unlock();
@@ -2379,7 +2386,7 @@ static int __clk_core_init(struct clk_core *core)
rate = core->parent->rate;
else
rate = 0;
- core->rate = core->req_rate = rate;
+ core->rate = rate;

/*
* walk the list of orphan clocks and reparent any that newly finds a
@@ -2809,6 +2816,7 @@ int __clk_get(struct clk *clk)

void __clk_put(struct clk *clk)
{
+ unsigned long rate;
struct module *owner;

if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
@@ -2817,9 +2825,13 @@ void __clk_put(struct clk *clk)
clk_prepare_lock();

hlist_del(&clk->clks_node);
- 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);
+
+ rate = clk->core->req_rate;
+ if (!rate)
+ rate = clk->core->rate;
+
+ if (clk->min_rate > rate || clk->max_rate < rate)
+ clk_core_set_rate_nolock(clk->core, rate);

owner = clk->core->owner;
kref_put(&clk->core->ref, __clk_release);
--
2.8.0.rc3