[PATCH v2] clk: check the actual phase if get_phase is provided

Shawn Lin
2016-02-18T01:43:13Z

set_phase does sanity checking of degree and ask sub-driver
to set the degree. If set_phase is limited to support the
degree what the caller need, sub-driver may select a
approximate value and return success state. In this case, it's
inappropriate to assign the degree directly to clk->core->phase.
We should ask sub-driver to decide the strategy. If sub-driver just
want to support accurate degree, it can fail the set_phase. Otherwise,
store the actual degree provided by sub-driver into clk->core->phase
if get_phase is provided. Another improvemnt by this patch is that
we can avoid to do unnecessary set_phase if the request defrees is
already there.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

---

Changes in v2:
- remove actual_degree to simplify the changes
- bail early if nothing to to

drivers/clk/clk.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b4db67a..275e70f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1902,6 +1902,10 @@ int clk_set_phase(struct clk *clk, int degrees)

clk_prepare_lock();

+ /* bail early if nothing to do */
+ if (degrees == clk->core->phase)
+ goto out;
+
trace_clk_set_phase(clk->core, degrees);

if (clk->core->ops->set_phase)
@@ -1909,9 +1913,13 @@ int clk_set_phase(struct clk *clk, int degrees)

trace_clk_set_phase_complete(clk->core, degrees);

- if (!ret)
- clk->core->phase = degrees;
+ if (!ret) {
+ if (clk->core->ops->get_phase)
+ degrees = clk->core->ops->get_phase(clk->core->hw);

+ clk->core->phase = degrees;
+ }
+out:
clk_prepare_unlock();

return ret;
--
2.3.7