[PATCH v3 1/9] clk: at91: clk-generated: remove useless divisor loop
From: Quentin Schulz <hidden>
Date: 2017-07-13 07:49:47
Also in:
alsa-devel, linux-clk, linux-devicetree, lkml
Subsystem:
common clk framework, the rest · Maintainers:
Michael Turquette, Stephen Boyd, Linus Torvalds
The driver requests the current clk rate of each of its parent clocks to decide whether a clock rate is suitable or not. It does not request determine_rate from a parent clock which could request a rate change in parent clock (i.e. there is no parent rate propagation). We know the rate we want (passed along req argument of the function) and the parent clock rate, thus we know the closest rounded divisor, we don't need to iterate over the available divisors to find the best one for a given clock. Signed-off-by: Quentin Schulz <redacted> Acked-by: Boris Brezillon <redacted> --- drivers/clk/at91/clk-generated.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/drivers/clk/at91/clk-generated.c b/drivers/clk/at91/clk-generated.c
index f0b7ae904ce2..ef4b4e03de04 100644
--- a/drivers/clk/at91/clk-generated.c
+++ b/drivers/clk/at91/clk-generated.c@@ -124,19 +124,18 @@ static int clk_generated_determine_rate(struct clk_hw *hw, (gck->range.max && min_rate > gck->range.max)) continue; - for (div = 1; div < GENERATED_MAX_DIV + 2; div++) { - tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div); - tmp_diff = abs(req->rate - tmp_rate); - - if (best_diff < 0 || best_diff > tmp_diff) { - best_rate = tmp_rate; - best_diff = tmp_diff; - req->best_parent_rate = parent_rate; - req->best_parent_hw = parent; - } - - if (!best_diff || tmp_rate < req->rate) - break; + div = DIV_ROUND_CLOSEST(parent_rate, req->rate); + if (!div) + tmp_rate = parent_rate; + else + tmp_rate = parent_rate / div; + tmp_diff = abs(req->rate - tmp_rate); + + if (best_diff < 0 || best_diff > tmp_diff) { + best_rate = tmp_rate; + best_diff = tmp_diff; + req->best_parent_rate = parent_rate; + req->best_parent_hw = parent; } if (!best_diff)
--
2.11.0