[PATCH v3 1/4] clk: at91: replace prog clk round_rate with determine_rate

From: Boris BREZILLON
Date: Tue Mar 11 2014 - 05:02:36 EST


From: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>

Implement the determine_rate callback to choose the best parent clk that
fulfills the requested rate.

Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx>
---
drivers/clk/at91/clk-programmable.c | 56 +++++++++++++++++------------------
1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/clk/at91/clk-programmable.c b/drivers/clk/at91/clk-programmable.c
index fd792b2..eff7016 100644
--- a/drivers/clk/at91/clk-programmable.c
+++ b/drivers/clk/at91/clk-programmable.c
@@ -102,40 +102,40 @@ static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
return parent_rate >> prog->pres;
}

-static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,
- unsigned long *parent_rate)
+static long clk_programmable_determine_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_clk)
{
- unsigned long best_rate = *parent_rate;
- unsigned long best_diff;
- unsigned long new_diff;
- unsigned long cur_rate;
- int shift = shift;
-
- if (rate > *parent_rate)
- return *parent_rate;
- else
- best_diff = *parent_rate - rate;
-
- if (!best_diff)
- return best_rate;
+ struct clk *parent = NULL;
+ long best_rate = -EINVAL;
+ unsigned long parent_rate;
+ unsigned long tmp_rate;
+ int shift;
+ int i;

- for (shift = 1; shift < PROG_PRES_MASK; shift++) {
- cur_rate = *parent_rate >> shift;
+ for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
+ parent = clk_get_parent_by_index(hw->clk, i);
+ if (!parent)
+ continue;

- if (cur_rate > rate)
- new_diff = cur_rate - rate;
- else
- new_diff = rate - cur_rate;
+ parent_rate = __clk_get_rate(parent);
+ for (shift = 0; shift < PROG_PRES_MASK; shift++) {
+ tmp_rate = parent_rate >> shift;
+ if (tmp_rate <= rate)
+ break;
+ }

- if (!new_diff)
- return cur_rate;
+ if (tmp_rate > rate)
+ continue;

- if (new_diff < best_diff) {
- best_diff = new_diff;
- best_rate = cur_rate;
+ if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
+ best_rate = tmp_rate;
+ *best_parent_rate = parent_rate;
+ *best_parent_clk = parent;
}

- if (rate > cur_rate)
+ if (!best_rate)
break;
}

@@ -228,7 +228,7 @@ static const struct clk_ops programmable_ops = {
.prepare = clk_programmable_prepare,
.is_prepared = clk_programmable_is_ready,
.recalc_rate = clk_programmable_recalc_rate,
- .round_rate = clk_programmable_round_rate,
+ .determine_rate = clk_programmable_determine_rate,
.get_parent = clk_programmable_get_parent,
.set_parent = clk_programmable_set_parent,
.set_rate = clk_programmable_set_rate,
--
1.7.9.5

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