[PATCH v10 01/15] clk: sunxi: factors: automatic reparenting support

Hans de Goede
2014-05-02T15:57:15Z

From: Emilio L?pez <emilio@elopez.com.ar>

This commit implements .determine_rate, so that our factor clocks can be
reparented when needed.

Signed-off-by: Emilio L?pez <emilio@elopez.com.ar>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/clk/sunxi/clk-factors.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
index 9e23264..3806d97 100644
--- a/drivers/clk/sunxi/clk-factors.c
+++ b/drivers/clk/sunxi/clk-factors.c
@@ -77,6 +77,41 @@ static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
return rate;
}

+static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_p)
+{
+ struct clk *clk = hw->clk, *parent, *best_parent = NULL;
+ int i, num_parents;
+ unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
+
+ /* find the parent that can help provide the fastest rate <= rate */
+ num_parents = __clk_get_num_parents(clk);
+ for (i = 0; i < num_parents; i++) {
+ parent = clk_get_parent_by_index(clk, i);
+ if (!parent)
+ continue;
+ if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT)
+ parent_rate = __clk_round_rate(parent, rate);
+ else
+ parent_rate = __clk_get_rate(parent);
+
+ child_rate = clk_factors_round_rate(hw, rate, &parent_rate);
+
+ if (child_rate <= rate && child_rate > best_child_rate) {
+ best_parent = parent;
+ best = parent_rate;
+ best_child_rate = child_rate;
+ }
+ }
+
+ if (best_parent)
+ *best_parent_p = best_parent;
+ *best_parent_rate = best;
+
+ return best_child_rate;
+}
+
static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
@@ -113,6 +148,7 @@ static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
}

const struct clk_ops clk_factors_ops = {
+ .determine_rate = clk_factors_determine_rate,
.recalc_rate = clk_factors_recalc_rate,
.round_rate = clk_factors_round_rate,
.set_rate = clk_factors_set_rate,
--
1.9.0