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authorStephen Boyd <sboyd@codeaurora.org>2015-01-19 18:05:28 -0800
committerMichael Turquette <mturquette@linaro.org>2015-01-27 11:48:39 -0800
commit15a02c1f6dd7c2bb150c61d00ffb33f584ff2288 (patch)
tree803aecc489bac86074b95d25cbdb2bbc426ffb38 /drivers/clk/clk.c
parent52bba9809a954d72bc77773bd560b9724b495eb7 (diff)
clk: Add __clk_mux_determine_rate_closest
Some clock drivers want to find the closest rate on the input of a mux instead of a rate that's less than or equal to the desired rate. Add a generic mux function to support this. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Tested-by: Kenneth Westfield <kwestfie@codeaurora.org> Signed-off-by: Michael Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/clk.c')
-rw-r--r--drivers/clk/clk.c47
1 files changed, 38 insertions, 9 deletions
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 30fff56e1f15..9fc209abcb48 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -690,14 +690,20 @@ struct clk *__clk_lookup(const char *name)
return NULL;
}
-/*
- * Helper for finding best parent to provide a given frequency. This can be used
- * directly as a determine_rate callback (e.g. for a mux), or from a more
- * complex clock that may combine a mux with other operations.
- */
-long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
- unsigned long *best_parent_rate,
- struct clk_hw **best_parent_p)
+static bool mux_is_better_rate(unsigned long rate, unsigned long now,
+ unsigned long best, unsigned long flags)
+{
+ if (flags & CLK_MUX_ROUND_CLOSEST)
+ return abs(now - rate) < abs(best - rate);
+
+ return now <= rate && now > best;
+}
+
+static long
+clk_mux_determine_rate_flags(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk_hw **best_parent_p,
+ unsigned long flags)
{
struct clk *clk = hw->clk, *parent, *best_parent = NULL;
int i, num_parents;
@@ -725,7 +731,7 @@ long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
parent_rate = __clk_round_rate(parent, rate);
else
parent_rate = __clk_get_rate(parent);
- if (parent_rate <= rate && parent_rate > best) {
+ if (mux_is_better_rate(rate, parent_rate, best, flags)) {
best_parent = parent;
best = parent_rate;
}
@@ -738,8 +744,31 @@ out:
return best;
}
+
+/*
+ * Helper for finding best parent to provide a given frequency. This can be used
+ * directly as a determine_rate callback (e.g. for a mux), or from a more
+ * complex clock that may combine a mux with other operations.
+ */
+long __clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk_hw **best_parent_p)
+{
+ return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
+ best_parent_p, 0);
+}
EXPORT_SYMBOL_GPL(__clk_mux_determine_rate);
+long __clk_mux_determine_rate_closest(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk_hw **best_parent_p)
+{
+ return clk_mux_determine_rate_flags(hw, rate, best_parent_rate,
+ best_parent_p,
+ CLK_MUX_ROUND_CLOSEST);
+}
+EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest);
+
/*** clk api ***/
void __clk_unprepare(struct clk *clk)