[v3,01/21] clk: divider: Make divider_round_rate take the parent clock

Commit Message

Maxime Ripard May 17, 2017, 7:40 a.m. UTC

So far, divider_round_rate only considers the parent clock returned by
clk_hw_get_parent.

This works fine on clocks that have a single parents, this doesn't work on
muxes, since we will only consider the first parent, while other parents
may totally be able to provide a better combination.

Clocks in that case cannot use divider_round_rate, so would have to come up
with a very similar logic to work around it. Instead of having to do
something like this, and duplicate that logic everywhere, create a
divider_round_rate parent to allow caller to give an additional parameter
for the parent clock to consider.

Reviewed-by: Chen-Yu Tsai <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
---
 drivers/clk/clk-divider.c    | 19 ++++++++++---------
 include/linux/clk-provider.h | 16 +++++++++++++---
 2 files changed, 23 insertions(+), 12 deletions(-)

Comments

Stephen Boyd May 19, 2017, 1:54 a.m. UTC | #1

On 05/17, Maxime Ripard wrote:
> So far, divider_round_rate only considers the parent clock returned by
> clk_hw_get_parent.
> 
> This works fine on clocks that have a single parents, this doesn't work on
> muxes, since we will only consider the first parent, while other parents
> may totally be able to provide a better combination.
> 
> Clocks in that case cannot use divider_round_rate, so would have to come up
> with a very similar logic to work around it. Instead of having to do
> something like this, and duplicate that logic everywhere, create a
> divider_round_rate parent to allow caller to give an additional parameter
> for the parent clock to consider.
> 
> Reviewed-by: Chen-Yu Tsai <[e-mail]>
> Signed-off-by: Maxime Ripard <[e-mail]>
> ---

Acked-by: Stephen Boyd <[e-mail]>

Patch

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 96386ffc8483..9bb472cccca6 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -275,7 +275,8 @@  static int _next_div(const struct clk_div_table *table, int div,
 	return div;
 }
 
-static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
+static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent,
+			       unsigned long rate,
 			       unsigned long *best_parent_rate,
 			       const struct clk_div_table *table, u8 width,
 			       unsigned long flags)
@@ -314,8 +315,7 @@  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 			*best_parent_rate = parent_rate_saved;
 			return i;
 		}
-		parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
-					       rate * i);
+		parent_rate = clk_hw_round_rate(parent, rate * i);
 		now = DIV_ROUND_UP_ULL((u64)parent_rate, i);
 		if (_is_best_div(rate, now, best, flags)) {
 			bestdiv = i;
@@ -326,23 +326,24 @@  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	if (!bestdiv) {
 		bestdiv = _get_maxdiv(table, width, flags);
-		*best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), 1);
+		*best_parent_rate = clk_hw_round_rate(parent, 1);
 	}
 
 	return bestdiv;
 }
 
-long divider_round_rate(struct clk_hw *hw, unsigned long rate,
-			unsigned long *prate, const struct clk_div_table *table,
-			u8 width, unsigned long flags)
+long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
+			       unsigned long rate, unsigned long *prate,
+			       const struct clk_div_table *table,
+			       u8 width, unsigned long flags)
 {
 	int div;
 
-	div = clk_divider_bestdiv(hw, rate, prate, table, width, flags);
+	div = clk_divider_bestdiv(hw, parent, rate, prate, table, width, flags);
 
 	return DIV_ROUND_UP_ULL((u64)*prate, div);
 }
-EXPORT_SYMBOL_GPL(divider_round_rate);
+EXPORT_SYMBOL_GPL(divider_round_rate_parent);
 
 static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 				unsigned long *prate)
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index a428aec36ace..c59c62571e4f 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -412,9 +412,10 @@  extern const struct clk_ops clk_divider_ro_ops;
 unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
 		unsigned int val, const struct clk_div_table *table,
 		unsigned long flags);
-long divider_round_rate(struct clk_hw *hw, unsigned long rate,
-		unsigned long *prate, const struct clk_div_table *table,
-		u8 width, unsigned long flags);
+long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
+			       unsigned long rate, unsigned long *prate,
+			       const struct clk_div_table *table,
+			       u8 width, unsigned long flags);
 int divider_get_val(unsigned long rate, unsigned long parent_rate,
 		const struct clk_div_table *table, u8 width,
 		unsigned long flags);
@@ -757,6 +758,15 @@  static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src)
 	dst->core = src->core;
 }
 
+static inline long divider_round_rate(struct clk_hw *hw, unsigned long rate,
+				      unsigned long *prate,
+				      const struct clk_div_table *table,
+				      u8 width, unsigned long flags)
+{
+	return divider_round_rate_parent(hw, clk_hw_get_parent(hw),
+					 rate, prate, table, width, flags);
+}
+
 /*
  * FIXME clock api without lock protection
  */