[PATCH 0/3] CCF clock divider changes

[PATCH 0/3] CCF clock divider changes

[Maxime COQUELIN]

Hi Mike,

First patch fixes round_rate for power-of-two and table-based dividers when
the CLK_SET_RATE_PARENT flag isn't set.

Second patch introduces a new flag to give the possibility to round the
divider to the closest one, instead of rounding up by default.

Third patch optimizes the for-loop when CLK_SET_RATE_PARENT is set for
power-of-two and table-based dividers.

The series applies on top of v3.13 tag.

Maxime Coquelin (3):
  clk: divider: Fix best div calculation for power-of-two and table
    dividers
  clk: divider: Add round to closest divider
  clk: divider: Optimize clk_divider_bestdiv loop

 drivers/clk/clk-divider.c    |  118 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/clk-provider.h |    3 ++
 2 files changed, 118 insertions(+), 3 deletions(-)

-- 
1.7.9.5

[PATCH 0/3] CCF clock divider changes

[Maxime COQUELIN]

Hi Mike,

First patch fixes round_rate for power-of-two and table-based dividers when
the CLK_SET_RATE_PARENT flag isn't set.

Second patch introduces a new flag to give the possibility to round the
divider to the closest one, instead of rounding up by default.

Third patch optimizes the for-loop when CLK_SET_RATE_PARENT is set for
power-of-two and table-based dividers.

The series applies on top of v3.13 tag.

Maxime Coquelin (3):
  clk: divider: Fix best div calculation for power-of-two and table
    dividers
  clk: divider: Add round to closest divider
  clk: divider: Optimize clk_divider_bestdiv loop

 drivers/clk/clk-divider.c    |  118 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/clk-provider.h |    3 ++
 2 files changed, 118 insertions(+), 3 deletions(-)

-- 
1.7.9.5

[PATCH 1/3] clk: divider: Fix best div calculation for power-of-two and table dividers

[Maxime COQUELIN]

The divider returned by clk_divider_bestdiv() is likely to be invalid in case
of power-of-two and table dividers when CLK_SET_RATE_PARENT flag isn't set.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 5543b7d..2137d58 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -144,6 +144,37 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
 	return true;
 }
 
+static int _round_up_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int up = _get_table_maxdiv(table);
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div < div)
+			continue;
+
+		if ((clkt->div - div) < (up - div))
+			up = clkt->div;
+	}
+
+	return up;
+}
+
+static int _div_round_up(struct clk_divider *divider,
+		unsigned long parent_rate, unsigned long rate)
+{
+	int div = DIV_ROUND_UP(parent_rate, rate);
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		div = __roundup_pow_of_two(div);
+	if (divider->table)
+		div = _round_up_table(divider->table, div);
+
+	return div;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -159,7 +190,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
 		parent_rate = *best_parent_rate;
-		bestdiv = DIV_ROUND_UP(parent_rate, rate);
+		bestdiv = _div_round_up(divider, parent_rate, rate);
 		bestdiv = bestdiv == 0 ? 1 : bestdiv;
 		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 		return bestdiv;
@@ -219,6 +250,10 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	u32 val;
 
 	div = parent_rate / rate;
+
+	if (!_is_valid_div(divider, div))
+		return -EINVAL;
+
 	value = _get_val(divider, div);
 
 	if (value > div_mask(divider))
-- 
1.7.9.5

[PATCH 1/3] clk: divider: Fix best div calculation for power-of-two and table dividers

[Maxime COQUELIN]

The divider returned by clk_divider_bestdiv() is likely to be invalid in case
of power-of-two and table dividers when CLK_SET_RATE_PARENT flag isn't set.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 5543b7d..2137d58 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -144,6 +144,37 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
 	return true;
 }
 
+static int _round_up_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int up = _get_table_maxdiv(table);
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div < div)
+			continue;
+
+		if ((clkt->div - div) < (up - div))
+			up = clkt->div;
+	}
+
+	return up;
+}
+
+static int _div_round_up(struct clk_divider *divider,
+		unsigned long parent_rate, unsigned long rate)
+{
+	int div = DIV_ROUND_UP(parent_rate, rate);
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		div = __roundup_pow_of_two(div);
+	if (divider->table)
+		div = _round_up_table(divider->table, div);
+
+	return div;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -159,7 +190,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
 		parent_rate = *best_parent_rate;
-		bestdiv = DIV_ROUND_UP(parent_rate, rate);
+		bestdiv = _div_round_up(divider, parent_rate, rate);
 		bestdiv = bestdiv == 0 ? 1 : bestdiv;
 		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 		return bestdiv;
@@ -219,6 +250,10 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	u32 val;
 
 	div = parent_rate / rate;
+
+	if (!_is_valid_div(divider, div))
+		return -EINVAL;
+
 	value = _get_val(divider, div);
 
 	if (value > div_mask(divider))
-- 
1.7.9.5

[PATCH 1/3] clk: divider: Fix best div calculation for power-of-two and table dividers

[Mike Turquette]

Quoting Maxime COQUELIN (2014-01-29 08:24:06)
> The divider returned by clk_divider_bestdiv() is likely to be invalid in case
> of power-of-two and table dividers when CLK_SET_RATE_PARENT flag isn't set.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>

I've taken this into clk-fixes for 3.15-rcX.

Thanks,
Mike

> ---
>  drivers/clk/clk-divider.c |   37 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index 5543b7d..2137d58 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -144,6 +144,37 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
>         return true;
>  }
>  
> +static int _round_up_table(const struct clk_div_table *table, int div)
> +{
> +       const struct clk_div_table *clkt;
> +       int up = _get_table_maxdiv(table);
> +
> +       for (clkt = table; clkt->div; clkt++) {
> +               if (clkt->div == div)
> +                       return clkt->div;
> +               else if (clkt->div < div)
> +                       continue;
> +
> +               if ((clkt->div - div) < (up - div))
> +                       up = clkt->div;
> +       }
> +
> +       return up;
> +}
> +
> +static int _div_round_up(struct clk_divider *divider,
> +               unsigned long parent_rate, unsigned long rate)
> +{
> +       int div = DIV_ROUND_UP(parent_rate, rate);
> +
> +       if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
> +               div = __roundup_pow_of_two(div);
> +       if (divider->table)
> +               div = _round_up_table(divider->table, div);
> +
> +       return div;
> +}
> +
>  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 unsigned long *best_parent_rate)
>  {
> @@ -159,7 +190,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>  
>         if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
>                 parent_rate = *best_parent_rate;
> -               bestdiv = DIV_ROUND_UP(parent_rate, rate);
> +               bestdiv = _div_round_up(divider, parent_rate, rate);
>                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
>                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
>                 return bestdiv;
> @@ -219,6 +250,10 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
>         u32 val;
>  
>         div = parent_rate / rate;
> +
> +       if (!_is_valid_div(divider, div))
> +               return -EINVAL;
> +
>         value = _get_val(divider, div);
>  
>         if (value > div_mask(divider))
> -- 
> 1.7.9.5
> 

Re: [PATCH 1/3] clk: divider: Fix best div calculation for power-of-two and table dividers

[Mike Turquette]

Quoting Maxime COQUELIN (2014-01-29 08:24:06)
> The divider returned by clk_divider_bestdiv() is likely to be invalid in case
> of power-of-two and table dividers when CLK_SET_RATE_PARENT flag isn't set.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>

I've taken this into clk-fixes for 3.15-rcX.

Thanks,
Mike

> ---
>  drivers/clk/clk-divider.c |   37 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index 5543b7d..2137d58 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -144,6 +144,37 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
>         return true;
>  }
>  
> +static int _round_up_table(const struct clk_div_table *table, int div)
> +{
> +       const struct clk_div_table *clkt;
> +       int up = _get_table_maxdiv(table);
> +
> +       for (clkt = table; clkt->div; clkt++) {
> +               if (clkt->div == div)
> +                       return clkt->div;
> +               else if (clkt->div < div)
> +                       continue;
> +
> +               if ((clkt->div - div) < (up - div))
> +                       up = clkt->div;
> +       }
> +
> +       return up;
> +}
> +
> +static int _div_round_up(struct clk_divider *divider,
> +               unsigned long parent_rate, unsigned long rate)
> +{
> +       int div = DIV_ROUND_UP(parent_rate, rate);
> +
> +       if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
> +               div = __roundup_pow_of_two(div);
> +       if (divider->table)
> +               div = _round_up_table(divider->table, div);
> +
> +       return div;
> +}
> +
>  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 unsigned long *best_parent_rate)
>  {
> @@ -159,7 +190,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>  
>         if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
>                 parent_rate = *best_parent_rate;
> -               bestdiv = DIV_ROUND_UP(parent_rate, rate);
> +               bestdiv = _div_round_up(divider, parent_rate, rate);
>                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
>                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
>                 return bestdiv;
> @@ -219,6 +250,10 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
>         u32 val;
>  
>         div = parent_rate / rate;
> +
> +       if (!_is_valid_div(divider, div))
> +               return -EINVAL;
> +
>         value = _get_val(divider, div);
>  
>         if (value > div_mask(divider))
> -- 
> 1.7.9.5
> 

[PATCH 2/3] clk: divider: Add round to closest divider

[Maxime COQUELIN]

In some cases, we want to be able to round the divider to the closest one,
instead than rounding up.

This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider
has to round to closest div, keeping rounding up as de default behaviour.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c    |   69 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/clk-provider.h |    3 ++
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 2137d58..1eaa5d8 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
 	return maxdiv;
 }
 
+static unsigned int _get_table_mindiv(const struct clk_div_table *table)
+{
+	unsigned int mindiv = UINT_MAX;
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div < mindiv)
+			mindiv = clkt->div;
+	return mindiv;
+}
+
 static unsigned int _get_maxdiv(struct clk_divider *divider)
 {
 	if (divider->flags & CLK_DIVIDER_ONE_BASED)
@@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div)
 	return up;
 }
 
+static int _round_down_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int down = _get_table_mindiv(table);
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div > div)
+			continue;
+
+		if ((div - clkt->div) < (div - down))
+			down = clkt->div;
+	}
+
+	return down;
+}
+
 static int _div_round_up(struct clk_divider *divider,
 		unsigned long parent_rate, unsigned long rate)
 {
@@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider,
 	return div;
 }
 
+static int _div_round_closest(struct clk_divider *divider,
+		unsigned long parent_rate, unsigned long rate)
+{
+	int up, down, div;
+
+	up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate);
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) {
+		up = __roundup_pow_of_two(div);
+		down = __rounddown_pow_of_two(div);
+	} else if (divider->table) {
+		up = _round_up_table(divider->table, div);
+		down = _round_down_table(divider->table, div);
+	}
+
+	return (up - div) <= (div - down) ? up : down;
+}
+
+static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
+		unsigned long rate)
+{
+	if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return _div_round_closest(divider, parent_rate, rate);
+
+	return _div_round_up(divider, parent_rate, rate);
+}
+
+static bool _is_best_div(struct clk_divider *divider,
+		int rate, int now, int best)
+{
+	if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return abs(rate - now) < abs(rate - best);
+
+	return now <= rate && now > best;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
 		parent_rate = *best_parent_rate;
-		bestdiv = _div_round_up(divider, parent_rate, rate);
+		bestdiv = _div_round(divider, parent_rate, rate);
 		bestdiv = bestdiv == 0 ? 1 : bestdiv;
 		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 		return bestdiv;
@@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
 				MULT_ROUND_UP(rate, i));
 		now = parent_rate / i;
-		if (now <= rate && now > best) {
+		if (_is_best_div(divider, rate, now, best)) {
 			bestdiv = i;
 			best = now;
 			*best_parent_rate = parent_rate;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7e59253..595f0ba 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -275,6 +275,8 @@ struct clk_div_table {
  *   of this register, and mask of divider bits are in higher 16-bit of this
  *   register.  While setting the divider bits, higher 16-bit should also be
  *   updated to indicate changing divider bits.
+ * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded
+ *	to the closest integer instead of the up one.
  */
 struct clk_divider {
 	struct clk_hw	hw;
@@ -290,6 +292,7 @@ struct clk_divider {
 #define CLK_DIVIDER_POWER_OF_TWO	BIT(1)
 #define CLK_DIVIDER_ALLOW_ZERO		BIT(2)
 #define CLK_DIVIDER_HIWORD_MASK		BIT(3)
+#define CLK_DIVIDER_ROUND_CLOSEST	BIT(4)
 
 extern const struct clk_ops clk_divider_ops;
 struct clk *clk_register_divider(struct device *dev, const char *name,
-- 
1.7.9.5

[PATCH 2/3] clk: divider: Add round to closest divider

[Maxime COQUELIN]

In some cases, we want to be able to round the divider to the closest one,
instead than rounding up.

This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider
has to round to closest div, keeping rounding up as de default behaviour.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c    |   69 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/clk-provider.h |    3 ++
 2 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 2137d58..1eaa5d8 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
 	return maxdiv;
 }
 
+static unsigned int _get_table_mindiv(const struct clk_div_table *table)
+{
+	unsigned int mindiv = UINT_MAX;
+	const struct clk_div_table *clkt;
+
+	for (clkt = table; clkt->div; clkt++)
+		if (clkt->div < mindiv)
+			mindiv = clkt->div;
+	return mindiv;
+}
+
 static unsigned int _get_maxdiv(struct clk_divider *divider)
 {
 	if (divider->flags & CLK_DIVIDER_ONE_BASED)
@@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div)
 	return up;
 }
 
+static int _round_down_table(const struct clk_div_table *table, int div)
+{
+	const struct clk_div_table *clkt;
+	int down = _get_table_mindiv(table);
+
+	for (clkt = table; clkt->div; clkt++) {
+		if (clkt->div == div)
+			return clkt->div;
+		else if (clkt->div > div)
+			continue;
+
+		if ((div - clkt->div) < (div - down))
+			down = clkt->div;
+	}
+
+	return down;
+}
+
 static int _div_round_up(struct clk_divider *divider,
 		unsigned long parent_rate, unsigned long rate)
 {
@@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider,
 	return div;
 }
 
+static int _div_round_closest(struct clk_divider *divider,
+		unsigned long parent_rate, unsigned long rate)
+{
+	int up, down, div;
+
+	up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate);
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) {
+		up = __roundup_pow_of_two(div);
+		down = __rounddown_pow_of_two(div);
+	} else if (divider->table) {
+		up = _round_up_table(divider->table, div);
+		down = _round_down_table(divider->table, div);
+	}
+
+	return (up - div) <= (div - down) ? up : down;
+}
+
+static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
+		unsigned long rate)
+{
+	if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return _div_round_closest(divider, parent_rate, rate);
+
+	return _div_round_up(divider, parent_rate, rate);
+}
+
+static bool _is_best_div(struct clk_divider *divider,
+		int rate, int now, int best)
+{
+	if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
+		return abs(rate - now) < abs(rate - best);
+
+	return now <= rate && now > best;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
 		parent_rate = *best_parent_rate;
-		bestdiv = _div_round_up(divider, parent_rate, rate);
+		bestdiv = _div_round(divider, parent_rate, rate);
 		bestdiv = bestdiv == 0 ? 1 : bestdiv;
 		bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 		return bestdiv;
@@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
 				MULT_ROUND_UP(rate, i));
 		now = parent_rate / i;
-		if (now <= rate && now > best) {
+		if (_is_best_div(divider, rate, now, best)) {
 			bestdiv = i;
 			best = now;
 			*best_parent_rate = parent_rate;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7e59253..595f0ba 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -275,6 +275,8 @@ struct clk_div_table {
  *   of this register, and mask of divider bits are in higher 16-bit of this
  *   register.  While setting the divider bits, higher 16-bit should also be
  *   updated to indicate changing divider bits.
+ * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded
+ *	to the closest integer instead of the up one.
  */
 struct clk_divider {
 	struct clk_hw	hw;
@@ -290,6 +292,7 @@ struct clk_divider {
 #define CLK_DIVIDER_POWER_OF_TWO	BIT(1)
 #define CLK_DIVIDER_ALLOW_ZERO		BIT(2)
 #define CLK_DIVIDER_HIWORD_MASK		BIT(3)
+#define CLK_DIVIDER_ROUND_CLOSEST	BIT(4)
 
 extern const struct clk_ops clk_divider_ops;
 struct clk *clk_register_divider(struct device *dev, const char *name,
-- 
1.7.9.5

[PATCH 2/3] clk: divider: Add round to closest divider

[Mike Turquette]

Quoting Maxime COQUELIN (2014-01-29 08:24:07)
> In some cases, we want to be able to round the divider to the closest one,
> instead than rounding up.
> 
> This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider
> has to round to closest div, keeping rounding up as de default behaviour.

I've taken patch #2 and #3 into clk-next for 3.16.

Thanks!
Mike

> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
> ---
>  drivers/clk/clk-divider.c    |   69 ++++++++++++++++++++++++++++++++++++++++--
>  include/linux/clk-provider.h |    3 ++
>  2 files changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index 2137d58..1eaa5d8 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
>         return maxdiv;
>  }
>  
> +static unsigned int _get_table_mindiv(const struct clk_div_table *table)
> +{
> +       unsigned int mindiv = UINT_MAX;
> +       const struct clk_div_table *clkt;
> +
> +       for (clkt = table; clkt->div; clkt++)
> +               if (clkt->div < mindiv)
> +                       mindiv = clkt->div;
> +       return mindiv;
> +}
> +
>  static unsigned int _get_maxdiv(struct clk_divider *divider)
>  {
>         if (divider->flags & CLK_DIVIDER_ONE_BASED)
> @@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div)
>         return up;
>  }
>  
> +static int _round_down_table(const struct clk_div_table *table, int div)
> +{
> +       const struct clk_div_table *clkt;
> +       int down = _get_table_mindiv(table);
> +
> +       for (clkt = table; clkt->div; clkt++) {
> +               if (clkt->div == div)
> +                       return clkt->div;
> +               else if (clkt->div > div)
> +                       continue;
> +
> +               if ((div - clkt->div) < (div - down))
> +                       down = clkt->div;
> +       }
> +
> +       return down;
> +}
> +
>  static int _div_round_up(struct clk_divider *divider,
>                 unsigned long parent_rate, unsigned long rate)
>  {
> @@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider,
>         return div;
>  }
>  
> +static int _div_round_closest(struct clk_divider *divider,
> +               unsigned long parent_rate, unsigned long rate)
> +{
> +       int up, down, div;
> +
> +       up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate);
> +
> +       if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) {
> +               up = __roundup_pow_of_two(div);
> +               down = __rounddown_pow_of_two(div);
> +       } else if (divider->table) {
> +               up = _round_up_table(divider->table, div);
> +               down = _round_down_table(divider->table, div);
> +       }
> +
> +       return (up - div) <= (div - down) ? up : down;
> +}
> +
> +static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
> +               unsigned long rate)
> +{
> +       if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
> +               return _div_round_closest(divider, parent_rate, rate);
> +
> +       return _div_round_up(divider, parent_rate, rate);
> +}
> +
> +static bool _is_best_div(struct clk_divider *divider,
> +               int rate, int now, int best)
> +{
> +       if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
> +               return abs(rate - now) < abs(rate - best);
> +
> +       return now <= rate && now > best;
> +}
> +
>  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 unsigned long *best_parent_rate)
>  {
> @@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>  
>         if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
>                 parent_rate = *best_parent_rate;
> -               bestdiv = _div_round_up(divider, parent_rate, rate);
> +               bestdiv = _div_round(divider, parent_rate, rate);
>                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
>                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
>                 return bestdiv;
> @@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
>                                 MULT_ROUND_UP(rate, i));
>                 now = parent_rate / i;
> -               if (now <= rate && now > best) {
> +               if (_is_best_div(divider, rate, now, best)) {
>                         bestdiv = i;
>                         best = now;
>                         *best_parent_rate = parent_rate;
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 7e59253..595f0ba 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -275,6 +275,8 @@ struct clk_div_table {
>   *   of this register, and mask of divider bits are in higher 16-bit of this
>   *   register.  While setting the divider bits, higher 16-bit should also be
>   *   updated to indicate changing divider bits.
> + * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded
> + *     to the closest integer instead of the up one.
>   */
>  struct clk_divider {
>         struct clk_hw   hw;
> @@ -290,6 +292,7 @@ struct clk_divider {
>  #define CLK_DIVIDER_POWER_OF_TWO       BIT(1)
>  #define CLK_DIVIDER_ALLOW_ZERO         BIT(2)
>  #define CLK_DIVIDER_HIWORD_MASK                BIT(3)
> +#define CLK_DIVIDER_ROUND_CLOSEST      BIT(4)
>  
>  extern const struct clk_ops clk_divider_ops;
>  struct clk *clk_register_divider(struct device *dev, const char *name,
> -- 
> 1.7.9.5
> 

Re: [PATCH 2/3] clk: divider: Add round to closest divider

[Mike Turquette]

Quoting Maxime COQUELIN (2014-01-29 08:24:07)
> In some cases, we want to be able to round the divider to the closest one,
> instead than rounding up.
> 
> This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider
> has to round to closest div, keeping rounding up as de default behaviour.

I've taken patch #2 and #3 into clk-next for 3.16.

Thanks!
Mike

> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
> ---
>  drivers/clk/clk-divider.c    |   69 ++++++++++++++++++++++++++++++++++++++++--
>  include/linux/clk-provider.h |    3 ++
>  2 files changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index 2137d58..1eaa5d8 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
>         return maxdiv;
>  }
>  
> +static unsigned int _get_table_mindiv(const struct clk_div_table *table)
> +{
> +       unsigned int mindiv = UINT_MAX;
> +       const struct clk_div_table *clkt;
> +
> +       for (clkt = table; clkt->div; clkt++)
> +               if (clkt->div < mindiv)
> +                       mindiv = clkt->div;
> +       return mindiv;
> +}
> +
>  static unsigned int _get_maxdiv(struct clk_divider *divider)
>  {
>         if (divider->flags & CLK_DIVIDER_ONE_BASED)
> @@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div)
>         return up;
>  }
>  
> +static int _round_down_table(const struct clk_div_table *table, int div)
> +{
> +       const struct clk_div_table *clkt;
> +       int down = _get_table_mindiv(table);
> +
> +       for (clkt = table; clkt->div; clkt++) {
> +               if (clkt->div == div)
> +                       return clkt->div;
> +               else if (clkt->div > div)
> +                       continue;
> +
> +               if ((div - clkt->div) < (div - down))
> +                       down = clkt->div;
> +       }
> +
> +       return down;
> +}
> +
>  static int _div_round_up(struct clk_divider *divider,
>                 unsigned long parent_rate, unsigned long rate)
>  {
> @@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider,
>         return div;
>  }
>  
> +static int _div_round_closest(struct clk_divider *divider,
> +               unsigned long parent_rate, unsigned long rate)
> +{
> +       int up, down, div;
> +
> +       up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate);
> +
> +       if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) {
> +               up = __roundup_pow_of_two(div);
> +               down = __rounddown_pow_of_two(div);
> +       } else if (divider->table) {
> +               up = _round_up_table(divider->table, div);
> +               down = _round_down_table(divider->table, div);
> +       }
> +
> +       return (up - div) <= (div - down) ? up : down;
> +}
> +
> +static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
> +               unsigned long rate)
> +{
> +       if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
> +               return _div_round_closest(divider, parent_rate, rate);
> +
> +       return _div_round_up(divider, parent_rate, rate);
> +}
> +
> +static bool _is_best_div(struct clk_divider *divider,
> +               int rate, int now, int best)
> +{
> +       if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
> +               return abs(rate - now) < abs(rate - best);
> +
> +       return now <= rate && now > best;
> +}
> +
>  static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 unsigned long *best_parent_rate)
>  {
> @@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>  
>         if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) {
>                 parent_rate = *best_parent_rate;
> -               bestdiv = _div_round_up(divider, parent_rate, rate);
> +               bestdiv = _div_round(divider, parent_rate, rate);
>                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
>                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
>                 return bestdiv;
> @@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
>                 parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
>                                 MULT_ROUND_UP(rate, i));
>                 now = parent_rate / i;
> -               if (now <= rate && now > best) {
> +               if (_is_best_div(divider, rate, now, best)) {
>                         bestdiv = i;
>                         best = now;
>                         *best_parent_rate = parent_rate;
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 7e59253..595f0ba 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -275,6 +275,8 @@ struct clk_div_table {
>   *   of this register, and mask of divider bits are in higher 16-bit of this
>   *   register.  While setting the divider bits, higher 16-bit should also be
>   *   updated to indicate changing divider bits.
> + * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded
> + *     to the closest integer instead of the up one.
>   */
>  struct clk_divider {
>         struct clk_hw   hw;
> @@ -290,6 +292,7 @@ struct clk_divider {
>  #define CLK_DIVIDER_POWER_OF_TWO       BIT(1)
>  #define CLK_DIVIDER_ALLOW_ZERO         BIT(2)
>  #define CLK_DIVIDER_HIWORD_MASK                BIT(3)
> +#define CLK_DIVIDER_ROUND_CLOSEST      BIT(4)
>  
>  extern const struct clk_ops clk_divider_ops;
>  struct clk *clk_register_divider(struct device *dev, const char *name,
> -- 
> 1.7.9.5
> 

[PATCH 3/3] clk: divider: Optimize clk_divider_bestdiv loop

[Maxime COQUELIN]

Currently, the for-loop used to try all the different dividers to find the
one that best fit tries all the values from 1 to max_div, incrementing by one.
In case of power-of-two, or table based divider, the loop isn't optimal.

Instead of incrementing by one, this patch provides directly the next divider.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 1eaa5d8..4aabf4f 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -240,6 +240,18 @@ static bool _is_best_div(struct clk_divider *divider,
 	return now <= rate && now > best;
 }
 
+static int _next_div(struct clk_divider *divider, int div)
+{
+	div++;
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		return __roundup_pow_of_two(div);
+	if (divider->table)
+		return _round_up_table(divider->table, div);
+
+	return div;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -267,7 +279,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 	 */
 	maxdiv = min(ULONG_MAX / rate, maxdiv);
 
-	for (i = 1; i <= maxdiv; i++) {
+	for (i = 1; i <= maxdiv; i = _next_div(divider, i)) {
 		if (!_is_valid_div(divider, i))
 			continue;
 		if (rate * i == parent_rate_saved) {
-- 
1.7.9.5

[PATCH 3/3] clk: divider: Optimize clk_divider_bestdiv loop

[Maxime COQUELIN]

Currently, the for-loop used to try all the different dividers to find the
one that best fit tries all the values from 1 to max_div, incrementing by one.
In case of power-of-two, or table based divider, the loop isn't optimal.

Instead of incrementing by one, this patch provides directly the next divider.

Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
---
 drivers/clk/clk-divider.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 1eaa5d8..4aabf4f 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -240,6 +240,18 @@ static bool _is_best_div(struct clk_divider *divider,
 	return now <= rate && now > best;
 }
 
+static int _next_div(struct clk_divider *divider, int div)
+{
+	div++;
+
+	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+		return __roundup_pow_of_two(div);
+	if (divider->table)
+		return _round_up_table(divider->table, div);
+
+	return div;
+}
+
 static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 		unsigned long *best_parent_rate)
 {
@@ -267,7 +279,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 	 */
 	maxdiv = min(ULONG_MAX / rate, maxdiv);
 
-	for (i = 1; i <= maxdiv; i++) {
+	for (i = 1; i <= maxdiv; i = _next_div(divider, i)) {
 		if (!_is_valid_div(divider, i))
 			continue;
 		if (rate * i == parent_rate_saved) {
-- 
1.7.9.5

Re: [PATCH 0/3] CCF clock divider changes

[Maxime Coquelin]

Hi Mike,

	Did you have a look at this series?

	If patch 1 gets accepted, should it also be submitted to the stable 
branches?

Thanks,
Maxime

On 01/29/2014 05:24 PM, Maxime COQUELIN wrote:
> Hi Mike,
>
> First patch fixes round_rate for power-of-two and table-based dividers when
> the CLK_SET_RATE_PARENT flag isn't set.
>
> Second patch introduces a new flag to give the possibility to round the
> divider to the closest one, instead of rounding up by default.
>
> Third patch optimizes the for-loop when CLK_SET_RATE_PARENT is set for
> power-of-two and table-based dividers.
>
> The series applies on top of v3.13 tag.
>
> Maxime Coquelin (3):
>    clk: divider: Fix best div calculation for power-of-two and table
>      dividers
>    clk: divider: Add round to closest divider
>    clk: divider: Optimize clk_divider_bestdiv loop
>
>   drivers/clk/clk-divider.c    |  118 ++++++++++++++++++++++++++++++++++++++++--
>   include/linux/clk-provider.h |    3 ++
>   2 files changed, 118 insertions(+), 3 deletions(-)
>

Re: [PATCH 0/3] CCF clock divider changes

[Maxime Coquelin]

Hi Mike,


     Did you have a look at this series?

     If patch 1 gets accepted, should it also be submitted to the stable 
branches?

Thanks,
Maxime

ps: Mail resent because our company mail server IP is blocked by Spamhaus.

On 01/29/2014 05:24 PM, Maxime COQUELIN wrote:
> Hi Mike,
>
> First patch fixes round_rate for power-of-two and table-based dividers when
> the CLK_SET_RATE_PARENT flag isn't set.
>
> Second patch introduces a new flag to give the possibility to round the
> divider to the closest one, instead of rounding up by default.
>
> Third patch optimizes the for-loop when CLK_SET_RATE_PARENT is set for
> power-of-two and table-based dividers.
>
> The series applies on top of v3.13 tag.
>
> Maxime Coquelin (3):
>    clk: divider: Fix best div calculation for power-of-two and table
>      dividers
>    clk: divider: Add round to closest divider
>    clk: divider: Optimize clk_divider_bestdiv loop
>
>   drivers/clk/clk-divider.c    |  118 ++++++++++++++++++++++++++++++++++++++++--
>   include/linux/clk-provider.h |    3 ++
>   2 files changed, 118 insertions(+), 3 deletions(-)
>