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authorMark Brown <broonie@kernel.org>2014-12-10 11:40:18 +0000
committerMark Brown <broonie@kernel.org>2014-12-10 11:40:18 +0000
commit7d8d2b5924c41ee249ee2280d4240d7cbba3fda8 (patch)
tree3f7c4bfd54f2223cd917dd887774e8c3256d9db6
parent2945d85a8371d230423fcb4f6c933be125632a90 (diff)
parent32a13f39f539963aee2c0b08f4da973db192a2ff (diff)
downloadlinux-linaro-stable-7d8d2b5924c41ee249ee2280d4240d7cbba3fda8.tar.gz
Merge branch 'linux-linaro-lsk' into linux-linaro-lsk-android
-rw-r--r--drivers/clk/clk-divider.c114
-rw-r--r--include/linux/clk-provider.h3
2 files changed, 110 insertions, 7 deletions
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 2ce22447d76e..a885284ead4d 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -24,7 +24,7 @@
* Traits of this clock:
* prepare - clk_prepare only ensures that parents are prepared
* enable - clk_enable only ensures that parents are enabled
- * rate - rate is adjustable. clk->rate = parent->rate / divisor
+ * rate - rate is adjustable. clk->rate = DIV_ROUND_UP(parent->rate / divisor)
* parent - fixed parent. No clk_set_parent support
*/
@@ -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)
@@ -115,7 +126,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
return parent_rate;
}
- return parent_rate / div;
+ return DIV_ROUND_UP(parent_rate, div);
}
/*
@@ -144,6 +155,91 @@ 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 = INT_MAX;
+
+ 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 _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)
+{
+ 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 _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,
+ unsigned long rate, unsigned long now, unsigned long 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)
{
@@ -158,7 +254,7 @@ 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(divider, parent_rate, rate);
bestdiv = bestdiv == 0 ? 1 : bestdiv;
bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
return bestdiv;
@@ -175,8 +271,8 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
continue;
parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
MULT_ROUND_UP(rate, i));
- now = parent_rate / i;
- if (now <= rate && now > best) {
+ now = DIV_ROUND_UP(parent_rate, i);
+ if (_is_best_div(divider, rate, now, best)) {
bestdiv = i;
best = now;
*best_parent_rate = parent_rate;
@@ -197,7 +293,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
int div;
div = clk_divider_bestdiv(hw, rate, prate);
- return *prate / div;
+ return DIV_ROUND_UP(*prate, div);
}
static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
@@ -208,7 +304,11 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long flags = 0;
u32 val;
- div = parent_rate / rate;
+ div = DIV_ROUND_UP(parent_rate, rate);
+
+ if (!_is_valid_div(divider, div))
+ return -EINVAL;
+
value = _get_val(divider, div);
if (value > div_mask(divider))
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 4c544c814d26..89b7ceed70db 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -257,6 +257,8 @@ struct clk_div_table {
* Some hardware implementations gracefully handle this case and allow a
* zero divisor by not modifying their input clock
* (divide by one / bypass).
+ * 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;
@@ -271,6 +273,7 @@ struct clk_divider {
#define CLK_DIVIDER_ONE_BASED BIT(0)
#define CLK_DIVIDER_POWER_OF_TWO BIT(1)
#define CLK_DIVIDER_ALLOW_ZERO BIT(2)
+#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,