[PATCH 4/8] clk: add divider_recalc_rate helper

[Lucas Stach <l.stach@pengutronix.de>]

Closer to Linux kernel implementation and needed for imx8mq
composite clock.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 drivers/clk/clk-divider.c | 30 ++++++++++++++++++++++--------
 include/linux/clk.h       |  5 +++++
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 791e10ea99cd..7b1bdde1ce18 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -20,6 +20,7 @@
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/log2.h>
+#include <asm-generic/div64.h>
 
 #define div_mask(d)	((1 << ((d)->width)) - 1)
 
@@ -56,17 +57,17 @@ static unsigned int _get_table_div(const struct clk_div_table *table,
 	return 0;
 }
 
-static unsigned int _get_div(struct clk_divider *divider, unsigned int val)
+static unsigned int _get_div(const struct clk_div_table *table,
+			     unsigned int val, unsigned long flags, u8 width)
 {
-	if (divider->flags & CLK_DIVIDER_ONE_BASED)
+	if (flags & CLK_DIVIDER_ONE_BASED)
 		return val;
-	if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+	if (flags & CLK_DIVIDER_POWER_OF_TWO)
 		return 1 << val;
-	if (divider->table)
-		return _get_table_div(divider->table, val);
+	if (table)
+		return _get_table_div(table, val);
 	return val + 1;
 }
-
 static unsigned int _get_table_val(const struct clk_div_table *table,
 							unsigned int div)
 {
@@ -89,6 +90,18 @@ static unsigned int _get_val(struct clk_divider *divider, unsigned int div)
 	return div - 1;
 }
 
+unsigned long divider_recalc_rate(struct clk *clk, unsigned long parent_rate,
+		unsigned int val,
+		const struct clk_div_table *table,
+		unsigned long flags, unsigned long width)
+{
+	unsigned int div;
+
+	div = _get_div(table, val, flags, width);
+
+	return DIV_ROUND_UP_ULL((u64)parent_rate, div);
+}
+
 static unsigned long clk_divider_recalc_rate(struct clk *clk,
 		unsigned long parent_rate)
 {
@@ -98,9 +111,10 @@ static unsigned long clk_divider_recalc_rate(struct clk *clk,
 	val = readl(divider->reg) >> divider->shift;
 	val &= div_mask(divider);
 
-	div = _get_div(divider, val);
+	div = _get_div(divider->table, val, divider->flags, divider->width);
 
-	return parent_rate / div;
+	return divider_recalc_rate(clk, parent_rate, val, divider->table,
+				   divider->flags, divider->width);
 }
 
 /*
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 13b1e529f57b..978a0a8a9aa7 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -259,6 +259,11 @@ struct clk_divider {
 
 extern struct clk_ops clk_divider_ops;
 
+unsigned long divider_recalc_rate(struct clk *clk, unsigned long parent_rate,
+		unsigned int val,
+		const struct clk_div_table *table,
+		unsigned long flags, unsigned long width);
+
 struct clk *clk_divider_alloc(const char *name, const char *parent,
 		void __iomem *reg, u8 shift, u8 width, unsigned flags);
 void clk_divider_free(struct clk *clk_divider);
-- 
2.20.1


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