We may do a calculation of the rounded rate based on (*prate / div) value in
case it is not 0. It's as much higher as power of two of nearest value to
(*prate / div / maxn). Thus, the patch replaces while-loop by direct
calculations.
While here, fix off-by-one error. maxn is the maximum value that can be hold by
a register which means all ones in it.
Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
---
drivers/clk/clk-fractional-divider.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/clk/clk-fractional-divider.c
b/drivers/clk/clk-fractional-divider.c
index 6aa72d9..4c0541b 100644
--- a/drivers/clk/clk-fractional-divider.c
+++ b/drivers/clk/clk-fractional-divider.c
@@ -14,6 +14,7 @@
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/gcd.h>
+#include <linux/log2.h>
#define to_clk_fd(_hw) container_of(_hw, struct clk_fractional_divider, hw)
@@ -49,18 +50,16 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned
long rate,
unsigned long *prate)
{
struct clk_fractional_divider *fd = to_clk_fd(hw);
- unsigned maxn = (fd->nmask >> fd->nshift) + 1;
- unsigned div;
+ unsigned maxn = fd->nmask >> fd->nshift;
+ unsigned long div, n;
if (!rate || rate >= *prate)
return *prate;
div = gcd(*prate, rate);
-
- while ((*prate / div) > maxn) {
- div <<= 1;
- rate <<= 1;
- }
+ n = *prate / div;
+ if (n > maxn)
+ return rate * roundup_pow_of_two(n / maxn);
return rate;
}
--
2.1.4
--
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