rtc: m41t80: fix m41t80_sqw_round_rate return value

commit c8384bb04261b9d32fe7402a6068ddaf38913b23 upstream.

Previously it was returning the best of
32768, 8192, 1024, 64, 2, 0

Now, best of
32768, 8192, 4096, 2048, 1024, 512, 256, 128,
64, 32, 16, 8, 4, 2, 1, 0

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Christoph Fritz <chf.fritz@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
index 8f58431..42fc735 100644 (file)
--- a/drivers/rtc/rtc-m41t80.c
+++ b/drivers/rtc/rtc-m41t80.c
@@ -468,18 +468,13 @@ static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
 static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
                                  unsigned long *prate)
 {
-       int i, freq = M41T80_SQW_MAX_FREQ;
-
-       if (freq <= rate)
-               return freq;
-
-       for (i = 2; i <= ilog2(M41T80_SQW_MAX_FREQ); i++) {
-               freq /= 1 << i;
-               if (freq <= rate)
-                       return freq;
-       }
-
-       return 0;
+       if (rate >= M41T80_SQW_MAX_FREQ)
+               return M41T80_SQW_MAX_FREQ;
+       if (rate >= M41T80_SQW_MAX_FREQ / 4)
+               return M41T80_SQW_MAX_FREQ / 4;
+       if (!rate)
+               return 0;
+       return 1 << ilog2(rate);
 }
 
 static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,