rtc: m41t80: fix m41t80_sqw_round_rate return value

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>

1 files changed, 7 insertions, 12 deletions

diff --git a/drivers/rtc/rtc-m41t80.c b/drivers/rtc/rtc-m41t80.c
index 8f5843169dc2..42fc735a5446 100644
--- 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,