rtc: ds1307: fix incorrect maximum clock rate handling

[ Upstream commit cf6eb54 ]

When ds3231_clk_sqw_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.

Fixes: 6c6ff14 ("rtc: ds1307: add clock provider support for DS3231")
Signed-off-by: Brian Masney <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Belloni <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: masneyb

drivers/rtc/rtc-ds1307.c

@@ -1466,7 +1466,7 @@ static long ds3231_clk_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
 			return ds3231_clk_sqw_rates[i];
 	}
 
-	return 0;
+	return ds3231_clk_sqw_rates[ARRAY_SIZE(ds3231_clk_sqw_rates) - 1];
 }
 
 static int ds3231_clk_sqw_set_rate(struct clk_hw *hw, unsigned long rate,