clk: renesas: rcar-gen3: Loop to find best rate in cpg_sd_clock_round_rate()

cpg_sd_clock_round_rate() really needs the best rate, not the best
divider.  Hence change the iteration to find the former, and get rid of
the final division.

Add an out-of-range rate check while at it.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20190830134515.11925-6-geert+renesas@glider.be

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c
index 261f7298309682bd66da68784a583ba72860d655..39cd0c4e4e791023746103da6ae2f25342b32892 100644 (file)
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -312,21 +312,25 @@ static unsigned long cpg_sd_clock_recalc_rate(struct clk_hw *hw,
 static long cpg_sd_clock_round_rate(struct clk_hw *hw, unsigned long rate,
                                      unsigned long *parent_rate)
 {
-       unsigned long calc_rate, diff, diff_min = ULONG_MAX;
+       unsigned long best_rate = ULONG_MAX, diff_min = ULONG_MAX;
        struct sd_clock *clock = to_sd_clock(hw);
-       unsigned int i, best_div = 0;
+       unsigned long calc_rate, diff;
+       unsigned int i;
 
        for (i = 0; i < clock->div_num; i++) {
                calc_rate = DIV_ROUND_CLOSEST(*parent_rate,
                                              clock->div_table[i].div);
                diff = calc_rate > rate ? calc_rate - rate : rate - calc_rate;
                if (diff < diff_min) {
-                       best_div = clock->div_table[i].div;
+                       best_rate = calc_rate;
                        diff_min = diff;
                }
        }
 
-       return DIV_ROUND_CLOSEST(*parent_rate, best_div);
+       if (best_rate > LONG_MAX)
+               return -EINVAL;
+
+       return best_rate;
 }
 
 static int cpg_sd_clock_set_rate(struct clk_hw *hw, unsigned long rate,