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

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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
This commit is contained in:
Geert Uytterhoeven 2019-08-30 15:45:12 +02:00
parent f1195d4ec7
commit 8a6d97a46d
1 changed files with 8 additions and 4 deletions
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12
drivers/clk/renesas/rcar-gen3-cpg.c
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@ -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, static long cpg_sd_clock_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_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); 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++) { for (i = 0; i < clock->div_num; i++) {
calc_rate = DIV_ROUND_CLOSEST(*parent_rate, calc_rate = DIV_ROUND_CLOSEST(*parent_rate,
clock->div_table[i].div); clock->div_table[i].div);
diff = calc_rate > rate ? calc_rate - rate : rate - calc_rate; diff = calc_rate > rate ? calc_rate - rate : rate - calc_rate;
if (diff < diff_min) { if (diff < diff_min) {
best_div = clock->div_table[i].div; best_rate = calc_rate;
diff_min = diff; 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, static int cpg_sd_clock_set_rate(struct clk_hw *hw, unsigned long rate,