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clk: renesas: rcar-gen3: Fix cpg_sd_clock_round_rate() return value

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cpg_sd_clock_round_rate() may return an unsupported clock rate for the
requested clock rate. Therefore, when cpg_sd_clock_set_rate() sets the
clock rate acquired by cpg_sd_clock_round_rate(), an error may occur.

This is not conform the clk API design.

This patch fixes that by making sure cpg_sd_clock_calc_div() considers
only the division values defined in cpg_sd_div_table[].
With this fix, the cpg_sd_clock_round_rate() always return a support
clock rate.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Fixes: 90c073e539 ("clk: shmobile: r8a7795: Add SD divider support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
This commit is contained in:
Takeshi Kihara 2019-02-25 11:48:38 +09:00 committed by Geert Uytterhoeven
parent 21ab095cbc
commit b953eaaeb5
1 changed files with 13 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/clk/renesas/rcar-gen3-cpg.c
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@ -3,6 +3,7 @@
* R-Car Gen3 Clock Pulse Generator
*
* Copyright (C) 2015-2018 Glider bvba
* Copyright (C) 2019 Renesas Electronics Corp.
*
* Based on clk-rcar-gen3.c
*
@ -236,8 +237,6 @@ struct sd_clock {
const struct sd_div_table *div_table;
struct cpg_simple_notifier csn;
unsigned int div_num;
unsigned int div_min;
unsigned int div_max;
unsigned int cur_div_idx;
};
@ -314,14 +313,20 @@ static unsigned int cpg_sd_clock_calc_div(struct sd_clock *clock,
unsigned long rate,
unsigned long parent_rate)
{
unsigned int div;
unsigned long calc_rate, diff, diff_min = ULONG_MAX;
unsigned int i, best_div = 0;
if (!rate)
rate = 1;
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;
diff_min = diff;
}
}
div = DIV_ROUND_CLOSEST(parent_rate, rate);
return clamp_t(unsigned int, div, clock->div_min, clock->div_max);
return best_div;
}
static long cpg_sd_clock_round_rate(struct clk_hw *hw, unsigned long rate,
@ -405,13 +410,6 @@ static struct clk * __init cpg_sd_clk_register(const char *name,
val |= CPG_SD_STP_MASK | (clock->div_table[0].val & CPG_SD_FC_MASK);
writel(val, clock->csn.reg);
clock->div_max = clock->div_table[0].div;
clock->div_min = clock->div_max;
for (i = 1; i < clock->div_num; i++) {
clock->div_max = max(clock->div_max, clock->div_table[i].div);
clock->div_min = min(clock->div_min, clock->div_table[i].div);
}
clk = clk_register(NULL, &clock->hw);
if (IS_ERR(clk))
goto free_clock;