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author | Takeshi Kihara <takeshi.kihara.df@renesas.com> | 2019-02-25 11:48:38 +0900 |
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committer | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-04-04 11:54:46 +0200 |
commit | b953eaaeb58efc944f51cffd3f6838657958f0f8 (patch) | |
tree | 2a5d1da5a5c6f0cdc1edc95d7e562da9a3774e41 /drivers/clk/renesas/rcar-gen3-cpg.c | |
parent | 21ab095cbc069a351fa9cef919f2dafc43a8fde7 (diff) | |
download | linux-stable-b953eaaeb58efc944f51cffd3f6838657958f0f8.tar.gz linux-stable-b953eaaeb58efc944f51cffd3f6838657958f0f8.tar.bz2 linux-stable-b953eaaeb58efc944f51cffd3f6838657958f0f8.zip |
clk: renesas: rcar-gen3: Fix cpg_sd_clock_round_rate() return value
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: 90c073e53909da85 ("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>
Diffstat (limited to 'drivers/clk/renesas/rcar-gen3-cpg.c')
-rw-r--r-- | drivers/clk/renesas/rcar-gen3-cpg.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c index d5fb768b089f..dc62ed0dadc2 100644 --- a/drivers/clk/renesas/rcar-gen3-cpg.c +++ b/drivers/clk/renesas/rcar-gen3-cpg.c @@ -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; - - if (!rate) - rate = 1; - - div = DIV_ROUND_CLOSEST(parent_rate, rate); + unsigned long calc_rate, diff, diff_min = ULONG_MAX; + unsigned int i, best_div = 0; + + 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; + } + } - 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; |