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authorMichał Mirosław <mirq-linux@rere.qmqm.pl>2018-12-18 12:20:48 +0100
committerStephen Boyd <sboyd@kernel.org>2019-02-22 09:54:17 -0800
commitbb631af3d55fa89a612a5f09f3a3dda76121385a (patch)
tree9a3d0af2bb4df8bea05ee70dae1d36f3414ff51f /drivers/clk/at91
parent77977b800451ea7f438bf0398c76e56ef92379fa (diff)
downloadlinux-bb631af3d55fa89a612a5f09f3a3dda76121385a.tar.bz2
clk: at91: optimize clk_round_rate() for AUDIO_PLL
Stop the search for parent rate when exact match is found. This makes for 3 clk_round_rate() calls instead of 64 of them on SAMA5D2-based board when searching for 12.288MHz clock. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Reviewed-by: Nicolas Ferre <nicolas.ferre@microchip.com> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'drivers/clk/at91')
-rw-r--r--drivers/clk/at91/clk-audio-pll.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/clk/at91/clk-audio-pll.c b/drivers/clk/at91/clk-audio-pll.c
index 36d77146a3bd..3cc4a82f4e9f 100644
--- a/drivers/clk/at91/clk-audio-pll.c
+++ b/drivers/clk/at91/clk-audio-pll.c
@@ -340,7 +340,12 @@ static long clk_audio_pll_pmc_round_rate(struct clk_hw *hw, unsigned long rate,
pr_debug("A PLL/PMC: %s, rate = %lu (parent_rate = %lu)\n", __func__,
rate, *parent_rate);
- for (div = 1; div <= AUDIO_PLL_QDPMC_MAX; div++) {
+ if (!rate)
+ return 0;
+
+ best_parent_rate = clk_round_rate(pclk->clk, 1);
+ div = max(best_parent_rate / rate, 1UL);
+ for (; div <= AUDIO_PLL_QDPMC_MAX; div++) {
best_parent_rate = clk_round_rate(pclk->clk, rate * div);
tmp_rate = best_parent_rate / div;
tmp_diff = abs(rate - tmp_rate);
@@ -350,6 +355,8 @@ static long clk_audio_pll_pmc_round_rate(struct clk_hw *hw, unsigned long rate,
best_rate = tmp_rate;
best_diff = tmp_diff;
tmp_qd = div;
+ if (!best_diff)
+ break; /* got exact match */
}
}