From: Michał Mirosław Date: Tue, 18 Dec 2018 11:20:48 +0000 (+0100) Subject: clk: at91: optimize clk_round_rate() for AUDIO_PLL X-Git-Tag: v5.1-rc1~34^2~5^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=bb631af3d55fa89a612a5f09f3a3dda76121385a;p=linux.git 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 Reviewed-by: Nicolas Ferre Signed-off-by: Stephen Boyd --- 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 */ } }