From 01f58153aefc158fd690b337d29ad140e963959d Mon Sep 17 00:00:00 2001 From: Ryo Tsutsui Date: Sun, 3 Feb 2013 17:18:00 +0900 Subject: [PATCH] ASoC: arizona: Fixed a bug in FLL fractional calculation Previously arizona_calc_fll() was checking if the target frequency is exactly divisible by reference frequency, but should have been product of the ratio and the reference frequency. Also scale down the Lamba and Theta coefficients be under 16-bits in order to match the registers. Signed-off-by: Ryo Tsutsui Signed-off-by: Charles Keepax Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- sound/soc/codecs/arizona.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c index ef62c435848e..2899cb909d1e 100644 --- a/sound/soc/codecs/arizona.c +++ b/sound/soc/codecs/arizona.c @@ -910,7 +910,7 @@ static int arizona_calc_fll(struct arizona_fll *fll, cfg->n = target / (ratio * Fref); - if (target % Fref) { + if (target % (ratio * Fref)) { gcd_fll = gcd(target, ratio * Fref); arizona_fll_dbg(fll, "GCD=%u\n", gcd_fll); @@ -922,6 +922,15 @@ static int arizona_calc_fll(struct arizona_fll *fll, cfg->lambda = 0; } + /* Round down to 16bit range with cost of accuracy lost. + * Denominator must be bigger than numerator so we only + * take care of it. + */ + while (cfg->lambda >= (1 << 16)) { + cfg->theta >>= 1; + cfg->lambda >>= 1; + } + arizona_fll_dbg(fll, "N=%x THETA=%x LAMBDA=%x\n", cfg->n, cfg->theta, cfg->lambda); arizona_fll_dbg(fll, "FRATIO=%x(%d) OUTDIV=%x REFCLK_DIV=%x\n", -- 2.39.5