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[1/6] ASoC: arizona: Correct handling of FLL theta in synchroniser mode

Message ID 1472831568-466-2-git-send-email-ckeepax@opensource.wolfsonmicro.com (mailing list archive)
State Accepted
Commit e87d9ae8886783f3a5a8dd6863e8261783214e3b
Headers show

Commit Message

Charles Keepax Sept. 2, 2016, 3:52 p.m. UTC
Theta/lambda is used to give the fractional portion of the FLL
frequency multiplication. When the synchroniser is active the
reference path lambda value is hard coded in the hardware to
65536. This patch corrects the handling of theta such that it
is scaled to match this denominator, when the synchroniser is
active.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
---
 sound/soc/codecs/arizona.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
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Patch

diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index ccb3ca2..ded235f 100644
--- a/sound/soc/codecs/arizona.c
+++ b/sound/soc/codecs/arizona.c
@@ -1920,8 +1920,8 @@  static struct {
 
 struct arizona_fll_cfg {
 	int n;
-	int theta;
-	int lambda;
+	unsigned int theta;
+	unsigned int lambda;
 	int refdiv;
 	int outdiv;
 	int fratio;
@@ -2233,6 +2233,10 @@  static int arizona_enable_fll(struct arizona_fll *fll)
 	    fll->ref_src != fll->sync_src) {
 		arizona_calc_fll(fll, &cfg, fll->ref_freq, false);
 
+		/* Ref path hardcodes lambda to 65536 when sync is on */
+		if (fll->sync_src >= 0 && cfg.lambda)
+			cfg.theta = (cfg.theta * (1 << 16)) / cfg.lambda;
+
 		arizona_apply_fll(arizona, fll->base, &cfg, fll->ref_src,
 				  false);
 		if (fll->sync_src >= 0) {