[PATCH] ASoC: arizona: Correct handling of FLL theta in synchroniser mode

From: Charles Keepax
Date: Fri Sep 02 2016 - 11:52:43 EST


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@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
sound/soc/codecs/arizona.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index ccb3ca2f77a4..ded235f3090f 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) {
--
2.9.3