When setting up an FLL in pseudo-fractional mode it is preferred
to use a lower FRATIO if possible to give a higher reference clock
frequency. This patch swaps the two loops in arizona_calc_fratio()
so that lower FRATIOs are tried first. The decrementing loop is also
changed to start from init_ratio because the original settings might
already give a fractional value for N.K
Signed-off-by: Richard Fitzgerald <r...@opensource.wolfsonmicro.com>
---
sound/soc/codecs/arizona.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index 0cd27e0..d1e1127 100644
--- a/sound/soc/codecs/arizona.c
+++ b/sound/soc/codecs/arizona.c
@@ -2039,7 +2039,21 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
init_ratio, Fref, refdiv);
while (div <= ARIZONA_FLL_MAX_REFDIV) {
- for (ratio = init_ratio; ratio <= ARIZONA_FLL_MAX_FRATIO;
+ /* start from init_ratio because this may already give a
+ * fractional N.K
+ */
+ for (ratio = init_ratio; ratio > 0; ratio--) {
+ if (target % (ratio * Fref)) {
+ cfg->refdiv = refdiv;
+ cfg->fratio = ratio - 1;
+ arizona_fll_dbg(fll,
+ "pseudo: found fref=%u refdiv=%d(%d)
ratio=%d\n",
+ Fref, refdiv, div, ratio);
+ return ratio;
+ }
+ }
+
+ for (ratio = init_ratio + 1; ratio <= ARIZONA_FLL_MAX_FRATIO;
ratio++) {
if ((ARIZONA_FLL_VCO_CORNER / 2) /
(fll->vco_mult * ratio) < Fref) {
@@ -2065,17 +2079,6 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
}
}
- for (ratio = init_ratio - 1; ratio > 0; ratio--) {
- if (target % (ratio * Fref)) {
- cfg->refdiv = refdiv;
- cfg->fratio = ratio - 1;
- arizona_fll_dbg(fll,
- "pseudo: found fref=%u refdiv=%d(%d)
ratio=%d\n",
- Fref, refdiv, div, ratio);
- return ratio;
- }
- }
-
div *= 2;
Fref /= 2;
refdiv++;
--
1.9.1
