From 01582a841493f28caf1688b2af4dafbcbee8135e Mon Sep 17 00:00:00 2001
From: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Date: Wed, 10 Feb 2016 11:56:13 +0000
Subject: [PATCH] ASoC: arizona: fref must be limited in pseudo-fractional mode
When the FLL is in pseudo-fractional mode there is an additional
limit on fref based on the fratio, to prevent aliasing around the
Nyquist frequency. If fref exceeds this limit the refclk divider
must be increased and the calculation tried again until a suitable
combination of fref and fratio is found or we have to fall back to
integer mode.
This patch also adds some debug log prints around this code.
Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
---
sound/soc/codecs/arizona.c | 43 +++++++++++++++++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index 33143fe1de0bd..91785318b2834 100644
--- a/sound/soc/codecs/arizona.c
+++ b/sound/soc/codecs/arizona.c
@@ -1929,6 +1929,25 @@ static struct {
{ 1000000, 13500000, 0, 1 },
};
+static const unsigned int pseudo_fref_max[ARIZONA_FLL_MAX_FRATIO] = {
+ 13500000,
+ 6144000,
+ 6144000,
+ 3072000,
+ 3072000,
+ 2822400,
+ 2822400,
+ 1536000,
+ 1536000,
+ 1536000,
+ 1536000,
+ 1536000,
+ 1536000,
+ 1536000,
+ 1536000,
+ 768000,
+};
+
static struct {
unsigned int min;
unsigned int max;
@@ -2042,16 +2061,32 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
/* Adjust FRATIO/refdiv to avoid integer mode if possible */
refdiv = cfg->refdiv;
+ arizona_fll_dbg(fll, "pseudo: initial ratio=%u fref=%u refdiv=%u\n",
+ init_ratio, Fref, refdiv);
+
while (div <= ARIZONA_FLL_MAX_REFDIV) {
for (ratio = init_ratio; ratio <= ARIZONA_FLL_MAX_FRATIO;
ratio++) {
if ((ARIZONA_FLL_VCO_CORNER / 2) /
- (fll->vco_mult * ratio) < Fref)
+ (fll->vco_mult * ratio) < Fref) {
+ arizona_fll_dbg(fll, "pseudo: hit VCO corner\n");
break;
+ }
+
+ if (Fref > pseudo_fref_max[ratio - 1]) {
+ arizona_fll_dbg(fll,
+ "pseudo: exceeded max fref(%u) for ratio=%u\n",
+ pseudo_fref_max[ratio - 1],
+ ratio);
+ break;
+ }
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;
}
}
@@ -2060,6 +2095,9 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
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;
}
}
@@ -2068,6 +2106,9 @@ static int arizona_calc_fratio(struct arizona_fll *fll,
Fref /= 2;
refdiv++;
init_ratio = arizona_find_fratio(Fref, NULL);
+ arizona_fll_dbg(fll,
+ "pseudo: change fref=%u refdiv=%d(%d) ratio=%u\n",
+ Fref, refdiv, div, init_ratio);
}
arizona_fll_warn(fll, "Falling back to integer mode operation\n");
--
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