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ASoC: arizona: Prefer lower FRATIO in pseudo-fractional mode

PATCH In review Richard Fitzgerald 2 participants 2 messages Apr 21, 2016

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Sound ASoC Wolfson microelectronics drivers
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Richard Fitzgerald

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PATCH 1/1 ASoC: arizona: Prefer lower FRATIO in pseudo-fractional mode

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 <[email protected]>
---
 sound/soc/codecs/arizona.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)
sound/soc/codecs/arizona.c +15 -12
index 0cd27e0..d1e1127 100644
@@ -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++;
Signature · 1 line
1.9.1
maintainer
#1 lore raw

Applied "ASoC: arizona: Prefer lower FRATIO in pseudo-fractional mode" to the asoc tree

The patch

ASoC: arizona: Prefer lower FRATIO in pseudo-fractional mode

has been applied to the asoc tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

Quoted 1 line

From 8e42db1eaab6c2558dbc2e6c1428730df0a295f4 Mon Sep 17 00:00:00 2001

From: Richard Fitzgerald <[email protected]>
Date: Thu, 21 Apr 2016 14:04:14 +0100
Subject: [PATCH] ASoC: arizona: Prefer lower FRATIO in pseudo-fractional mode

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 <[email protected]>
Signed-off-by Mark Brown <[email protected]>
---
 sound/soc/codecs/arizona.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)
sound/soc/codecs/arizona.c +15 -12
index d8a682302580..0caecc6f78df 100644
@@ -2037,7 +2037,21 @@ 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) {

@@ -2063,17 +2077,6 @@ 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++;
Signature · 1 line
2.8.0.rc3