linux-kernel - [14/89] ASoC: Disable register synchronisation for low frequency WM8996 SYSCLK

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Message-Id: <20120201210045.130551019@clark.kroah.org>
Date:	Wed, 01 Feb 2012 12:59:38 -0800
From:	Greg KH <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [14/89] ASoC: Disable register synchronisation for low frequency WM8996 SYSCLK

3.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mark Brown <broonie@...nsource.wolfsonmicro.com>

commit fed22007113cb857e917913ce016d9b539dc3a80 upstream.

With a low frequency SYSCLK and a fast I2C clock register synchronisation
may occasionally take too long to take effect, causing I/O issues. Disable
synchronisation in order to avoid any issues.

Signed-off-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 sound/soc/codecs/wm8996.c |    4 ++++
 sound/soc/codecs/wm8996.h |    4 ++++
 2 files changed, 8 insertions(+)

--- a/sound/soc/codecs/wm8996.c
+++ b/sound/soc/codecs/wm8996.c
@@ -1932,6 +1932,7 @@ static int wm8996_set_sysclk(struct snd_
 	struct wm8996_priv *wm8996 = snd_soc_codec_get_drvdata(codec);
 	int lfclk = 0;
 	int ratediv = 0;
+	int sync = WM8996_REG_SYNC;
 	int src;
 	int old;
 
@@ -1976,6 +1977,7 @@ static int wm8996_set_sysclk(struct snd_
 	case 32000:
 	case 32768:
 		lfclk = WM8996_LFCLK_ENA;
+		sync = 0;
 		break;
 	default:
 		dev_warn(codec->dev, "Unsupported clock rate %dHz\n",
@@ -1989,6 +1991,8 @@ static int wm8996_set_sysclk(struct snd_
 			    WM8996_SYSCLK_SRC_MASK | WM8996_SYSCLK_DIV_MASK,
 			    src << WM8996_SYSCLK_SRC_SHIFT | ratediv);
 	snd_soc_update_bits(codec, WM8996_CLOCKING_1, WM8996_LFCLK_ENA, lfclk);
+	snd_soc_update_bits(codec, WM8996_CONTROL_INTERFACE_1,
+			    WM8996_REG_SYNC, sync);
 	snd_soc_update_bits(codec, WM8996_AIF_CLOCKING_1,
 			    WM8996_SYSCLK_ENA, old);
 
--- a/sound/soc/codecs/wm8996.h
+++ b/sound/soc/codecs/wm8996.h
@@ -1567,6 +1567,10 @@ int wm8996_detect(struct snd_soc_codec *
 /*
  * R257 (0x101) - Control Interface (1)
  */
+#define WM8996_REG_SYNC                         0x8000  /* REG_SYNC */
+#define WM8996_REG_SYNC_MASK                    0x8000  /* REG_SYNC */
+#define WM8996_REG_SYNC_SHIFT                       15  /* REG_SYNC */
+#define WM8996_REG_SYNC_WIDTH                        1  /* REG_SYNC */
 #define WM8996_AUTO_INC                         0x0004  /* AUTO_INC */
 #define WM8996_AUTO_INC_MASK                    0x0004  /* AUTO_INC */
 #define WM8996_AUTO_INC_SHIFT                        2  /* AUTO_INC */


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