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From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: alsa-devel@alsa-project.org, patches@opensource.wolfsonmicro.com,
	Mark Brown <broonie@opensource.wolfsonmicro.com>
Subject: [PATCH] ASoC: Remove volatility from WM8900 POWER1 register
Date: Fri, 29 Oct 2010 16:08:36 -0700	[thread overview]
Message-ID: <1288393716-19903-1-git-send-email-broonie@opensource.wolfsonmicro.com> (raw)

Not all bits can be read back from POWER1 so avoid corruption when using
a read/modify/write cycle by marking it non-volatile - the only thing we
read back from it is the chip revision which has diagnostic value only.
We can re-add later but that's a more invasive change than is suitable
for a bugfix.

Change-Id: I846ac8bba474275dcbda5ff82fc006554a06d21e
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 sound/soc/codecs/wm8900.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/sound/soc/codecs/wm8900.c b/sound/soc/codecs/wm8900.c
index b4f1172..aca4b1e 100644
--- a/sound/soc/codecs/wm8900.c
+++ b/sound/soc/codecs/wm8900.c
@@ -186,7 +186,6 @@ static int wm8900_volatile_register(unsigned int reg)
 {
 	switch (reg) {
 	case WM8900_REG_ID:
-	case WM8900_REG_POWER1:
 		return 1;
 	default:
 		return 0;
@@ -1200,11 +1199,6 @@ static int wm8900_probe(struct snd_soc_codec *codec)
 		return -ENODEV;
 	}
 
-	/* Read back from the chip */
-	reg = snd_soc_read(codec, WM8900_REG_POWER1);
-	reg = (reg >> 12) & 0xf;
-	dev_info(codec->dev, "WM8900 revision %d\n", reg);
-
 	wm8900_reset(codec);
 
 	/* Turn the chip on */
-- 
1.7.1

             reply	other threads:[~2010-10-29 23:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-29 23:08 Mark Brown [this message]
2010-10-30 16:28 ` [PATCH] ASoC: Remove volatility from WM8900 POWER1 register Liam Girdwood

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