ASoC: Do not write to invalid registers on the wm9712.

This patch fixes a bug where "virtual" registers were being written to the ac97
bus.  This was causing unrelated registers to become corrupted (headphone 0x04,
touchscreen 0x78, etc).

This patch duplicates protection that was included in the wm9713 driver.

Signed-off-by: Eric Millbrandt <emillbrandt@dekaresearch.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org

1 files changed, 2 insertions, 1 deletions

diff --git a/sound/soc/codecs/wm9712.c b/sound/soc/codecs/wm9712.c
index 0ac1215dcd9b..e237bf615129 100644
--- a/sound/soc/codecs/wm9712.c
+++ b/sound/soc/codecs/wm9712.c
@@ -463,7 +463,8 @@ static int ac97_write(struct snd_soc_codec *codec, unsigned int reg,
 {
         u16 *cache = codec->reg_cache;
 
-        soc_ac97_ops.write(codec->ac97, reg, val);
+        if (reg < 0x7c)
+                soc_ac97_ops.write(codec->ac97, reg, val);
         reg = reg >> 1;
         if (reg < (ARRAY_SIZE(wm9712_reg)))
                 cache[reg] = val;