ASoC: Remove volatility from WM8900 POWER1 register

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.

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

diff --git a/sound/soc/codecs/wm8900.c b/sound/soc/codecs/wm8900.c
index b4f11724a63ffc771c1a1d83909e31ae5cccaab7..aca4b1ea10bb710cd733ea730d22171895df620e 100644 (file)
--- 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 */