mfd: Keep a cache of WM8350 volatile values

Due to the way that the WM8350 audio driver handles CODEC_ENA many of
the WM8350 audio registers are marked as volatile when they aren't
actually so. Allow the audio driver to see a cache of these values for
inspection during interrupt context.

To do this we need to stop satisfying any bits from volatile registers
from cache - there's no real benefit from doing so anyway, we did the
read already.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm8350-core.c

@@ -79,10 +79,6 @@ static int wm8350_phys_read(struct wm8350 *wm8350, u8 reg, int num_regs,
 		/* Cache is CPU endian */
 		dest[i - reg] = be16_to_cpu(dest[i - reg]);
 
-		/* Satisfy non-volatile bits from cache */
-		dest[i - reg] &= wm8350_reg_io_map[i].vol;
-		dest[i - reg] |= wm8350->reg_cache[i];
-
 		/* Mask out non-readable bits */
 		dest[i - reg] &= wm8350_reg_io_map[i].readable;
 	}
@@ -182,9 +178,6 @@ static int wm8350_write(struct wm8350 *wm8350, u8 reg, int num_regs, u16 *src)
 			(wm8350->reg_cache[i] & ~wm8350_reg_io_map[i].writable)
 			| src[i - reg];
 
-		/* Don't store volatile bits */
-		wm8350->reg_cache[i] &= ~wm8350_reg_io_map[i].vol;
-
 		src[i - reg] = cpu_to_be16(src[i - reg]);
 	}
 
@@ -1261,7 +1254,6 @@ static int wm8350_create_cache(struct wm8350 *wm8350, int type, int mode)
 		    (i < WM8350_CLOCK_CONTROL_1 || i > WM8350_AIF_TEST)) {
 			value = be16_to_cpu(wm8350->reg_cache[i]);
 			value &= wm8350_reg_io_map[i].readable;
-			value &= ~wm8350_reg_io_map[i].vol;
 			wm8350->reg_cache[i] = value;
 		} else
 			wm8350->reg_cache[i] = reg_map[i];