On the wm5102 the register patches are applied manually, rather than by
the regmap core. This application is wrapped in calls to
regcache_cache_bypass. However, this is dangerous as other threads may
be accessing the hardware at the same time as the pm_runtime operations
and if they do so during the period whilst cache_bypass is enabled those
writes will miss the cache when they shouldn't.

Apply the register patch using the new regmap_apply_patch function to
avoid this problem. Also remove the call to regcache_cache_bypass from
the hardware patch application as it is unneeded there and creates a
similar window for writes to miss the cache.

Signed-off-by: Charles Keepax <ckee...@opensource.wolfsonmicro.com>
---
 drivers/mfd/arizona-core.c  |    4 ----
 drivers/mfd/wm5102-tables.c |   19 ++-----------------
 2 files changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index a45aab9..1c3ae57 100644
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -251,8 +251,6 @@ static int arizona_apply_hardware_patch(struct arizona* 
arizona)
        unsigned int fll, sysclk;
        int ret, err;
 
-       regcache_cache_bypass(arizona->regmap, true);
-
        /* Cache existing FLL and SYSCLK settings */
        ret = regmap_read(arizona->regmap, ARIZONA_FLL1_CONTROL_1, &fll);
        if (ret != 0) {
@@ -322,8 +320,6 @@ err_fll:
                        err);
        }
 
-       regcache_cache_bypass(arizona->regmap, false);
-
        if (ret != 0)
                return ret;
        else
diff --git a/drivers/mfd/wm5102-tables.c b/drivers/mfd/wm5102-tables.c
index 1e9a4b2..237020d 100644
--- a/drivers/mfd/wm5102-tables.c
+++ b/drivers/mfd/wm5102-tables.c
@@ -80,8 +80,7 @@ static const struct reg_default wm5102_revb_patch[] = {
 int wm5102_patch(struct arizona *arizona)
 {
        const struct reg_default *wm5102_patch;
-       int ret = 0;
-       int i, patch_size;
+       int patch_size;
 
        switch (arizona->rev) {
        case 0:
@@ -92,21 +91,7 @@ int wm5102_patch(struct arizona *arizona)
                patch_size = ARRAY_SIZE(wm5102_revb_patch);
        }
 
-       regcache_cache_bypass(arizona->regmap, true);
-
-       for (i = 0; i < patch_size; i++) {
-               ret = regmap_write(arizona->regmap, wm5102_patch[i].reg,
-                                  wm5102_patch[i].def);
-               if (ret != 0) {
-                       dev_err(arizona->dev, "Failed to write %x = %x: %d\n",
-                               wm5102_patch[i].reg, wm5102_patch[i].def, ret);
-                       goto out;
-               }
-       }
-
-out:
-       regcache_cache_bypass(arizona->regmap, false);
-       return ret;
+       return regmap_apply_patch(arizona->regmap, wm5102_patch, patch_size);
 }
 
 static const struct regmap_irq wm5102_aod_irqs[ARIZONA_NUM_IRQ] = {
-- 
1.7.2.5

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