mfd: arizona: Use new regmap features for manual register patch

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_multi_reg_write_bypassed
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 <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 4 insertions, 17 deletions

diff --git a/drivers/mfd/wm5102-tables.c b/drivers/mfd/wm5102-tables.c
index 1e9a4b2102f9..bffc584e4a43 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 +91,9 @@ 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_multi_reg_write_bypassed(arizona->regmap,
+                                               wm5102_patch,
+                                               patch_size);
 }
 
 static const struct regmap_irq wm5102_aod_irqs[ARIZONA_NUM_IRQ] = {