[PATCH] mfd: wm5102: Remove cache_bypass from manual register patching

Charles Keepax
2014-02-20T16:35:06Z

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.

As the cache_bypass is not strictly necessary for applying the patches
(the device is always powered on whilst it is applied) remove the calls
to regcache_cache_bypass to avoid this situation.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
---
drivers/mfd/arizona-core.c | 4 ----
drivers/mfd/wm5102-tables.c | 10 +++-------
2 files changed, 3 insertions(+), 11 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 187ee86..b9556bc 100644
--- a/drivers/mfd/wm5102-tables.c
+++ b/drivers/mfd/wm5102-tables.c
@@ -81,7 +81,7 @@ static const struct reg_default wm5102_revb_patch[] = {
int wm5102_patch(struct arizona *arizona)
{
const struct reg_default *wm5102_patch;
- int ret = 0;
+ int ret;
int i, patch_size;

switch (arizona->rev) {
@@ -93,21 +93,17 @@ 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;
+ return ret;
}
}

-out:
- regcache_cache_bypass(arizona->regmap, false);
- return ret;
+ return 0;
}

static const struct regmap_irq wm5102_aod_irqs[ARIZONA_NUM_IRQ] = {
--
1.7.2.5