regmap: regcache: allow read-only regs to be cached

PATCH Applied Ionut Nicu 2 participants 2 messages Aug 9, 2013

Subsystems (2)

Driver core Register map abstraction

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Ionut Nicu

author

2013-08-09 10:10 UTC #0 lore raw

PATCH 3/3 regmap: regcache: allow read-only regs to be cached

The regmap_writeable() check should not be done in regcache_write() because this prevents read-only registers to be cached. After a read on a read-only register its value will not be stored in the cache and the next time someone will try to read it the value will be read from the bus instead of the cache.

Instead the regmap_writeable() check should be done in _regmap_write() to prevent callers from writing to read-only registers.

Signed-off-by Ionut Nicu <[email protected]>

---
 drivers/base/regmap/regcache.c |    3 ---
 drivers/base/regmap/regmap.c   |    3 +++
 2 files changed, 3 insertions(+), 3 deletions(-)

drivers/base/regmap/regcache.c +0 -3

index 3455f83..e2abd05 100644
@@ -241,9 +241,6 @@ int regcache_write(struct regmap *map,
 
 	BUG_ON(!map->cache_ops);
 
-	if (!regmap_writeable(map, reg))
-		return -EIO;
-
 	if (!regmap_volatile(map, reg))
 		return map->cache_ops->write(map, reg, value);

drivers/base/regmap/regmap.c +3 -0

index fa76b61..42b45ac 100644
@@ -1267,6 +1267,9 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 	int ret;
 	void *context = _regmap_map_get_context(map);
 
+	if (!regmap_writeable(map, reg))
+		return -EIO;
+
 	if (!map->cache_bypass && !map->defer_caching) {
 		ret = regcache_write(map, reg, val);
 		if (ret != 0)

Signature · 1 line

1.7.1

Mark Brown

maintainer Applied

2013-08-09 11:47 UTC #1 lore raw

Quoted 7 lines · Ionut Nicu

The regmap_writeable() check should not be done in regcache_write() because this prevents read-only registers to be cached. After a read on a read-only register its value will not be stored in the cache and the next time someone will try to read it the value will be read from the bus instead of the cache.

Applied, thanks.