linux-kernel - [PATCH v2 2/2] regmap: Drop check whether a register is readable in regcache

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Date:	Wed, 16 Nov 2011 20:34:04 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>
Cc:	linux-kernel@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>
Subject: [PATCH v2 2/2] regmap: Drop check whether a register is readable in regcache_read

One of the reasons for using a cache is to have a software shadow of a register
which is writable but not readable. This allows us to do a read-modify-write
operation on such a register.

Currently regcache checks whether a register is readable when performing a
cached read and returns an error if it is not. Drop this check, since it will
prevent us from using the cache for registers where read-back is not possible.

Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>

---
Changes since v1:
	* Drop the check instead of replaceing it with a check whether the register
	  is writable since this would break once we start adding read-back values
	  to the cache.
---
 drivers/base/regmap/regcache.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 6d93e49..e21eebd 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -199,9 +199,6 @@ int regcache_read(struct regmap *map,
 
 	BUG_ON(!map->cache_ops);
 
-	if (!regmap_readable(map, reg))
-		return -EIO;
-
 	if (!regmap_volatile(map, reg))
 		return map->cache_ops->read(map, reg, value);
 
-- 
1.7.7.1

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