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From: Lars-Peter Clausen <lars@metafoo.de>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>,
	Dimitris Papastamos <dp@opensource.wolfsonmicro.com>,
	Jonathan Cameron <jic23@kernel.org>
Cc: Michael Hennerich <michael.hennerich@analog.com>,
	<linux-kernel@vger.kernel.org>, <linux-iio@vger.kernel.org>,
	<device-drivers-devel@blackfin.uclinux.org>, <drivers@analog.com>,
	Lars-Peter Clausen <lars@metafoo.de>
Subject: [PATCH 5/7] regmap: Check if a register is writable instead of readable in regcache_read
Date: Wed, 16 Nov 2011 16:28:20 +0100	[thread overview]
Message-ID: <1321457302-8724-5-git-send-email-lars@metafoo.de> (raw)
In-Reply-To: <1321457302-8724-1-git-send-email-lars@metafoo.de>

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 not. Change this check to test whether the
register is writable. This makes more sense, since reading from the cache when
the register is not readable allows the operation described above, but if the
register is not writable there shouldn't  be a value for it in the cache anyway.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 drivers/base/regmap/regcache.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 6f0dbc0..a004a7a 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -206,7 +206,7 @@ int regcache_read(struct regmap *map,
 
 	BUG_ON(!map->cache_ops);
 
-	if (!regmap_readable(map, reg))
+	if (!regmap_writeable(map, reg))
 		return -EIO;
 
 	if (!regmap_volatile(map, reg))
-- 
1.7.7.1



  parent reply	other threads:[~2011-11-16 15:28 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-16 15:28 [PATCH 1/7] regmap: Move initialization of regcache related fields to regcache_init Lars-Peter Clausen
2011-11-16 15:28 ` [PATCH 2/7] regmap: Make reg_config reg_defaults const Lars-Peter Clausen
2011-11-16 16:13   ` Mark Brown
2011-11-16 16:23     ` Lars-Peter Clausen
2011-11-16 16:24       ` Mark Brown
2011-11-16 16:36         ` Lars-Peter Clausen
2011-11-16 16:39           ` Mark Brown
2011-11-16 16:50             ` Lars-Peter Clausen
2011-11-16 16:51               ` Mark Brown
2011-11-16 17:01                 ` Lars-Peter Clausen
2011-11-16 17:09                   ` Mark Brown
2011-11-16 17:20                     ` Lars-Peter Clausen
2011-11-16 17:26                       ` Mark Brown
2011-11-16 17:35   ` Mark Brown
2011-11-16 15:28 ` [PATCH 3/7] regmap: Properly round cache_word_size Lars-Peter Clausen
2011-11-16 16:14   ` Mark Brown
2011-11-16 16:25     ` Lars-Peter Clausen
2011-11-16 15:28 ` [PATCH 4/7] regmap: Try cached read before checking if a hardware read is possible Lars-Peter Clausen
2011-11-16 17:35   ` Mark Brown
2011-11-16 15:28 ` Lars-Peter Clausen [this message]
2011-11-16 16:16   ` [PATCH 5/7] regmap: Check if a register is writable instead of readable in regcache_read Mark Brown
2011-11-16 16:34     ` Lars-Peter Clausen
2011-11-16 16:38       ` Mark Brown
2011-11-16 16:52         ` Lars-Peter Clausen
2011-11-16 16:56           ` Mark Brown
2011-11-16 17:09             ` Lars-Peter Clausen
2011-11-16 17:12               ` Mark Brown
2011-11-16 17:15                 ` Lars-Peter Clausen
2011-11-16 17:22                   ` Mark Brown
2011-11-16 15:28 ` [PATCH 6/7] regmap: Add support for 10/14 register formating Lars-Peter Clausen
2011-11-16 17:37   ` Mark Brown
2011-11-16 15:28 ` [PATCH 7/7] staging:iio:dac: Add AD5380 driver Lars-Peter Clausen
2011-11-16 16:56   ` Lars-Peter Clausen
2011-11-17 20:24   ` Jonathan Cameron
2011-11-18  9:08     ` Lars-Peter Clausen
2011-11-18  9:51       ` J.I. Cameron
2011-11-16 17:35 ` [PATCH 1/7] regmap: Move initialization of regcache related fields to regcache_init Mark Brown

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