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authorLinus Torvalds <torvalds@linux-foundation.org>2014-10-08 04:57:56 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-08 04:57:56 +0400
commitc831dd7352c0eedb270b9b6430590da5991bb65c (patch)
tree89d808ddea1eeb039eeff2e5815d2ba3b55a1cba /Documentation
parent2b425a3f112aa24666fc5f415c8bf0e9132bb6c0 (diff)
parentf5b313a2bcd4c436560c044c726d9ad84a3e4bb3 (diff)
downloadlinux-c831dd7352c0eedb270b9b6430590da5991bb65c.tar.xz
Merge tag 'regmap-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap
Pull regmap updates from Mark Brown: "The main update this time around is the addition of a standard DT binding for specifying the endianness of devices. This allows drivers to support any endianness of device register map without any code, useful for configurable IP blocks. There's also a few bug fixes that I didn't get round to sending, none of them terribly severe or new, and a reduction in size for struct regmap" * tag 'regmap-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: regmap: Fix debugfs-file 'registers' mode regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error. regmap: debugfs: fix possbile NULL pointer dereference regmap: fix NULL pointer dereference in _regmap_write/read regmap: fix NULL pointer dereference in regmap_get_val_endian regmap: cache: Do not fail silently from regcache_sync calls regmap: change struct regmap's internal locks as union regmap: Split regmap_get_endian() in two functions regmap: of_regmap_get_endian() cleanup regmap: Fix DT endianess parsing logic regmap: Add explicit dependencies to catch "select" misuse regmap: Restore L: linux-kernel@vger.kernel.org entry regmap: Add the DT binding documentation for endianness regmap: add DT endianness binding support.
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/regmap/regmap.txt47
1 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/regmap/regmap.txt b/Documentation/devicetree/bindings/regmap/regmap.txt
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+Device-Tree binding for regmap
+
+The endianness mode of CPU & Device scenarios:
+Index Device Endianness properties
+---------------------------------------------------
+1 BE 'big-endian'
+2 LE 'little-endian'
+
+For one device driver, which will run in different scenarios above
+on different SoCs using the devicetree, we need one way to simplify
+this.
+
+Required properties:
+- {big,little}-endian: these are boolean properties, if absent
+ meaning that the CPU and the Device are in the same endianness mode,
+ these properties are for register values and all the buffers only.
+
+Examples:
+Scenario 1 : CPU in LE mode & device in LE mode.
+dev: dev@40031000 {
+ compatible = "name";
+ reg = <0x40031000 0x1000>;
+ ...
+};
+
+Scenario 2 : CPU in LE mode & device in BE mode.
+dev: dev@40031000 {
+ compatible = "name";
+ reg = <0x40031000 0x1000>;
+ ...
+ big-endian;
+};
+
+Scenario 3 : CPU in BE mode & device in BE mode.
+dev: dev@40031000 {
+ compatible = "name";
+ reg = <0x40031000 0x1000>;
+ ...
+};
+
+Scenario 4 : CPU in BE mode & device in LE mode.
+dev: dev@40031000 {
+ compatible = "name";
+ reg = <0x40031000 0x1000>;
+ ...
+ little-endian;
+};