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regmap: Add explict native endian flag to DT bindings 

Currently the binding document says that if no endianness is configured
we use native endian but this is not in fact true for all binding types
and we do have some devices that really want native endianness such as
Broadcom MIPS SoCs where switching the endianness of the CPU also
switches the endianness of external IPs.

Provide an explicit option for this.

Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Mark Brown 2016-01-26 17:59:30 +00:00
parent 92e963f50f
commit a06c488da0
2 changed files with 9 additions and 4 deletions
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11
Documentation/devicetree/bindings/regmap/regmap.txt
View File

@ -5,15 +5,18 @@ Index Device Endianness properties
---------------------------------------------------
1 BE 'big-endian'
2 LE 'little-endian'
3 Native 'native-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.
Optional properties:
- {big,little,native}-endian: these are boolean properties, if absent
then the implementation will choose a default based on the device
being controlled. These properties are for register values and all
the buffers only. Native endian means that the CPU and device have
the same endianness.
Examples:
Scenario 1 : CPU in LE mode & device in LE mode.

2
drivers/base/regmap/regmap.c
View File

@ -557,6 +557,8 @@ enum regmap_endian regmap_get_val_endian(struct device *dev,
endian = REGMAP_ENDIAN_BIG;
else if (of_property_read_bool(np, "little-endian"))
endian = REGMAP_ENDIAN_LITTLE;
else if (of_property_read_bool(np, "native-endian"))
endian = REGMAP_ENDIAN_NATIVE;
/* If the endianness was specified in DT, use that */
if (endian != REGMAP_ENDIAN_DEFAULT)