a06c488da0
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>
51 lines
1.3 KiB
Plaintext
51 lines
1.3 KiB
Plaintext
Device-Tree binding for regmap
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The endianness mode of CPU & Device scenarios:
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Index Device Endianness properties
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---------------------------------------------------
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1 BE 'big-endian'
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2 LE 'little-endian'
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3 Native 'native-endian'
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For one device driver, which will run in different scenarios above
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on different SoCs using the devicetree, we need one way to simplify
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this.
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Optional properties:
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- {big,little,native}-endian: these are boolean properties, if absent
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then the implementation will choose a default based on the device
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being controlled. These properties are for register values and all
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the buffers only. Native endian means that the CPU and device have
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the same endianness.
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Examples:
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Scenario 1 : CPU in LE mode & device in LE mode.
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dev: dev@40031000 {
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compatible = "name";
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reg = <0x40031000 0x1000>;
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...
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};
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Scenario 2 : CPU in LE mode & device in BE mode.
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dev: dev@40031000 {
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compatible = "name";
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reg = <0x40031000 0x1000>;
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...
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big-endian;
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};
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Scenario 3 : CPU in BE mode & device in BE mode.
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dev: dev@40031000 {
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compatible = "name";
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reg = <0x40031000 0x1000>;
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...
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};
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Scenario 4 : CPU in BE mode & device in LE mode.
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dev: dev@40031000 {
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compatible = "name";
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reg = <0x40031000 0x1000>;
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...
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little-endian;
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};
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