81 lines
1.9 KiB
Plaintext
81 lines
1.9 KiB
Plaintext
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= NVMEM(Non Volatile Memory) Data Device Tree Bindings =
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This binding is intended to represent the location of hardware
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configuration data stored in NVMEMs like eeprom, efuses and so on.
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On a significant proportion of boards, the manufacturer has stored
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some data on NVMEM, for the OS to be able to retrieve these information
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and act upon it. Obviously, the OS has to know about where to retrieve
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these data from, and where they are stored on the storage device.
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This document is here to document this.
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= Data providers =
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Contains bindings specific to provider drivers and data cells as children
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of this node.
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Optional properties:
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read-only: Mark the provider as read only.
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= Data cells =
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These are the child nodes of the provider which contain data cell
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information like offset and size in nvmem provider.
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Required properties:
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reg: specifies the offset in byte within the storage device.
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Optional properties:
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bits: Is pair of bit location and number of bits, which specifies offset
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in bit and number of bits within the address range specified by reg property.
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Offset takes values from 0-7.
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For example:
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/* Provider */
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qfprom: qfprom@700000 {
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...
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/* Data cells */
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tsens_calibration: calib@404 {
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reg = <0x404 0x10>;
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};
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tsens_calibration_bckp: calib_bckp@504 {
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reg = <0x504 0x11>;
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bits = <6 128>
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};
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pvs_version: pvs-version@6 {
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reg = <0x6 0x2>
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bits = <7 2>
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};
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speed_bin: speed-bin@c{
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reg = <0xc 0x1>;
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bits = <2 3>;
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};
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...
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};
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= Data consumers =
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Are device nodes which consume nvmem data cells/providers.
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Required-properties:
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nvmem-cells: list of phandle to the nvmem data cells.
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nvmem-cell-names: names for the each nvmem-cells specified. Required if
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nvmem-cells is used.
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Optional-properties:
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nvmem : list of phandles to nvmem providers.
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nvmem-names: names for the each nvmem provider. required if nvmem is used.
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For example:
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tsens {
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...
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nvmem-cells = <&tsens_calibration>;
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nvmem-cell-names = "calibration";
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};
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