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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /Documentation/devicetree/bindings/nvmem/nvmem.txt
parentInitial commit. (diff)
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Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+= NVMEM(Non Volatile Memory) Data Device Tree Bindings =
+
+This binding is intended to represent the location of hardware
+configuration data stored in NVMEMs like eeprom, efuses and so on.
+
+On a significant proportion of boards, the manufacturer has stored
+some data on NVMEM, for the OS to be able to retrieve these information
+and act upon it. Obviously, the OS has to know about where to retrieve
+these data from, and where they are stored on the storage device.
+
+This document is here to document this.
+
+= Data providers =
+Contains bindings specific to provider drivers and data cells as children
+of this node.
+
+Optional properties:
+ read-only: Mark the provider as read only.
+
+= Data cells =
+These are the child nodes of the provider which contain data cell
+information like offset and size in nvmem provider.
+
+Required properties:
+reg: specifies the offset in byte within the storage device.
+
+Optional properties:
+
+bits: Is pair of bit location and number of bits, which specifies offset
+ in bit and number of bits within the address range specified by reg property.
+ Offset takes values from 0-7.
+
+For example:
+
+ /* Provider */
+ qfprom: qfprom@700000 {
+ ...
+
+ /* Data cells */
+ tsens_calibration: calib@404 {
+ reg = <0x404 0x10>;
+ };
+
+ tsens_calibration_bckp: calib_bckp@504 {
+ reg = <0x504 0x11>;
+ bits = <6 128>
+ };
+
+ pvs_version: pvs-version@6 {
+ reg = <0x6 0x2>
+ bits = <7 2>
+ };
+
+ speed_bin: speed-bin@c{
+ reg = <0xc 0x1>;
+ bits = <2 3>;
+
+ };
+ ...
+ };
+
+= Data consumers =
+Are device nodes which consume nvmem data cells/providers.
+
+Required-properties:
+nvmem-cells: list of phandle to the nvmem data cells.
+nvmem-cell-names: names for the each nvmem-cells specified. Required if
+ nvmem-cells is used.
+
+Optional-properties:
+nvmem : list of phandles to nvmem providers.
+nvmem-names: names for the each nvmem provider. required if nvmem is used.
+
+For example:
+
+ tsens {
+ ...
+ nvmem-cells = <&tsens_calibration>;
+ nvmem-cell-names = "calibration";
+ };