xref: /linux/Documentation/devicetree/bindings/nvmem/nvmem.yaml (revision 9f2c9170934eace462499ba0bfe042cc72900173) 
1# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/nvmem/nvmem.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: NVMEM (Non Volatile Memory)
8
9maintainers:
10  - Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
11
12description: |
13  This binding is intended to represent the location of hardware
14  configuration data stored in NVMEMs like eeprom, efuses and so on.
15
16  On a significant proportion of boards, the manufacturer has stored
17  some data on NVMEM, for the OS to be able to retrieve these
18  information and act upon it. Obviously, the OS has to know about
19  where to retrieve these data from, and where they are stored on the
20  storage device.
21
22properties:
23  "#address-cells":
24    const: 1
25
26  "#size-cells":
27    const: 1
28
29  read-only:
30    $ref: /schemas/types.yaml#/definitions/flag
31    description:
32      Mark the provider as read only.
33
34  wp-gpios:
35    description:
36      GPIO to which the write-protect pin of the chip is connected.
37      The write-protect GPIO is asserted, when it's driven high
38      (logical '1') to block the write operation. It's deasserted,
39      when it's driven low (logical '0') to allow writing.
40    maxItems: 1
41
42  nvmem-layout:
43    $ref: /schemas/nvmem/layouts/nvmem-layout.yaml
44    description:
45      Alternative to the statically defined nvmem cells, this
46      container may reference more advanced (dynamic) layout
47      parsers.
48
49patternProperties:
50  "@[0-9a-f]+(,[0-7])?$":
51    type: object
52
53    properties:
54      reg:
55        maxItems: 1
56        description:
57          Offset and size in bytes within the storage device.
58
59      bits:
60        $ref: /schemas/types.yaml#/definitions/uint32-array
61        items:
62          - minimum: 0
63            maximum: 7
64            description:
65              Offset in bit within the address range specified by reg.
66          - minimum: 1
67            description:
68              Size in bit within the address range specified by reg.
69
70additionalProperties: true
71
72examples:
73  - |
74      #include <dt-bindings/gpio/gpio.h>
75
76      qfprom: eeprom@700000 {
77          compatible = "qcom,msm8974-qfprom", "qcom,qfprom";
78          #address-cells = <1>;
79          #size-cells = <1>;
80          reg = <0x00700000 0x100000>;
81
82          wp-gpios = <&gpio1 3 GPIO_ACTIVE_HIGH>;
83
84          /* ... */
85
86          /* Data cells */
87          tsens_calibration: calib@404 {
88              reg = <0x404 0x10>;
89          };
90
91          tsens_calibration_bckp: calib_bckp@504 {
92              reg = <0x504 0x11>;
93              bits = <6 128>;
94          };
95
96          pvs_version: pvs-version@6 {
97              reg = <0x6 0x2>;
98              bits = <7 2>;
99          };
100
101          speed_bin: speed-bin@c{
102              reg = <0xc 0x1>;
103              bits = <2 3>;
104          };
105      };
106
107...
108