xref: /linux/Documentation/devicetree/bindings/hwmon/baikal,bt1-pvt.yaml (revision a1c3be890440a1769ed6f822376a3e3ab0d42994) 
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
3%YAML 1.2
4---
5$id: http://devicetree.org/schemas/hwmon/baikal,bt1-pvt.yaml#
6$schema: http://devicetree.org/meta-schemas/core.yaml#
7
8title: Baikal-T1 PVT Sensor
9
10maintainers:
11  - Serge Semin <fancer.lancer@gmail.com>
12
13description: |
14  Baikal-T1 SoC provides an embedded process, voltage and temperature
15  sensor to monitor an internal SoC environment (chip temperature, supply
16  voltage and process monitor) and on time detect critical situations,
17  which may cause the system instability and even damages. The IP-block
18  is based on the Analog Bits PVT sensor, but is equipped with a dedicated
19  control wrapper, which provides a MMIO registers-based access to the
20  sensor core functionality (APB3-bus based) and exposes an additional
21  functions like thresholds/data ready interrupts, its status and masks,
22  measurements timeout. Its internal structure is depicted on the next
23  diagram:
24
25     Analog Bits core                     Bakal-T1 PVT control block
26  +--------------------+                  +------------------------+
27  | Temperature sensor |-+         +------| Sensors control        |
28  |--------------------| |<---En---|      |------------------------|
29  | Voltage sensor     |-|<--Mode--| +--->| Sampled data           |
30  |--------------------| |<--Trim--+ |    |------------------------|
31  | Low-Vt sensor      |-|           | +--| Thresholds comparator  |
32  |--------------------| |---Data----| |  |------------------------|
33  | High-Vt sensor     |-|           | +->| Interrupts status      |
34  |--------------------| |--Valid--+-+ |  |------------------------|
35  | Standard-Vt sensor |-+         +---+--| Interrupts mask        |
36  +--------------------+                  |------------------------|
37           ^                              | Interrupts timeout     |
38           |                              +------------------------+
39           |                                        ^  ^
40  Rclk-----+----------------------------------------+  |
41  APB3-------------------------------------------------+
42
43  This bindings describes the external Baikal-T1 PVT control interfaces
44  like MMIO registers space, interrupt request number and clocks source.
45  These are then used by the corresponding hwmon device driver to
46  implement the sysfs files-based access to the sensors functionality.
47
48properties:
49  compatible:
50    const: baikal,bt1-pvt
51
52  reg:
53    maxItems: 1
54
55  interrupts:
56    maxItems: 1
57
58  clocks:
59    items:
60      - description: PVT reference clock
61      - description: APB3 interface clock
62
63  clock-names:
64    items:
65      - const: ref
66      - const: pclk
67
68  "#thermal-sensor-cells":
69    description: Baikal-T1 can be referenced as the CPU thermal-sensor
70    const: 0
71
72  baikal,pvt-temp-offset-millicelsius:
73    description: |
74      Temperature sensor trimming factor. It can be used to manually adjust the
75      temperature measurements within 7.130 degrees Celsius.
76    default: 0
77    minimum: 0
78    maximum: 7130
79
80additionalProperties: false
81
82required:
83  - compatible
84  - reg
85  - interrupts
86  - clocks
87  - clock-names
88
89examples:
90  - |
91    #include <dt-bindings/interrupt-controller/mips-gic.h>
92
93    pvt@1f200000 {
94      compatible = "baikal,bt1-pvt";
95      reg = <0x1f200000 0x1000>;
96      #thermal-sensor-cells = <0>;
97
98      interrupts = <GIC_SHARED 31 IRQ_TYPE_LEVEL_HIGH>;
99
100      baikal,pvt-temp-offset-millicelsius = <1000>;
101
102      clocks = <&ccu_sys>, <&ccu_sys>;
103      clock-names = "ref", "pclk";
104    };
105...
106