0001 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
0002 # Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
0003 %YAML 1.2
0004 ---
0005 $id: http://devicetree.org/schemas/hwmon/baikal,bt1-pvt.yaml#
0006 $schema: http://devicetree.org/meta-schemas/core.yaml#
0007
0008 title: Baikal-T1 PVT Sensor
0009
0010 maintainers:
0011 - Serge Semin <fancer.lancer@gmail.com>
0012
0013 description: |
0014 Baikal-T1 SoC provides an embedded process, voltage and temperature
0015 sensor to monitor an internal SoC environment (chip temperature, supply
0016 voltage and process monitor) and on time detect critical situations,
0017 which may cause the system instability and even damages. The IP-block
0018 is based on the Analog Bits PVT sensor, but is equipped with a dedicated
0019 control wrapper, which provides a MMIO registers-based access to the
0020 sensor core functionality (APB3-bus based) and exposes an additional
0021 functions like thresholds/data ready interrupts, its status and masks,
0022 measurements timeout. Its internal structure is depicted on the next
0023 diagram:
0024
0025 Analog Bits core Bakal-T1 PVT control block
0026 +--------------------+ +------------------------+
0027 | Temperature sensor |-+ +------| Sensors control |
0028 |--------------------| |<---En---| |------------------------|
0029 | Voltage sensor |-|<--Mode--| +--->| Sampled data |
0030 |--------------------| |<--Trim--+ | |------------------------|
0031 | Low-Vt sensor |-| | +--| Thresholds comparator |
0032 |--------------------| |---Data----| | |------------------------|
0033 | High-Vt sensor |-| | +->| Interrupts status |
0034 |--------------------| |--Valid--+-+ | |------------------------|
0035 | Standard-Vt sensor |-+ +---+--| Interrupts mask |
0036 +--------------------+ |------------------------|
0037 ^ | Interrupts timeout |
0038 | +------------------------+
0039 | ^ ^
0040 Rclk-----+----------------------------------------+ |
0041 APB3-------------------------------------------------+
0042
0043 This bindings describes the external Baikal-T1 PVT control interfaces
0044 like MMIO registers space, interrupt request number and clocks source.
0045 These are then used by the corresponding hwmon device driver to
0046 implement the sysfs files-based access to the sensors functionality.
0047
0048 properties:
0049 compatible:
0050 const: baikal,bt1-pvt
0051
0052 reg:
0053 maxItems: 1
0054
0055 interrupts:
0056 maxItems: 1
0057
0058 clocks:
0059 items:
0060 - description: PVT reference clock
0061 - description: APB3 interface clock
0062
0063 clock-names:
0064 items:
0065 - const: ref
0066 - const: pclk
0067
0068 "#thermal-sensor-cells":
0069 description: Baikal-T1 can be referenced as the CPU thermal-sensor
0070 const: 0
0071
0072 baikal,pvt-temp-offset-millicelsius:
0073 description: |
0074 Temperature sensor trimming factor. It can be used to manually adjust the
0075 temperature measurements within 7.130 degrees Celsius.
0076 default: 0
0077 minimum: 0
0078 maximum: 7130
0079
0080 additionalProperties: false
0081
0082 required:
0083 - compatible
0084 - reg
0085 - interrupts
0086 - clocks
0087 - clock-names
0088
0089 examples:
0090 - |
0091 #include <dt-bindings/interrupt-controller/mips-gic.h>
0092
0093 pvt@1f200000 {
0094 compatible = "baikal,bt1-pvt";
0095 reg = <0x1f200000 0x1000>;
0096 #thermal-sensor-cells = <0>;
0097
0098 interrupts = <GIC_SHARED 31 IRQ_TYPE_LEVEL_HIGH>;
0099
0100 baikal,pvt-temp-offset-millicelsius = <1000>;
0101
0102 clocks = <&ccu_sys>, <&ccu_sys>;
0103 clock-names = "ref", "pclk";
0104 };
0105 ...
