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authorSerge Semin <Sergey.Semin@baikalelectronics.ru>2020-05-28 17:28:03 +0300
committerGuenter Roeck <linux@roeck-us.net>2020-05-28 07:59:45 -0700
commitddc65caa56660813af1c8cff979bdc80f81456f2 (patch)
tree99af0b9b2405db1753797b3228b1d62064188148 /Documentation
parentfff2d0f701e6753591609739f8ab9be1c8e80ebb (diff)
dt-bindings: hwmon: Add Baikal-T1 PVT sensor binding
Baikal-T1 SoC is equipped with an embedded process, voltage and temperature sensor to monitor the chip internal environment like temperature, supply voltage and transistors performance. This bindings describes the external Baikal-T1 PVT control interfaces like MMIO registers space, interrupt request number and clocks source. These are then used by the corresponding hwmon device driver to implement the sysfs files-based access to the sensors functionality. Co-developed-by: Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru> Signed-off-by: Maxim Kaurkin <maxim.kaurkin@baikalelectronics.ru> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Rob Herring <robh@kernel.org> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-mips@vger.kernel.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/baikal,bt1-pvt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 PVT Sensor
+
+maintainers:
+ - Serge Semin <fancer.lancer@gmail.com>
+
+description: |
+ Baikal-T1 SoC provides an embedded process, voltage and temperature
+ sensor to monitor an internal SoC environment (chip temperature, supply
+ voltage and process monitor) and on time detect critical situations,
+ which may cause the system instability and even damages. The IP-block
+ is based on the Analog Bits PVT sensor, but is equipped with a dedicated
+ control wrapper, which provides a MMIO registers-based access to the
+ sensor core functionality (APB3-bus based) and exposes an additional
+ functions like thresholds/data ready interrupts, its status and masks,
+ measurements timeout. Its internal structure is depicted on the next
+ diagram:
+
+ Analog Bits core Bakal-T1 PVT control block
+ +--------------------+ +------------------------+
+ | Temperature sensor |-+ +------| Sensors control |
+ |--------------------| |<---En---| |------------------------|
+ | Voltage sensor |-|<--Mode--| +--->| Sampled data |
+ |--------------------| |<--Trim--+ | |------------------------|
+ | Low-Vt sensor |-| | +--| Thresholds comparator |
+ |--------------------| |---Data----| | |------------------------|
+ | High-Vt sensor |-| | +->| Interrupts status |
+ |--------------------| |--Valid--+-+ | |------------------------|
+ | Standard-Vt sensor |-+ +---+--| Interrupts mask |
+ +--------------------+ |------------------------|
+ ^ | Interrupts timeout |
+ | +------------------------+
+ | ^ ^
+ Rclk-----+----------------------------------------+ |
+ APB3-------------------------------------------------+
+
+ This bindings describes the external Baikal-T1 PVT control interfaces
+ like MMIO registers space, interrupt request number and clocks source.
+ These are then used by the corresponding hwmon device driver to
+ implement the sysfs files-based access to the sensors functionality.
+
+properties:
+ compatible:
+ const: baikal,bt1-pvt
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ clocks:
+ items:
+ - description: PVT reference clock
+ - description: APB3 interface clock
+
+ clock-names:
+ items:
+ - const: ref
+ - const: pclk
+
+ "#thermal-sensor-cells":
+ description: Baikal-T1 can be referenced as the CPU thermal-sensor
+ const: 0
+
+ baikal,pvt-temp-offset-millicelsius:
+ description: |
+ Temperature sensor trimming factor. It can be used to manually adjust the
+ temperature measurements within 7.130 degrees Celsius.
+ maxItems: 1
+ items:
+ default: 0
+ minimum: 0
+ maximum: 7130
+
+unevaluatedProperties: false
+
+required:
+ - compatible
+ - reg
+ - interrupts
+ - clocks
+ - clock-names
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/mips-gic.h>
+
+ pvt@1f200000 {
+ compatible = "baikal,bt1-pvt";
+ reg = <0x1f200000 0x1000>;
+ #thermal-sensor-cells = <0>;
+
+ interrupts = <GIC_SHARED 31 IRQ_TYPE_LEVEL_HIGH>;
+
+ baikal,pvt-temp-trim-millicelsius = <1000>;
+
+ clocks = <&ccu_sys>, <&ccu_sys>;
+ clock-names = "ref", "pclk";
+ };
+...