[PATCH v3 0/2] Add a generic virtual thermal sensor

[PATCH v3 0/2] Add a generic virtual thermal sensor

[Alexandre Bailon]

This series add a virtual thermal sensor.
It could be used to get a temperature using some thermal sensors.
Currently, the supported operations are max, min and avg.
The virtual sensor could be easily extended to support others operations.

Changes in v2:
- Fix some warnings / errors reported by kernel test robot
- rename some struct and functions with a more accurate name
- update the dt bindings: rename type attribute to aggregation-function
- factorize a little bit the aggregation functions
Changes in v3:
- Aggregate thermal zone instead of thermal sensors
- Use try_get_module / put_module to prevent thermal providers to be removed
- Update the bindings, to be more accurate

Alexandre Bailon (2):
  dt-bindings: Add DT bindings for the DT-based virtual sensor driver
  thermal: add a virtual sensor to aggregate temperatures

 .../thermal/virtual,thermal-sensor.yaml       |  80 +++++++
 drivers/thermal/Kconfig                       |   8 +
 drivers/thermal/Makefile                      |   1 +
 drivers/thermal/virtual_thermal_sensor.c      | 219 ++++++++++++++++++
 include/dt-bindings/thermal/virtual-sensor.h  |  15 ++
 5 files changed, 323 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/thermal/virtual,thermal-sensor.yaml
 create mode 100644 drivers/thermal/virtual_thermal_sensor.c
 create mode 100644 include/dt-bindings/thermal/virtual-sensor.h

-- 
2.32.0

[PATCH v3 1/2] dt-bindings: Add DT bindings for the DT-based virtual sensor driver

[Alexandre Bailon]

This adds the DT bindings for the DT-based virtual sensor driver.
This driver provides a way, using DT, to aggregate the temperature
of multiple thermal zones and get some useful data from it.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
 .../thermal/virtual,thermal-sensor.yaml       | 86 +++++++++++++++++++
 include/dt-bindings/thermal/virtual-sensor.h  | 15 ++++
 2 files changed, 101 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/thermal/virtual,thermal-sensor.yaml
 create mode 100644 include/dt-bindings/thermal/virtual-sensor.h

diff --git a/Documentation/devicetree/bindings/thermal/virtual,thermal-sensor.yaml b/Documentation/devicetree/bindings/thermal/virtual,thermal-sensor.yaml
new file mode 100644
index 000000000000..b404fd4b2b38
--- /dev/null
+++ b/Documentation/devicetree/bindings/thermal/virtual,thermal-sensor.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright 2021 BayLibre
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/virtual,thermal-sensor.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Virtual thermal sensor binding
+
+maintainers:
+  - Alexandre Bailon <abailon@baylibre.com>
+
+description: |
+  The virtual thermal sensor device provides a way to aggregate the temperature
+  from multiple thermal zones. Basically, this could be used to get the
+  maximum, minimum or average temperature.
+
+allOf:
+  - $ref: thermal-sensor.yaml#
+
+properties:
+  compatible:
+    const: virtual,thermal-sensor
+
+  aggregation-function:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Used to select the operations to perform on the sensors to get the virtual
+      sensor temperature.
+    enum:
+      - VIRTUAL_THERMAL_SENSOR_MIN_VAL
+      - VIRTUAL_THERMAL_SENSOR_MAX_VAL
+      - VIRTUAL_THERMAL_SENSOR_AVG_VAL
+
+  thermal-sensors:
+    $ref: /schemas/types.yaml#/definitions/string-array
+    description:
+      The names of the thermal zone to aggregate.
+
+required:
+  - aggregation-function
+  - thermal-sensors
+
+additionalProperties: true
+
+examples:
+  - |
+    #include <dt-bindings/thermal/thermal.h>
+    #include <dt-bindings/thermal/virtual-sensor.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/mt8192-clk.h>
+
+    lvts: lvts@1100b000 {
+        compatible = "mediatek,mt6873-lvts";
+        reg = <0x1100b000 0x1000>;
+        clocks = <&infracfg CLK_INFRA_THERM>;
+        clock-names = "lvts_clk";
+        #thermal-sensor-cells = <1>;
+        interrupts = <GIC_SPI 147 IRQ_TYPE_LEVEL_HIGH>;
+    };
+
+    cpu_max_sensor: cpu_max_sensor {
+      compatible = "virtual,thermal-sensor";
+      #thermal-sensor-cells = <1>;
+      aggregation-function = <VIRTUAL_THERMAL_SENSOR_MAX_VAL>;
+      thermal-sensors = "cpu1", "cpu2";
+    };
+
+    thermal_zones: thermal-zones {
+      cpu1 {
+        polling-delay = <0>; /* milliseconds */
+        polling-delay-passive = <0>; /* milliseconds */
+        thermal-sensors = <&lvts 0>;
+      };
+      cpu2 {
+        polling-delay = <0>; /* milliseconds */
+        polling-delay-passive = <0>; /* milliseconds */
+        thermal-sensors = <&lvts 1>;
+      };
+      cpu_max {
+        polling-delay = <0>; /* milliseconds */
+        polling-delay-passive = <0>; /* milliseconds */
+        thermal-sensors = <&cpu_max_sensor 0>;
+      };
+    };
+...
diff --git a/include/dt-bindings/thermal/virtual-sensor.h b/include/dt-bindings/thermal/virtual-sensor.h
new file mode 100644
index 000000000000..6254b2aa8f5c
--- /dev/null
+++ b/include/dt-bindings/thermal/virtual-sensor.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This header provides constants for virtual thermal sensor bindings.
+ *
+ * Copyright (C) 2021 BayLibre
+ */
+
+#ifndef _DT_BINDINGS_THERMAL_VIRTUAL_SENSOR_H
+#define _DT_BINDINGS_THERMAL_VIRTUAL_SENSOR_H
+
+#define VIRTUAL_THERMAL_SENSOR_MIN_VAL 0
+#define VIRTUAL_THERMAL_SENSOR_MAX_VAL 1
+#define VIRTUAL_THERMAL_SENSOR_AVG_VAL 2
+
+#endif /* _DT_BINDINGS_THERMAL_VIRTUAL_SENSOR_H */
-- 
2.32.0

[PATCH v3 2/2] thermal: add a virtual sensor to aggregate temperatures

[Alexandre Bailon]

This adds a virtual thermal sensor driver that reads temperature from
multiple hardware sensors and returns an aggregated temperature.
Currently, this supports three aggregations:
the minimum, maximum and average temperature.

Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
---
 drivers/thermal/Kconfig                  |   8 +
 drivers/thermal/Makefile                 |   1 +
 drivers/thermal/virtual_thermal_sensor.c | 218 +++++++++++++++++++++++
 3 files changed, 227 insertions(+)
 create mode 100644 drivers/thermal/virtual_thermal_sensor.c

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index d7f44deab5b1..b326fae5ad1d 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -228,6 +228,14 @@ config THERMAL_MMIO
 	  register or shared memory, is a potential candidate to work with this
 	  driver.
 
+config VIRTUAL_THERMAL
+	tristate "DT-based virtual thermal sensor driver"
+	depends on THERMAL_OF || COMPILE_TEST
+	help
+	  This option enables the generic DT-based thermal sensor aggregator.
+	  This driver creates a thermal sensor that reads multiple hardware
+	  sensors and aggregates their output.
+
 config HISI_THERMAL
 	tristate "Hisilicon thermal driver"
 	depends on ARCH_HISI || COMPILE_TEST
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 82fc3e616e54..8bf55973059c 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -60,3 +60,4 @@ obj-$(CONFIG_UNIPHIER_THERMAL)	+= uniphier_thermal.o
 obj-$(CONFIG_AMLOGIC_THERMAL)     += amlogic_thermal.o
 obj-$(CONFIG_SPRD_THERMAL)	+= sprd_thermal.o
 obj-$(CONFIG_KHADAS_MCU_FAN_THERMAL)	+= khadas_mcu_fan.o
+obj-$(CONFIG_VIRTUAL_THERMAL) += virtual_thermal_sensor.o
diff --git a/drivers/thermal/virtual_thermal_sensor.c b/drivers/thermal/virtual_thermal_sensor.c
new file mode 100644
index 000000000000..b1c5ea308abb
--- /dev/null
+++ b/drivers/thermal/virtual_thermal_sensor.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * virtual_thermal_sensor.c - DT-based virtual thermal sensor driver.
+ *
+ * Copyright (c) 2021 BayLibre
+ */
+
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/types.h>
+#include <linux/string.h>
+
+#include <dt-bindings/thermal/virtual-sensor.h>
+
+struct virtual_thermal_zone_device {
+	struct thermal_zone_device *zone;
+	struct module *owner;
+};
+
+struct virtual_thermal_sensor {
+	int count;
+	struct virtual_thermal_zone_device *zones;
+	struct thermal_zone_device *tzd;
+	int (*aggr_temp)(int temp1, int temp2);
+
+	struct list_head node;
+};
+
+static int max_temp(int temp1, int temp2)
+{
+	return max(temp1, temp2);
+}
+
+static int min_temp(int temp1, int temp2)
+{
+	return min(temp1, temp2);
+}
+
+static int avg_temp(int temp1, int temp2)
+{
+	return (temp1 + temp2) / 2;
+}
+
+static int virtual_thermal_sensor_get_temp(void *data, int *temperature)
+{
+	struct virtual_thermal_sensor *sensor = data;
+	int max_temp = INT_MIN;
+	int temp;
+	int i;
+
+	for (i = 0; i < sensor->count; i++) {
+		struct thermal_zone_device *zone;
+
+		zone = sensor->zones[i].zone;
+		zone->ops->get_temp(zone, &temp);
+		max_temp = sensor->aggr_temp(max_temp, temp);
+	}
+
+	*temperature = max_temp;
+
+	return 0;
+}
+
+static const struct thermal_zone_of_device_ops virtual_thermal_sensor_ops = {
+	.get_temp = virtual_thermal_sensor_get_temp,
+};
+
+int virtual_thermal_sensor_get_module(struct virtual_thermal_zone_device *zone,
+				      const char *name)
+{
+		struct platform_device *sensor_pdev;
+		struct device_node *node;
+
+		node = of_find_node_by_name(NULL, name);
+		if (!node)
+			return -ENODEV;
+
+		node = of_parse_phandle(node, "thermal-sensors", 0);
+		if (!node)
+			return -ENODEV;
+
+		sensor_pdev = of_find_device_by_node(node);
+		if (!sensor_pdev)
+			return -ENODEV;
+
+		if (!sensor_pdev->dev.driver)
+			return -EPROBE_DEFER;
+
+		if (!try_module_get(sensor_pdev->dev.driver->owner))
+			return -ENODEV;
+
+		zone->owner = sensor_pdev->dev.driver->owner;
+
+		return 0;
+}
+
+void virtual_thermal_sensor_put_modules(struct virtual_thermal_sensor *sensor)
+{
+	int i;
+
+	for (i = 0; i < sensor->count; i++) {
+		if (sensor->zones[i].zone)
+			module_put(sensor->zones[i].owner);
+	}
+}
+
+static int virtual_thermal_sensor_probe(struct platform_device *pdev)
+{
+	struct virtual_thermal_sensor *sensor;
+	struct device *dev = &pdev->dev;
+	struct property *prop;
+	const char *name;
+	u32 type;
+	int ret;
+	int i = 0;
+
+	sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
+	if (!sensor)
+		return -ENOMEM;
+	sensor->count = of_property_count_strings(dev->of_node, "thermal-sensors");
+	if (sensor->count <= 0)
+		return -EINVAL;
+
+	sensor->zones = devm_kmalloc_array(dev, sensor->count,
+					     sizeof(*sensor->zones),
+					     GFP_KERNEL);
+	if (!sensor->zones)
+		return -ENOMEM;
+
+	of_property_for_each_string(dev->of_node, "thermal-sensors", prop, name) {
+		struct virtual_thermal_zone_device *virtual_zone;
+		struct thermal_zone_device *zone;
+
+		virtual_zone = &sensor->zones[i++];
+
+		zone = thermal_zone_get_zone_by_name(name);
+		if (IS_ERR(zone))
+			return PTR_ERR(zone);
+
+		ret = virtual_thermal_sensor_get_module(virtual_zone, name);
+		if (ret)
+			goto err;
+
+		virtual_zone->zone = zone;
+	}
+
+	ret = of_property_read_u32(dev->of_node, "aggregation-function", &type);
+	if (ret)
+		return ret;
+
+	switch (type) {
+	case VIRTUAL_THERMAL_SENSOR_MAX_VAL:
+		sensor->aggr_temp = max_temp;
+		break;
+	case VIRTUAL_THERMAL_SENSOR_MIN_VAL:
+		sensor->aggr_temp = min_temp;
+		break;
+	case VIRTUAL_THERMAL_SENSOR_AVG_VAL:
+		sensor->aggr_temp = avg_temp;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	sensor->tzd = devm_thermal_zone_of_sensor_register(dev, 0, sensor,
+							   &virtual_thermal_sensor_ops);
+	if (IS_ERR(sensor->tzd))
+		return PTR_ERR(sensor->tzd);
+
+	platform_set_drvdata(pdev, sensor);
+
+	return 0;
+
+err:
+	virtual_thermal_sensor_put_modules(sensor);
+
+	return ret;
+}
+
+static int virtual_thermal_sensor_remove(struct platform_device *pdev)
+{
+	struct virtual_thermal_sensor *sensor;
+
+	sensor = platform_get_drvdata(pdev);
+	list_del(&sensor->node);
+
+	virtual_thermal_sensor_put_modules(sensor);
+
+	return 0;
+}
+
+static const struct of_device_id virtual_thermal_sensor_of_match[] = {
+	{
+		.compatible = "virtual,thermal-sensor",
+	},
+	{
+	},
+};
+MODULE_DEVICE_TABLE(of, virtual_thermal_sensor_of_match);
+
+static struct platform_driver virtual_thermal_sensor = {
+	.probe = virtual_thermal_sensor_probe,
+	.remove = virtual_thermal_sensor_remove,
+	.driver = {
+		.name = "virtual-thermal-sensor",
+		.of_match_table = virtual_thermal_sensor_of_match,
+	},
+};
+
+module_platform_driver(virtual_thermal_sensor);
+MODULE_AUTHOR("Alexandre Bailon <abailon@baylibre.com>");
+MODULE_DESCRIPTION("Virtual thermal sensor");
+MODULE_LICENSE("GPL v2");
-- 
2.32.0

Re: [PATCH v3 2/2] thermal: add a virtual sensor to aggregate temperatures

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3366 bytes --]

Hi Alexandre,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rafael-pm/thermal]
[also build test ERROR on v5.15-rc7 next-20211029]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Alexandre-Bailon/Add-a-generic-virtual-thermal-sensor/20211029-231137
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git thermal
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/be0e058f9a82f32140e4e96cf67a3e0842da9f70
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Alexandre-Bailon/Add-a-generic-virtual-thermal-sensor/20211029-231137
        git checkout be0e058f9a82f32140e4e96cf67a3e0842da9f70
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/thermal/virtual_thermal_sensor.c:73:5: error: no previous prototype for 'virtual_thermal_sensor_get_module' [-Werror=missing-prototypes]
      73 | int virtual_thermal_sensor_get_module(struct virtual_thermal_zone_device *zone,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/thermal/virtual_thermal_sensor.c:102:6: error: no previous prototype for 'virtual_thermal_sensor_put_modules' [-Werror=missing-prototypes]
     102 | void virtual_thermal_sensor_put_modules(struct virtual_thermal_sensor *sensor)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: all warnings being treated as errors


vim +/virtual_thermal_sensor_get_module +73 drivers/thermal/virtual_thermal_sensor.c

    72	
  > 73	int virtual_thermal_sensor_get_module(struct virtual_thermal_zone_device *zone,
    74					      const char *name)
    75	{
    76			struct platform_device *sensor_pdev;
    77			struct device_node *node;
    78	
    79			node = of_find_node_by_name(NULL, name);
    80			if (!node)
    81				return -ENODEV;
    82	
    83			node = of_parse_phandle(node, "thermal-sensors", 0);
    84			if (!node)
    85				return -ENODEV;
    86	
    87			sensor_pdev = of_find_device_by_node(node);
    88			if (!sensor_pdev)
    89				return -ENODEV;
    90	
    91			if (!sensor_pdev->dev.driver)
    92				return -EPROBE_DEFER;
    93	
    94			if (!try_module_get(sensor_pdev->dev.driver->owner))
    95				return -ENODEV;
    96	
    97			zone->owner = sensor_pdev->dev.driver->owner;
    98	
    99			return 0;
   100	}
   101	
 > 102	void virtual_thermal_sensor_put_modules(struct virtual_thermal_sensor *sensor)
   103	{
   104		int i;
   105	
   106		for (i = 0; i < sensor->count; i++) {
   107			if (sensor->zones[i].zone)
   108				module_put(sensor->zones[i].owner);
   109		}
   110	}
   111	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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Re: [PATCH v3 2/2] thermal: add a virtual sensor to aggregate temperatures

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3129 bytes --]

Hi Alexandre,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on rafael-pm/thermal]
[also build test WARNING on v5.15 next-20211108]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Alexandre-Bailon/Add-a-generic-virtual-thermal-sensor/20211029-231137
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git thermal
config: i386-allmodconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/be0e058f9a82f32140e4e96cf67a3e0842da9f70
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Alexandre-Bailon/Add-a-generic-virtual-thermal-sensor/20211029-231137
        git checkout be0e058f9a82f32140e4e96cf67a3e0842da9f70
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/thermal/virtual_thermal_sensor.c:73:5: warning: no previous prototype for 'virtual_thermal_sensor_get_module' [-Wmissing-prototypes]
      73 | int virtual_thermal_sensor_get_module(struct virtual_thermal_zone_device *zone,
         |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/thermal/virtual_thermal_sensor.c:102:6: warning: no previous prototype for 'virtual_thermal_sensor_put_modules' [-Wmissing-prototypes]
     102 | void virtual_thermal_sensor_put_modules(struct virtual_thermal_sensor *sensor)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/virtual_thermal_sensor_get_module +73 drivers/thermal/virtual_thermal_sensor.c

    72	
  > 73	int virtual_thermal_sensor_get_module(struct virtual_thermal_zone_device *zone,
    74					      const char *name)
    75	{
    76			struct platform_device *sensor_pdev;
    77			struct device_node *node;
    78	
    79			node = of_find_node_by_name(NULL, name);
    80			if (!node)
    81				return -ENODEV;
    82	
    83			node = of_parse_phandle(node, "thermal-sensors", 0);
    84			if (!node)
    85				return -ENODEV;
    86	
    87			sensor_pdev = of_find_device_by_node(node);
    88			if (!sensor_pdev)
    89				return -ENODEV;
    90	
    91			if (!sensor_pdev->dev.driver)
    92				return -EPROBE_DEFER;
    93	
    94			if (!try_module_get(sensor_pdev->dev.driver->owner))
    95				return -ENODEV;
    96	
    97			zone->owner = sensor_pdev->dev.driver->owner;
    98	
    99			return 0;
   100	}
   101	
 > 102	void virtual_thermal_sensor_put_modules(struct virtual_thermal_sensor *sensor)
   103	{
   104		int i;
   105	
   106		for (i = 0; i < sensor->count; i++) {
   107			if (sensor->zones[i].zone)
   108				module_put(sensor->zones[i].owner);
   109		}
   110	}
   111	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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