Messages in this thread Patch in this message | | | From | Alexandre Bailon <> | Subject | [PATCH v4 RESEND 2/2] thermal: add a virtual sensor to aggregate temperatures | Date | Tue, 11 Jan 2022 11:33:46 +0100 |
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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..9f38af925fd1 --- /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, +}; + +static 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; +} + +static 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"); -- 2.25.1
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