Messages in this thread | | | Date | Thu, 9 Sep 2021 15:29:37 -0700 | From | Matthias Kaehlcke <> | Subject | Re: [PATCH 2/2] thermal: add a virtual sensor to aggregate temperatures |
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On Mon, Sep 06, 2021 at 09:04:54PM +0200, Alexandre Bailon wrote: > This adds a virtual thermal sensor that reads temperature from > hardware sensor and return an aggregated temperature.
s/hardware sensor/hardware sensors/
> Currently, this only return the max temperature.
it seems this is outdated.
> Signed-off-by: Alexandre Bailon <abailon@baylibre.com> > --- > drivers/thermal/Kconfig | 8 + > drivers/thermal/Makefile | 1 + > drivers/thermal/virtual-sensor.h | 51 ++++ > drivers/thermal/virtual_sensor.c | 400 +++++++++++++++++++++++++++++++ > 4 files changed, 460 insertions(+) > create mode 100644 drivers/thermal/virtual-sensor.h > create mode 100644 drivers/thermal/virtual_sensor.c > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > index 7a4ba50ba97d0..23dc903da2fc5 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 "Generic virtual thermal sensor driver"
Not sure if 'Generic' adds much value here.
> + depends on THERMAL_OF || COMPILE_TEST > + help > + This option enables the generic thermal sensor aggregator. > + This driver creates a thermal sensor that reads the hardware sensors > + and aggregate the temperature. > + > config HISI_THERMAL > tristate "Hisilicon thermal driver" > depends on ARCH_HISI || COMPILE_TEST > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > index 9729a2b089919..76dfa1d61bfc5 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_sensor.o > diff --git a/drivers/thermal/virtual-sensor.h b/drivers/thermal/virtual-sensor.h > new file mode 100644 > index 0000000000000..e024d434856c7 > --- /dev/null > +++ b/drivers/thermal/virtual-sensor.h > @@ -0,0 +1,51 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Copyright (c) 2021 BayLibre > + */ > + > +#ifndef __THERMAL_VIRTUAL_SENSOR_H__ > +#define __THERMAL_VIRTUAL_SENSOR_H__ > + > +struct virtual_sensor; > +struct virtual_sensor_data;
Other types of virtual sensors could be added in the future, you might want to name these virtual_thermal_sensor(_data). Then again, these structs are of internal use only, so it's probably not super important.
> + > +#ifdef CONFIG_VIRTUAL_THERMAL > +struct virtual_sensor_data * > +thermal_virtual_sensor_register(struct device *dev, int sensor_id, void *data, > + const struct thermal_zone_of_device_ops *ops); > +void thermal_virtual_sensor_unregister(struct device *dev, > + struct virtual_sensor_data *sensor_data); > +struct virtual_sensor_data * > +devm_thermal_virtual_sensor_register(struct device *dev, int sensor_id, void *data, > + const struct thermal_zone_of_device_ops *ops); > + > +void devm_thermal_virtual_sensor_unregister(struct device *dev, > + struct virtual_sensor *sensor); > +#else > +static inline struct virtual_sensor_data * > +thermal_virtual_sensor_register(struct device *dev, int sensor_id, void *data, > + const struct thermal_zone_of_device_ops *ops) > +{ > + return ERR_PTR(-ENODEV); > +} > + > +void thermal_virtual_sensor_unregister(struct device *dev, > + struct virtual_sensor_data *sensor_data) > +{ > +} > + > +static inline struct virtual_sensor_data * > +devm_thermal_virtual_sensor_register(struct device *dev, int sensor_id, void *data, > + const struct thermal_zone_of_device_ops *ops) > +{ > + return ERR_PTR(-ENODEV); > +} > + > +static inline > +void devm_thermal_virtual_sensor_unregister(struct device *dev, > + struct virtual_sensor *sensor) > +{ > +} > +#endif > + > +#endif /* __THERMAL_VIRTUAL_SENSOR_H__ */ > diff --git a/drivers/thermal/virtual_sensor.c b/drivers/thermal/virtual_sensor.c > new file mode 100644 > index 0000000000000..e5bb0ef9adb39 > --- /dev/null > +++ b/drivers/thermal/virtual_sensor.c > @@ -0,0 +1,400 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * 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> > + > +#include "virtual-sensor.h" > + > +struct virtual_sensor_data {
This struct (typically) corresponds to an actual sensor, maybe name it 'thermal_sensor_data' instead?
> + struct list_head node; > + > + /* sensor interface */ > + int id; > + void *sensor_data; > + const struct thermal_zone_of_device_ops *ops; > +}; > + > +struct virtual_sensor { > + int count; > + struct virtual_sensor_data *sensors; > + struct thermal_zone_device *tzd; > + > + struct list_head node; > +}; > + > +static LIST_HEAD(thermal_sensors); > +static LIST_HEAD(virtual_sensors); > + > +static int virtual_sensor_get_temp_max(void *data, int *temperature) > +{ > + struct virtual_sensor *sensor = data; > + int max_temp = INT_MIN; > + int temp; > + int i; > + > + for (i = 0; i < sensor->count; i++) { > + struct virtual_sensor_data *hw_sensor; > + > + hw_sensor = &sensor->sensors[i]; > + if (!hw_sensor->ops) > + return -ENODEV; > + > + hw_sensor->ops->get_temp(hw_sensor->sensor_data, &temp); > + max_temp = max(max_temp, temp); > + } > + > + *temperature = max_temp; > + > + return 0; > +} > + > +static const struct thermal_zone_of_device_ops virtual_sensor_max_ops = { > + .get_temp = virtual_sensor_get_temp_max, > +}; > + > +static int virtual_sensor_get_temp_min(void *data, int *temperature) > +{ > + struct virtual_sensor *sensor = data; > + int min_temp = INT_MAX; > + int temp; > + int i; > + > + for (i = 0; i < sensor->count; i++) { > + struct virtual_sensor_data *hw_sensor; > + > + hw_sensor = &sensor->sensors[i]; > + if (!hw_sensor->ops) > + return -ENODEV; > + > + hw_sensor->ops->get_temp(hw_sensor->sensor_data, &temp); > + min_temp = min(min_temp, temp); > + } > + > + *temperature = min_temp; > + > + return 0; > +} > + > +static const struct thermal_zone_of_device_ops virtual_sensor_min_ops = { > + .get_temp = virtual_sensor_get_temp_min, > +}; > + > +static int do_avg(int val1, int val2) > +{ > + return ((val1) / 2) + ((val2) / 2) + (((val1) % 2 + (val2) % 2) / 2); > +} > + > +static int virtual_sensor_get_temp_avg(void *data, int *temperature) > +{ > + struct virtual_sensor *sensor = data; > + int avg_temp = 0; > + int temp; > + int i; > + > + for (i = 0; i < sensor->count; i++) { > + struct virtual_sensor_data *hw_sensor; > + > + hw_sensor = &sensor->sensors[i]; > + if (!hw_sensor->ops) > + return -ENODEV; > + > + hw_sensor->ops->get_temp(hw_sensor->sensor_data, &temp); > + avg_temp = do_avg(avg_temp, temp); > + } > + > + *temperature = avg_temp; > + > + return 0; > +}
_get_temp_min(), _get_temp_max() and _get_temp_avg() have the same structure, the only differences is the aggregator function and the initialization value. If you wanted to save a few lines of code you could have a meta-function that receives the initialization value and a pointer of the aggregator function.
The functions are relatively short though, so I wouldn't claim that it would be a huge improvement, one could also argue that the code is easier to follow as is.
> + > +static const struct thermal_zone_of_device_ops virtual_sensor_avg_ops = { > + .get_temp = virtual_sensor_get_temp_avg, > +}; > + > +static int register_virtual_sensor(struct virtual_sensor *sensor, > + struct of_phandle_args args, > + int index)
Does this really register a virtual sensor? IIUC the registered sensor is (typically) an actual sensor, which is used by a virtual sensor.
Shouldn't it be something like 'register_thermal_sensor' or 'virtual_sensor_add_sensor'?
> +{ > + struct virtual_sensor_data *sensor_data; > + int id; > + > + list_for_each_entry(sensor_data, &thermal_sensors, node) { > + id = args.args_count ? args.args[0] : 0; > + if (sensor_data->id == id) { > + memcpy(&sensor->sensors[index], sensor_data, > + sizeof(*sensor_data)); > + return 0; > + } > + } > + > + return -ENODEV; > +} > + > +static int virtual_sensor_probe(struct platform_device *pdev) > +{ > + const struct thermal_zone_of_device_ops *ops; > + struct virtual_sensor *sensor; > + struct device *dev = &pdev->dev; > + struct of_phandle_args args; > + u32 type; > + int ret; > + int i; > + > + sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL); > + if (!sensor) > + return -ENOMEM; > + > + sensor->count = of_count_phandle_with_args(dev->of_node, > + "thermal-sensors", > + "#thermal-sensor-cells"); > + if (sensor->count <= 0) > + return -EINVAL; > + > + sensor->sensors = devm_kmalloc_array(dev, sensor->count, > + sizeof(*sensor->sensors), > + GFP_KERNEL); > + if (!sensor->sensors) > + return -ENOMEM; > + > + for (i = 0; i < sensor->count; i++) { > + ret = of_parse_phandle_with_args(dev->of_node, > + "thermal-sensors", > + "#thermal-sensor-cells", > + i, > + &args); > + if (ret) > + return ret; > + > + ret = register_virtual_sensor(sensor, args, i); > + if (ret) > + return ret; > + } > + > + ret = of_property_read_u32(dev->of_node, "type", &type);
More a question for the binding, butthis should probably be something more specific than 'type', like 'aggregation-function'.
> + if (ret) > + return ret; > + > + switch (type) { > + case VIRTUAL_SENSOR_MAX: > + ops = &virtual_sensor_max_ops; > + break; > + case VIRTUAL_SENSOR_MIN: > + ops = &virtual_sensor_min_ops; > + break; > + case VIRTUAL_SENSOR_AVG: > + ops = &virtual_sensor_avg_ops; > + break; > + default: > + return -EINVAL; > + } > + > + sensor->tzd = devm_thermal_zone_of_sensor_register(dev, 0, sensor, ops); > + if (IS_ERR(sensor->tzd)) > + return PTR_ERR(sensor->tzd); > + > + platform_set_drvdata(pdev, sensor); > + list_add(&sensor->node, &virtual_sensors);
If you also added the sensor to 'thermal_sensors' you could support virtual sensors using virtual sensors, though it's not clear how useful that would be in practice and it could raise issues with the initialization order.
> + > + return 0; > +} > + > +static int virtual_sensor_remove(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct virtual_sensor *sensor; > + > + sensor = platform_get_drvdata(pdev); > + list_del(&sensor->node); > + > + devm_thermal_zone_of_sensor_unregister(dev, sensor->tzd); > + devm_kfree(dev, sensor->sensors); > + devm_kfree(dev, sensor);
Are the above 3 statements really needed, shouldn't devm_* handle that automagically?
> + > + return 0; > +} > + > +static const struct of_device_id virtual_sensor_of_match[] = { > + { > + .compatible = "virtual,thermal-sensor", > + }, > + { > + }, > +}; > +MODULE_DEVICE_TABLE(of, thermal_aggr_of_match); > + > +static struct platform_driver virtual_sensor = { > + .probe = virtual_sensor_probe, > + .remove = virtual_sensor_remove, > + .driver = { > + .name = "virtual-sensor",
I suggest to change it to 'virtual-thermal-sensor' since there might be other types of virtual sensors.
> + .of_match_table = virtual_sensor_of_match, > + }, > +}; > + > +/** > + * thermal_virtual_sensor_register - registers a sensor that could by a virtual
s/by/be/
> + * sensor > + * @dev: a valid struct device pointer of a sensor device. Must contain > + * a valid .of_node, for the sensor node. > + * @sensor_id: a sensor identifier, in case the sensor IP has more > + * than one sensors
s/sensors/sensor/
> + * @data: a private pointer (owned by the caller) that will be passed > + * back, when a temperature reading is needed. > + * @ops: struct thermal_zone_of_device_ops *. Must contain at least .get_temp. > + * > + * This function will register a thermal sensor to make it available for later > + * usage by a virtual sensor. > + * > + * The thermal zone temperature is provided by the @get_temp function > + * pointer. When called, it will have the private pointer @data back. > + * > + * Return: On success returns a valid struct thermal_zone_device, > + * otherwise, it returns a corresponding ERR_PTR(). Caller must > + * check the return value with help of IS_ERR() helper. > + */ > +struct virtual_sensor_data *thermal_virtual_sensor_register( > + struct device *dev, int sensor_id, void *data, > + const struct thermal_zone_of_device_ops *ops) > +{ > + struct virtual_sensor_data *sensor_data; > + > + sensor_data = devm_kzalloc(dev, sizeof(*sensor_data), GFP_KERNEL); > + if (!sensor_data) > + return ERR_PTR(-ENOMEM); > + > + sensor_data->id = sensor_id; > + sensor_data->sensor_data = data; > + sensor_data->ops = ops; > + > + list_add(&sensor_data->node, &thermal_sensors); > + > + return sensor_data; > +} > +EXPORT_SYMBOL_GPL(thermal_virtual_sensor_register); > + > +/** > + * thermal_virtual_sensor_unregister - unregisters a sensor > + * @dev: a valid struct device pointer of a sensor device. > + * @sensor_data: a pointer to struct virtual_sensor_data to unregister. > + * > + * This function removes the sensor from the list of available thermal sensors. > + * If the sensor is in use, then the next call to .get_temp will return -ENODEV. > + */ > +void thermal_virtual_sensor_unregister(struct device *dev, > + struct virtual_sensor_data *sensor_data) > +{ > + struct virtual_sensor_data *temp;
'temp' might not be the best name in this context, since it's associated with temperature. Maybe name it 'sd'?
> + struct virtual_sensor *sensor; > + int i; > + > + list_del(&sensor_data->node); > + > + list_for_each_entry(sensor, &virtual_sensors, node) { > + for (i = 0; i < sensor->count; i++) { > + temp = &sensor->sensors[i]; > + if (temp->id == sensor_data->id && > + temp->sensor_data == sensor_data->sensor_data) { > + temp->ops = NULL; > + } > + } > + } > + devm_kfree(dev, sensor_data);
Does it actually make sense to allocate the memory with devm_kzalloc() if it is explicitly freed here?
> +} > +EXPORT_SYMBOL_GPL(thermal_virtual_sensor_unregister); > + > +static void devm_thermal_virtual_sensor_release(struct device *dev, void *res) > +{ > + thermal_virtual_sensor_unregister(dev, > + *(struct virtual_sensor_data **)res); > +} > + > +static int devm_thermal_virtual_sensor_match(struct device *dev, void *res, > + void *data) > +{ > + struct virtual_sensor_data **r = res; > + > + if (WARN_ON(!r || !*r)) > + return 0; > + > + return *r == data; > +} > + > +
delete one of the empty lines
> +/** > + * devm_thermal_virtual_sensor_register - Resource managed version of > + * thermal_virtual_sensor_register() > + * @dev: a valid struct device pointer of a sensor device. Must contain > + * a valid .of_node, for the sensor node. > + * @sensor_id: a sensor identifier, in case the sensor IP has more > + * than one sensors
s/sensors/sensor/
> + * @data: a private pointer (owned by the caller) that will be passed > + * back, when a temperature reading is needed. > + * @ops: struct thermal_zone_of_device_ops *. Must contain at least .get_temp. > + * > + * Refer thermal_zone_of_sensor_register() for more details. > + * > + * Return: On success returns a valid struct virtual_sensor_data, > + * otherwise, it returns a corresponding ERR_PTR(). Caller must > + * check the return value with help of IS_ERR() helper. > + * Registered virtual_sensor_data device will automatically be > + * released when device is unbounded.
s/unbounded/unbound/
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