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Date: Thu, 23 May 2024 15:23:59 +0200
From: Alexandre Bailon <abailon@...libre.com>
To: Pin-yen Lin <treapking@...omium.org>
Cc: rafael@...nel.org, daniel.lezcano@...aro.org, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, rui.zhang@...el.com,
lukasz.luba@....com, linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, Hsin-Te Yuan <yuanhsinte@...omium.org>
Subject: Re: [PATCH v2 2/3] thermal: Add support of multi sensors to
thermal_core
Hi Pin-yen,
> Hi Alexandre,
>
> On Thu, Apr 11, 2024 at 4:34 PM Alexandre Bailon <abailon@...libre.com> wrote:
>>
>> This adds support of multi sensors to thermal.
>> Currently, this only support the get_temp operation.
>> This returns an average temperature of all the sensors.
>> If defined, a coefficient is applied to the value read from the sensor
>> before computing the average.
>>
>> Signed-off-by: Alexandre Bailon <abailon@...libre.com>
>> ---
>> drivers/thermal/Makefile | 1 +
>> drivers/thermal/thermal_core.h | 7 ++
>> drivers/thermal/thermal_multi.c | 178 ++++++++++++++++++++++++++++++++
>> 3 files changed, 186 insertions(+)
>> create mode 100644 drivers/thermal/thermal_multi.c
>>
>> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
>> index c934cab309ae..757289a406f7 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -6,6 +6,7 @@ CFLAGS_thermal_core.o := -I$(src)
>> obj-$(CONFIG_THERMAL) += thermal_sys.o
>> thermal_sys-y += thermal_core.o thermal_sysfs.o
>> thermal_sys-y += thermal_trip.o thermal_helpers.o
>> +thermal_sys-y += thermal_multi.o
>>
>> # netlink interface to manage the thermal framework
>> thermal_sys-$(CONFIG_THERMAL_NETLINK) += thermal_netlink.o
>> diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
>> index 0a3b3ec5120b..26e83a5c8298 100644
>> --- a/drivers/thermal/thermal_core.h
>> +++ b/drivers/thermal/thermal_core.h
>> @@ -138,6 +138,13 @@ ssize_t weight_show(struct device *, struct device_attribute *, char *);
>> ssize_t weight_store(struct device *, struct device_attribute *, const char *,
>> size_t);
>>
>> +/* Multi sensors */
>> +int thermal_multi_sensor_validate_coeff(int *coeff, int count, int offset);
>> +int thermal_multi_sensor_register(const char *name,
>> + struct thermal_zone_device *sensor_tz, int coeff);
>> +void thermal_multi_sensor_unregister(struct thermal_zone_device *sensor_tz);
>> +
>> +
>> #ifdef CONFIG_THERMAL_STATISTICS
>> void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
>> unsigned long new_state);
>> diff --git a/drivers/thermal/thermal_multi.c b/drivers/thermal/thermal_multi.c
>> new file mode 100644
>> index 000000000000..a5a4f1f2d594
>> --- /dev/null
>> +++ b/drivers/thermal/thermal_multi.c
>> @@ -0,0 +1,178 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/err.h>
>> +#include <linux/export.h>
>> +#include <linux/of.h>
>> +#include <linux/slab.h>
>> +#include <linux/thermal.h>
>> +#include <linux/types.h>
>> +#include <linux/string.h>
>> +
>> +#include "thermal_core.h"
>> +
>> +struct sensor_interface {
>> + struct thermal_zone_device *tz;
>> + int coeff;
>> +
>> + struct list_head node;
>> +};
>> +
>> +struct multi_sensor_thermal_zone {
>> + struct thermal_zone_device *tz;
>> + struct mutex sensors_lock;
>> + struct list_head sensors;
>> +
>> + struct list_head node;
>> +};
>> +
>> +static DEFINE_MUTEX(multi_tz_mutex);
>> +static LIST_HEAD(multi_tz_list);
>> +
>> +#define TJ_MAX 120000
>> +
>> +static int multi_sensor_get_temp(struct thermal_zone_device *tz, int *temp)
>> +{
>> + struct multi_sensor_thermal_zone *multi_tz = tz->devdata;
>> + struct sensor_interface *sensor;
>> + int accumulated_temp = 0;
>> + u32 accumulated_coeff;
>
> Should we initialize accumulated_coeff to 0 as well?
Yes, indeed, I will fix it.
>
>> + int ret;
>> +
>> + mutex_lock(&multi_tz->sensors_lock);
>> +
>> + if (list_empty(&multi_tz->sensors)) {
>> + mutex_unlock(&multi_tz->sensors_lock);
>> + return -ENODEV;
>> + }
>> +
>> + list_for_each_entry(sensor, &multi_tz->sensors, node) {
>> + ret = thermal_zone_get_temp(sensor->tz, temp);
>> + if (ret) {
>> + mutex_unlock(&multi_tz->sensors_lock);
>> + return ret;
>> + }
>> +
>> + accumulated_temp += *temp * sensor->coeff;
>> + accumulated_coeff += sensor->coeff;
>> + }
>> +
>> + mutex_unlock(&multi_tz->sensors_lock);
>> +
>> + *temp = accumulated_temp / accumulated_coeff;
>> + return ret;
>> +}
>> +
>> +struct thermal_zone_device_ops multi_sensor_ops = {
>> + .get_temp = multi_sensor_get_temp,
>> +};
>> +
>> +int thermal_multi_sensor_validate_coeff(int *coeff, int count, int offset)
>> +{
>> + int max_accumulated_temp = 0;
>> + int i;
>> +
>> + for (i = 0; i < count; i++) {
>> + max_accumulated_temp += TJ_MAX * coeff[i];
>> + if (max_accumulated_temp < 0)
>> + return -EOVERFLOW;
>> + }
>> +
>> + max_accumulated_temp += offset;
>> + return max_accumulated_temp < 0 ? -EOVERFLOW : 0;
>> +}
>> +
>> +static struct thermal_zone_device *multi_sensor_tz_alloc(const char *name)
>> +{
>> + struct thermal_zone_device *tz;
>> + struct thermal_zone_params tzp = {};
>> + struct multi_sensor_thermal_zone *multi_tz;
>> +
>> + tz = thermal_zone_get_zone_by_name(name);
>> + if (!IS_ERR(tz)) {
>> + mutex_unlock(&multi_tz_mutex);
>> + return tz;
>> + }
>> +
>> + multi_tz = kzalloc(sizeof(*multi_tz), GFP_KERNEL);
>> + if (!multi_tz)
>> + return ERR_PTR(-ENOMEM);
>> + mutex_init(&multi_tz->sensors_lock);
>> + INIT_LIST_HEAD(&multi_tz->sensors);
>> +
>> + tzp.no_hwmon = true;
>> + tzp.slope = 1;
>> + tzp.offset = 0;
>> +
>> + tz = thermal_tripless_zone_device_register(name, multi_tz,
>> + &multi_sensor_ops, &tzp);
>> + if (IS_ERR(tz)) {
>> + kfree(multi_tz);
>> + } else {
>> + multi_tz->tz = tz;
>> + list_add(&multi_tz->node, &multi_tz_list);
>> + }
>> +
>> + return tz;
>> +}
>> +
>> +int thermal_multi_sensor_register(const char *name,
>> + struct thermal_zone_device *sensor_tz, int coeff)
>> +{
>> + struct thermal_zone_device *tz;
>> + struct multi_sensor_thermal_zone *multi_tz;
>> + struct sensor_interface *sensor;
>> +
>> + mutex_lock(&multi_tz_mutex);
>> +
>> + tz = multi_sensor_tz_alloc(name);
>> + if (IS_ERR(tz)) {
>> + mutex_unlock(&multi_tz_mutex);
>> + return PTR_ERR(tz);
>> + }
>> + multi_tz = tz->devdata;
>> +
>> + sensor = kzalloc(sizeof(*sensor), GFP_KERNEL);
>> + if (!sensor) {
>> + mutex_unlock(&multi_tz_mutex);
>> + return -ENOMEM;
>> + }
>> +
>> + sensor->tz = sensor_tz;
>> + sensor->coeff = coeff;
>> + mutex_lock(&multi_tz->sensors_lock);
>> + list_add(&sensor->node, &multi_tz->sensors);
>> + mutex_unlock(&multi_tz->sensors_lock);
>> +
>> + thermal_zone_device_enable(tz);
>> +
>> + mutex_unlock(&multi_tz_mutex);
>> +
>> + return 0;
>> +}
>> +
>> +void thermal_multi_sensor_unregister(struct thermal_zone_device *sensor_tz)
>> +{
>> + struct multi_sensor_thermal_zone *multi_tz;
>> + struct sensor_interface *sensor, *tmp;
>> +
>> + mutex_lock(&multi_tz_mutex);
>> + list_for_each_entry(multi_tz, &multi_tz_list, node) {
>> + mutex_lock(&multi_tz->sensors_lock);
>> + list_for_each_entry_safe(sensor, tmp, &multi_tz->sensors, node) {
>> + if (sensor->tz == sensor_tz) {
>> + list_del(&sensor->node);
>> + kfree(sensor);
>> + break;
>> + }
>> + }
>> +
>> + if (list_empty(&multi_tz->sensors)) {
>> + thermal_zone_device_unregister(multi_tz->tz);
>> + mutex_unlock(&multi_tz->sensors_lock);
>> + kfree(multi_tz);
>> + } else {
>> + mutex_unlock(&multi_tz->sensors_lock);
>> + }
>> + }
>> + mutex_unlock(&multi_tz_mutex);
>> +}
>> --
>> 2.41.0
>>
>
> By the way, may I know why min/max aggregation is dropped in this
> version? I thought that checking max temperature is the most direct
> approach to protect the hardware and the users from high temperature.
You are right. The main reason was device tree bindings.
I was expecting getting this accepted first before adding max and min.
Thanks,
Alexandre
>
> Best regards,
> Pin-yen
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