Subject: Re: [PATCH v12 1/2] thermal: loongson-2: add thermal management
 support
To:     Daniel Lezcano <daniel.lezcano@linaro.org>
Cc:     "Rafael J . Wysocki" <rafael@kernel.org>,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        zhanghongchen <zhanghongchen@loongson.cn>,
        Liu Peibao <liupeibao@loongson.cn>, lvjianmin@loongson.cn,
        wanghongliang@loongson.cn, zhuyinbo@loongson.cn
References: <20221114024709.7975-1-zhuyinbo@loongson.cn>
 <20230206135921.GA15176@linaro.org>
From:   zhuyinbo <zhuyinbo@loongson.cn>
Message-ID: <64d9782c-cafd-cdc3-3602-719c386d98cc@loongson.cn>
Date:   Wed, 8 Feb 2023 11:13:33 +0800
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在 2023/2/6 下午9:59, Daniel Lezcano 写道:

> On Mon, Nov 14, 2022 at 10:47:08AM +0800, Yinbo Zhu wrote:
>> This patch adds the support for Loongson-2 thermal sensor controller,
>> which can support maximum 4 sensors.
>>
>> It's based on thermal of framework:
>>   - Trip points defined in device tree.
>>   - Cpufreq as cooling device registered in Loongson-2 cpufreq driver.
>>   - Pwm fan as cooling device registered in hwmon pwm-fan driver.
>>
> This changelog is not helpful.
>
> Please describe how works the sensor.
okay, I got it.
>
>> Signed-off-by: zhanghongchen <zhanghongchen@loongson.cn>
>> Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
>> ---
>> Change in v12:
>> 		1. Fixup it about min and max.
>> 		2. Use dev_err_probe replace dev_err in devm_request_threaded_irq context.
>> Change in v11:
>> 		1. Add min() and max() to replace related code in function
>> 		   loongson2_thermal_set.
>> 		2. Add dev_err_probe to to replace related code for function
>> 		   return value use devm_thermal_of_zone_register.
>> 		3. Replace thermal_add_hwmon_sysfs with devm_thermal_add_hwmon_sysfs
>> 		   and use dev_warn replace dev_err in this context.
>> Change in v10:
>> 		1. Add all history change log information.
>> Change in v9:
>> 		1. Switch new API that use devm_thermal_of_zone_register
>> 		   to replace previous interfaces.
>> 		2. Add depend on LOONGARCH || COMPILE_TEST.
>> Change in v8:
>>                  1. Replace string loongson2/Loongson2/LOONGSON2 with loongson-2/
>>                     Loongson-2/LOONGSON-2 in Kconfig and commit log and MAINTAINERS
>> 		   files.
>> Change in v7:
>> 		1. Split the modification of patch 3 and merge it into this patch.
>> 		2. Remove the unless code annotation to fix the compile warning
>> 		   when compile C code with W=1.
>> Change in v6:
>> 		1. NO change, but other patch in this series of patches set has
>> 		   changes.
>> Change in v5:
>> 		1. NO change, but other patch in this series of patches set has
>> 		   changes.
>> Change in v4:
>> 		1. Fixup the compatible.
>> Change in v3:
>> 		1. Add a function to gain sensor id an remove dts id.
>> Change in v2:
>> 		1. Remove error msg printing when addr ioremap has error.
>> 		2. Make loongson2 thermal driver was built-in by default.
>> 		3. Replace ls2k with loongson2.
>> 		4. Remove CONFIG_PM_SLEEP and set pm function type was
>> 		   __maybe_unused.
>>
>>   MAINTAINERS                         |   7 +
>>   drivers/thermal/Kconfig             |  10 ++
>>   drivers/thermal/Makefile            |   1 +
>>   drivers/thermal/loongson2_thermal.c | 260 ++++++++++++++++++++++++++++
>>   4 files changed, 278 insertions(+)
>>   create mode 100644 drivers/thermal/loongson2_thermal.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 1b391ca7cf91..0d867573fe4c 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -12013,6 +12013,13 @@ F:	drivers/*/*loongarch*
>>   F:	Documentation/loongarch/
>>   F:	Documentation/translations/zh_CN/loongarch/
>>   
>> +LOONGSON-2 SOC SERIES THERMAL DRIVER
>> +M:	zhanghongchen <zhanghongchen@loongson.cn>
>> +M:	Yinbo Zhu <zhuyinbo@loongson.cn>
>> +L:	linux-pm@vger.kernel.org
>> +S:	Maintained
>> +F:	drivers/thermal/loongson2_thermal.c
>> +
>>   LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
>>   M:	Sathya Prakash <sathya.prakash@broadcom.com>
>>   M:	Sreekanth Reddy <sreekanth.reddy@broadcom.com>
>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
>> index e052dae614eb..93d84bcb16dd 100644
>> --- a/drivers/thermal/Kconfig
>> +++ b/drivers/thermal/Kconfig
>> @@ -504,4 +504,14 @@ config KHADAS_MCU_FAN_THERMAL
>>   	  If you say yes here you get support for the FAN controlled
>>   	  by the Microcontroller found on the Khadas VIM boards.
>>   
>> +config LOONGSON2_THERMAL
>> +	tristate "Loongson-2 SoC series thermal driver"
>> +	depends on LOONGARCH || COMPILE_TEST
>> +	depends on OF
> Please check commit 8df4ef3eaa62b
I will remove the 'COMPILE_TEST'.
>
>> +	help
>> +	  Support for Thermal driver found on Loongson-2 SoC series platforms.
>> +	  It supports one critical trip point and one passive trip point. The
>> +	  cpufreq and the pwm fan is used as the cooling device to throttle
>> +	  CPUs when the passive trip is crossed.
> The help is misleading. The thermal framework supports the trip points, not the
> driver. Also, the cooling devices association is related to the thermal zone,
> not the sensor.
okay, I will change it.
>
>>   endif
>> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
>> index 2506c6c8ca83..02f3db809858 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -61,3 +61,4 @@ 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_LOONGSON2_THERMAL)	+= loongson2_thermal.o
>> diff --git a/drivers/thermal/loongson2_thermal.c b/drivers/thermal/loongson2_thermal.c
>> new file mode 100644
>> index 000000000000..2d495469e8dd
>> --- /dev/null
>> +++ b/drivers/thermal/loongson2_thermal.c
>> @@ -0,0 +1,260 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +/*
>> + * Author: zhanghongchen <zhanghongchen@loongson.cn>
>> + *         Yinbo Zhu <zhuyinbo@loongson.cn>
>> + * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
>> + */
>> +
>> +#include <linux/cpufreq.h>
>> +#include <linux/delay.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/io.h>
>> +#include <linux/of_device.h>
>> +#include <linux/thermal.h>
>> +#include "thermal_hwmon.h"
>> +
>> +#define LOONGSON2_SOC_MAX_SENSOR_NUM			4
>> +
>> +#define LOONGSON2_TSENSOR_CTRL_HI			0x0
>> +#define LOONGSON2_TSENSOR_CTRL_LO			0x8
>> +#define LOONGSON2_TSENSOR_STATUS			0x10
>> +#define LOONGSON2_TSENSOR_OUT				0x14
>> +
>> +struct loongson2_thermal_data {
>> +	struct thermal_zone_device *tzd;
> 'tzd' won't be needed after taking into account the comments

The 'tzd' element is needed,  because the thermal_zone_device_update 
need pass a data->tzd element.

static irqreturn_t loongson2_thermal_irq_thread(int irq, void *dev)
{
         struct loongson2_thermal_data *data = dev;

         thermal_zone_device_update(data->tzd,
                                    THERMAL_EVENT_UNSPECIFIED);
         enable_irq(data->irq);

         return IRQ_HANDLED;
}

>
>> +	int irq;
> 'irq' won't be needed after taking into account the comments
I will drop it.
>> +	int id;
>> +	void __iomem *regs;
>> +	struct platform_device *pdev;
> 'pdev' is not needed
I will drop it.
>
>> +	u16 ctrl_low_val;
>> +	u16 ctrl_hi_val;
> Those fields won't be needed after taking into account the comments
I will drop it.
>> +};
>> +
>> +static int loongson2_thermal_set(struct loongson2_thermal_data *data,
>> +					int low, int high, bool enable)
>> +{
>> +	u64 reg_ctrl = 0;
>> +	int reg_off = data->id * 2;
>> +
>> +	if (low > high)
>> +		return -EINVAL;
>> +
>> +	low = max(low, -100);
>> +	high = min(high, 155);
>> +
>> +	low += 100;
>> +	high += 100;
> Why are those values added to the low and high ? Did you mean low += 0x100 ?
>
> Mind to describe a bit the register layout?

node(cpu) temp = Thens0_out -100,

low and high is record node temp, so low and high need add '100' as 
Thens0_out.


eg.  Thsens_int_ctrl_Hi  register layout:

[7:0]:  High temperature range (Thens0_out range)

[8:8]: High temperature interrupt enable bit

>
>> +	reg_ctrl |= low;
> 	reg_ctrl = low;
okay,  I will change it.
>
>> +	reg_ctrl |= enable ? 0x100 : 0;
>> +	writew(reg_ctrl, data->regs + LOONGSON2_TSENSOR_CTRL_LO + reg_off);
>> +
>> +	reg_ctrl = 0;
> No need to reset the variable.
>
> 	reg_ctrl = high;
okay,  I will change it.
>
>> +	reg_ctrl |= high;
>> +	reg_ctrl |= enable ? 0x100 : 0;
>> +	writew(reg_ctrl, data->regs + LOONGSON2_TSENSOR_CTRL_HI + reg_off);
>> +
>> +	return 0;
>> +}
>> +
>> +static int loongson2_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
>> +{
>> +	u32 reg_val;
>> +	struct loongson2_thermal_data *data = tz->devdata;
>> +
>> +	reg_val = readl(data->regs + LOONGSON2_TSENSOR_OUT);
>> +	*temp = ((reg_val & 0xff) - 100) * 1000;
> Why '-100' ?
>
> Is the unit returned 'degrees' ?

node(cpu) temp = Thens0_out -100,

Here we need to get a node temp.

>
>> +	return 0;
>> +}
>> +
>> +static int loongson2_thermal_get_sensor_id(void)
>> +{
>> +	int ret, id;
>> +	struct of_phandle_args sensor_specs;
>> +	struct device_node *np, *sensor_np;
>> +
>> +	np = of_find_node_by_name(NULL, "thermal-zones");
>> +	if (!np)
>> +		return -ENODEV;
>> +
>> +	sensor_np = of_get_next_child(np, NULL);
>> +	ret = of_parse_phandle_with_args(sensor_np, "thermal-sensors",
>> +			"#thermal-sensor-cells",
>> +			0, &sensor_specs);
>> +	if (ret) {
>> +		of_node_put(np);
>> +		of_node_put(sensor_np);
>> +		return ret;
>> +	}
>> +
>> +	if (sensor_specs.args_count >= 1) {
>> +		id = sensor_specs.args[0];
>> +		WARN(sensor_specs.args_count > 1,
>> +				"%s: too many cells in sensor specifier %d\n",
>> +				sensor_specs.np->name, sensor_specs.args_count);
>> +	} else {
>> +		id = 0;
>> +	}
>> +
>> +	of_node_put(np);
>> +	of_node_put(sensor_np);
>> +
>> +	return id;
>> +}
> This is not needed. Please do not tamper with the OF code in the sensor.
>
> You should know the id in this sensor driver
okay, I got it, I will change it.
>
>> +static irqreturn_t loongson2_thermal_alarm_irq(int irq, void *dev)
>> +{
>> +	struct loongson2_thermal_data *data = dev;
>> +
>> +	/* clear interrupt */
>> +	writeb(0x3, data->regs + LOONGSON2_TSENSOR_STATUS);
>> +
>> +	disable_irq_nosync(irq);
>> +
>> +	return IRQ_WAKE_THREAD;
>> +}
>> +
>> +static irqreturn_t loongson2_thermal_irq_thread(int irq, void *dev)
>> +{
>> +	struct loongson2_thermal_data *data = dev;
>> +
>> +	thermal_zone_device_update(data->tzd,
>> +				   THERMAL_EVENT_UNSPECIFIED);
>> +	enable_irq(data->irq);
>> +
>> +	return IRQ_HANDLED;
>> +}
> It is not necessary to create a couple of irq callback for this.
>
> Just clear the interrupt in loongson2_thermal_irq_thread() and drop loongson2_thermal_alarm_irq().
okay, I will change it.
>
>> +
>> +static int loongson2_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
>> +{
>> +	struct loongson2_thermal_data *data = tz->devdata;
>> +
>> +	return loongson2_thermal_set(data, low/1000, high/1000, true);
>> +}
>> +
>> +static const struct thermal_zone_device_ops loongson2_of_thermal_ops = {
>> +	.get_temp = loongson2_thermal_get_temp,
>> +	.set_trips = loongson2_thermal_set_trips,
>> +};
>> +
>> +static int loongson2_thermal_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *res;
>> +	struct loongson2_thermal_data *data;
>> +	int ret;
>> +
>> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>> +	if (!data)
>> +		return -ENOMEM;
>> +
>> +	data->pdev = pdev;
>> +	platform_set_drvdata(pdev, data);
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	data->regs = devm_ioremap(dev, res->start, resource_size(res));
>> +	if (IS_ERR(data->regs))
>> +		return PTR_ERR(data->regs);
>> +
>> +	/* get irq */
>> +	data->irq = platform_get_irq(pdev, 0);
>> +	if (data->irq < 0)
>> +		return data->irq;
>> +
>> +	/* get id */
>> +	data->id = loongson2_thermal_get_sensor_id();
>> +	if (data->id > LOONGSON2_SOC_MAX_SENSOR_NUM - 1 || data->id < 0) {
>> +		dev_err(dev, "sensor id error,must be in <0 ~ %d>\n",
>> +				LOONGSON2_SOC_MAX_SENSOR_NUM - 1);
>> +		return -EINVAL;
>> +	}
>> +
>> +	writeb(0xff, data->regs + LOONGSON2_TSENSOR_STATUS);
>> +
>> +	loongson2_thermal_set(data, 0, 0, false);
> It would be nicer to use a reset line if it is available
sorry, I don't get your meaning. Please describe more details about 
'reset line'.
>
>> +	data->tzd = devm_thermal_of_zone_register(&pdev->dev, data->id, data,
>> +			&loongson2_of_thermal_ops);
>> +	if (IS_ERR(data->tzd))
>> +		return dev_err_probe(&pdev->dev, PTR_ERR(data->tzd),
>> +				"failed to register");
> If you want to not care about the kind of SoC the sensor belongs to, you can
> use the return value of devm_thermal_of_zone_register() which returns -ENODEV
> and which is not considered as an error.
okay, I got it.
>
> IOW:
>
> 	for (i = 0; i < LOONGSON2_SOC_MAX_SENSOR_NUM; i++) {
>
> 		tzd = devm_thermal_of_zone_register(&pdev->dev, i,
> 			data, &loongson2_of_thermal_ops);
> 		if (!IS_ERR(tzd))
> 			break;
>
> 		if (PTR_ERR(tzd) != ENODEV)
> 			continue;
>
> 		return dev_err_probe(&pdev->dev, PTR_ERR(tzd),
> 	                             "failed to register");
> 	}
>
>> +	ret = devm_request_threaded_irq(dev, data->irq,
>> +			loongson2_thermal_alarm_irq, loongson2_thermal_irq_thread,
>> +			IRQF_ONESHOT, "loongson2_thermal", data);
> Pass 'tzd' instead of 'data'
I will change it.
>
>> +	if (ret < 0)
>> +		return dev_err_probe(dev, ret, "failed to request alarm irq\n");
>> +
>> +	/*
>> +	 * Thermal_zone doesn't enable hwmon as default,
>> +	 * enable it here
>> +	 */
>> +	data->tzd->tzp->no_hwmon = false;
> This is used when registering the thermal zone. Setting it after registering
> the thermal zone has no effect. The line can be dropped.
okay, I will drop it.
>
>> +	if (devm_thermal_add_hwmon_sysfs(data->tzd))
>> +		dev_warn(&pdev->dev, "Failed to add hwmon sysfs attributes\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static int loongson2_thermal_remove(struct platform_device *pdev)
>> +{
>> +	struct loongson2_thermal_data *data = platform_get_drvdata(pdev);
>> +	int reg_off = data->id * 2;
>> +
>> +	/* disable interrupt */
>> +	writew(0, data->regs + LOONGSON2_TSENSOR_CTRL_LO + reg_off);
>> +	writew(0, data->regs + LOONGSON2_TSENSOR_CTRL_HI + reg_off);
> The interrupt is disabled with the driver removal as it was registered with the
> devres version devm_thermal_of_zone_register()
I will remove it.
>
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id of_loongson2_thermal_match[] = {
>> +	{ .compatible = "loongson,ls2k-thermal",},
> You may want to add the sensor id in the data field. Probably depending on the
> kind of SoC, one or several sensors will be used.
okay, I will add it.
>
>> +	{ /* end */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, of_loongson2_thermal_match);
>> +
>> +static int __maybe_unused loongson2_thermal_suspend(struct device *dev)
>> +{
>> +	struct loongson2_thermal_data *data = dev_get_drvdata(dev);
>> +	int reg_off = data->id * 2;
>> +
>> +	data->ctrl_low_val = readw(data->regs + LOONGSON2_TSENSOR_CTRL_LO + reg_off);
>> +	data->ctrl_hi_val = readw(data->regs + LOONGSON2_TSENSOR_CTRL_HI + reg_off);
>> +
>> +	writew(0, data->regs + LOONGSON2_TSENSOR_CTRL_LO + reg_off);
>> +	writew(0, data->regs + LOONGSON2_TSENSOR_CTRL_HI + reg_off);
>> +
>> +	return 0;
>> +}
>> +
>> +static int __maybe_unused loongson2_thermal_resume(struct device *dev)
>> +{
>> +	struct loongson2_thermal_data *data = dev_get_drvdata(dev);
>> +	int reg_off = data->id * 2;
>> +
>> +	writew(data->ctrl_low_val, data->regs + LOONGSON2_TSENSOR_CTRL_LO + reg_off);
>> +	writew(data->ctrl_hi_val, data->regs + LOONGSON2_TSENSOR_CTRL_HI + reg_off);
>> +
>> +	return 0;
>> +}
> It is not necessary to save and restore the low and high temperatures for the
> $trip points because the thermal framework core code will call at POST_SUSPEND
> thermal_zone_device_update() which in turns get the temperature and sets the
> trip points.
I will remove the save and restore function.
>
>> +
>> +static SIMPLE_DEV_PM_OPS(loongson2_thermal_pm_ops,
>> +			 loongson2_thermal_suspend, loongson2_thermal_resume);
>> +
>> +static struct platform_driver loongson2_thermal_driver = {
>> +	.driver = {
>> +		.name		= "loongson2_thermal",
>> +		.pm = &loongson2_thermal_pm_ops,
>> +		.of_match_table = of_loongson2_thermal_match,
>> +	},
>> +	.probe	= loongson2_thermal_probe,
>> +	.remove	= loongson2_thermal_remove,
>> +};
>> +module_platform_driver(loongson2_thermal_driver);
>> +
>> +MODULE_DESCRIPTION("Loongson2 thermal driver");
>> +MODULE_LICENSE("GPL");
>> -- 
>> 2.31.1
>>