[v6,1/3] thermal/acpi: Add ACPI trip point routines

  The ACPI specification describes the trip points, the device tree
bindings as well.

The OF code uses the generic trip point structures.

The ACPI has their own trip points structure and uses the get_trip_*
ops to retrieve them.

We can do the same as the OF code and create a set of ACPI functions
to retrieve a trip point description. Having a common code for ACPI
will help to cleanup the remaining Intel drivers and get rid of the
get_trip_* functions.

These changes add the ACPI thermal calls to retrieve the basic
information we need to be reused in the thermal ACPI and Intel
drivers.

The different ACPI functions have the generic trip point structure
passed as parameter where it is filled.

This structure aims to be the one used by all the thermal drivers and
the thermal framework.

After this series, a couple of Intel drivers and the ACPI thermal
driver will still have their own trip points definition but a new
series on top of this one will finish the conversion to the generic
trip point handling.

This series depends on the generic trip point added to the thermal
framework and available in the thermal/linux-next branch.

 https://lkml.org/lkml/2022/10/3/456

It has been tested on a Intel i7-8650U - x280 with the INT3400, the
PCH, ACPITZ, and x86_pkg_temp. No regression observed so far.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: srinivas pandruvada <srinivas.pandruvada@linux.intel.com>
---
 V6:
   - Changed the functions name and prototype to return the temperature
     instead of passing a pointer
   - Removed the GTSH function as it does not belong to the ACPI standard
   - Changed hysteresis -> hyst, temperature -> temp
   - Changed message level info -> debug
   - Changed error messages
   - Return -ENODATA error only
   - Fixed description functions

 V5:
   - Fixed GTSH unit conversion, deciK -> milli C

 V3:
   - Removed too simple wrappers
   - Changed the API to return an error and check the validity of the value
   - Removed the comments describing the objects
   - Added kerneldoc
   - Made the Kconfig option silent
   - Set the hysteresis value to zero by default

 V2:
   - Fixed the missing thermal_acpi.c in the patch

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/Kconfig        |   4 +
 drivers/thermal/Makefile       |   1 +
 drivers/thermal/thermal_acpi.c | 185 +++++++++++++++++++++++++++++++++
 include/linux/thermal.h        |   7 ++
 4 files changed, 197 insertions(+)
 create mode 100644 drivers/thermal/thermal_acpi.c
  

On Saturday, January 21, 2023 12:15:28 AM CET Daniel Lezcano wrote:
> The ACPI specification describes the trip points, the device tree
> bindings as well.
> 
> The OF code uses the generic trip point structures.
> 
> The ACPI has their own trip points structure and uses the get_trip_*
> ops to retrieve them.
> 
> We can do the same as the OF code and create a set of ACPI functions
> to retrieve a trip point description. Having a common code for ACPI
> will help to cleanup the remaining Intel drivers and get rid of the
> get_trip_* functions.
> 
> These changes add the ACPI thermal calls to retrieve the basic
> information we need to be reused in the thermal ACPI and Intel
> drivers.
> 
> The different ACPI functions have the generic trip point structure
> passed as parameter where it is filled.
> 
> This structure aims to be the one used by all the thermal drivers and
> the thermal framework.
> 
> After this series, a couple of Intel drivers and the ACPI thermal
> driver will still have their own trip points definition but a new
> series on top of this one will finish the conversion to the generic
> trip point handling.
> 
> This series depends on the generic trip point added to the thermal
> framework and available in the thermal/linux-next branch.
> 
>  https://lkml.org/lkml/2022/10/3/456
> 
> It has been tested on a Intel i7-8650U - x280 with the INT3400, the
> PCH, ACPITZ, and x86_pkg_temp. No regression observed so far.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Reviewed-by: Zhang Rui <rui.zhang@intel.com>
> Tested-by: srinivas pandruvada <srinivas.pandruvada@linux.intel.com>

Co-developed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Also I'm not sure if this version has been tested and reviewed.

There are still a few things to improve in it, but overall I think that
something like the patch below would be better - it is fewer lines of code
and less duplication.

I haven't compiled it, but it should be easy enough to fix if it fails to
build.  I am also not sure about the included header files (kernel.h and
uapi/linux/thermal.h in particular).

---
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Subject: [PATCH] thermal: ACPI: Add ACPI trip point routines

Add library routines to populate a generic thermal trip point
structure with data obtained by evaluating a specific object in the
ACPI Namespace.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Co-developed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/Kconfig        |    4 +
 drivers/thermal/Makefile       |    1 
 drivers/thermal/thermal_acpi.c |  153 +++++++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h        |    8 ++
 4 files changed, 166 insertions(+)
 create mode 100644 drivers/thermal/thermal_acpi.c

Index: linux-pm/drivers/thermal/Kconfig
===================================================================
--- linux-pm.orig/drivers/thermal/Kconfig
+++ linux-pm/drivers/thermal/Kconfig
@@ -76,6 +76,10 @@ config THERMAL_OF
 	  Say 'Y' here if you need to build thermal infrastructure
 	  based on device tree.
 
+config THERMAL_ACPI
+       depends on ACPI
+       bool
+
 config THERMAL_WRITABLE_TRIPS
 	bool "Enable writable trip points"
 	help
Index: linux-pm/drivers/thermal/Makefile
===================================================================
--- linux-pm.orig/drivers/thermal/Makefile
+++ linux-pm/drivers/thermal/Makefile
@@ -13,6 +13,7 @@ thermal_sys-$(CONFIG_THERMAL_NETLINK)		+
 # interface to/from other layers providing sensors
 thermal_sys-$(CONFIG_THERMAL_HWMON)		+= thermal_hwmon.o
 thermal_sys-$(CONFIG_THERMAL_OF)		+= thermal_of.o
+thermal_sys-$(CONFIG_THERMAL_ACPI)		+= thermal_acpi.o
 
 # governors
 thermal_sys-$(CONFIG_THERMAL_GOV_FAIR_SHARE)	+= gov_fair_share.o
Index: linux-pm/drivers/thermal/thermal_acpi.c
===================================================================
--- /dev/null
+++ linux-pm/drivers/thermal/thermal_acpi.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Linaro Limited
+ * Copyright 2023 Intel Corporation
+ *
+ * Library routines for populating a generic thermal trip point structure
+ * with data obtained by evaluating a specific object in the ACPI Namespace.
+ */
+#include <linux/acpi.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/units.h>
+#include <uapi/linux/thermal.h>
+
+#include "thermal_core.h"
+
+/*
+ * Minimum temperature for full military grade is 218°K (-55°C) and
+ * max temperature is 448°K (175°C). We can consider those values as
+ * the boundaries for the [trips] temperature returned by the
+ * firmware. Any values out of these boundaries may be considered
+ * bogus and we can assume the firmware has no data to provide.
+ */
+#define TEMP_MIN_DECIK	2180
+#define TEMP_MAX_DECIK	4480
+
+static int thermal_acpi_trip_init(struct acpi_device *adev,
+				  enum thermal_trip_type type, int id,
+				  struct thermal_trip *trip)
+{
+	unsigned long long temp;
+	acpi_status status;
+	char obj_name[5];
+
+	switch (type) {
+	case THERMAL_TRIP_ACTIVE:
+		if (id < 0 || id > 9)
+			return -EINVAL;
+
+		obj_name[1] = 'A';
+		obj_name[2] = 'C';
+		obj_name[3] = '0' + id;
+		break;
+	case THERMAL_TRIP_PASSIVE:
+		obj_name[1] = 'P';
+		obj_name[2] = 'S';
+		obj_name[3] = 'V';
+		break;
+	case THERMAL_TRIP_HOT:
+		obj_name[1] = 'H';
+		obj_name[2] = 'O';
+		obj_name[3] = 'T';
+		break;
+	case THERMAL_TRIP_CRITICAL:
+		obj_name[1] = 'C';
+		obj_name[2] = 'R';
+		obj_name[3] = 'T';
+		break;
+	}
+
+	obj_name[0] = '_';
+	obj_name[4] = '\0';
+
+	status = acpi_evaluate_integer(adev->handle, obj_name, NULL, &temp);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_debug(adev->handle, "%s evaluation failed\n", obj_name);
+		return -ENODATA;
+	}
+
+	if (temp < TEMP_MIN_DECIK || temp >= TEMP_MAX_DECIK) {
+		acpi_handle_debug(adev->handle, "%s result %llu out of range\n",
+				  temp, obj_name);
+		return -ENODATA;
+	}
+
+	trip->temperature = deci_kelvin_to_millicelsius(temp);
+	trip->hysteresis = 0;
+	trip->type = type;
+
+	return 0;
+}
+
+/**
+ * thermal_acpi_trip_active - Get the specified active trip point
+ * @adev: Thermal zone ACPI device object to get the description from.
+ * @id: Active cooling level (0 - 9).
+ * @trip: Trip point structure to be populated on success.
+ *
+ * Evaluate the _ACx object for the thermal zone represented by @adev to obtain
+ * the temperature of the active cooling trip point corresponding to the active
+ * cooling level given by @id and initialize @trip as an active trip point using
+ * that temperature value.
+ *
+ * Return 0 on success or a negative error value on failure.
+ */
+int thermal_acpi_trip_active(struct acpi_device *adev, int id,
+			     struct thermal_trip *trip)
+{
+	return thermal_acpi_trip_init(adev, THERMAL_TRIP_ACTIVE, id, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_active);
+
+/**
+ * thermal_acpi_trip_passive - Get the passive trip point
+ * @adev: Thermal zone ACPI device object to get the description from.
+ * @trip: Trip point structure to be populated on success.
+ *
+ * Evaluate the _PSV object for the thermal zone represented by @adev to obtain
+ * the temperature of the passive cooling trip point and initialize @trip as a
+ * passive trip point using that temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_passive(struct acpi_device *adev, struct thermal_trip *trip)
+{
+	return thermal_acpi_trip_init(adev, THERMAL_TRIP_PASSIVE, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_passive);
+
+/**
+ * thermal_acpi_trip_hot - Get the near critical trip point
+ * @adev: the ACPI device to get the description from.
+ * @trip: a &struct thermal_trip to be filled if the function succeed.
+ *
+ * Evaluate the _HOT object for the thermal zone represented by @adev to obtain
+ * the temperature of the trip point at which the system is expected to be put
+ * into the S4 sleep state and initialize @trip as a hot trip point using that
+ * temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_hot(struct acpi_device *adev, struct thermal_trip *trip)
+{
+	return thermal_acpi_trip_init(adev, THERMAL_TRIP_HOT, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_hot);
+
+/**
+ * thermal_acpi_trip_critical - Get the critical trip point
+ * @adev: the ACPI device to get the description from.
+ * @trip: a &struct thermal_trip to be filled if the function succeed.
+ *
+ * Evaluate the _CRT object for the thermal zone represented by @adev to obtain
+ * the temperature of the critical cooling trip point and initialize @trip as a
+ * critical trip point using that temperature value.
+ *
+ * Return 0 on success or -ENODATA on failure.
+ */
+int thermal_acpi_trip_critical(struct acpi_device *adev, struct thermal_trip *trip)
+{
+	return thermal_acpi_trip_init(adev, THERMAL_TRIP_CRITICAL, INT_MAX, trip);
+}
+EXPORT_SYMBOL_GPL(thermal_acpi_trip_critical);
Index: linux-pm/include/linux/thermal.h
===================================================================
--- linux-pm.orig/include/linux/thermal.h
+++ linux-pm/include/linux/thermal.h
@@ -334,6 +334,14 @@ static inline void devm_thermal_of_zone_
 }
 #endif
 
+#ifdef CONFIG_THERMAL_ACPI
+int thermal_acpi_trip_active(struct acpi_device *adev, int id,
+			     struct thermal_trip *trip);
+int thermal_acpi_trip_passive(struct acpi_device *adev, struct thermal_trip *trip);
+int thermal_acpi_trip_hot(struct acpi_device *adev, struct thermal_trip *trip);
+int thermal_acpi_trip_critical(struct acpi_device *adev, struct thermal_trip *trip);
+#endif
+
 #ifdef CONFIG_THERMAL
 struct thermal_zone_device *thermal_zone_device_register(const char *, int, int,
 		void *, struct thermal_zone_device_ops *,
  

On 22/01/2023 23:08, Rafael J. Wysocki wrote:
> On Saturday, January 21, 2023 12:15:28 AM CET Daniel Lezcano wrote:
>> The ACPI specification describes the trip points, the device tree
>> bindings as well.
>>
>> The OF code uses the generic trip point structures.
>>
>> The ACPI has their own trip points structure and uses the get_trip_*
>> ops to retrieve them.
>>
>> We can do the same as the OF code and create a set of ACPI functions
>> to retrieve a trip point description. Having a common code for ACPI
>> will help to cleanup the remaining Intel drivers and get rid of the
>> get_trip_* functions.
>>
>> These changes add the ACPI thermal calls to retrieve the basic
>> information we need to be reused in the thermal ACPI and Intel
>> drivers.
>>
>> The different ACPI functions have the generic trip point structure
>> passed as parameter where it is filled.
>>
>> This structure aims to be the one used by all the thermal drivers and
>> the thermal framework.
>>
>> After this series, a couple of Intel drivers and the ACPI thermal
>> driver will still have their own trip points definition but a new
>> series on top of this one will finish the conversion to the generic
>> trip point handling.
>>
>> This series depends on the generic trip point added to the thermal
>> framework and available in the thermal/linux-next branch.
>>
>>   https://lkml.org/lkml/2022/10/3/456
>>
>> It has been tested on a Intel i7-8650U - x280 with the INT3400, the
>> PCH, ACPITZ, and x86_pkg_temp. No regression observed so far.
>>
>> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>> Reviewed-by: Zhang Rui <rui.zhang@intel.com>
>> Tested-by: srinivas pandruvada <srinivas.pandruvada@linux.intel.com>
> 
> Co-developed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Also I'm not sure if this version has been tested and reviewed.
> 
> There are still a few things to improve in it, but overall I think that
> something like the patch below would be better - it is fewer lines of code
> and less duplication.

I'm always in favor of the simplest code, in terms of line of code and 
readability. I'm perfectly fine with your proposal.