platform/x86: lenovo: Decouple lenovo-wmi-gamezone and lenovo-wmi-other

Currently, lenovo-wmi-gamezone depends on lenovo-wmi-other as the former
imports symbols from the latter. The imported symbols are just used to
register a notifier block. However, there is no runtime dependency
between both drivers, and either of them can run without the other,
which is the major purpose of using the notifier framework.

Such a link-time dependency is non-optimal. A previous attempt to "fix"
it made LENOVO_WMI_GAMEZONE select LENOVO_WMI_TUNING, which was
fundamentally broken and resulted in undefined Kconfig behavior, as
`select' cannot be used on a symbol with potentially unmet dependencies.

Decouple both drivers by moving the thermal mode notifier chain to
lenovo-wmi-helpers. Methods for notifier block (un)registration are
exported for lenovo-wmi-gamezone, while a method for querying the
current thermal mode are exported for lenovo-wmi-other.

This turns the dependency graph from

            +------------ lenovo-wmi-gamezone
            |                     |
            v                     |
    lenovo-wmi-helpers            |
            ^                     |
            |                     V
            +------------ lenovo-wmi-other

into

            +------------ lenovo-wmi-gamezone
            |
            v
    lenovo-wmi-helpers
            ^
            |
            +------------ lenovo-wmi-other

To make it clear, the name of the notifier chain is also renamed from
`om_chain_head' to `tm_chain_head', indicating that it's used to query
the current thermal mode.

No functional change intended.

Fixes: 6e38b9f ("platform/x86: lenovo: gamezone needs "other mode"")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202603252259.gHvJDyh3-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202603260302.X0NjQOda-lkp@intel.com/
Signed-off-by: Rong Zhang <i@rong.moe>

Author: Rongronggg9

drivers/platform/x86/lenovo/Kconfig

@@ -252,7 +252,6 @@ config LENOVO_WMI_GAMEZONE
 	select ACPI_PLATFORM_PROFILE
 	select LENOVO_WMI_EVENTS
 	select LENOVO_WMI_HELPERS
-	select LENOVO_WMI_TUNING
 	help
 	  Say Y here if you have a WMI aware Lenovo Legion device and would like to use the
 	  platform-profile firmware interface to manage power usage.

drivers/platform/x86/lenovo/wmi-gamezone.c

@@ -23,7 +23,6 @@
 #include "wmi-events.h"
 #include "wmi-gamezone.h"
 #include "wmi-helpers.h"
-#include "wmi-other.h"
 
 #define LENOVO_GAMEZONE_GUID "887B54E3-DDDC-4B2C-8B88-68A26A8835D0"
 
@@ -385,7 +384,7 @@ static int lwmi_gz_probe(struct wmi_device *wdev, const void *context)
 		return ret;
 
 	priv->mode_nb.notifier_call = lwmi_gz_mode_call;
-	return devm_lwmi_om_register_notifier(&wdev->dev, &priv->mode_nb);
+	return devm_lwmi_tm_register_notifier(&wdev->dev, &priv->mode_nb);
 }
 
 static const struct wmi_device_id lwmi_gz_id_table[] = {
@@ -407,7 +406,6 @@ module_wmi_driver(lwmi_gz_driver);
 
 MODULE_IMPORT_NS("LENOVO_WMI_EVENTS");
 MODULE_IMPORT_NS("LENOVO_WMI_HELPERS");
-MODULE_IMPORT_NS("LENOVO_WMI_OTHER");
 MODULE_DEVICE_TABLE(wmi, lwmi_gz_id_table);
 MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
 MODULE_DESCRIPTION("Lenovo GameZone WMI Driver");

drivers/platform/x86/lenovo/wmi-helpers.c

@@ -21,11 +21,15 @@
 #include <linux/errno.h>
 #include <linux/export.h>
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/unaligned.h>
 #include <linux/wmi.h>
 
 #include "wmi-helpers.h"
 
+/* Thermal mode notifier chain. */
+static BLOCKING_NOTIFIER_HEAD(tm_chain_head);
+
 /**
  * lwmi_dev_evaluate_int() - Helper function for calling WMI methods that
  * return an integer.
@@ -85,6 +89,103 @@ int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
 };
 EXPORT_SYMBOL_NS_GPL(lwmi_dev_evaluate_int, "LENOVO_WMI_HELPERS");
 
+/**
+ * lwmi_tm_register_notifier() - Add a notifier to the blocking notifier chain
+ * @nb: The notifier_block struct to register
+ *
+ * Call blocking_notifier_chain_register to register the notifier block to the
+ * thermal mode notifier chain.
+ *
+ * Return: 0 on success, %-EEXIST on error.
+ */
+int lwmi_tm_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&tm_chain_head, nb);
+}
+EXPORT_SYMBOL_NS_GPL(lwmi_tm_register_notifier, "LENOVO_WMI_HELPERS");
+
+/**
+ * lwmi_tm_unregister_notifier() - Remove a notifier from the blocking notifier
+ * chain.
+ * @nb: The notifier_block struct to register
+ *
+ * Call blocking_notifier_chain_unregister to unregister the notifier block from the
+ * thermal mode notifier chain.
+ *
+ * Return: 0 on success, %-ENOENT on error.
+ */
+int lwmi_tm_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&tm_chain_head, nb);
+}
+EXPORT_SYMBOL_NS_GPL(lwmi_tm_unregister_notifier, "LENOVO_WMI_HELPERS");
+
+/**
+ * devm_lwmi_tm_unregister_notifier() - Remove a notifier from the blocking
+ * notifier chain.
+ * @data: Void pointer to the notifier_block struct to register.
+ *
+ * Call lwmi_tm_unregister_notifier to unregister the notifier block from the
+ * thermal mode notifier chain.
+ *
+ * Return: 0 on success, %-ENOENT on error.
+ */
+static void devm_lwmi_tm_unregister_notifier(void *data)
+{
+	struct notifier_block *nb = data;
+
+	lwmi_tm_unregister_notifier(nb);
+}
+
+/**
+ * devm_lwmi_tm_register_notifier() - Add a notifier to the blocking notifier
+ * chain.
+ * @dev: The parent device of the notifier_block struct.
+ * @nb: The notifier_block struct to register
+ *
+ * Call lwmi_tm_register_notifier to register the notifier block to the
+ * thermal mode notifier chain. Then add devm_lwmi_tm_unregister_notifier
+ * as a device managed action to automatically unregister the notifier block
+ * upon parent device removal.
+ *
+ * Return: 0 on success, or an error code.
+ */
+int devm_lwmi_tm_register_notifier(struct device *dev,
+				   struct notifier_block *nb)
+{
+	int ret;
+
+	ret = lwmi_tm_register_notifier(nb);
+	if (ret < 0)
+		return ret;
+
+	return devm_add_action_or_reset(dev, devm_lwmi_tm_unregister_notifier,
+					nb);
+}
+EXPORT_SYMBOL_NS_GPL(devm_lwmi_tm_register_notifier, "LENOVO_WMI_HELPERS");
+
+/**
+ * lwmi_tm_notifier_call() - Call functions for the notifier call chain.
+ * @mode: Pointer to a thermal mode enum to retrieve the data from.
+ *
+ * Call blocking_notifier_call_chain to retrieve the thermal mode from the
+ * lenovo-wmi-gamezone driver.
+ *
+ * Return: 0 on success, or an error code.
+ */
+int lwmi_tm_notifier_call(enum thermal_mode *mode)
+{
+	int ret;
+
+	ret = blocking_notifier_call_chain(&tm_chain_head,
+					   LWMI_GZ_GET_THERMAL_MODE, &mode);
+	if ((ret & ~NOTIFY_STOP_MASK) != NOTIFY_OK)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(lwmi_tm_notifier_call, "LENOVO_WMI_HELPERS");
+
 MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
 MODULE_DESCRIPTION("Lenovo WMI Helpers Driver");
 MODULE_LICENSE("GPL");

drivers/platform/x86/lenovo/wmi-helpers.h

@@ -7,6 +7,8 @@
 
 #include <linux/types.h>
 
+struct device;
+struct notifier_block;
 struct wmi_device;
 
 struct wmi_method_args_32 {
@@ -17,4 +19,10 @@ struct wmi_method_args_32 {
 int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
 			  unsigned char *buf, size_t size, u32 *retval);
 
+int lwmi_tm_register_notifier(struct notifier_block *nb);
+int lwmi_tm_unregister_notifier(struct notifier_block *nb);
+int devm_lwmi_tm_register_notifier(struct device *dev,
+				   struct notifier_block *nb);
+int lwmi_tm_notifier_call(enum thermal_mode *mode);
+
 #endif /* !_LENOVO_WMI_HELPERS_H_ */

drivers/platform/x86/lenovo/wmi-other.c

@@ -40,7 +40,6 @@
 #include <linux/kobject.h>
 #include <linux/limits.h>
 #include <linux/module.h>
-#include <linux/notifier.h>
 #include <linux/platform_profile.h>
 #include <linux/types.h>
 #include <linux/wmi.h>
@@ -49,7 +48,6 @@
 #include "wmi-events.h"
 #include "wmi-gamezone.h"
 #include "wmi-helpers.h"
-#include "wmi-other.h"
 #include "../firmware_attributes_class.h"
 
 #define LENOVO_OTHER_MODE_GUID "DC2A8805-3A8C-41BA-A6F7-092E0089CD3B"
@@ -81,7 +79,6 @@
 #define LWMI_OM_FW_ATTR_BASE_PATH "lenovo-wmi-other"
 #define LWMI_OM_HWMON_NAME "lenovo_wmi_other"
 
-static BLOCKING_NOTIFIER_HEAD(om_chain_head);
 static DEFINE_IDA(lwmi_om_ida);
 
 enum attribute_property {
@@ -109,7 +106,6 @@ struct lwmi_om_priv {
 	struct device *hwmon_dev;
 	struct device *fw_attr_dev;
 	struct kset *fw_attr_kset;
-	struct notifier_block nb;
 	struct wmi_device *wdev;
 	int ida_id;
 
@@ -577,102 +573,6 @@ struct capdata01_attr_group {
 	struct tunable_attr_01 *tunable_attr;
 };
 
-/**
- * lwmi_om_register_notifier() - Add a notifier to the blocking notifier chain
- * @nb: The notifier_block struct to register
- *
- * Call blocking_notifier_chain_register to register the notifier block to the
- * lenovo-wmi-other driver notifier chain.
- *
- * Return: 0 on success, %-EEXIST on error.
- */
-int lwmi_om_register_notifier(struct notifier_block *nb)
-{
-	return blocking_notifier_chain_register(&om_chain_head, nb);
-}
-EXPORT_SYMBOL_NS_GPL(lwmi_om_register_notifier, "LENOVO_WMI_OTHER");
-
-/**
- * lwmi_om_unregister_notifier() - Remove a notifier from the blocking notifier
- * chain.
- * @nb: The notifier_block struct to register
- *
- * Call blocking_notifier_chain_unregister to unregister the notifier block from the
- * lenovo-wmi-other driver notifier chain.
- *
- * Return: 0 on success, %-ENOENT on error.
- */
-int lwmi_om_unregister_notifier(struct notifier_block *nb)
-{
-	return blocking_notifier_chain_unregister(&om_chain_head, nb);
-}
-EXPORT_SYMBOL_NS_GPL(lwmi_om_unregister_notifier, "LENOVO_WMI_OTHER");
-
-/**
- * devm_lwmi_om_unregister_notifier() - Remove a notifier from the blocking
- * notifier chain.
- * @data: Void pointer to the notifier_block struct to register.
- *
- * Call lwmi_om_unregister_notifier to unregister the notifier block from the
- * lenovo-wmi-other driver notifier chain.
- *
- * Return: 0 on success, %-ENOENT on error.
- */
-static void devm_lwmi_om_unregister_notifier(void *data)
-{
-	struct notifier_block *nb = data;
-
-	lwmi_om_unregister_notifier(nb);
-}
-
-/**
- * devm_lwmi_om_register_notifier() - Add a notifier to the blocking notifier
- * chain.
- * @dev: The parent device of the notifier_block struct.
- * @nb: The notifier_block struct to register
- *
- * Call lwmi_om_register_notifier to register the notifier block to the
- * lenovo-wmi-other driver notifier chain. Then add devm_lwmi_om_unregister_notifier
- * as a device managed action to automatically unregister the notifier block
- * upon parent device removal.
- *
- * Return: 0 on success, or an error code.
- */
-int devm_lwmi_om_register_notifier(struct device *dev,
-				   struct notifier_block *nb)
-{
-	int ret;
-
-	ret = lwmi_om_register_notifier(nb);
-	if (ret < 0)
-		return ret;
-
-	return devm_add_action_or_reset(dev, devm_lwmi_om_unregister_notifier,
-					nb);
-}
-EXPORT_SYMBOL_NS_GPL(devm_lwmi_om_register_notifier, "LENOVO_WMI_OTHER");
-
-/**
- * lwmi_om_notifier_call() - Call functions for the notifier call chain.
- * @mode: Pointer to a thermal mode enum to retrieve the data from.
- *
- * Call blocking_notifier_call_chain to retrieve the thermal mode from the
- * lenovo-wmi-gamezone driver.
- *
- * Return: 0 on success, or an error code.
- */
-static int lwmi_om_notifier_call(enum thermal_mode *mode)
-{
-	int ret;
-
-	ret = blocking_notifier_call_chain(&om_chain_head,
-					   LWMI_GZ_GET_THERMAL_MODE, &mode);
-	if ((ret & ~NOTIFY_STOP_MASK) != NOTIFY_OK)
-		return -EINVAL;
-
-	return 0;
-}
-
 /* Attribute Methods */
 
 /**
@@ -780,7 +680,7 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
 	u32 value;
 	int ret;
 
-	ret = lwmi_om_notifier_call(&mode);
+	ret = lwmi_tm_notifier_call(&mode);
 	if (ret)
 		return ret;
 
@@ -843,7 +743,7 @@ static ssize_t attr_current_value_show(struct kobject *kobj,
 	int retval;
 	int ret;
 
-	ret = lwmi_om_notifier_call(&mode);
+	ret = lwmi_tm_notifier_call(&mode);
 	if (ret)
 		return ret;