// SPDX-License-Identifier: GPL-2.0-or-later /* * Lenovo Legion WMI helpers driver. * * The Lenovo Legion WMI interface is broken up into multiple GUID interfaces * that require cross-references between GUID's for some functionality. The * "Custom Mode" interface is a legacy interface for managing and displaying * CPU & GPU power and hwmon settings and readings. The "Other Mode" interface * is a modern interface that replaces or extends the "Custom Mode" interface * methods. The "Gamezone" interface adds advanced features such as fan * profiles and overclocking. The "Lighting" interface adds control of various * status lights related to different hardware components. Each of these * drivers uses a common procedure to get data from the WMI interface, * enumerated here. * * Copyright (C) 2025 Derek J. Clark <derekjohn.clark@gmail.com> */ #include <linux/acpi.h> #include <linux/cleanup.h> #include <linux/debugfs.h> #include <linux/device.h> #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. * @wdev: Pointer to the WMI device to be called. * @instance: Instance of the called method. * @method_id: WMI Method ID for the method to be called. * @buf: Buffer of all arguments for the given method_id. * @size: Length of the buffer. * @retval: Pointer for the return value to be assigned. * * Calls wmidev_evaluate_method for Lenovo WMI devices that return an ACPI * integer. Validates the return value type and assigns the value to the * retval pointer. * * Return: 0 on success, or an error code. */ int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id, unsigned char *buf, size_t size, u32 *retval) { struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; struct acpi_buffer input = { size, buf }; acpi_status status; status = wmidev_evaluate_method(wdev, instance, method_id, &input, &output); if (ACPI_FAILURE(status)) return -EIO; union acpi_object *ret_obj __free(kfree) = output.pointer; if (retval) { if (!ret_obj) return -ENODATA; switch (ret_obj->type) { /* * The ACPI method may simply return a buffer when a u32 * is expected. This is valid on Windows as its WMI-ACPI * driver converts everything to a common buffer. */ case ACPI_TYPE_BUFFER: if (ret_obj->buffer.length < sizeof(u32)) return -ENXIO; *retval = get_unaligned_le32(ret_obj->buffer.pointer); return 0; case ACPI_TYPE_INTEGER: *retval = (u32)ret_obj->integer.value; return 0; default: return -ENXIO; } } return 0; }; 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"); static struct dentry *lwmi_debugfs_dir; /** * lwmi_debugfs_create_dir() - Helper function for creating a debugfs directory * for a device. * @wdev: Pointer to the WMI device to be called. * * Caller must remove the directory with debugfs_remove_recursive() on device * removal. * * Return: Pointer to the created directory. */ struct dentry *lwmi_debugfs_create_dir(struct wmi_device *wdev) { return debugfs_create_dir(dev_name(&wdev->dev), lwmi_debugfs_dir); } EXPORT_SYMBOL_NS_GPL(lwmi_debugfs_create_dir, "LENOVO_WMI_HELPERS"); static int __init lwmi_helpers_init(void) { lwmi_debugfs_dir = debugfs_create_dir("lenovo_wmi", NULL); return 0; } subsys_initcall(lwmi_helpers_init) static void __exit lwmi_helpers_exit(void) { debugfs_remove_recursive(lwmi_debugfs_dir); } module_exit(lwmi_helpers_exit) MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>"); MODULE_DESCRIPTION("Lenovo WMI Helpers Driver"); MODULE_LICENSE("GPL");
