Re: [External] : [PATCH v6 3/6] platform/x86: Add Lenovo WMI Events Driver

[ALOK TIWARI <alok.a.tiwari@oracle.com>]

On 28-04-2025 06:48, Derek J. Clark wrote:
> --- /dev/null
> +++ b/drivers/platform/x86/lenovo-wmi-events.c
> @@ -0,0 +1,196 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Lenovo WMI Events driver. Lenovo WMI interfaces provide various
> + * hardware triggered events that many drivers need to have propagated.
> + * This driver provides a uniform entrypoint for these events so that
> + * any driver that needs to respond to these events can subscribe to a
> + * notifier chain.
> + *
> + * Copyright(C) 2025 Derek J. Clark <derekjohn.clark@gmail.com>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/export.h>
> +#include <linux/module.h>
> +#include <linux/notifier.h>
> +#include <linux/types.h>
> +#include <linux/wmi.h>
> +
> +#include "lenovo-wmi-events.h"
> +#include "lenovo-wmi-gamezone.h"
> +
> +#define THERMAL_MODE_EVENT_GUID "D320289E-8FEA-41E0-86F9-911D83151B5F"
> +
> +#define LWMI_EVENT_DEVICE(guid, type)                        \
> +	.guid_string = (guid), .context = &(enum lwmi_events_type) \
> +	{                                                          \
> +		type                                               \
> +	}
> +
> +static BLOCKING_NOTIFIER_HEAD(events_chain_head);
> +
> +struct lwmi_events_priv {
> +	struct wmi_device *wdev;
> +	enum lwmi_events_type type;
> +};
> +
> +/**
> + * lwmi_events_register_notifier() - Add a notifier to the notifier chain.
> + * @nb: The notifier_block struct to register
> + *
> + * Call blocking_notifier_chain_register to register the notifier block to the
> + * lenovo-wmi-events driver blocking notifer chain.

typo notifer -> notifier in all register/unregister

> + *
> + * Return: 0 on success, %-EEXIST on error.
> + */
> +int lwmi_events_register_notifier(struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_register(&events_chain_head, nb);
> +}
> +EXPORT_SYMBOL_NS_GPL(lwmi_events_register_notifier, "LENOVO_WMI_EVENTS");
> +
> +/**
> + * lwmi_events_unregister_notifier() - Remove a notifier from the notifier
> + * chain.
> + * @nb: The notifier_block struct to register

the @nb parameter is described inconsistently:
@nb: The notifier_block struct to unregister

> + *
> + * Call blocking_notifier_chain_unregister to unregister the notifier block
> + * from the lenovo-wmi-events driver blocking notifer chain.
> + *
> + * Return: 0 on success, %-ENOENT on error.
> + */
> +int lwmi_events_unregister_notifier(struct notifier_block *nb)
> +{
> +	return blocking_notifier_chain_unregister(&events_chain_head, nb);
> +}
> +EXPORT_SYMBOL_NS_GPL(lwmi_events_unregister_notifier, "LENOVO_WMI_EVENTS");

can be consider lwmi_events_un/register_notifier as static
if they are wrapper func?

> +
> +/**
> + * devm_lwmi_events_unregister_notifier() - Remove a notifier from the notifier
> + * chain.
> + * @data: Void pointer to the notifier_block struct to register.

* @data: Void pointer to the notifier_block struct to unregister.

> + *
> + * Call lwmi_events_unregister_notifier to unregister the notifier block from
> + * the lenovo-wmi-events driver blocking notifer chain.
> + *
> + * Return: 0 on success, %-ENOENT on error.
> + */
> +static void devm_lwmi_events_unregister_notifier(void *data)
> +{
> +	struct notifier_block *nb = data;
> +

if (nb) Consider checking NULL pointer

> +	lwmi_events_unregister_notifier(nb);
> +}
> +
> +/**
> + * devm_lwmi_events_register_notifier() - Add a notifier to the notifier chain.
> + * @dev: The parent device of the notifier_block struct.
> + * @nb: The notifier_block struct to register
> + *
> + * Call lwmi_events_register_notifier to register the notifier block to the
> + * lenovo-wmi-events driver blocking notifer chain. Then add, as a device
> + * managed action, unregister_notifier to automatically unregister the
> + * notifier block upon its parent device removal.
> + *
> + * Return: 0 on success, or an error code.
> + */
> +int devm_lwmi_events_register_notifier(struct device *dev,
> +				       struct notifier_block *nb)
> +{
> +	int ret;
> +
> +	ret = lwmi_events_register_notifier(nb);
> +	if (ret < 0)
> +		return ret;
> +
> +	return devm_add_action_or_reset(dev, devm_lwmi_events_unregister_notifier, nb);
> +}
> +EXPORT_SYMBOL_NS_GPL(devm_lwmi_events_register_notifier, "LENOVO_WMI_EVENTS");
> +
> +/**
> + * lwmi_events_notify() - Call functions for the notifier call chain.
> + * @wdev: The parent WMI device of the driver.
> + * @obj: ACPI object passed by the registered WMI Event.
> + *
> + * Validate WMI event data and notify all registered drivers of the event and
> + * its output.
> + *
> + * Return: 0 on success, or an error code.
> + */
> +static void lwmi_events_notify(struct wmi_device *wdev, union acpi_object *obj)
> +{
> +	struct lwmi_events_priv *priv = dev_get_drvdata(&wdev->dev);
> +	int sel_prof;
> +	int ret;
> +
> +	switch (priv->type) {
> +	case LWMI_EVENT_THERMAL_MODE:
> +		if (obj->type != ACPI_TYPE_INTEGER)
> +			return;
> +
> +		sel_prof = obj->integer.value;
> +
> +		switch (sel_prof) {
> +		case LWMI_GZ_THERMAL_MODE_QUIET:
> +		case LWMI_GZ_THERMAL_MODE_BALANCED:
> +		case LWMI_GZ_THERMAL_MODE_PERFORMANCE:
> +		case LWMI_GZ_THERMAL_MODE_EXTREME:
> +		case LWMI_GZ_THERMAL_MODE_CUSTOM:
> +			ret = blocking_notifier_call_chain(&events_chain_head,
> +							   LWMI_EVENT_THERMAL_MODE,
> +							   &sel_prof);
> +			if (ret == NOTIFY_BAD)
> +				dev_err(&wdev->dev,
> +					"Failed to send notification to call chain for WMI Events\n");
> +			return;
> +		default:
> +			dev_err(&wdev->dev, "Got invalid thermal mode: %x",
> +				sel_prof);
> +			return;
> +		}
> +		break;
> +	default:
> +		return;
> +	}
> +}
> +
> +static int lwmi_events_probe(struct wmi_device *wdev, const void *context)
> +{
> +	struct lwmi_events_priv *priv;
> +
> +	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	if (!context)
> +		return -EINVAL;
> +

might want to check context before using devm_kzalloc()
to avoid unnecessary memory allocation

> +	priv->wdev = wdev;
> +	priv->type = *(enum lwmi_events_type *)context;
> +
> +	dev_set_drvdata(&wdev->dev, priv);
> +	return 0;
> +}
> +
> +static const struct wmi_device_id lwmi_events_id_table[] = {
> +	{ LWMI_EVENT_DEVICE(THERMAL_MODE_EVENT_GUID, LWMI_EVENT_THERMAL_MODE) },
> +	{}
> +};
> +
> +static struct wmi_driver lwmi_events_driver = {
> +	.driver = {
> +		.name = "lenovo_wmi_events",
> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> +	},
> +	.id_table = lwmi_events_id_table,
> +	.probe = lwmi_events_probe,
> +	.notify = lwmi_events_notify,
> +	.no_singleton = true,
> +};
> +
> +module_wmi_driver(lwmi_events_driver);
> +
> +MODULE_DEVICE_TABLE(wmi, lwmi_events_id_table);
> +MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
> +MODULE_DESCRIPTION("Lenovo WMI Events Driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/platform/x86/lenovo-wmi-events.h b/drivers/platform/x86/lenovo-wmi-events.h
> new file mode 100644
> index 000000000000..e4c5459c2f24
> --- /dev/null
> +++ b/drivers/platform/x86/lenovo-wmi-events.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +
> +/* Copyright(C) 2025 Derek J. Clark <derekjohn.clark@gmail.com> */
> +
> +#ifndef _LENOVO_WMI_EVENTS_H_
> +#define _LENOVO_WMI_EVENTS_H_
> +
> +struct device;
> +struct notifier_block;
> +
> +enum lwmi_events_type {
> +	LWMI_EVENT_THERMAL_MODE = 1,
> +};
> +
> +int lwmi_events_register_notifier(struct notifier_block *nb);
> +int lwmi_events_unregister_notifier(struct notifier_block *nb);
> +int devm_lwmi_events_register_notifier(struct device *dev,
> +				       struct notifier_block *nb);

why devm_lwmi_events_unregister_notifier not here ?

> +
> +#endif /* !_LENOVO_WMI_EVENTS_H_ */


Thanks,
Alok