Adds lenovo-wmi-helpers, which provides a common wrapper function for
wmidev_evaluate_method that does data validation and error handling.

Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
v6:
 - Fix typos and rewordings from v5 review.
v5:
 - Fixes from v4 review.
 - Combine all previous methods into a single function that takes a
   buffer for the wmi method arguments.
v4:
 - Changed namespace to LENOVO_WMI_HELPERS from LENOVO_WMI.
 - Changed filenames to lenovo-wmi-helpers from lenovo-wmi.
 - Removed structs and functions implemented by other drivers.
MAINTAINERS                               |  1 +
 drivers/platform/x86/Kconfig              |  4 ++
 drivers/platform/x86/Makefile             |  1 +
 drivers/platform/x86/lenovo-wmi-helpers.c | 74 +++++++++++++++++++++++
 drivers/platform/x86/lenovo-wmi-helpers.h | 20 ++++++
 5 files changed, 100 insertions(+)
 create mode 100644 drivers/platform/x86/lenovo-wmi-helpers.c
 create mode 100644 drivers/platform/x86/lenovo-wmi-helpers.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 675f4b26426d..aab59a777693 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13164,6 +13164,7 @@ L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
 F:	Documentation/wmi/devices/lenovo-wmi-gamezone.rst
 F:	Documentation/wmi/devices/lenovo-wmi-other.rst
+F:	drivers/platform/x86/lenovo-wmi-helpers.*
 
 LENOVO WMI HOTKEY UTILITIES DRIVER
 M:	Jackie Dong <xy-jackie@139.com>
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 43407e76476b..bece1ba61417 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -459,6 +459,10 @@ config IBM_RTL
 	 state = 0 (BIOS SMIs on)
 	 state = 1 (BIOS SMIs off)
 
+config LENOVO_WMI_HELPERS
+	tristate
+	depends on ACPI_WMI
+
 config IDEAPAD_LAPTOP
 	tristate "Lenovo IdeaPad Laptop Extras"
 	depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 650dfbebb6c8..5a9f4e94f78b 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
 obj-$(CONFIG_YOGABOOK)		+= lenovo-yogabook.o
 obj-$(CONFIG_YT2_1380)		+= lenovo-yoga-tab2-pro-1380-fastcharger.o
 obj-$(CONFIG_LENOVO_WMI_CAMERA)	+= lenovo-wmi-camera.o
+obj-$(CONFIG_LENOVO_WMI_HELPERS)	+= lenovo-wmi-helpers.o
 
 # Intel
 obj-y				+= intel/
diff --git a/drivers/platform/x86/lenovo-wmi-helpers.c b/drivers/platform/x86/lenovo-wmi-helpers.c
new file mode 100644
index 000000000000..2df0408e2a9c
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-helpers.c
@@ -0,0 +1,74 @@
+// 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/errno.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/wmi.h>
+
+#include "lenovo-wmi-helpers.h"
+
+/**
+ * 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_valuate_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 };
+	union acpi_object *ret_obj __free(kfree) = 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;
+
+	if (retval) {
+		ret_obj = output.pointer;
+		if (!ret_obj)
+			return -ENODATA;
+
+		if (ret_obj->type != ACPI_TYPE_INTEGER)
+			return -ENXIO;
+
+		*retval = (u32)ret_obj->integer.value;
+	}
+	return 0;
+};
+EXPORT_SYMBOL_NS_GPL(lwmi_dev_evaluate_int, "LENOVO_WMI_HELPERS");
+
+MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@gmail.com>");
+MODULE_DESCRIPTION("Lenovo WMI Helpers Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/platform/x86/lenovo-wmi-helpers.h b/drivers/platform/x86/lenovo-wmi-helpers.h
new file mode 100644
index 000000000000..b76633603dcc
--- /dev/null
+++ b/drivers/platform/x86/lenovo-wmi-helpers.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_HELPERS_H_
+#define _LENOVO_WMI_HELPERS_H_
+
+#include <linux/types.h>
+
+struct wmi_device;
+
+struct wmi_method_args_32 {
+	u32 arg0;
+	u32 arg1;
+};
+
+int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
+			  unsigned char *buf, size_t size, u32 *retval);
+
+#endif /* !_LENOVO_WMI_HELPERS_H_ */
-- 
2.49.0

> diff --git a/drivers/platform/x86/lenovo-wmi-helpers.c b/drivers/platform/x86/lenovo-wmi-helpers.c
> new file mode 100644
> index 000000000000..2df0408e2a9c
> --- /dev/null
> +++ b/drivers/platform/x86/lenovo-wmi-helpers.c
> @@ -0,0 +1,74 @@
> +// 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>
> + */

add a space after "Copyright" before "(C)".
Copyright (C) 2025

> +
> +#include <linux/acpi.h>
> +#include <linux/cleanup.h>
> +#include <linux/errno.h>
> +#include <linux/export.h>
> +#include <linux/module.h>
> +#include <linux/wmi.h>
> +
> +#include "lenovo-wmi-helpers.h"
> +
> +/**
> + * 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_valuate_method for Lenovo WMI devices that return an ACPI
> + * integer. Validates the return value type and assigns the value to the
> + * retval pointer.

assuming you meant to refer to wmidev_evaluate_method, the real function
typo wmidev_valuate_method -> wmidev_evaluate_method

> + *
> + * 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 };
> +	union acpi_object *ret_obj __free(kfree) = 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;
> +
> +	if (retval) {
> +		ret_obj = output.pointer;
> +		if (!ret_obj)
> +			return -ENODATA;
> +
> +		if (ret_obj->type != ACPI_TYPE_INTEGER)
> +			return -ENXIO;
> +
> +		*retval = (u32)ret_obj->integer.value;
> +	}
> +	return 0;
> +};

Thanks,
Alok

On April 28, 2025 12:36:03 PM PDT, ALOK TIWARI <alok.a.tiwari@oracle.com> wrote:
>> diff --git a/drivers/platform/x86/lenovo-wmi-helpers.c b/drivers/platform/x86/lenovo-wmi-helpers.c
>> new file mode 100644
>> index 000000000000..2df0408e2a9c
>> --- /dev/null
>> +++ b/drivers/platform/x86/lenovo-wmi-helpers.c
>> @@ -0,0 +1,74 @@
>> +// 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>
>> + */
>
>add a space after "Copyright" before "(C)".
>Copyright (C) 2025
>
>> +
>> +#include <linux/acpi.h>
>> +#include <linux/cleanup.h>
>> +#include <linux/errno.h>
>> +#include <linux/export.h>
>> +#include <linux/module.h>
>> +#include <linux/wmi.h>
>> +
>> +#include "lenovo-wmi-helpers.h"
>> +
>> +/**
>> + * 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_valuate_method for Lenovo WMI devices that return an ACPI
>> + * integer. Validates the return value type and assigns the value to the
>> + * retval pointer.
>
>assuming you meant to refer to wmidev_evaluate_method, the real function
>typo wmidev_valuate_method -> wmidev_evaluate_method
>
>> + *
>> + * 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 };
>> +	union acpi_object *ret_obj __free(kfree) = 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;
>> +
>> +	if (retval) {
>> +		ret_obj = output.pointer;
>> +		if (!ret_obj)
>> +			return -ENODATA;
>> +
>> +		if (ret_obj->type != ACPI_TYPE_INTEGER)
>> +			return -ENXIO;
>> +
>> +		*retval = (u32)ret_obj->integer.value;
>> +	}
>> +	return 0;
>> +};
>
>Thanks,
>Alok

Ack all. Thanks for taking a look.
- Derek