Re: [PATCH v4 2/6 RESEND] platform/x86: Add lenovo-wmi-helpers

[Matthew Schwartz <matthew.schwartz@linux.dev>]

On 3/17/25 7:43 AM, Derek J. Clark wrote:
> Adds documentation for all new lenovo-wmi drivers.
> 
> Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>

The helpers are working with the other drivers on my Legion Go
and Legion Go S. I left one minor comment for a typo in-line.

Tested-by: Matthew Schwartz <matthew.schwartz@linux.dev>

> ---
> 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                               |  2 +
>  drivers/platform/x86/Kconfig              |  4 ++
>  drivers/platform/x86/Makefile             |  1 +
>  drivers/platform/x86/lenovo-wmi-helpers.c | 64 +++++++++++++++++++++++
>  drivers/platform/x86/lenovo-wmi-helpers.h | 24 +++++++++
>  5 files changed, 95 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..3a370a18b806 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13164,6 +13164,8 @@ 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.c
> +F:	drivers/platform/x86/lenovo-wmi-helpers.h
>  
>  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..36d553502223
> --- /dev/null
> +++ b/drivers/platform/x86/lenovo-wmi-helpers.c
> @@ -0,0 +1,64 @@
> +// 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 Method" 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 Method" 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 fro the WMI interface, enumerated here.
"fro" should be "from" right?

> + *
> + * Copyright(C) 2025 Derek J. Clark <derekjohn.clark@gmail.com>
> + *
> + */
> +
> +#include <linux/wmi.h>
> +#include "lenovo-wmi-helpers.h"
> +
> +/*
> + * lwmi_dev_evaluate_method() - Helper function to call wmidev_evaluate_method
> + * for Lenovo WMI device method calls that return an ACPI 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.
> + *
> + * Returns: 0, or an error.
> + */
> +int lwmi_dev_evaluate_method(struct wmi_device *wdev, u8 instance,
> +			     u32 method_id, unsigned char *buf, size_t size,
> +			     u32 *retval)
> +{
> +	struct acpi_buffer input = { size, buf };
> +	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *ret_obj __free(kfree) = NULL;
> +	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_method, "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..7e0d7870790e
> --- /dev/null
> +++ b/drivers/platform/x86/lenovo-wmi-helpers.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later
> + *
> + * Copyright(C) 2025 Derek J. Clark <derekjohn.clark@gmail.com>
> + *
> + */
> +#include <linux/notifier.h>
> +#include <linux/platform_profile.h>
> +
> +#ifndef _LENOVO_WMI_HELPERS_H_
> +#define _LENOVO_WMI_HELPERS_H_
> +
> +#include <linux/types.h>
> +#include <linux/wmi.h>
> +
> +struct wmi_method_args_32 {
> +	u32 arg0;
> +	u32 arg1;
> +};
> +
> +int lwmi_dev_evaluate_method(struct wmi_device *wdev, u8 instance,
> +			     u32 method_id, unsigned char *buf, size_t size,
> +			     u32 *retval);
> +
> +#endif /* !_LENOVO_WMI_HELPERS_H_ */