Re: [PATCH v4 1/9] platform/x86: asus-wmi: export symbols used for read/write WMI

[Mario Limonciello <superm1@kernel.org>]

On 9/26/2024 04:29, Luke D. Jones wrote:
> Export some rather helpful read/write WMI symbols using a namespace.
> These are DEVS and DSTS only, or require the arg0 input.
> 
> Also does a slight refactor of internals of these functions.
> 
> Signed-off-by: Luke D. Jones <luke@ljones.dev>

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

> ---
>   drivers/platform/x86/asus-wmi.c            | 51 ++++++++++++++++++++--
>   include/linux/platform_data/x86/asus-wmi.h | 10 +++++
>   2 files changed, 58 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 6725a27df62f..0a5221d65130 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -385,7 +385,7 @@ int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval)
>   {
>   	return asus_wmi_evaluate_method3(method_id, arg0, arg1, 0, retval);
>   }
> -EXPORT_SYMBOL_GPL(asus_wmi_evaluate_method);
> +EXPORT_SYMBOL_NS_GPL(asus_wmi_evaluate_method, ASUS_WMI);
>   
>   static int asus_wmi_evaluate_method5(u32 method_id,
>   		u32 arg0, u32 arg1, u32 arg2, u32 arg3, u32 arg4, u32 *retval)
> @@ -549,12 +549,57 @@ static int asus_wmi_get_devstate(struct asus_wmi *asus, u32 dev_id, u32 *retval)
>   	return 0;
>   }
>   
> -static int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param,
> -				 u32 *retval)
> +/**
> + * asus_wmi_get_devstate_dsts() - Get the WMI function state.
> + * @dev_id: The WMI function to call.
> + * @retval: A pointer to where to store the value returned from WMI.
> + *
> + * The returned WMI function state can also be used to determine if the WMI
> + * function is supported by checking if the asus_wmi_get_devstate_dsts()
> + * returns an error.
> + *
> + * On success the return value is 0, and the retval is a valid value returned
> + * by the successful WMI function call. An error value is returned only if the
> + * WMI function failed, or if it returns "unsupported" which is typically a 0
> + * (no return, and no 'supported' bit set), or a 0xFFFFFFFE (~1) which if not
> + * caught here can result in unexpected behaviour later.
> + */
> +int asus_wmi_get_devstate_dsts(u32 dev_id, u32 *retval)
> +{
> +	int err;
> +
> +	err = asus_wmi_evaluate_method(ASUS_WMI_METHODID_DSTS, dev_id, 0, retval);
> +	if (err)
> +		return err;
> +
> +	*retval &= ~ASUS_WMI_DSTS_PRESENCE_BIT;
> +	if (*retval == ASUS_WMI_UNSUPPORTED_METHOD)
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(asus_wmi_get_devstate_dsts, ASUS_WMI);
> +
> +/**
> + * asus_wmi_set_devstate() - Set the WMI function state.
> + * @dev_id: The WMI function to call.
> + * @ctrl_param: The argument to be used for this WMI function.
> + * @retval: A pointer to where to store the value returned from WMI.
> + *
> + * The returned WMI function state if not checked here for error as
> + * asus_wmi_set_devstate() is not called unless first paired with a call to
> + * asus_wmi_get_devstate_dsts() to check that the WMI function is supported.
> + *
> + * On success the return value is 0, and the retval is a valid value returned
> + * by the successful WMI function call. An error value is returned only if the
> + * WMI function failed.
> + */
> +int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param, u32 *retval)
>   {
>   	return asus_wmi_evaluate_method(ASUS_WMI_METHODID_DEVS, dev_id,
>   					ctrl_param, retval);
>   }
> +EXPORT_SYMBOL_NS_GPL(asus_wmi_set_devstate, ASUS_WMI);
>   
>   /* Helper for special devices with magic return codes */
>   static int asus_wmi_get_devstate_bits(struct asus_wmi *asus,
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 365e119bebaa..6ea4dedfb85e 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -158,8 +158,18 @@
>   #define ASUS_WMI_DSTS_LIGHTBAR_MASK	0x0000000F
>   
>   #if IS_REACHABLE(CONFIG_ASUS_WMI)
> +int asus_wmi_get_devstate_dsts(u32 dev_id, u32 *retval);
> +int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param, u32 *retval);
>   int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval);
>   #else
> +static inline int asus_wmi_get_devstate_dsts(u32 dev_id, u32 *retval)
> +{
> +	return -ENODEV;
> +}
> +static inline int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param, u32 *retval)
> +{
> +	return -ENODEV;
> +}
>   static inline int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1,
>   					   u32 *retval)
>   {