HID: asus: Add WMI communication infrastructure

Add infrastructure for the HID driver to communicate with the asus-wmi
driver for handling special keys that require WMI communication.

This includes:
- Define ASUS_WMI_METHODID_NOTIF method ID in asus-wmi.h
- Implement asus_wmi_send_event() function to send events to asus-wmi

Reviewed-by: Denis Benato <benato.denis96@gmail.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Ionut Nechita <ionut_n2001@yahoo.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

Author: ionutnechita

drivers/hid/hid-asus.c

@@ -23,6 +23,7 @@
 /*
  */
 
+#include <linux/acpi.h>
 #include <linux/dmi.h>
 #include <linux/hid.h>
 #include <linux/module.h>
@@ -320,6 +321,29 @@ static int asus_e1239t_event(struct asus_drvdata *drvdat, u8 *data, int size)
 	return 0;
 }
 
+/*
+ * Send events to asus-wmi driver for handling special keys
+ */
+static int asus_wmi_send_event(struct asus_drvdata *drvdata, u8 code)
+{
+	int err;
+	u32 retval;
+
+	err = asus_wmi_evaluate_method(ASUS_WMI_METHODID_DEVS,
+				       ASUS_WMI_METHODID_NOTIF, code, &retval);
+	if (err) {
+		pr_warn("Failed to notify asus-wmi: %d\n", err);
+		return err;
+	}
+
+	if (retval != 0) {
+		pr_warn("Failed to notify asus-wmi (retval): 0x%x\n", retval);
+		return -EIO;
+	}
+
+	return 0;
+}
+
 static int asus_event(struct hid_device *hdev, struct hid_field *field,
 		      struct hid_usage *usage, __s32 value)
 {

include/linux/platform_data/x86/asus-wmi.h

@@ -27,6 +27,7 @@
 #define ASUS_WMI_METHODID_KBFT		0x5446424B /* KeyBoard FilTer */
 #define ASUS_WMI_METHODID_INIT		0x54494E49 /* INITialize */
 #define ASUS_WMI_METHODID_HKEY		0x59454B48 /* Hot KEY ?? */
+#define ASUS_WMI_METHODID_NOTIF		0x00100021 /* Notify method */
 
 #define ASUS_WMI_UNSUPPORTED_METHOD	0xFFFFFFFE