platform/x86: wmi: add context pointer field to struct wmi_device_id

When using wmi_install_notify_handler() to initialize a WMI handler a
data pointer can be supplied which will be passed on to the notification
handler. No similar feature exist when handling WMI events via struct
wmi_driver.

Add a context field pointer to struct wmi_device_id and add a function
find_guid_context() to retrieve that context pointer.

Signed-off-by: Mattias Jacobsson <[e-mail]>
Signed-off-by: Andy Shevchenko <[e-mail]>

drivers/platform/x86/wmi.c

···
 	return false;
 }
 
+static const void *find_guid_context(struct wmi_block *wblock,
+				      struct wmi_driver *wdriver)
+{
+	const struct wmi_device_id *id;
+	uuid_le guid_input;
+
+	if (wblock == NULL || wdriver == NULL)
+		return NULL;
+	if (wdriver->id_table == NULL)
+		return NULL;
+
+	id = wdriver->id_table;
+	while (*id->guid_string) {
+		if (uuid_le_to_bin(id->guid_string, &guid_input))
+			continue;
+		if (!memcmp(wblock->gblock.guid, &guid_input, 16))
+			return id->context;
+		id++;
+	}
+	return NULL;
+}
+
 static int get_subobj_info(acpi_handle handle, const char *pathname,
 			   struct acpi_device_info **info)
 {

include/linux/mod_devicetable.h

···
  */
 struct wmi_device_id {
 	const char guid_string[UUID_STRING_LEN+1];
+	const void *context;
 };
 
 #endif /* LINUX_MOD_DEVICETABLE_H */