mei: bus: export client protocol version

export me client protocol version to sysfs and uevent

Signed-off-by: Tomas Winkler <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-bus-mei

···
 Contact:	Tomas Winkler <[e-mail]>
 Description:	Stores mei client device uuid
 		Format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+
+What:		/sys/bus/mei/devices/.../version
+Date:		Aug 2015
+KernelVersion:	4.3
+Contact:	Tomas Winkler <[e-mail]>
+Description:	Stores mei client protocol version
+		Format: %d

drivers/misc/mei/bus.c

···
 }
 static DEVICE_ATTR_RO(uuid);
 
+static ssize_t version_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	u8 version = mei_me_cl_ver(cldev->me_cl);
+	size_t len;
+
+	len = snprintf(buf, PAGE_SIZE, "%02X", version);
+
+	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
+}
+static DEVICE_ATTR_RO(version);
+
 static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
 			     char *buf)
 {
···
 static struct attribute *mei_cl_dev_attrs[] = {
 	&dev_attr_name.attr,
 	&dev_attr_uuid.attr,
+	&dev_attr_version.attr,
 	&dev_attr_modalias.attr,
 	NULL,
 };
···
 {
 	struct mei_cl_device *cldev = to_mei_cl_device(dev);
 	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
+	u8 version = mei_me_cl_ver(cldev->me_cl);
+
+	if (add_uevent_var(env, "MEI_CL_VERSION=%d", version))
+		return -ENOMEM;
 
 	if (add_uevent_var(env, "MEI_CL_UUID=%pUl", uuid))
 		return -ENOMEM;

drivers/misc/mei/client.h

···
 	return &me_cl->props.protocol_name;
 }
 
+/**
+ * mei_me_cl_ver - return me client protocol version
+ *
+ * @me_cl: me client
+ *
+ * Return: me client protocol version
+ */
+static inline u8 mei_me_cl_ver(const struct mei_me_client *me_cl)
+{
+	return me_cl->props.protocol_version;
+}
+
 /*
  * MEI IO Functions
  */