1 files changed, 70 insertions, 5 deletions

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 1d21a9c1d33e..4fb3165384c4 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -34,7 +34,9 @@ static int tty_port_default_receive_buf(struct tty_port *port,
         if (!disc)
                 return 0;
 
+        mutex_lock(&tty->atomic_write_lock);
         ret = tty_ldisc_receive_buf(disc, p, (char *)f, count);
+        mutex_unlock(&tty->atomic_write_lock);
 
         tty_ldisc_deref(disc);
 
@@ -129,19 +131,85 @@ struct device *tty_port_register_device_attr(struct tty_port *port,
                 struct device *device, void *drvdata,
                 const struct attribute_group **attr_grp)
 {
+        tty_port_link_device(port, driver, index);
+        return tty_register_device_attr(driver, index, device, drvdata,
+                        attr_grp);
+}
+EXPORT_SYMBOL_GPL(tty_port_register_device_attr);
+
+/**
+ * tty_port_register_device_attr_serdev - register tty or serdev device
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ * @device: parent if exists, otherwise NULL
+ * @drvdata: driver data for the device
+ * @attr_grp: attribute group for the device
+ *
+ * Register a serdev or tty device depending on if the parent device has any
+ * defined serdev clients or not.
+ */
+struct device *tty_port_register_device_attr_serdev(struct tty_port *port,
+                struct tty_driver *driver, unsigned index,
+                struct device *device, void *drvdata,
+                const struct attribute_group **attr_grp)
+{
         struct device *dev;
 
         tty_port_link_device(port, driver, index);
 
         dev = serdev_tty_port_register(port, device, driver, index);
-        if (PTR_ERR(dev) != -ENODEV)
+        if (PTR_ERR(dev) != -ENODEV) {
                 /* Skip creating cdev if we registered a serdev device */
                 return dev;
+        }
 
         return tty_register_device_attr(driver, index, device, drvdata,
                         attr_grp);
 }
-EXPORT_SYMBOL_GPL(tty_port_register_device_attr);
+EXPORT_SYMBOL_GPL(tty_port_register_device_attr_serdev);
+
+/**
+ * tty_port_register_device_serdev - register tty or serdev device
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ * @device: parent if exists, otherwise NULL
+ *
+ * Register a serdev or tty device depending on if the parent device has any
+ * defined serdev clients or not.
+ */
+struct device *tty_port_register_device_serdev(struct tty_port *port,
+                struct tty_driver *driver, unsigned index,
+                struct device *device)
+{
+        return tty_port_register_device_attr_serdev(port, driver, index,
+                        device, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(tty_port_register_device_serdev);
+
+/**
+ * tty_port_unregister_device - deregister a tty or serdev device
+ * @port: tty_port of the device
+ * @driver: tty_driver for this device
+ * @index: index of the tty
+ *
+ * If a tty or serdev device is registered with a call to
+ * tty_port_register_device_serdev() then this function must be called when
+ * the device is gone.
+ */
+void tty_port_unregister_device(struct tty_port *port,
+                struct tty_driver *driver, unsigned index)
+{
+        int ret;
+
+        ret = serdev_tty_port_unregister(port);
+        if (ret == 0)
+                return;
+
+        tty_unregister_device(driver, index);
+}
+EXPORT_SYMBOL_GPL(tty_port_unregister_device);
 
 int tty_port_alloc_xmit_buf(struct tty_port *port)
 {
@@ -189,9 +257,6 @@ static void tty_port_destructor(struct kref *kref)
         /* check if last port ref was dropped before tty release */
         if (WARN_ON(port->itty))
                 return;
-
-        serdev_tty_port_unregister(port);
-
         if (port->xmit_buf)
                 free_page((unsigned long)port->xmit_buf);
         tty_port_destroy(port);