2 files changed, 52 insertions, 7 deletions

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 1c4829a56351..f71b47334149 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -116,6 +116,12 @@ void serdev_device_close(struct serdev_device *serdev)
 }
 EXPORT_SYMBOL_GPL(serdev_device_close);
 
+void serdev_device_write_wakeup(struct serdev_device *serdev)
+{
+	complete(&serdev->write_comp);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
+
 int serdev_device_write_buf(struct serdev_device *serdev,
 			    const unsigned char *buf, size_t count)
 {
@@ -128,6 +134,36 @@ int serdev_device_write_buf(struct serdev_device *serdev,
 }
 EXPORT_SYMBOL_GPL(serdev_device_write_buf);
 
+int serdev_device_write(struct serdev_device *serdev,
+			const unsigned char *buf, size_t count,
+			unsigned long timeout)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+	int ret;
+
+	if (!ctrl || !ctrl->ops->write_buf ||
+	    (timeout && !serdev->ops->write_wakeup))
+		return -EINVAL;
+
+	mutex_lock(&serdev->write_lock);
+	do {
+		reinit_completion(&serdev->write_comp);
+
+		ret = ctrl->ops->write_buf(ctrl, buf, count);
+		if (ret < 0)
+			break;
+
+		buf += ret;
+		count -= ret;
+
+	} while (count &&
+		 (timeout = wait_for_completion_timeout(&serdev->write_comp,
+							timeout)));
+	mutex_unlock(&serdev->write_lock);
+	return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write);
+
 void serdev_device_write_flush(struct serdev_device *serdev)
 {
 	struct serdev_controller *ctrl = serdev->ctrl;
@@ -262,6 +298,8 @@ struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
 	serdev->dev.parent = &ctrl->dev;
 	serdev->dev.bus = &serdev_bus_type;
 	serdev->dev.type = &serdev_device_type;
+	init_completion(&serdev->write_comp);
+	mutex_init(&serdev->write_lock);
 	return serdev;
 }
 EXPORT_SYMBOL_GPL(serdev_device_alloc);
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 487c88f6aa0e..d0a021c93986 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -102,9 +102,6 @@ static int ttyport_open(struct serdev_controller *ctrl)
 		return PTR_ERR(tty);
 	serport->tty = tty;
 
-	serport->port->client_ops = &client_ops;
-	serport->port->client_data = ctrl;
-
 	if (tty->ops->open)
 		tty->ops->open(serport->tty, NULL);
 	else
@@ -215,6 +212,7 @@ struct device *serdev_tty_port_register(struct tty_port *port,
 					struct device *parent,
 					struct tty_driver *drv, int idx)
 {
+	const struct tty_port_client_operations *old_ops;
 	struct serdev_controller *ctrl;
 	struct serport *serport;
 	int ret;
@@ -233,28 +231,37 @@ struct device *serdev_tty_port_register(struct tty_port *port,
 
 	ctrl->ops = &ctrl_ops;
 
+	old_ops = port->client_ops;
+	port->client_ops = &client_ops;
+	port->client_data = ctrl;
+
 	ret = serdev_controller_add(ctrl);
 	if (ret)
-		goto err_controller_put;
+		goto err_reset_data;
 
 	dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
 	return &ctrl->dev;
 
-err_controller_put:
+err_reset_data:
+	port->client_data = NULL;
+	port->client_ops = old_ops;
 	serdev_controller_put(ctrl);
+
 	return ERR_PTR(ret);
 }
 
-void serdev_tty_port_unregister(struct tty_port *port)
+int serdev_tty_port_unregister(struct tty_port *port)
 {
 	struct serdev_controller *ctrl = port->client_data;
 	struct serport *serport = serdev_controller_get_drvdata(ctrl);
 
 	if (!serport)
-		return;
+		return -ENODEV;
 
 	serdev_controller_remove(ctrl);
 	port->client_ops = NULL;
 	port->client_data = NULL;
 	serdev_controller_put(ctrl);
+
+	return 0;
 }