1 files changed, 31 insertions, 5 deletions

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index f4c6c90add78..6701d1011fce 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -116,17 +116,41 @@ void serdev_device_close(struct serdev_device *serdev)
 }
 EXPORT_SYMBOL_GPL(serdev_device_close);
 
-int serdev_device_write_buf(struct serdev_device *serdev,
-			    const unsigned char *buf, size_t count)
+void serdev_device_write_wakeup(struct serdev_device *serdev)
+{
+	complete(&serdev->write_comp);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
+
+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)
+	if (!ctrl || !ctrl->ops->write_buf ||
+	    (timeout && !serdev->ops->write_wakeup))
 		return -EINVAL;
 
-	return ctrl->ops->write_buf(ctrl, buf, count);
+	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_buf);
+EXPORT_SYMBOL_GPL(serdev_device_write);
 
 void serdev_device_write_flush(struct serdev_device *serdev)
 {
@@ -232,6 +256,8 @@ 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);