Document the asynchronous serdev_device_write_buf() and synchronous
serdev_device_write() functions using kernel-doc.
Specifically, mention that writing data only means that data has been
buffered by the controller, and that the synchronous helper depends on
serdev_device_write_wakeup() being called in the driver write_wakeup()
callback.
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/tty/serdev/core.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index c7006bbb793a..a0ac16ee6575 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -217,6 +217,21 @@ void serdev_device_write_wakeup(struct serdev_device *serdev)
}
EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
+/**
+ * serdev_device_write_buf() - write data asynchronously
+ * @serdev: serdev device
+ * @buf: data to be written
+ * @count: number of bytes to write
+ *
+ * Write data to the device asynchronously.
+ *
+ * Note that any accepted data has only been buffered by the controller; use
+ * serdev_device_wait_until_sent() to make sure the controller write buffer
+ * has actually been emptied.
+ *
+ * Return: The number of bytes written (less than count if not enough room in
+ * the write buffer), or a negative errno on errors.
+ */
int serdev_device_write_buf(struct serdev_device *serdev,
const unsigned char *buf, size_t count)
{
@@ -229,6 +244,28 @@ int serdev_device_write_buf(struct serdev_device *serdev,
}
EXPORT_SYMBOL_GPL(serdev_device_write_buf);
+/**
+ * serdev_device_write() - write data synchronously
+ * @serdev: serdev device
+ * @buf: data to be written
+ * @count: number of bytes to write
+ * @timeout: timeout in jiffies, or 0 to wait indefinitely
+ *
+ * Write data to the device synchronously by repeatedly calling
+ * serdev_device_write() until the controller has accepted all data (unless
+ * interrupted by a timeout or a signal).
+ *
+ * Note that any accepted data has only been buffered by the controller; use
+ * serdev_device_wait_until_sent() to make sure the controller write buffer
+ * has actually been emptied.
+ *
+ * Note that this function depends on serdev_device_write_wakeup() being
+ * called in the serdev driver write_wakeup() callback.
+ *
+ * Return: The number of bytes written (less than count if interrupted),
+ * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
+ * a negative errno on errors.
+ */
int serdev_device_write(struct serdev_device *serdev,
const unsigned char *buf, size_t count,
long timeout)
--
2.19.1
