[PATCH v2 03/12] tty: serdev: Add flag buffer aware receive_buf_fp()

[Christoph Fritz <christoph.fritz@xxxxxxxxx>]

This patch introduces an additional receive buffer callback variation
besides the already existing receive_buf(). This new callback function
also passes the flag buffer (TTY_NORMAL, TTY_BREAK, and friends).

If defined, this function gets prioritized and called instead of the
standard receive_buf().

An alternative approach could have been to enhance the receive_buf()
function and update all drivers that use it.

Signed-off-by: Christoph Fritz <christoph.fritz@xxxxxxxxx>
---
 drivers/tty/serdev/serdev-ttyport.c |  2 +-
 include/linux/serdev.h              | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 3d7ae7fa50186..bb47691afdb21 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -32,7 +32,7 @@ static size_t ttyport_receive_buf(struct tty_port *port, const u8 *cp,
 	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
 		return 0;
 
-	ret = serdev_controller_receive_buf(ctrl, cp, count);
+	ret = serdev_controller_receive_buf(ctrl, cp, fp, count);
 
 	dev_WARN_ONCE(&ctrl->dev, ret > count,
 				"receive_buf returns %zu (count = %zu)\n",
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index ff78efc1f60df..c6ef5a8988e07 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -23,11 +23,17 @@ struct serdev_device;
  * struct serdev_device_ops - Callback operations for a serdev device
  * @receive_buf:	Function called with data received from device;
  *			returns number of bytes accepted; may sleep.
+ * @receive_buf_fp:	Function called with data and flag buffer received
+ *			from device; If defined, this function gets called
+ *			instead of @receive_buf;
+ *			returns number of bytes accepted; may sleep.
  * @write_wakeup:	Function called when ready to transmit more data; must
  *			not sleep.
  */
 struct serdev_device_ops {
 	size_t (*receive_buf)(struct serdev_device *, const u8 *, size_t);
+	ssize_t (*receive_buf_fp)(struct serdev_device *, const u8 *,
+				  const u8 *, size_t);
 	void (*write_wakeup)(struct serdev_device *);
 };
 
@@ -186,15 +192,20 @@ static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl
 }
 
 static inline size_t serdev_controller_receive_buf(struct serdev_controller *ctrl,
-						   const u8 *data,
+						   const u8 *data, const u8 *fp,
 						   size_t count)
 {
 	struct serdev_device *serdev = ctrl->serdev;
 
-	if (!serdev || !serdev->ops->receive_buf)
+	if (!serdev || !serdev->ops)
 		return 0;
 
-	return serdev->ops->receive_buf(serdev, data, count);
+	if (serdev->ops->receive_buf_fp)
+		return serdev->ops->receive_buf_fp(serdev, data, fp, count);
+	else if (serdev->ops->receive_buf)
+		return serdev->ops->receive_buf(serdev, data, count);
+
+	return 0;
 }
 
 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
-- 
2.39.2