tty: serdev: drop serdev_controller_ops::write_room()

In particular, serdev_device_write_room() is not called, so the whole
serdev's write_room() can go.

Signed-off-by: Jiri Slaby (SUSE) <[email protected]>
Cc: Rob Herring <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Jiri Slaby (SUSE)

drivers/tty/serdev/core.c

@@ -316,17 +316,6 @@ void serdev_device_write_flush(struct serdev_device *serdev)
 }
 EXPORT_SYMBOL_GPL(serdev_device_write_flush);
 
-int serdev_device_write_room(struct serdev_device *serdev)
-{
-	struct serdev_controller *ctrl = serdev->ctrl;
-
-	if (!ctrl || !ctrl->ops->write_room)
-		return 0;
-
-	return serdev->ctrl->ops->write_room(ctrl);
-}
-EXPORT_SYMBOL_GPL(serdev_device_write_room);
-
 unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
 {
 	struct serdev_controller *ctrl = serdev->ctrl;

drivers/tty/serdev/serdev-ttyport.c

@@ -92,14 +92,6 @@ static void ttyport_write_flush(struct serdev_controller *ctrl)
 	tty_driver_flush_buffer(tty);
 }
 
-static int ttyport_write_room(struct serdev_controller *ctrl)
-{
-	struct serport *serport = serdev_controller_get_drvdata(ctrl);
-	struct tty_struct *tty = serport->tty;
-
-	return tty_write_room(tty);
-}
-
 static int ttyport_open(struct serdev_controller *ctrl)
 {
 	struct serport *serport = serdev_controller_get_drvdata(ctrl);
@@ -259,7 +251,6 @@ static int ttyport_break_ctl(struct serdev_controller *ctrl, unsigned int break_
 static const struct serdev_controller_ops ctrl_ops = {
 	.write_buf = ttyport_write_buf,
 	.write_flush = ttyport_write_flush,
-	.write_room = ttyport_write_room,
 	.open = ttyport_open,
 	.close = ttyport_close,
 	.set_flow_control = ttyport_set_flow_control,

include/linux/serdev.h

@@ -84,7 +84,6 @@ enum serdev_parity {
 struct serdev_controller_ops {
 	ssize_t (*write_buf)(struct serdev_controller *, const u8 *, size_t);
 	void (*write_flush)(struct serdev_controller *);
-	int (*write_room)(struct serdev_controller *);
 	int (*open)(struct serdev_controller *);
 	void (*close)(struct serdev_controller *);
 	void (*set_flow_control)(struct serdev_controller *, bool);
@@ -212,7 +211,6 @@ int serdev_device_break_ctl(struct serdev_device *serdev, int break_state);
 void serdev_device_write_wakeup(struct serdev_device *);
 ssize_t serdev_device_write(struct serdev_device *, const u8 *, size_t, long);
 void serdev_device_write_flush(struct serdev_device *);
-int serdev_device_write_room(struct serdev_device *);
 
 /*
  * serdev device driver functions
@@ -273,10 +271,6 @@ static inline ssize_t serdev_device_write(struct serdev_device *sdev,
 	return -ENODEV;
 }
 static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
-static inline int serdev_device_write_room(struct serdev_device *sdev)
-{
-	return 0;
-}
 
 #define serdev_device_driver_register(x)
 #define serdev_device_driver_unregister(x)