[PATCH 07/10] serdev: add serdev_device_wait_until_sent

[Sebastian Reichel]

Add method, which waits until the transmission buffer has been sent.

Signed-off-by: Sebastian Reichel <s...@kernel.org>
---
 drivers/tty/serdev/core.c           | 11 +++++++++++
 drivers/tty/serdev/serdev-ttyport.c | 15 ++++++++++++++-
 include/linux/serdev.h              |  3 +++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index f4c6c90add78..a63b74031e22 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -173,6 +173,17 @@ void serdev_device_set_flow_control(struct serdev_device 
*serdev, bool enable)
 }
 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 
+void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
+{
+       struct serdev_controller *ctrl = serdev->ctrl;
+
+       if (!ctrl || !ctrl->ops->wait_until_sent)
+               return;
+
+       ctrl->ops->wait_until_sent(ctrl, timeout);
+}
+EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
+
 static int serdev_drv_probe(struct device *dev)
 {
        const struct serdev_device_driver *sdrv = 
to_serdev_device_driver(dev->driver);
diff --git a/drivers/tty/serdev/serdev-ttyport.c 
b/drivers/tty/serdev/serdev-ttyport.c
index d05393594f15..db2bc601e554 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -14,6 +14,7 @@
 #include <linux/serdev.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
+#include <linux/poll.h>
 
 #define SERPORT_ACTIVE         1
 
@@ -47,10 +48,13 @@ static void ttyport_write_wakeup(struct tty_port *port)
        struct serport *serport = serdev_controller_get_drvdata(ctrl);
 
        if (!test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags))
-               return;
+               goto out;
 
        if (test_bit(SERPORT_ACTIVE, &serport->flags))
                serdev_controller_write_wakeup(ctrl);
+
+out:
+       wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT);
 }
 
 static const struct tty_port_client_operations client_ops = {
@@ -167,6 +171,14 @@ static void ttyport_set_flow_control(struct 
serdev_controller *ctrl, bool enable
        tty_set_termios(tty, &ktermios);
 }
 
+static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long 
timeout)
+{
+       struct serport *serport = serdev_controller_get_drvdata(ctrl);
+       struct tty_struct *tty = serport->tty;
+
+       tty_wait_until_sent(tty, timeout);
+}
+
 static const struct serdev_controller_ops ctrl_ops = {
        .write_buf = ttyport_write_buf,
        .write_flush = ttyport_write_flush,
@@ -175,6 +187,7 @@ static const struct serdev_controller_ops ctrl_ops = {
        .close = ttyport_close,
        .set_flow_control = ttyport_set_flow_control,
        .set_baudrate = ttyport_set_baudrate,
+       .wait_until_sent = ttyport_wait_until_sent,
 };
 
 struct device *serdev_tty_port_register(struct tty_port *port,
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 9519da6253a8..a308b206d204 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -81,6 +81,7 @@ struct serdev_controller_ops {
        void (*close)(struct serdev_controller *);
        void (*set_flow_control)(struct serdev_controller *, bool);
        unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
+       void (*wait_until_sent)(struct serdev_controller *, long);
 };
 
 /**
@@ -186,6 +187,7 @@ int serdev_device_open(struct serdev_device *);
 void serdev_device_close(struct serdev_device *);
 unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
 void serdev_device_set_flow_control(struct serdev_device *, bool);
+void serdev_device_wait_until_sent(struct serdev_device *, long);
 int serdev_device_write_buf(struct serdev_device *, const unsigned char *, 
size_t);
 void serdev_device_write_flush(struct serdev_device *);
 int serdev_device_write_room(struct serdev_device *);
@@ -223,6 +225,7 @@ static inline unsigned int 
serdev_device_set_baudrate(struct serdev_device *sdev
        return 0;
 }
 static inline void serdev_device_set_flow_control(struct serdev_device *sdev, 
bool enable) {}
+static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, 
long timeout) {}
 static inline int serdev_device_write_buf(struct serdev_device *sdev, const 
unsigned char *buf, size_t count)
 {
        return -ENODEV;
-- 
2.11.0