[PATCH] serdev: Restore serdev_device_write_buf for atomic context

[Stefan Wahren]

Starting with commit 6fe729c4bdae ("serdev: Add serdev_device_write
subroutine") the function serdev_device_write_buf cannot be used in
atomic context anymore (mutex_lock is sleeping). So restore the old
behavior.

Signed-off-by: Stefan Wahren <stefan.wah...@i2se.com>
Fixes: 6fe729c4bdae ("serdev: Add serdev_device_write subroutine")
---
 drivers/tty/serdev/core.c | 12 ++++++++++++
 include/linux/serdev.h    | 14 +++++++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 433de5e..f71b473 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -122,6 +122,18 @@ void serdev_device_write_wakeup(struct serdev_device 
*serdev)
 }
 EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
 
+int serdev_device_write_buf(struct serdev_device *serdev,
+                           const unsigned char *buf, size_t count)
+{
+       struct serdev_controller *ctrl = serdev->ctrl;
+
+       if (!ctrl || !ctrl->ops->write_buf)
+               return -EINVAL;
+
+       return ctrl->ops->write_buf(ctrl, buf, count);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_buf);
+
 int serdev_device_write(struct serdev_device *serdev,
                        const unsigned char *buf, size_t count,
                        unsigned long timeout)
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index cda76c6..e2a225b 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -195,6 +195,7 @@ 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);
+int serdev_device_write_buf(struct serdev_device *, const unsigned char *, 
size_t);
 void serdev_device_wait_until_sent(struct serdev_device *, long);
 int serdev_device_get_tiocm(struct serdev_device *);
 int serdev_device_set_tiocm(struct serdev_device *, int, int);
@@ -236,6 +237,12 @@ 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 int serdev_device_write_buf(struct serdev_device *serdev,
+                                         const unsigned char *buf,
+                                         size_t count)
+{
+       return -ENODEV;
+}
 static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, 
long timeout) {}
 static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
 {
@@ -312,11 +319,4 @@ static inline struct device 
*serdev_tty_port_register(struct tty_port *port,
 static inline void serdev_tty_port_unregister(struct tty_port *port) {}
 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
 
-static inline int serdev_device_write_buf(struct serdev_device *serdev,
-                                         const unsigned char *data,
-                                         size_t count)
-{
-       return serdev_device_write(serdev, data, count, 0);
-}
-
 #endif /*_LINUX_SERDEV_H */
-- 
2.1.4