On 31. 05. 22, 6:36, Mychaela N. Falconia wrote:
From: Johan Hovold <johan@xxxxxxxxxx>
Add a nordy sysfs attribute to suppress raising the modem-control lines
on open to signal DTE readiness.
This can be used to prevent undesirable side-effects on open for
applications where the DTR and RTS lines are used for non-standard
purposes such as generating power-on and reset pulses.
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Mychaela N. Falconia <falcon@xxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-tty | 7 +++++++
drivers/tty/serial/serial_core.c | 26 ++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-tty b/Documentation/ABI/testing/sysfs-tty
index 820e412d38a8..98cb5cf0af75 100644
--- a/Documentation/ABI/testing/sysfs-tty
+++ b/Documentation/ABI/testing/sysfs-tty
@@ -161,3 +161,10 @@ Contact: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Description:
Allows user to detach or attach back the given device as
kernel console. It shows and accepts a boolean variable.
+
+What: /sys/class/tty/ttyS0/nordy
s@ttyS0@ttyS<x>@
+Date: November 2020
+Contact: Johan Hovold <johan@xxxxxxxxxx>
+Description:
+ Show and store the port NORDY flag which suppresses raising
+ the modem-control lines on open to signal DTE readiness.
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 9a85b41caa0a..a17ac4efaceb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2870,6 +2870,30 @@ static ssize_t console_store(struct device *dev,
return ret < 0 ? ret : count;
}
+static ssize_t nordy_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct tty_port *port = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", tty_port_nordy(port));
sysfs_emit()? (Even if I know %d won't overflow PAGE_SIZE :P.)
thanks,
--
js
suse labs
