wake up from a serial port
Enable wakeup from serial ports, make it run-time configurable over sysfs,
e.g.,
echo enabled > /sys/devices/platform/serial8250.0/tty/ttyS0/power/wakeup
Requires
# CONFIG_SYSFS_DEPRECATED is not set
Following suggestions from Alan and Russell moved the may_wake_up checks
to serial_core.c. This time actually tested - it does even work. Could
someone, please, verify, that put_device after device_find_child is
correct?
Also would be nice to test with a Natsemi UART, that can wake up the system,
if such systems exist.
For this you just have to apply the patch below, issue the above "echo"
command to one of your Natsemi port, suspend and resume your system, and
verify that your Natsemi port still works. If you are actually capable of
waking up the system from that port, would be nice to test that as well.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index a3bd3a3..68aa4da 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1938,9 +1938,24 @@
}
}
+struct uart_match {
+ struct uart_port *port;
+ struct uart_driver *driver;
+};
+
+static int serial_match_port(struct device *dev, void *data)
+{
+ struct uart_match *match = data;
+ dev_t devt = MKDEV(match->driver->major, match->driver->minor) + match->port->line;
+
+ return dev->devt == devt; /* Actually, only one tty per port */
+}
+
int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
{
struct uart_state *state = drv->state + port->line;
+ struct device *tty_dev;
+ struct uart_match match = {port, drv};
mutex_lock(&state->mutex);
@@ -1951,6 +1966,15 @@
}
#endif
+ tty_dev = device_find_child(port->dev, &match, serial_match_port);
+ if (device_may_wakeup(tty_dev)) {
+ enable_irq_wake(port->irq);
+ put_device(tty_dev);
+ mutex_unlock(&state->mutex);
+ return 0;
+ }
+ port->suspended = 1;
+
if (state->info && state->info->flags & UIF_INITIALIZED) {
const struct uart_ops *ops = port->ops;
@@ -1999,6 +2023,13 @@
}
#endif
+ if (!port->suspended) {
+ disable_irq_wake(port->irq);
+ mutex_unlock(&state->mutex);
+ return 0;
+ }
+ port->suspended = 0;
+
uart_change_pm(state, 0);
/*
@@ -2278,6 +2309,7 @@
{
struct uart_state *state;
int ret = 0;
+ struct device *tty_dev;
BUG_ON(in_interrupt());
@@ -2314,7 +2346,13 @@
* Register the port whether it's detected or not. This allows
* setserial to be used to alter this ports parameters.
*/
- tty_register_device(drv->tty_driver, port->line, port->dev);
+ tty_dev = tty_register_device(drv->tty_driver, port->line, port->dev);
+ if (likely(!IS_ERR(tty_dev))) {
+ device_can_wakeup(tty_dev) = 1;
+ device_set_wakeup_enable(tty_dev, 0);
+ } else
+ printk(KERN_ERR "Cannot register tty device on line %d\n",
+ port->line);
/*
* Ensure UPF_DEAD is not set.