[PATCH v5 7/7] console: Introduce ->exit() callback

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

Some consoles might require special operations on unregistering.
For instance, serial console, when registered in the kernel,
keeps power on for entire time, until it gets unregistered.
Example of use:

	->setup(console):
		pm_runtime_get(...);

	->exit(console):
		pm_runtime_put(...);

For such cases to have a balance we would provide ->exit() callback.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v5: Return error code from ->exit() (Sergey)

 include/linux/console.h | 1 +
 kernel/printk/printk.c  | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/linux/console.h b/include/linux/console.h
index f33016b3a401..7a140f4e5d0c 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -148,6 +148,7 @@ struct console {
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
 	int	(*setup)(struct console *, char *);
+	int	(*exit)(struct console *);
 	int	(*match)(struct console *, char *name, int idx, char *options);
 	short	flags;
 	short	index;
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index abd9b92ae0e3..43b5cb88c607 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2860,6 +2860,9 @@ int unregister_console(struct console *console)
 	console_unlock();
 	console_sysfs_notify();
 
+	if (console->exit)
+		res = console->exit(console);
+
 	return res;
 
 out_disable_unlock:
-- 
2.24.1