braille-console: Fix value returned by _braille_console_setup

commit bbeddf52adc1 ("printk: move braille console support into
separate braille.[ch] files") introduced _braille_console_setup()
to outline the braille initialization code.  There was however some
confusion over the value it was supposed to return. commit 2cfe6c4ac7ee
("printk: Fix return of braille_register_console()") tried to fix it
but failed to.

This fixes and documents the returned value according to the use
in printk.c: non-zero return means a parsing error, and thus this
console configuration should be ignored.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/kernel/printk/braille.h b/kernel/printk/braille.h
index 769d771145c8..749a6756843a 100644
--- a/kernel/printk/braille.h
+++ b/kernel/printk/braille.h
@@ -9,7 +9,14 @@ braille_set_options(struct console_cmdline *c, char *brl_options)
 	c->brl_options = brl_options;
 }
 
-char *
+/*
+ * Setup console according to braille options.
+ * Return -EINVAL on syntax error, 0 on success (or no braille option was
+ * actually given).
+ * Modifies str to point to the serial options
+ * Sets brl_options to the parsed braille options.
+ */
+int
 _braille_console_setup(char **str, char **brl_options);
 
 int
@@ -25,10 +32,10 @@ braille_set_options(struct console_cmdline *c, char *brl_options)
 {
 }
 
-static inline char *
+static inline int
 _braille_console_setup(char **str, char **brl_options)
 {
-	return NULL;
+	return 0;
 }
 
 static inline int