ALSA: jack: Allow building the jack layer without input device

Since the recent integration of kctl jack and input jack layers, we
can basically build the jack layer even without input devices.  That
is, the jack layer itself can be built with conditional to enable the
input device support or not, while the users may enable always
CONFIG_SND_JACK unconditionally.

For achieving it, this patch changes the following:
- A new Kconfig, CONFIG_SND_JACK_INPUT_DEV, was introduced to indicate
  whether the jack layer supports the input device,
- A few items in snd_jack struct and relevant codes are conditionally
  built upon CONFIG_SND_JACK_INPUT_DEV,
- The users of CONFIG_SND_JACK drop the messy dependency on
  CONFIG_INPUT.

This change also automagically fixes a potential bug in HD-audio
driver Arnd reported, where the NULL or uninitialized jack instance is
dereferenced.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 14 insertions, 9 deletions

diff --git a/include/sound/jack.h b/include/sound/jack.h
index 23bede121c78..1e84bfb553cf 100644
--- a/include/sound/jack.h
+++ b/include/sound/jack.h
@@ -72,14 +72,16 @@ enum snd_jack_types {
 #define SND_JACK_SWITCH_TYPES 6
 
 struct snd_jack {
-	struct input_dev *input_dev;
 	struct list_head kctl_list;
 	struct snd_card *card;
+	const char *id;
+#ifdef CONFIG_SND_JACK_INPUT_DEV
+	struct input_dev *input_dev;
 	int registered;
 	int type;
-	const char *id;
 	char name[100];
 	unsigned int key[6];   /* Keep in sync with definitions above */
+#endif /* CONFIG_SND_JACK_INPUT_DEV */
 	void *private_data;
 	void (*private_free)(struct snd_jack *);
 };
@@ -89,10 +91,11 @@ struct snd_jack {
 int snd_jack_new(struct snd_card *card, const char *id, int type,
 		 struct snd_jack **jack, bool initial_kctl, bool phantom_jack);
 int snd_jack_add_new_kctl(struct snd_jack *jack, const char * name, int mask);
+#ifdef CONFIG_SND_JACK_INPUT_DEV
 void snd_jack_set_parent(struct snd_jack *jack, struct device *parent);
 int snd_jack_set_key(struct snd_jack *jack, enum snd_jack_types type,
 		     int keytype);
-
+#endif
 void snd_jack_report(struct snd_jack *jack, int status);
 
 #else
@@ -107,6 +110,13 @@ static inline int snd_jack_add_new_kctl(struct snd_jack *jack, const char * name
 	return 0;
 }
 
+static inline void snd_jack_report(struct snd_jack *jack, int status)
+{
+}
+
+#endif
+
+#if !defined(CONFIG_SND_JACK) || !defined(CONFIG_SND_JACK_INPUT_DEV)
 static inline void snd_jack_set_parent(struct snd_jack *jack,
 				       struct device *parent)
 {
@@ -118,11 +128,6 @@ static inline int snd_jack_set_key(struct snd_jack *jack,
 {
 	return 0;
 }
-
-static inline void snd_jack_report(struct snd_jack *jack, int status)
-{
-}
-
-#endif
+#endif /* !CONFIG_SND_JACK || !CONFIG_SND_JACK_INPUT_DEV */
 
 #endif