Re: [PATCH v7 3/7] ALSA: jack: extend snd_jack_new to support phantom jack

[Takashi Iwai <tiwai@suse.de>]

At Tue, 21 Apr 2015 16:05:41 +0800,
Jie Yang wrote:
> 
> For phantom jack, we won't create real jack device, but jack kctl
> may be needed.
> 
> Here, we extend snd_jack_new() to support phantom jack creating:
> pass in a bool param for [non-]phantom flag, and a non-Null param
> (struct snd_jack_kctl **) to indicate that we need create kctl
> at this jack creating stage.
> 
> We can also add kctl to a jack after the jack is created.
> 
> This make the integrating the existing HDA jack kctl and soc jack
> kctl possible.
> 
> Signed-off-by: Jie Yang <yang.jie@intel.com>
> ---
>  include/sound/jack.h            |  4 +--
>  sound/core/jack.c               | 56 +++++++++++++++++++++++++----------------
>  sound/pci/hda/hda_jack.c        |  2 +-
>  sound/pci/oxygen/xonar_wm87x6.c |  2 +-
>  sound/soc/soc-jack.c            |  2 +-
>  5 files changed, 39 insertions(+), 27 deletions(-)
> 
> diff --git a/include/sound/jack.h b/include/sound/jack.h
> index 9781e75..34b6849 100644
> --- a/include/sound/jack.h
> +++ b/include/sound/jack.h
> @@ -93,7 +93,7 @@ struct snd_jack_kctl {
>  #ifdef CONFIG_SND_JACK
>  
>  int snd_jack_new(struct snd_card *card, const char *id, int type,
> -		 struct snd_jack **jack);
> +		 struct snd_jack **jack, bool phantom_jack, struct snd_jack_kctl **jjack_kctl);
>  int snd_jack_add_new_kctl(struct snd_jack *jack, const char * name, int mask);
>  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,
> @@ -103,7 +103,7 @@ void snd_jack_report(struct snd_jack *jack, int status);
>  
>  #else
>  static inline int snd_jack_new(struct snd_card *card, const char *id, int type,
> -			       struct snd_jack **jack)
> +			       struct snd_jack **jack, bool phantom_jack, struct snd_jack_kctl **jjack_kctl)
>  {
>  	return 0;
>  }
> diff --git a/sound/core/jack.c b/sound/core/jack.c
> index b13d0b1..edd55c8 100644
> --- a/sound/core/jack.c
> +++ b/sound/core/jack.c
> @@ -198,6 +198,10 @@ EXPORT_SYMBOL(snd_jack_add_new_kctl);
>   * @type:  a bitmask of enum snd_jack_type values that can be detected by
>   *         this jack
>   * @jjack: Used to provide the allocated jack object to the caller.
> + * @phantom_jack: for phantom jack, only create needed kctl, won't create
> + *         real jackdevice
> + * @jjack_kctl: create kctl if non-NULL pointer passed in, and provide it to
> + *         the caller. also add it to the non-phantom jack kctl list
>   *
>   * Creates a new jack object.
>   *
> @@ -205,7 +209,7 @@ EXPORT_SYMBOL(snd_jack_add_new_kctl);
>   * On success @jjack will be initialised.
>   */
>  int snd_jack_new(struct snd_card *card, const char *id, int type,
> -		 struct snd_jack **jjack)
> +		 struct snd_jack **jjack, bool phantom_jack, struct snd_jack_kctl **jjack_kctl)

The caller doesn't need to get struct snd_jack_kctl.  Instead, it's
better to get struct snd_kcontrol.  In that way, you can move the
definition of struct snd_jack_kctl locally into jack.c.  It's merely
an internal object only for jack after all.

>  {
>  	struct snd_jack *jack;
>  	int err;
> @@ -216,35 +220,43 @@ int snd_jack_new(struct snd_card *card, const char *id, int type,
>  		.dev_disconnect = snd_jack_dev_disconnect,
>  	};
>  
> -	jack = kzalloc(sizeof(struct snd_jack), GFP_KERNEL);
> -	if (jack == NULL)
> -		return -ENOMEM;
> +	if (jjack_kctl)
> +		*jjack_kctl = snd_jack_kctl_new(card, id, type);
>  
> -	jack->id = kstrdup(id, GFP_KERNEL);
> +	/* don't creat real jack device for phantom jack */
> +	if (!phantom_jack) {
> +		jack = kzalloc(sizeof(struct snd_jack), GFP_KERNEL);

We need to create a jack object even for a phantom jack.  It's the
place managing the list of kctls.  Otherwise we can't track these
kctls.

Just skip creating jack->input_dev for phantom jacks.


Takashi