[alsa-devel] [PATCH 1/2] ALSA: Add snd_ctl_update() to dynamically update a control
Add a function to dynamically update a given control. If the control does not already exist, a third parameter is used to determine whether to actually add that control. This is useful in cases where downloadable firmware at runtime can add or update existing controls. A separate patch needs to be made to make ALSA Mixer cope with this.
Signed-off-by: Dimitris Papastamos dp@opensource.wolfsonmicro.com --- include/sound/control.h | 1 + sound/core/control.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/include/sound/control.h b/include/sound/control.h index e67db28..12e4de7 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -113,6 +113,7 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, v void snd_ctl_free_one(struct snd_kcontrol * kcontrol); int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol); int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol); +int snd_ctl_update(struct snd_card * card, struct snd_kcontrol * kcontrol, int add_on_update); int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id); int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id); int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, diff --git a/sound/core/control.c b/sound/core/control.c index db51e4e..db23745 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -397,6 +397,50 @@ int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol) EXPORT_SYMBOL(snd_ctl_remove);
/** + * snd_ctl_update - update the control instance of the card + * @card: the card instance + * @kcontrol: the control instance to update + * @add_on_update: add the control if not already added + * + * Updates the control instance created via snd_ctl_new() or + * snd_ctl_new1() of the given card. + * + * Returns zero if successful, or a negative error code on failure. + * + */ +int snd_ctl_update(struct snd_card *card, struct snd_kcontrol *kcontrol, + int add_on_update) +{ + struct snd_ctl_elem_id id; + struct snd_kcontrol *old; + int ret; + + if (!kcontrol) + return -EINVAL; + if (snd_BUG_ON(!card || !kcontrol->info)) + return -EINVAL; + id = kcontrol->id; + down_write(&card->controls_rwsem); + old = snd_ctl_find_id(card, &id); + if (!old) { + up_write(&card->controls_rwsem); + if (add_on_update) + return snd_ctl_add(card, kcontrol); + return -EINVAL; + } + ret = snd_ctl_remove(card, old); + if (ret < 0) + return ret; + up_write(&card->controls_rwsem); + ret = snd_ctl_add(card, kcontrol); + if (ret < 0) + return ret; + return 0; +} + +EXPORT_SYMBOL(snd_ctl_update); + +/** * snd_ctl_remove_id - remove the control of the given id and release it * @card: the card instance * @id: the control id to remove
This function can be used to update or add controls at runtime. It will always try to add a given control if it does not already exist.
Signed-off-by: Dimitris Papastamos dp@opensource.wolfsonmicro.com --- include/sound/soc.h | 2 ++ sound/soc/soc-core.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/include/sound/soc.h b/include/sound/soc.h index bfa4836..509c1ea 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -344,6 +344,8 @@ struct snd_kcontrol *snd_soc_cnew(const struct snd_kcontrol_new *_template, const char *prefix); int snd_soc_add_controls(struct snd_soc_codec *codec, const struct snd_kcontrol_new *controls, int num_controls); +int snd_soc_update_controls(struct snd_soc_codec *codec, + const struct snd_kcontrol_new *controls, int num_controls); int snd_soc_info_enum_double(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo); int snd_soc_info_enum_ext(struct snd_kcontrol *kcontrol, diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 17efacd..815103a 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2420,6 +2420,39 @@ int snd_soc_add_controls(struct snd_soc_codec *codec, EXPORT_SYMBOL_GPL(snd_soc_add_controls);
/** + * snd_soc_update_controls - update an array of controls + * Convienience function to update a list of controls. + * + * @codec: codec to update controls of + * @controls: array of controls to update + * @num_controls: number of elements in the array + * + * Return 0 for success, else error. + */ +int snd_soc_update_controls(struct snd_soc_codec *codec, + const struct snd_kcontrol_new *controls, int num_controls) +{ + struct snd_card *card = codec->card->snd_card; + int err, i; + + for (i = 0; i < num_controls; i++) { + const struct snd_kcontrol_new *control = &controls[i]; + /* always add on update if not already added */ + err = snd_ctl_update(card, snd_soc_cnew(control, codec, + control->name, + codec->name_prefix), 1); + if (err < 0) { + dev_err(codec->dev, "%s: Failed to update %s: %d\n", + codec->name, control->name, err); + return err; + } + } + + return 0; +} +EXPORT_SYMBOL_GPL(snd_soc_update_controls); + +/** * snd_soc_info_enum_double - enumerated double mixer info callback * @kcontrol: mixer control * @uinfo: control element information
At Tue, 15 Mar 2011 12:21:41 +0000, Dimitris Papastamos wrote:
Add a function to dynamically update a given control. If the control does not already exist, a third parameter is used to determine whether to actually add that control. This is useful in cases where downloadable firmware at runtime can add or update existing controls. A separate patch needs to be made to make ALSA Mixer cope with this.
Signed-off-by: Dimitris Papastamos dp@opensource.wolfsonmicro.com
The change looks OK to me, but I think the name snd_ctl_update() is a bit confusing. It sounds as if it updates its content or such.
I thought of snd_ctl_replace(), but this should take two instances or so ("replace A with B"). If no better name comes up, I'm fine with snd_ctl_update().
thanks,
Takashi
include/sound/control.h | 1 + sound/core/control.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/include/sound/control.h b/include/sound/control.h index e67db28..12e4de7 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -113,6 +113,7 @@ struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new * kcontrolnew, v void snd_ctl_free_one(struct snd_kcontrol * kcontrol); int snd_ctl_add(struct snd_card * card, struct snd_kcontrol * kcontrol); int snd_ctl_remove(struct snd_card * card, struct snd_kcontrol * kcontrol); +int snd_ctl_update(struct snd_card * card, struct snd_kcontrol * kcontrol, int add_on_update); int snd_ctl_remove_id(struct snd_card * card, struct snd_ctl_elem_id *id); int snd_ctl_rename_id(struct snd_card * card, struct snd_ctl_elem_id *src_id, struct snd_ctl_elem_id *dst_id); int snd_ctl_activate_id(struct snd_card *card, struct snd_ctl_elem_id *id, diff --git a/sound/core/control.c b/sound/core/control.c index db51e4e..db23745 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -397,6 +397,50 @@ int snd_ctl_remove(struct snd_card *card, struct snd_kcontrol *kcontrol) EXPORT_SYMBOL(snd_ctl_remove);
/**
- snd_ctl_update - update the control instance of the card
- @card: the card instance
- @kcontrol: the control instance to update
- @add_on_update: add the control if not already added
- Updates the control instance created via snd_ctl_new() or
- snd_ctl_new1() of the given card.
- Returns zero if successful, or a negative error code on failure.
- */
+int snd_ctl_update(struct snd_card *card, struct snd_kcontrol *kcontrol,
int add_on_update)+{
- struct snd_ctl_elem_id id;
- struct snd_kcontrol *old;
- int ret;
- if (!kcontrol)
return -EINVAL;- if (snd_BUG_ON(!card || !kcontrol->info))
return -EINVAL;- id = kcontrol->id;
- down_write(&card->controls_rwsem);
- old = snd_ctl_find_id(card, &id);
- if (!old) {
up_write(&card->controls_rwsem);if (add_on_update)return snd_ctl_add(card, kcontrol);return -EINVAL;- }
- ret = snd_ctl_remove(card, old);
- if (ret < 0)
return ret;- up_write(&card->controls_rwsem);
- ret = snd_ctl_add(card, kcontrol);
- if (ret < 0)
return ret;- return 0;
+}
+EXPORT_SYMBOL(snd_ctl_update);
+/**
- snd_ctl_remove_id - remove the control of the given id and release it
- @card: the card instance
- @id: the control id to remove
-- 1.7.4.1
participants (2)
-
Dimitris Papastamos -
Takashi Iwai