[alsa-devel] [PATCH v2 1/2] ASoC: dapm: support user-defined stop condition in dai_get_connected_widgets
Piotr Stankiewicz
piotrs at opensource.wolfsonmicro.com
Wed May 4 14:28:23 CEST 2016
Certain situations may warrant examining DAPM paths only to a certain
arbitrary point, as opposed to always following them to the end. For
instance, when establishing a connection between a front-end DAI link
and a back-end DAI link in a DPCM path, it does not make sense to walk
the DAPM graph beyond the first widget associated with a back-end link.
This patch introduces a mechanism which lets a user of
dai_get_connected_widgets supply a function which will be called for
every node during the graph walk. When invoked, this function can
execute arbitrary logic to decide whether the walk, given a DAPM widget
and walk direction, should be terminated at that point or continued
as normal.
Signed-off-by: Piotr Stankiewicz <piotrs at opensource.wolfsonmicro.com>
---
include/sound/soc-dapm.h | 5 +++-
sound/soc/soc-dapm.c | 68 +++++++++++++++++++++++++++++++++++++---------
sound/soc/soc-pcm.c | 3 +-
3 files changed, 61 insertions(+), 15 deletions(-)
diff --git a/include/sound/soc-dapm.h b/include/sound/soc-dapm.h
index 9706946..fe5bc93 100644
--- a/include/sound/soc-dapm.h
+++ b/include/sound/soc-dapm.h
@@ -357,6 +357,7 @@ struct snd_soc_dapm_context;
struct regulator;
struct snd_soc_dapm_widget_list;
struct snd_soc_dapm_update;
+enum snd_soc_dapm_direction;
int dapm_regulator_event(struct snd_soc_dapm_widget *w,
struct snd_kcontrol *kcontrol, int event);
@@ -450,7 +451,9 @@ void dapm_mark_endpoints_dirty(struct snd_soc_card *card);
/* dapm path query */
int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
- struct snd_soc_dapm_widget_list **list);
+ struct snd_soc_dapm_widget_list **list,
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+ enum snd_soc_dapm_direction));
struct snd_soc_dapm_context *snd_soc_dapm_kcontrol_dapm(
struct snd_kcontrol *kcontrol);
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 801ae1a..075f0d7 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1073,7 +1073,11 @@ static int dapm_widget_list_create(struct snd_soc_dapm_widget_list **list,
*/
static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
struct list_head *list, enum snd_soc_dapm_direction dir,
- int (*fn)(struct snd_soc_dapm_widget *, struct list_head *))
+ int (*fn)(struct snd_soc_dapm_widget *, struct list_head *,
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+ enum snd_soc_dapm_direction)),
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+ enum snd_soc_dapm_direction))
{
enum snd_soc_dapm_direction rdir = SND_SOC_DAPM_DIR_REVERSE(dir);
struct snd_soc_dapm_path *path;
@@ -1088,6 +1092,13 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
if (list)
list_add_tail(&widget->work_list, list);
+ if (custom_stop_condition) {
+ con = custom_stop_condition(widget, dir);
+ if (con >= 0)
+ return con;
+ con = 0;
+ }
+
if ((widget->is_ep & SND_SOC_DAPM_DIR_TO_EP(dir)) && widget->connected) {
widget->endpoints[dir] = snd_soc_dapm_suspend_check(widget);
return widget->endpoints[dir];
@@ -1106,7 +1117,7 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
if (path->connect) {
path->walking = 1;
- con += fn(path->node[dir], list);
+ con += fn(path->node[dir], list, custom_stop_condition);
path->walking = 0;
}
}
@@ -1119,23 +1130,41 @@ static __always_inline int is_connected_ep(struct snd_soc_dapm_widget *widget,
/*
* Recursively check for a completed path to an active or physically connected
* output widget. Returns number of complete paths.
+ *
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, and should return an integer, as follows:
+ * - >=0: if the walk is to be stopped (this should indicate the number of
+ * endpoints the widget has),
+ * - <0 : if the walk is to be continued as normal.
*/
static int is_connected_output_ep(struct snd_soc_dapm_widget *widget,
- struct list_head *list)
+ struct list_head *list,
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *i,
+ enum snd_soc_dapm_direction))
{
return is_connected_ep(widget, list, SND_SOC_DAPM_DIR_OUT,
- is_connected_output_ep);
+ is_connected_output_ep, custom_stop_condition);
}
/*
* Recursively check for a completed path to an active or physically connected
* input widget. Returns number of complete paths.
+ *
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, and should return an integer, as follows:
+ * - >=0: if the walk is to be stopped (this should indicate the number of
+ * endpoints the widget has),
+ * - <0 : if the walk is to be continued as normal.
*/
static int is_connected_input_ep(struct snd_soc_dapm_widget *widget,
- struct list_head *list)
+ struct list_head *list,
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *i,
+ enum snd_soc_dapm_direction))
{
return is_connected_ep(widget, list, SND_SOC_DAPM_DIR_IN,
- is_connected_input_ep);
+ is_connected_input_ep, custom_stop_condition);
}
/**
@@ -1143,15 +1172,26 @@ static int is_connected_input_ep(struct snd_soc_dapm_widget *widget,
* @dai: the soc DAI.
* @stream: stream direction.
* @list: list of active widgets for this stream.
+ * @custom_stop_condition: (optional) a function meant to stop the widget graph
+ * walk based on custom logic.
*
* Queries DAPM graph as to whether an valid audio stream path exists for
* the initial stream specified by name. This takes into account
* current mixer and mux kcontrol settings. Creates list of valid widgets.
*
+ * Optionally, can be supplied with a function acting as a stopping condition.
+ * This function takes the dapm widget currently being examined and the walk
+ * direction as an arguments, and should return an integer, as follows:
+ * - >=0: if the walk is to be stopped (this should indicate the number of
+ * endpoints the widget has),
+ * - <0 : if the walk is to be continued as normal.
+ *
* Returns the number of valid paths or negative error.
*/
int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
- struct snd_soc_dapm_widget_list **list)
+ struct snd_soc_dapm_widget_list **list,
+ int (*custom_stop_condition)(struct snd_soc_dapm_widget *,
+ enum snd_soc_dapm_direction))
{
struct snd_soc_card *card = dai->component->card;
struct snd_soc_dapm_widget *w;
@@ -1171,9 +1211,11 @@ int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
}
if (stream == SNDRV_PCM_STREAM_PLAYBACK)
- paths = is_connected_output_ep(dai->playback_widget, &widgets);
+ paths = is_connected_output_ep(dai->playback_widget, &widgets,
+ custom_stop_condition);
else
- paths = is_connected_input_ep(dai->capture_widget, &widgets);
+ paths = is_connected_input_ep(dai->capture_widget, &widgets,
+ custom_stop_condition);
/* Drop starting point */
list_del(widgets.next);
@@ -1268,8 +1310,8 @@ static int dapm_generic_check_power(struct snd_soc_dapm_widget *w)
DAPM_UPDATE_STAT(w, power_checks);
- in = is_connected_input_ep(w, NULL);
- out = is_connected_output_ep(w, NULL);
+ in = is_connected_input_ep(w, NULL, NULL);
+ out = is_connected_output_ep(w, NULL, NULL);
return out != 0 && in != 0;
}
@@ -1928,8 +1970,8 @@ static ssize_t dapm_widget_power_read_file(struct file *file,
in = 0;
out = 0;
} else {
- in = is_connected_input_ep(w, NULL);
- out = is_connected_output_ep(w, NULL);
+ in = is_connected_input_ep(w, NULL, NULL);
+ out = is_connected_output_ep(w, NULL, NULL);
}
ret = snprintf(buf, PAGE_SIZE, "%s: %s%s in %d out %d",
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index aa99dac..c2b0aa8 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1294,7 +1294,8 @@ int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
int paths;
/* get number of valid DAI paths and their widgets */
- paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list);
+ paths = snd_soc_dapm_dai_get_connected_widgets(cpu_dai, stream, list,
+ NULL);
dev_dbg(fe->dev, "ASoC: found %d audio %s paths\n", paths,
stream ? "capture" : "playback");
--
1.7.10.4
More information about the Alsa-devel
mailing list