Merge tag 'mute-led-rework' of https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound into asoc-5.13

ALSA: control - add generic LED API

This patchset tries to resolve the diversity in the audio LED
control among the ALSA drivers. A new control layer registration
is introduced which allows to run additional operations on
top of the elementary ALSA sound controls.

A new control access group (three bits in the access flags)
was introduced to carry the LED group information for
the sound controls. The low-level sound drivers can just
mark those controls using this access group. This information
is not exported to the user space, but user space can
manage the LED sound control associations through sysfs
(last patch) per Mark's request. It makes things fully
configurable in the kernel and user space (UCM).

The actual state ('route') evaluation is really easy
(the minimal value check for all channels / controls / cards).
If there's more complicated logic for a given hardware,
the card driver may eventually export a new read-only
sound control for the LED group and do the logic itself.

The new LED trigger control code is completely separated
and possibly optional (there's no symbol dependency).
The full code separation allows eventually to move this
LED trigger control to the user space in future.
Actually it replaces the already present functionality
in the kernel space (HDA drivers) and allows a quick adoption
for the recent hardware (ASoC codecs including SoundWire).

snd_ctl_led            24576  0

The sound driver implementation is really easy:

1) call snd_ctl_led_request() when control LED layer should be
   automatically activated
   / it calls module_request("snd-ctl-led") on demand /
2) mark all related kcontrols with
        SNDRV_CTL_ELEM_ACCESS_SPK_LED or
        SNDRV_CTL_ELEM_ACCESS_MIC_LED

Link: https://lore.kernel.org/r/20210317172945.842280-1-perex@perex.cz
Signed-off-by: Takashi Iwai <tiwai@suse.de>

2 files changed, 27 insertions, 23 deletions

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index c2689386a906..1556998425d5 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1492,7 +1492,11 @@ static struct dev_pm_opp *_opp_get_next(struct opp_table *opp_table,
 
 	mutex_lock(&opp_table->lock);
 	list_for_each_entry(temp, &opp_table->opp_list, node) {
-		if (dynamic == temp->dynamic) {
+		/*
+		 * Refcount must be dropped only once for each OPP by OPP core,
+		 * do that with help of "removed" flag.
+		 */
+		if (!temp->removed && dynamic == temp->dynamic) {
 			opp = temp;
 			break;
 		}
@@ -1502,10 +1506,27 @@ static struct dev_pm_opp *_opp_get_next(struct opp_table *opp_table,
 	return opp;
 }
 
-bool _opp_remove_all_static(struct opp_table *opp_table)
+/*
+ * Can't call dev_pm_opp_put() from under the lock as debugfs removal needs to
+ * happen lock less to avoid circular dependency issues. This routine must be
+ * called without the opp_table->lock held.
+ */
+static void _opp_remove_all(struct opp_table *opp_table, bool dynamic)
 {
 	struct dev_pm_opp *opp;
 
+	while ((opp = _opp_get_next(opp_table, dynamic))) {
+		opp->removed = true;
+		dev_pm_opp_put(opp);
+
+		/* Drop the references taken by dev_pm_opp_add() */
+		if (dynamic)
+			dev_pm_opp_put_opp_table(opp_table);
+	}
+}
+
+bool _opp_remove_all_static(struct opp_table *opp_table)
+{
 	mutex_lock(&opp_table->lock);
 
 	if (!opp_table->parsed_static_opps) {
@@ -1520,13 +1541,7 @@ bool _opp_remove_all_static(struct opp_table *opp_table)
 
 	mutex_unlock(&opp_table->lock);
 
-	/*
-	 * Can't remove the OPP from under the lock, debugfs removal needs to
-	 * happen lock less to avoid circular dependency issues.
-	 */
-	while ((opp = _opp_get_next(opp_table, false)))
-		dev_pm_opp_put(opp);
-
+	_opp_remove_all(opp_table, false);
 	return true;
 }
 
@@ -1539,25 +1554,12 @@ bool _opp_remove_all_static(struct opp_table *opp_table)
 void dev_pm_opp_remove_all_dynamic(struct device *dev)
 {
 	struct opp_table *opp_table;
-	struct dev_pm_opp *opp;
-	int count = 0;
 
 	opp_table = _find_opp_table(dev);
 	if (IS_ERR(opp_table))
 		return;
 
-	/*
-	 * Can't remove the OPP from under the lock, debugfs removal needs to
-	 * happen lock less to avoid circular dependency issues.
-	 */
-	while ((opp = _opp_get_next(opp_table, true))) {
-		dev_pm_opp_put(opp);
-		count++;
-	}
-
-	/* Drop the references taken by dev_pm_opp_add() */
-	while (count--)
-		dev_pm_opp_put_opp_table(opp_table);
+	_opp_remove_all(opp_table, true);
 
 	/* Drop the reference taken by _find_opp_table() */
 	dev_pm_opp_put_opp_table(opp_table);
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 50fb9dced3c5..407c3bfe51d9 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -56,6 +56,7 @@ extern struct list_head opp_tables, lazy_opp_tables;
  * @dynamic:	not-created from static DT entries.
  * @turbo:	true if turbo (boost) OPP
  * @suspend:	true if suspend OPP
+ * @removed:	flag indicating that OPP's reference is dropped by OPP core.
  * @pstate: Device's power domain's performance state.
  * @rate:	Frequency in hertz
  * @level:	Performance level
@@ -78,6 +79,7 @@ struct dev_pm_opp {
 	bool dynamic;
 	bool turbo;
 	bool suspend;
+	bool removed;
 	unsigned int pstate;
 	unsigned long rate;
 	unsigned int level;