Merge tag 'tags/mute-led-rework' into for-next

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>

1 files changed, 27 insertions, 17 deletions

diff --git a/drivers/s390/char/zcore.c b/drivers/s390/char/zcore.c
index 1515fdc3c1ab..bd3c724bf695 100644
--- a/drivers/s390/char/zcore.c
+++ b/drivers/s390/char/zcore.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
+#include <linux/reboot.h>
 
 #include <asm/asm-offsets.h>
 #include <asm/ipl.h>
@@ -238,6 +239,28 @@ static int __init zcore_reipl_init(void)
 	return 0;
 }
 
+static int zcore_reboot_and_on_panic_handler(struct notifier_block *self,
+					     unsigned long	   event,
+					     void		   *data)
+{
+	if (hsa_available)
+		release_hsa();
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block zcore_reboot_notifier = {
+	.notifier_call	= zcore_reboot_and_on_panic_handler,
+	/* we need to be notified before reipl and kdump */
+	.priority	= INT_MAX,
+};
+
+static struct notifier_block zcore_on_panic_notifier = {
+	.notifier_call	= zcore_reboot_and_on_panic_handler,
+	/* we need to be notified before reipl and kdump */
+	.priority	= INT_MAX,
+};
+
 static int __init zcore_init(void)
 {
 	unsigned char arch;
@@ -293,28 +316,15 @@ static int __init zcore_init(void)
 		goto fail;
 
 	zcore_dir = debugfs_create_dir("zcore" , NULL);
-	if (!zcore_dir) {
-		rc = -ENOMEM;
-		goto fail;
-	}
 	zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 						NULL, &zcore_reipl_fops);
-	if (!zcore_reipl_file) {
-		rc = -ENOMEM;
-		goto fail_dir;
-	}
 	zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 					     NULL, &zcore_hsa_fops);
-	if (!zcore_hsa_file) {
-		rc = -ENOMEM;
-		goto fail_reipl_file;
-	}
-	return 0;
 
-fail_reipl_file:
-	debugfs_remove(zcore_reipl_file);
-fail_dir:
-	debugfs_remove(zcore_dir);
+	register_reboot_notifier(&zcore_reboot_notifier);
+	atomic_notifier_chain_register(&panic_notifier_list, &zcore_on_panic_notifier);
+
+	return 0;
 fail:
 	diag308(DIAG308_REL_HSA, NULL);
 	return rc;