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, 11 insertions, 18 deletions

diff --git a/drivers/media/rc/keymaps/Makefile b/drivers/media/rc/keymaps/Makefile
index b252a1d2ebd6..cc6662e1903f 100644
--- a/drivers/media/rc/keymaps/Makefile
+++ b/drivers/media/rc/keymaps/Makefile
@@ -21,7 +21,6 @@ obj-$(CONFIG_RC_MAP) += rc-adstech-dvb-t-pci.o \
 			rc-behold.o \
 			rc-behold-columbus.o \
 			rc-budget-ci-old.o \
-			rc-cec.o \
 			rc-cinergy-1400.o \
 			rc-cinergy.o \
 			rc-d680-dmb.o \
diff --git a/drivers/media/rc/keymaps/rc-cec.c b/drivers/media/rc/keymaps/rc-cec.c
index 3e3bd11092b4..068e22aeac8c 100644
--- a/drivers/media/rc/keymaps/rc-cec.c
+++ b/drivers/media/rc/keymaps/rc-cec.c
@@ -1,6 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /* Keytable for the CEC remote control
  *
+ * This keymap is unusual in that it can't be built as a module,
+ * instead it is registered directly in rc-main.c if CONFIG_MEDIA_CEC_RC
+ * is set. This is because it can be called from drm_dp_cec_set_edid() via
+ * cec_register_adapter() in an asynchronous context, and it is not
+ * allowed to use request_module() to load rc-cec.ko in that case.
+ *
+ * Since this keymap is only used if CONFIG_MEDIA_CEC_RC is set, we
+ * just compile this keymap into the rc-core module and never as a
+ * separate module.
+ *
  * Copyright (c) 2015 by Kamil Debski
  */
 
@@ -152,7 +162,7 @@ static struct rc_map_table cec[] = {
 	/* 0x77-0xff: Reserved */
 };
 
-static struct rc_map_list cec_map = {
+struct rc_map_list cec_map = {
 	.map = {
 		.scan		= cec,
 		.size		= ARRAY_SIZE(cec),
@@ -160,19 +170,3 @@ static struct rc_map_list cec_map = {
 		.name		= RC_MAP_CEC,
 	}
 };
-
-static int __init init_rc_map_cec(void)
-{
-	return rc_map_register(&cec_map);
-}
-
-static void __exit exit_rc_map_cec(void)
-{
-	rc_map_unregister(&cec_map);
-}
-
-module_init(init_rc_map_cec);
-module_exit(exit_rc_map_cec);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Kamil Debski");