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 exported to the user space and eventually the user space can create sound controls which can belong to a LED group.
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 (SoundWire ASoC codecs).
# lsmod | grep snd_ctl_led snd_ctl_led 16384 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
v3 changes: - reorder the controls_rwsem use to fix the remaining mutex issue card->controls_rwsem <-> snd_ctl_layer_rwsem v2 changes: - fix the locking - remove the controls_rwsem read lock in the element get (the consistency is already protected with the global snd_ctl_led_mutex and possible partial value writes are catched with the next value change notification callback) - rename state to brightness and show the brightness unsigned integer value instead the text on/off string (sync with the LED core routines) - remove snd_ctl_led_hello() function (CI warning) - make snd_ctl_led_get_by_access() function static (CI warning) - move snd_ctl_layer_rwsem lock before the registraction callback call in snd_ctl_register_layer() - optimization v1: - https://lore.kernel.org/alsa-devel/20210211111400.1131020-1-perex@perex.cz/ Original RFC: - https://lore.kernel.org/alsa-devel/20210207201157.869972-1-perex@perex.cz/
Cc: Hans de Goede hdegoede@redhat.com Cc: Perry Yuan Perry.Yuan@dell.com
Jaroslav Kysela (5): ALSA: control - introduce snd_ctl_notify_one() helper ALSA: control - add layer registration routines ALSA: control - add generic LED trigger module as the new control layer ALSA: HDA - remove the custom implementation for the audio LED trigger ALSA: control - add sysfs support to the LED trigger module
include/sound/control.h | 27 ++- include/uapi/sound/asound.h | 6 +- sound/core/Kconfig | 6 + sound/core/Makefile | 2 + sound/core/control.c | 179 ++++++++++++--- sound/core/control_led.c | 377 ++++++++++++++++++++++++++++++++ sound/pci/hda/Kconfig | 4 +- sound/pci/hda/hda_codec.c | 69 +----- sound/pci/hda/hda_generic.c | 162 +++----------- sound/pci/hda/hda_generic.h | 15 +- sound/pci/hda/hda_local.h | 16 +- sound/pci/hda/patch_ca0132.c | 4 +- sound/pci/hda/patch_realtek.c | 2 +- sound/pci/hda/patch_sigmatel.c | 6 +- sound/pci/hda/thinkpad_helper.c | 2 +- 15 files changed, 614 insertions(+), 263 deletions(-) create mode 100644 sound/core/control_led.c