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>

1 files changed, 8 insertions, 37 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 02d81d79deeb..bba150fdd265 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2687,44 +2687,15 @@ out:
 	return rth;
 }
 
-static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 cookie)
-{
-	return NULL;
-}
-
-static unsigned int ipv4_blackhole_mtu(const struct dst_entry *dst)
-{
-	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
-
-	return mtu ? : dst->dev->mtu;
-}
-
-static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
-					  struct sk_buff *skb, u32 mtu,
-					  bool confirm_neigh)
-{
-}
-
-static void ipv4_rt_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
-				       struct sk_buff *skb)
-{
-}
-
-static u32 *ipv4_rt_blackhole_cow_metrics(struct dst_entry *dst,
-					  unsigned long old)
-{
-	return NULL;
-}
-
 static struct dst_ops ipv4_dst_blackhole_ops = {
-	.family			=	AF_INET,
-	.check			=	ipv4_blackhole_dst_check,
-	.mtu			=	ipv4_blackhole_mtu,
-	.default_advmss		=	ipv4_default_advmss,
-	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
-	.redirect		=	ipv4_rt_blackhole_redirect,
-	.cow_metrics		=	ipv4_rt_blackhole_cow_metrics,
-	.neigh_lookup		=	ipv4_neigh_lookup,
+	.family			= AF_INET,
+	.default_advmss		= ipv4_default_advmss,
+	.neigh_lookup		= ipv4_neigh_lookup,
+	.check			= dst_blackhole_check,
+	.cow_metrics		= dst_blackhole_cow_metrics,
+	.update_pmtu		= dst_blackhole_update_pmtu,
+	.redirect		= dst_blackhole_redirect,
+	.mtu			= dst_blackhole_mtu,
 };
 
 struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)