ASoC: wm8904: Add DMIC and DRC support

Merge series from Francesco Dolcini <francesco@dolcini.it>:

This patch series adds DMIC and DRC support to the WM8904 driver, a new
of_ helper is added to simplify the driver code.

DRC functionality is added in the same patch series to provide the
necessary dynamic range control to make DMIC support useful.

The WM8904 supports digital microphones on two of its inputs:
IN1L/DMICDAT1 and IN1R/DMICDAT2. These two inputs can either be
connected to an ADC or to the DMIC system. There is an ADC for each
line, and only one DMIC block. This DMIC block is either connected to
DMICDAT1 or to DMICDAT2. One DMIC data line supports two digital
microphones via time multiplexing.

The pin's functionality is decided during hardware design (IN1L vs
DMICDAT1 and IN1R vs DMICDAT2). This is reflected in the Device Tree.

If one line is analog and one is DMIC, we need to be able to switch
between ADC and DMIC at runtime. The DMIC source is known from the
Device Tree. If both are DMIC inputs, we need to be able to switch the
DMIC source. There is no need to switch between ADC and DMIC at runtime.

Therefore, kcontrols are dynamically added by the driver depending on
its Device Tree configuration.

This is a heavy rework of a previous patch series provided by Alifer
Moraes and Pierluigi Passaro,
https://lore.kernel.org/lkml/20220307141041.27538-1-alifer.m@variscite.com.

1 files changed, 18 insertions, 7 deletions

diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 6488ead9e464..4d5fbacef496 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -472,7 +472,7 @@ bool switchdev_port_obj_act_is_deferred(struct net_device *dev,
 EXPORT_SYMBOL_GPL(switchdev_port_obj_act_is_deferred);
 
 static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain);
-static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain);
+static RAW_NOTIFIER_HEAD(switchdev_blocking_notif_chain);
 
 /**
  *	register_switchdev_notifier - Register notifier
@@ -518,17 +518,27 @@ EXPORT_SYMBOL_GPL(call_switchdev_notifiers);
 
 int register_switchdev_blocking_notifier(struct notifier_block *nb)
 {
-	struct blocking_notifier_head *chain = &switchdev_blocking_notif_chain;
+	struct raw_notifier_head *chain = &switchdev_blocking_notif_chain;
+	int err;
+
+	rtnl_lock();
+	err = raw_notifier_chain_register(chain, nb);
+	rtnl_unlock();
 
-	return blocking_notifier_chain_register(chain, nb);
+	return err;
 }
 EXPORT_SYMBOL_GPL(register_switchdev_blocking_notifier);
 
 int unregister_switchdev_blocking_notifier(struct notifier_block *nb)
 {
-	struct blocking_notifier_head *chain = &switchdev_blocking_notif_chain;
+	struct raw_notifier_head *chain = &switchdev_blocking_notif_chain;
+	int err;
 
-	return blocking_notifier_chain_unregister(chain, nb);
+	rtnl_lock();
+	err = raw_notifier_chain_unregister(chain, nb);
+	rtnl_unlock();
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(unregister_switchdev_blocking_notifier);
 
@@ -536,10 +546,11 @@ int call_switchdev_blocking_notifiers(unsigned long val, struct net_device *dev,
 				      struct switchdev_notifier_info *info,
 				      struct netlink_ext_ack *extack)
 {
+	ASSERT_RTNL();
 	info->dev = dev;
 	info->extack = extack;
-	return blocking_notifier_call_chain(&switchdev_blocking_notif_chain,
-					    val, info);
+	return raw_notifier_call_chain(&switchdev_blocking_notif_chain,
+				       val, info);
 }
 EXPORT_SYMBOL_GPL(call_switchdev_blocking_notifiers);