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, 33 insertions, 0 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index a76bb50b6202..dcba4281ea48 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -6066,6 +6066,36 @@ void usb_hub_cleanup(void)
 } /* usb_hub_cleanup() */
 
 /**
+ * hub_hc_release_resources - clear resources used by host controller
+ * @udev: pointer to device being released
+ *
+ * Context: task context, might sleep
+ *
+ * Function releases the host controller resources in correct order before
+ * making any operation on resuming usb device. The host controller resources
+ * allocated for devices in tree should be released starting from the last
+ * usb device in tree toward the root hub. This function is used only during
+ * resuming device when usb device require reinitialization – that is, when
+ * flag udev->reset_resume is set.
+ *
+ * This call is synchronous, and may not be used in an interrupt context.
+ */
+static void hub_hc_release_resources(struct usb_device *udev)
+{
+	struct usb_hub *hub = usb_hub_to_struct_hub(udev);
+	struct usb_hcd *hcd = bus_to_hcd(udev->bus);
+	int i;
+
+	/* Release up resources for all children before this device */
+	for (i = 0; i < udev->maxchild; i++)
+		if (hub->ports[i]->child)
+			hub_hc_release_resources(hub->ports[i]->child);
+
+	if (hcd->driver->reset_device)
+		hcd->driver->reset_device(hcd, udev);
+}
+
+/**
  * usb_reset_and_verify_device - perform a USB port reset to reinitialize a device
  * @udev: device to reset (not in SUSPENDED or NOTATTACHED state)
  *
@@ -6129,6 +6159,9 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 	bos = udev->bos;
 	udev->bos = NULL;
 
+	if (udev->reset_resume)
+		hub_hc_release_resources(udev);
+
 	mutex_lock(hcd->address0_mutex);
 
 	for (i = 0; i < PORT_INIT_TRIES; ++i) {