[RFC PATCH 0/2] soundwire: add master_device/driver support

[RFC PATCH 0/2] soundwire: add master_device/driver support

[Pierre-Louis Bossart]

The SoundWire master representation needs to evolve to take into account:

a) a May 2019 recommendation from Greg KH to remove platform devices

b) the need on Intel platforms to support hardware startup only once
the power rail dependencies are settled. The SoundWire master is not
an independent IP at all.

c) the need to deal with external wakes handled by the PCI subsystem
in specific low-power modes

In case it wasn't clear, the SoundWire subsystem is currently unusable
with v5.5 on devices hitting the shelves very soon (race conditions,
power management, suspend/resume, etc). v5.6 will only provide
interface changes and no functional improvement. We've circled on the
same concepts since September 2019, and I hope this direction is now
aligned with the suggestions from Vinod Koul and that we can target
v5.7 as the 'SoundWire just works(tm)' version.

This series is provided as an RFC since it depends on patches already
for review.

Pierre-Louis Bossart (2):
  soundwire: bus_type: add master_device/driver support
  soundwire: intel: transition to sdw_master_device/driver support

 drivers/soundwire/Makefile         |   2 +-
 drivers/soundwire/bus_type.c       | 141 +++++++++++++-
 drivers/soundwire/intel.c          |  96 ++++++----
 drivers/soundwire/intel.h          |   8 +-
 drivers/soundwire/intel_init.c     | 283 ++++++++++++++++++++++-------
 drivers/soundwire/master.c         | 119 ++++++++++++
 drivers/soundwire/slave.c          |   7 +-
 include/linux/soundwire/sdw.h      |  83 +++++++++
 include/linux/soundwire/sdw_type.h |  36 +++-
 9 files changed, 662 insertions(+), 113 deletions(-)
 create mode 100644 drivers/soundwire/master.c

-- 
2.20.1

[RFC PATCH 1/2] soundwire: bus_type: add master_device/driver support

[Pierre-Louis Bossart]

In the existing SoundWire code, Master Devices are not explicitly
represented - only SoundWire Slave Devices are exposed (the use of
capital letters follows the SoundWire specification conventions).

The SoundWire Master Device provides the clock, synchronization
information and command/control channels. When multiple links are
supported, a Controller may expose more than one Master Device; they
are typically embedded inside a larger audio cluster (be it in an
SOC/chipset or an external audio codec), and we need to describe it
using the Linux device and driver model.  This will allow for
configuration functions to account for external dependencies such as
power rails, clock sources or wake-up mechanisms. This transition will
also allow for better sysfs support without the reference count issues
mentioned in the initial reviews.

In this patch, we convert the existing code to use an explicit
sdw_slave_type, then define new objects (sdw_master_device and
sdw_master_driver).

A parent (such as the Intel audio controller or its equivalent on
Qualcomm devices) would use sdw_master_device_add() to create the
device, passing a driver name as a parameter. The master device would
be released when device_unregister() is invoked by the parent.

Note that since there is no standard for the Master host-facing
interface, so the bus matching relies on a simple string matching (as
previously done with platform devices).

The 'Master Device' driver exposes callbacks for
probe/startup/shutdown/remove/process_wake. The startup, shutdown, and
process wake need to be called by the parent directly (using
wrappers), while the probe/remove are handled by the SoundWire bus
core upon device creation and release.

Additional callbacks will be added in the future for e.g. autonomous
clock stop modes.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/Makefile         |   2 +-
 drivers/soundwire/bus_type.c       | 141 +++++++++++++++++++++++++++--
 drivers/soundwire/master.c         | 119 ++++++++++++++++++++++++
 drivers/soundwire/slave.c          |   7 +-
 include/linux/soundwire/sdw.h      |  83 +++++++++++++++++
 include/linux/soundwire/sdw_type.h |  36 +++++++-
 6 files changed, 377 insertions(+), 11 deletions(-)
 create mode 100644 drivers/soundwire/master.c

diff --git a/drivers/soundwire/Makefile b/drivers/soundwire/Makefile
index e2cdff990e9f..7319918e0aec 100644
--- a/drivers/soundwire/Makefile
+++ b/drivers/soundwire/Makefile
@@ -4,7 +4,7 @@
 #
 
 #Bus Objs
-soundwire-bus-objs := bus_type.o bus.o slave.o mipi_disco.o stream.o
+soundwire-bus-objs := bus_type.o bus.o master.o slave.o mipi_disco.o stream.o
 obj-$(CONFIG_SOUNDWIRE) += soundwire-bus.o
 
 ifdef CONFIG_DEBUG_FS
diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
index 17f096dd6806..e610f1d3b840 100644
--- a/drivers/soundwire/bus_type.c
+++ b/drivers/soundwire/bus_type.c
@@ -33,13 +33,33 @@ sdw_get_device_id(struct sdw_slave *slave, struct sdw_driver *drv)
 
 static int sdw_bus_match(struct device *dev, struct device_driver *ddrv)
 {
-	struct sdw_slave *slave = dev_to_sdw_dev(dev);
-	struct sdw_driver *drv = drv_to_sdw_driver(ddrv);
+	struct sdw_slave *slave;
+	struct sdw_driver *drv;
+	struct sdw_master_device *md;
+	struct sdw_master_driver *mdrv;
+	int ret = 0;
 
-	return !!sdw_get_device_id(slave, drv);
+	if (is_sdw_slave(dev)) {
+		slave = dev_to_sdw_dev(dev);
+		drv = drv_to_sdw_driver(ddrv);
+
+		ret = !!sdw_get_device_id(slave, drv);
+	} else {
+		md = dev_to_sdw_master_device(dev);
+		mdrv = drv_to_sdw_master_driver(ddrv);
+
+		/*
+		 * we don't have any hardware information so
+		 * match with a hopefully unique string
+		 */
+		ret = !strncmp(md->master_name, mdrv->driver.name,
+			       strlen(md->master_name));
+	}
+	return ret;
 }
 
-int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size)
+static int sdw_slave_modalias(const struct sdw_slave *slave, char *buf,
+			      size_t size)
 {
 	/* modalias is sdw:m<mfg_id>p<part_id> */
 
@@ -47,12 +67,31 @@ int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size)
 			slave->id.mfg_id, slave->id.part_id);
 }
 
+static int sdw_master_modalias(const struct sdw_master_device *md,
+			       char *buf, size_t size)
+{
+	/* modalias is sdw:<string> since we don't have any hardware info */
+
+	return snprintf(buf, size, "sdw:%s\n",
+			md->master_name);
+}
+
 static int sdw_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+	struct sdw_slave *slave;
+	struct sdw_master_device *md;
 	char modalias[32];
 
-	sdw_slave_modalias(slave, modalias, sizeof(modalias));
+	if (is_sdw_slave(dev)) {
+		slave = dev_to_sdw_dev(dev);
+
+		sdw_slave_modalias(slave, modalias, sizeof(modalias));
+
+	} else {
+		md = dev_to_sdw_master_device(dev);
+
+		sdw_master_modalias(md, modalias, sizeof(modalias));
+	}
 
 	if (add_uevent_var(env, "MODALIAS=%s", modalias))
 		return -ENOMEM;
@@ -113,8 +152,6 @@ static int sdw_drv_probe(struct device *dev)
 	slave->probed = true;
 	complete(&slave->probe_complete);
 
-	dev_dbg(dev, "probe complete\n");
-
 	return 0;
 }
 
@@ -181,6 +218,94 @@ void sdw_unregister_driver(struct sdw_driver *drv)
 }
 EXPORT_SYMBOL_GPL(sdw_unregister_driver);
 
+static int sdw_master_drv_probe(struct device *dev)
+{
+	struct sdw_master_device *md = dev_to_sdw_master_device(dev);
+	struct sdw_master_driver *mdrv = drv_to_sdw_master_driver(dev->driver);
+	int ret;
+
+	/*
+	 * attach to power domain but don't turn on (last arg)
+	 */
+	ret = dev_pm_domain_attach(dev, false);
+	if (ret)
+		return ret;
+
+	ret = mdrv->probe(md, md->pdata);
+	if (ret) {
+		dev_err(dev, "Probe of %s failed: %d\n",
+			mdrv->driver.name, ret);
+		dev_pm_domain_detach(dev, false);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int sdw_master_drv_remove(struct device *dev)
+{
+	struct sdw_master_device *md = dev_to_sdw_master_device(dev);
+	struct sdw_master_driver *mdrv = drv_to_sdw_master_driver(dev->driver);
+	int ret = 0;
+
+	if (mdrv->remove)
+		ret = mdrv->remove(md);
+
+	dev_pm_domain_detach(dev, false);
+
+	return ret;
+}
+
+static void sdw_master_drv_shutdown(struct device *dev)
+{
+	struct sdw_master_device *md = dev_to_sdw_master_device(dev);
+	struct sdw_master_driver *mdrv = drv_to_sdw_master_driver(dev->driver);
+
+	if (mdrv->shutdown)
+		mdrv->shutdown(md);
+}
+
+/**
+ * __sdw_register_master_driver() - register a SoundWire Master driver
+ * @mdrv: 'Master driver' to register
+ * @owner: owning module/driver
+ *
+ * Return: zero on success, else a negative error code.
+ */
+int __sdw_register_master_driver(struct sdw_master_driver *mdrv,
+				 struct module *owner)
+{
+	mdrv->driver.bus = &sdw_bus_type;
+
+	if (!mdrv->probe) {
+		pr_err("driver %s didn't provide SDW probe routine\n",
+		       mdrv->driver.name);
+		return -EINVAL;
+	}
+
+	mdrv->driver.owner = owner;
+	mdrv->driver.probe = sdw_master_drv_probe;
+
+	if (mdrv->remove)
+		mdrv->driver.remove = sdw_master_drv_remove;
+
+	if (mdrv->shutdown)
+		mdrv->driver.shutdown = sdw_master_drv_shutdown;
+
+	return driver_register(&mdrv->driver);
+}
+EXPORT_SYMBOL_GPL(__sdw_register_master_driver);
+
+/**
+ * sdw_unregister_master_driver() - unregisters the SoundWire Master driver
+ * @mdrv: driver to unregister
+ */
+void sdw_unregister_master_driver(struct sdw_master_driver *mdrv)
+{
+	driver_unregister(&mdrv->driver);
+}
+EXPORT_SYMBOL_GPL(sdw_unregister_master_driver);
+
 static int __init sdw_bus_init(void)
 {
 	sdw_debugfs_init();
diff --git a/drivers/soundwire/master.c b/drivers/soundwire/master.c
new file mode 100644
index 000000000000..721bdd562b73
--- /dev/null
+++ b/drivers/soundwire/master.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: (GPL-2.0)
+// Copyright(c) 2019-2020 Intel Corporation.
+
+#include <linux/device.h>
+#include <linux/acpi.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
+#include "bus.h"
+
+static void sdw_master_device_release(struct device *dev)
+{
+	struct sdw_master_device *md = dev_to_sdw_master_device(dev);
+
+	kfree(md);
+}
+
+struct device_type sdw_master_type = {
+	.name =		"soundwire_master",
+	.release =	sdw_master_device_release,
+};
+
+struct sdw_master_device
+*sdw_master_device_add(const char *master_name,
+		       struct device *parent,
+		       struct fwnode_handle *fwnode,
+		       int link_id,
+		       void *pdata)
+{
+	struct sdw_master_device *md;
+	int ret;
+
+	md = kzalloc(sizeof(*md), GFP_KERNEL);
+	if (!md)
+		return ERR_PTR(-ENOMEM);
+
+	md->link_id = link_id;
+	md->pdata = pdata;
+	md->master_name = master_name;
+
+	init_completion(&md->probe_complete);
+
+	md->dev.parent = parent;
+	md->dev.fwnode = fwnode;
+	md->dev.bus = &sdw_bus_type;
+	md->dev.type = &sdw_master_type;
+	md->dev.dma_mask = md->dev.parent->dma_mask;
+	dev_set_name(&md->dev, "sdw-master-%d", md->link_id);
+
+	ret = device_register(&md->dev);
+	if (ret) {
+		dev_err(parent, "Failed to add master: ret %d\n", ret);
+		/*
+		 * On err, don't free but drop ref as this will be freed
+		 * when release method is invoked.
+		 */
+		put_device(&md->dev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return md;
+}
+EXPORT_SYMBOL_GPL(sdw_master_device_add);
+
+int sdw_master_device_startup(struct sdw_master_device *md)
+{
+	struct sdw_master_driver *mdrv;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR_OR_NULL(md))
+		return -EINVAL;
+
+	dev = &md->dev;
+	mdrv = drv_to_sdw_master_driver(dev->driver);
+
+	if (mdrv && mdrv->startup)
+		ret = mdrv->startup(md);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdw_master_device_startup);
+
+int sdw_master_device_shutdown(struct sdw_master_device *md)
+{
+	struct sdw_master_driver *mdrv;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR_OR_NULL(md))
+		return -EINVAL;
+
+	dev = &md->dev;
+	mdrv = drv_to_sdw_master_driver(dev->driver);
+
+	if (mdrv && mdrv->shutdown)
+		ret = mdrv->shutdown(md);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdw_master_device_shutdown);
+
+int sdw_master_device_process_wake_event(struct sdw_master_device *md)
+{
+	struct sdw_master_driver *mdrv;
+	struct device *dev;
+	int ret = 0;
+
+	if (IS_ERR_OR_NULL(md))
+		return -EINVAL;
+
+	dev = &md->dev;
+	mdrv = drv_to_sdw_master_driver(dev->driver);
+
+	if (mdrv && mdrv->process_wake_event)
+		ret = mdrv->process_wake_event(md);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdw_master_device_process_wake_event);
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
index aace57fae7f8..7ca4f2d9bfa6 100644
--- a/drivers/soundwire/slave.c
+++ b/drivers/soundwire/slave.c
@@ -14,6 +14,11 @@ static void sdw_slave_release(struct device *dev)
 	kfree(slave);
 }
 
+struct device_type sdw_slave_type = {
+	.name =		"sdw_slave",
+	.release =	sdw_slave_release,
+};
+
 static int sdw_slave_add(struct sdw_bus *bus,
 			 struct sdw_slave_id *id, struct fwnode_handle *fwnode)
 {
@@ -41,9 +46,9 @@ static int sdw_slave_add(struct sdw_bus *bus,
 			     id->class_id, id->unique_id);
 	}
 
-	slave->dev.release = sdw_slave_release;
 	slave->dev.bus = &sdw_bus_type;
 	slave->dev.of_node = of_node_get(to_of_node(fwnode));
+	slave->dev.type = &sdw_slave_type;
 	slave->bus = bus;
 	slave->status = SDW_SLAVE_UNATTACHED;
 	init_completion(&slave->enumeration_complete);
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index b8427df034ce..95857e93f5c2 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -607,6 +607,31 @@ struct sdw_slave {
 
 #define dev_to_sdw_dev(_dev) container_of(_dev, struct sdw_slave, dev)
 
+/**
+ * struct sdw_master_device - SoundWire 'Master Device' representation
+ *
+ * @dev: Linux device for this Master
+ * @master_name: Linux driver name
+ * @driver: Linux driver for this Master (set by SoundWire core during probe)
+ * @probe_complete: used by parent if synchronous probe behavior is needed
+ * @link_id: link index as defined by MIPI DisCo specification
+ * @pm_runtime_suspended: flag to restore pm_runtime state after system resume
+ * @pdata: private data typically provided with sdw_master_device_add()
+ */
+
+struct sdw_master_device {
+	struct device dev;
+	const char *master_name;
+	struct sdw_master_driver *driver;
+	struct completion probe_complete;
+	int link_id;
+	bool pm_runtime_suspended;
+	void *pdata;
+};
+
+#define dev_to_sdw_master_device(d)	\
+	container_of(d, struct sdw_master_device, dev)
+
 struct sdw_driver {
 	const char *name;
 
@@ -621,6 +646,26 @@ struct sdw_driver {
 	struct device_driver driver;
 };
 
+/**
+ * struct sdw_master_driver - SoundWire 'Master Device' driver
+ *
+ * @probe: initializations and allocation (hardware may not be enabled yet)
+ * @startup: initialization handled after the hardware is enabled, all
+ * clock/power dependencies are available (optional)
+ * @shutdown: cleanups before hardware is disabled (optional)
+ * @remove: free all remaining resources
+ * @process_wake_event: handle external wake (optional)
+ * @driver: baseline structure used for name/PM hooks.
+ */
+struct sdw_master_driver {
+	int (*probe)(struct sdw_master_device *md, void *link_ctx);
+	int (*startup)(struct sdw_master_device *md);
+	int (*shutdown)(struct sdw_master_device *md);
+	int (*remove)(struct sdw_master_device *md);
+	int (*process_wake_event)(struct sdw_master_device *md);
+	struct device_driver driver;
+};
+
 #define SDW_SLAVE_ENTRY(_mfg_id, _part_id, _drv_data) \
 	{ .mfg_id = (_mfg_id), .part_id = (_part_id), \
 	  .driver_data = (unsigned long)(_drv_data) }
@@ -810,6 +855,44 @@ struct sdw_bus {
 int sdw_add_bus_master(struct sdw_bus *bus);
 void sdw_delete_bus_master(struct sdw_bus *bus);
 
+/**
+ * sdw_master_device_add() - create a Linux Master Device representation.
+ *
+ * @master_name: Linux driver name
+ * @parent: the parent Linux device (e.g. a PCI device)
+ * @fwnode: the parent fwnode (e.g. an ACPI companion device to the parent)
+ * @link_id: link index as defined by MIPI DisCo specification
+ * @pdata: private data (e.g. register base, offsets, platform quirks, etc).
+ */
+struct sdw_master_device
+*sdw_master_device_add(const char *master_name,
+		       struct device *parent,
+		       struct fwnode_handle *fwnode,
+		       int link_id,
+		       void *pdata);
+
+/**
+ * sdw_master_device_startup() - startup hardware
+ *
+ * @md: Linux Soundwire master device
+ */
+int sdw_master_device_startup(struct sdw_master_device *md);
+
+/**
+ * sdw_master_device_shutdown() - shutdown hardware
+ *
+ * @md: Linux Soundwire master device
+ */
+int sdw_master_device_shutdown(struct sdw_master_device *md);
+
+/**
+ * sdw_master_device_process_wake_event() - handle external wake
+ * event, e.g. handled at the PCI level
+ *
+ * @md: Linux Soundwire master device
+ */
+int sdw_master_device_process_wake_event(struct sdw_master_device *md);
+
 /**
  * sdw_port_config: Master or Slave Port configuration
  *
diff --git a/include/linux/soundwire/sdw_type.h b/include/linux/soundwire/sdw_type.h
index aaa7f4267c14..331ba58bda27 100644
--- a/include/linux/soundwire/sdw_type.h
+++ b/include/linux/soundwire/sdw_type.h
@@ -5,16 +5,36 @@
 #define __SOUNDWIRE_TYPES_H
 
 extern struct bus_type sdw_bus_type;
+extern struct device_type sdw_slave_type;
+extern struct device_type sdw_master_type;
+
+static inline int is_sdw_slave(const struct device *dev)
+{
+	return dev->type == &sdw_slave_type;
+}
 
 #define drv_to_sdw_driver(_drv) container_of(_drv, struct sdw_driver, driver)
 
 #define sdw_register_driver(drv) \
 	__sdw_register_driver(drv, THIS_MODULE)
 
+static inline int is_sdw_master_device(const struct device *dev)
+{
+	return dev->type == &sdw_master_type;
+}
+
+#define drv_to_sdw_master_driver(_drv) \
+	container_of(_drv, struct sdw_master_driver, driver)
+
+#define sdw_register_master_driver(drv) \
+	__sdw_register_master_driver(drv, THIS_MODULE)
+
 int __sdw_register_driver(struct sdw_driver *drv, struct module *owner);
 void sdw_unregister_driver(struct sdw_driver *drv);
 
-int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size);
+int __sdw_register_master_driver(struct sdw_master_driver *mdrv,
+				 struct module *owner);
+void sdw_unregister_master_driver(struct sdw_master_driver *mdrv);
 
 /**
  * module_sdw_driver() - Helper macro for registering a Soundwire driver
@@ -27,4 +47,18 @@ int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size);
 #define module_sdw_driver(__sdw_driver) \
 	module_driver(__sdw_driver, sdw_register_driver, \
 			sdw_unregister_driver)
+
+/**
+ * module_sdw_master_driver() - Helper macro for registering a Soundwire
+ * Master driver
+ * @__sdw_master_driver: soundwire Master driver struct
+ *
+ * Helper macro for Soundwire Master drivers which do not do anything special in
+ * module init/exit. This eliminates a lot of boilerplate. Each module may only
+ * use this macro once, and calling it replaces module_init() and module_exit()
+ */
+#define module_sdw_master_driver(__sdw_master_driver) \
+	module_driver(__sdw_master_driver, sdw_register_master_driver, \
+			sdw_unregister_master_driver)
+
 #endif /* __SOUNDWIRE_TYPES_H */
-- 
2.20.1

[RFC PATCH 2/2] soundwire: intel: transition to sdw_master_device/driver support

[Pierre-Louis Bossart]

Use sdw_master_device and driver instead of platform devices

In addition, rather than a plain-vanilla init/exit, this patch
provides 3 steps in the initialization (ACPI scan, probe, startup)
which makes it easier to detect platform support for SoundWire,
allocate required resources as early as possible, and conversely help
make the startup() callback lighter-weight with only hardware register
setup.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/intel.c      |  96 +++++++----
 drivers/soundwire/intel.h      |   8 +-
 drivers/soundwire/intel_init.c | 283 +++++++++++++++++++++++++--------
 3 files changed, 285 insertions(+), 102 deletions(-)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index e0c1fff7c4a0..b0599e3d9950 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -17,6 +17,7 @@
 #include <linux/soundwire/sdw_registers.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_intel.h>
+#include <linux/soundwire/sdw_type.h>
 #include "cadence_master.h"
 #include "bus.h"
 #include "intel.h"
@@ -92,8 +93,6 @@
 #define SDW_ALH_STRMZCFG_DMAT		GENMASK(7, 0)
 #define SDW_ALH_STRMZCFG_CHN		GENMASK(19, 16)
 
-#define SDW_INTEL_QUIRK_MASK_BUS_DISABLE	BIT(1)
-
 enum intel_pdi_type {
 	INTEL_PDI_IN = 0,
 	INTEL_PDI_OUT = 1,
@@ -1082,24 +1081,23 @@ static int intel_init(struct sdw_intel *sdw)
 /*
  * probe and init
  */
-static int intel_probe(struct platform_device *pdev)
+static int intel_master_probe(struct sdw_master_device *md, void *link_ctx)
 {
-	struct sdw_cdns_stream_config config;
 	struct sdw_intel *sdw;
 	int ret;
 
-	sdw = devm_kzalloc(&pdev->dev, sizeof(*sdw), GFP_KERNEL);
+	sdw = devm_kzalloc(&md->dev, sizeof(*sdw), GFP_KERNEL);
 	if (!sdw)
 		return -ENOMEM;
 
-	sdw->instance = pdev->id;
-	sdw->link_res = dev_get_platdata(&pdev->dev);
-	sdw->cdns.dev = &pdev->dev;
+	sdw->instance = md->link_id;
+	sdw->link_res = link_ctx;
+	sdw->cdns.dev = &md->dev;
 	sdw->cdns.registers = sdw->link_res->registers;
-	sdw->cdns.instance = sdw->instance;
+	sdw->cdns.instance = md->link_id;
 	sdw->cdns.msg_count = 0;
-	sdw->cdns.bus.dev = &pdev->dev;
-	sdw->cdns.bus.link_id = pdev->id;
+	sdw->cdns.bus.dev = &md->dev;
+	sdw->cdns.bus.link_id = md->link_id;
 
 	sdw_cdns_probe(&sdw->cdns);
 
@@ -1107,16 +1105,52 @@ static int intel_probe(struct platform_device *pdev)
 	sdw_intel_ops.read_prop = intel_prop_read;
 	sdw->cdns.bus.ops = &sdw_intel_ops;
 
-	platform_set_drvdata(pdev, sdw);
+	md->pdata = sdw;
+
+	/* set driver data, accessed by snd_soc_dai_set_drvdata() */
+	dev_set_drvdata(&md->dev, &sdw->cdns);
 
 	ret = sdw_add_bus_master(&sdw->cdns.bus);
 	if (ret) {
-		dev_err(&pdev->dev, "sdw_add_bus_master fail: %d\n", ret);
+		dev_err(&md->dev, "sdw_add_bus_master fail: %d\n", ret);
 		return ret;
 	}
 
 	if (sdw->cdns.bus.prop.hw_disabled) {
-		dev_info(&pdev->dev, "SoundWire master %d is disabled, ignoring\n",
+		dev_info(&md->dev, "SoundWire master %d is disabled, ignoring\n",
+			 sdw->cdns.bus.link_id);
+		return 0;
+	}
+
+	/* Acquire IRQ */
+	ret = request_threaded_irq(sdw->link_res->irq,
+				   sdw_cdns_irq, sdw_cdns_thread,
+				   IRQF_SHARED, KBUILD_MODNAME, &sdw->cdns);
+	if (ret < 0) {
+		dev_err(sdw->cdns.dev, "unable to grab IRQ %d, disabling device\n",
+			sdw->link_res->irq);
+		goto err_init;
+	}
+
+	complete(&md->probe_complete);
+
+	return 0;
+
+err_init:
+	sdw_delete_bus_master(&sdw->cdns.bus);
+	return ret;
+}
+
+static int intel_master_startup(struct sdw_master_device *md)
+{
+	struct sdw_cdns_stream_config config;
+	struct sdw_intel *sdw;
+	int ret;
+
+	sdw = md->pdata;
+
+	if (sdw->cdns.bus.prop.hw_disabled) {
+		dev_info(&md->dev, "SoundWire master %d is disabled, ignoring\n",
 			 sdw->cdns.bus.link_id);
 		return 0;
 	}
@@ -1134,16 +1168,6 @@ static int intel_probe(struct platform_device *pdev)
 
 	intel_pdi_ch_update(sdw);
 
-	/* Acquire IRQ */
-	ret = request_threaded_irq(sdw->link_res->irq,
-				   sdw_cdns_irq, sdw_cdns_thread,
-				   IRQF_SHARED, KBUILD_MODNAME, &sdw->cdns);
-	if (ret < 0) {
-		dev_err(sdw->cdns.dev, "unable to grab IRQ %d, disabling device\n",
-			sdw->link_res->irq);
-		goto err_init;
-	}
-
 	ret = sdw_cdns_enable_interrupt(&sdw->cdns, true);
 	if (ret < 0) {
 		dev_err(sdw->cdns.dev, "cannot enable interrupts\n");
@@ -1170,17 +1194,17 @@ static int intel_probe(struct platform_device *pdev)
 
 err_interrupt:
 	sdw_cdns_enable_interrupt(&sdw->cdns, false);
-	free_irq(sdw->link_res->irq, sdw);
 err_init:
+	free_irq(sdw->link_res->irq, sdw);
 	sdw_delete_bus_master(&sdw->cdns.bus);
 	return ret;
 }
 
-static int intel_remove(struct platform_device *pdev)
+static int intel_master_remove(struct sdw_master_device *md)
 {
 	struct sdw_intel *sdw;
 
-	sdw = platform_get_drvdata(pdev);
+	sdw = md->pdata;
 
 	if (!sdw->cdns.bus.prop.hw_disabled) {
 		intel_debugfs_exit(sdw);
@@ -1193,17 +1217,19 @@ static int intel_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct platform_driver sdw_intel_drv = {
-	.probe = intel_probe,
-	.remove = intel_remove,
-	.driver = {
-		.name = "int-sdw",
 
+struct sdw_master_driver intel_sdw_driver = {
+	.driver = {
+		.name = "intel-master",
+		.owner = THIS_MODULE,
+		.bus = &sdw_bus_type,
 	},
+	.probe = intel_master_probe,
+	.startup = intel_master_startup,
+	.remove = intel_master_remove,
 };
-
-module_platform_driver(sdw_intel_drv);
+module_sdw_master_driver(intel_sdw_driver);
 
 MODULE_LICENSE("Dual BSD/GPL");
-MODULE_ALIAS("platform:int-sdw");
+MODULE_ALIAS("sdw:intel-master");
 MODULE_DESCRIPTION("Intel Soundwire Master Driver");
diff --git a/drivers/soundwire/intel.h b/drivers/soundwire/intel.h
index 38b7c125fb10..795d6213eba5 100644
--- a/drivers/soundwire/intel.h
+++ b/drivers/soundwire/intel.h
@@ -7,7 +7,7 @@
 /**
  * struct sdw_intel_link_res - Soundwire Intel link resource structure,
  * typically populated by the controller driver.
- * @pdev: platform_device
+ * @md: master device
  * @mmio_base: mmio base of SoundWire registers
  * @registers: Link IO registers base
  * @shim: Audio shim pointer
@@ -17,7 +17,7 @@
  * @dev: device implementing hw_params and free callbacks
  */
 struct sdw_intel_link_res {
-	struct platform_device *pdev;
+	struct sdw_master_device *md;
 	void __iomem *mmio_base; /* not strictly needed, useful for debug */
 	void __iomem *registers;
 	void __iomem *shim;
@@ -27,4 +27,8 @@ struct sdw_intel_link_res {
 	struct device *dev;
 };
 
+#define SDW_INTEL_QUIRK_MASK_BUS_DISABLE      BIT(1)
+
+#define SDW_INTEL_MASTER_PROBE_TIMEOUT 2000
+
 #endif /* __SDW_INTEL_LOCAL_H */
diff --git a/drivers/soundwire/intel_init.c b/drivers/soundwire/intel_init.c
index 4b769409f6f8..d2517ed1aed2 100644
--- a/drivers/soundwire/intel_init.c
+++ b/drivers/soundwire/intel_init.c
@@ -11,7 +11,7 @@
 #include <linux/export.h>
 #include <linux/io.h>
 #include <linux/module.h>
-#include <linux/platform_device.h>
+#include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_intel.h>
 #include "intel.h"
 
@@ -23,22 +23,51 @@
 #define SDW_LINK_BASE		0x30000
 #define SDW_LINK_SIZE		0x10000
 
-static int link_mask;
-module_param_named(sdw_link_mask, link_mask, int, 0444);
+static int ctrl_link_mask;
+module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
 MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");
 
-static int sdw_intel_cleanup_pdev(struct sdw_intel_ctx *ctx)
+static bool is_link_enabled(struct fwnode_handle *fw_node, int i)
+{
+	struct fwnode_handle *link;
+	char name[32];
+	u32 quirk_mask = 0;
+
+	/* Find master handle */
+	snprintf(name, sizeof(name),
+		 "mipi-sdw-link-%d-subproperties", i);
+
+	link = fwnode_get_named_child_node(fw_node, name);
+	if (!link)
+		return false;
+
+	fwnode_property_read_u32(link,
+				 "intel-quirk-mask",
+				 &quirk_mask);
+
+	if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
+		return false;
+
+	return true;
+}
+
+static int sdw_intel_cleanup(struct sdw_intel_ctx *ctx)
 {
 	struct sdw_intel_link_res *link = ctx->links;
+	u32 link_mask;
 	int i;
 
 	if (!link)
 		return 0;
 
-	for (i = 0; i < ctx->count; i++) {
-		if (link->pdev)
-			platform_device_unregister(link->pdev);
-		link++;
+	link_mask = ctx->link_mask;
+
+	for (i = 0; i < ctx->count; i++, link++) {
+		if (link_mask && !(link_mask & BIT(i)))
+			continue;
+
+		if (!IS_ERR_OR_NULL(link->md))
+			device_unregister(&link->md->dev);
 	}
 
 	kfree(ctx->links);
@@ -47,112 +76,207 @@ static int sdw_intel_cleanup_pdev(struct sdw_intel_ctx *ctx)
 	return 0;
 }
 
-static struct sdw_intel_ctx
-*sdw_intel_add_controller(struct sdw_intel_res *res)
+static int
+sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
 {
-	struct platform_device_info pdevinfo;
-	struct platform_device *pdev;
-	struct sdw_intel_link_res *link;
-	struct sdw_intel_ctx *ctx;
 	struct acpi_device *adev;
 	int ret, i;
 	u8 count;
-	u32 caps;
 
-	if (acpi_bus_get_device(res->handle, &adev))
-		return NULL;
+	if (acpi_bus_get_device(info->handle, &adev))
+		return -EINVAL;
 
 	/* Found controller, find links supported */
 	count = 0;
 	ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
 					    "mipi-sdw-master-count", &count, 1);
 
-	/* Don't fail on error, continue and use hw value */
+	/*
+	 * In theory we could check the number of links supported in
+	 * hardware, but in that step we cannot assume SoundWire IP is
+	 * powered.
+	 *
+	 * In addition, if the BIOS doesn't even provide this
+	 * 'master-count' property then all the inits based on link
+	 * masks will fail as well.
+	 *
+	 * We will check the hardware capabilities in the startup() step
+	 */
+
 	if (ret) {
 		dev_err(&adev->dev,
 			"Failed to read mipi-sdw-master-count: %d\n", ret);
-		count = SDW_MAX_LINKS;
+		return -EINVAL;
 	}
 
-	/* Check SNDWLCAP.LCOUNT */
-	caps = ioread32(res->mmio_base + SDW_SHIM_BASE + SDW_SHIM_LCAP);
-	caps &= GENMASK(2, 0);
-
-	/* Check HW supported vs property value and use min of two */
-	count = min_t(u8, caps, count);
-
 	/* Check count is within bounds */
 	if (count > SDW_MAX_LINKS) {
 		dev_err(&adev->dev, "Link count %d exceeds max %d\n",
 			count, SDW_MAX_LINKS);
-		return NULL;
+		return -EINVAL;
 	} else if (!count) {
 		dev_warn(&adev->dev, "No SoundWire links detected\n");
-		return NULL;
+		return -EINVAL;
 	}
+	dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
+
+	info->count = count;
+
+	for (i = 0; i < count; i++) {
+		if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
+			dev_dbg(&adev->dev,
+				"Link %d masked, will not be enabled\n", i);
+			continue;
+		}
+
+		if (!is_link_enabled(acpi_fwnode_handle(adev), i)) {
+			dev_dbg(&adev->dev,
+				"Link %d not selected in firmware\n", i);
+			continue;
+		}
+
+		info->link_mask |= BIT(i);
+	}
+
+	return 0;
+}
+
+static struct sdw_intel_ctx
+*sdw_intel_probe_controller(struct sdw_intel_res *res)
+{
+	struct sdw_intel_link_res *link;
+	struct sdw_intel_ctx *ctx;
+	struct acpi_device *adev;
+	struct sdw_master_device *md;
+	unsigned long time;
+	u32 link_mask;
+	int count;
+	int i;
+
+	if (!res)
+		return NULL;
+
+	if (acpi_bus_get_device(res->handle, &adev))
+		return NULL;
+
+	if (!res->count)
+		return NULL;
 
+	count = res->count;
 	dev_dbg(&adev->dev, "Creating %d SDW Link devices\n", count);
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return NULL;
 
-	ctx->count = count;
-	ctx->links = kcalloc(ctx->count, sizeof(*ctx->links), GFP_KERNEL);
+	ctx->links = kcalloc(count, sizeof(*ctx->links), GFP_KERNEL);
 	if (!ctx->links)
 		goto link_err;
 
+	ctx->count = count;
+	ctx->mmio_base = res->mmio_base;
+	ctx->link_mask = res->link_mask;
+	ctx->handle = res->handle;
+
 	link = ctx->links;
+	link_mask = ctx->link_mask;
 
 	/* Create SDW Master devices */
-	for (i = 0; i < count; i++) {
-		if (link_mask && !(link_mask & BIT(i))) {
-			dev_dbg(&adev->dev,
-				"Link %d masked, will not be enabled\n", i);
-			link++;
+	for (i = 0; i < count; i++, link++) {
+		if (link_mask && !(link_mask & BIT(i)))
 			continue;
-		}
 
+		link->mmio_base = res->mmio_base;
 		link->registers = res->mmio_base + SDW_LINK_BASE
-					+ (SDW_LINK_SIZE * i);
+			+ (SDW_LINK_SIZE * i);
 		link->shim = res->mmio_base + SDW_SHIM_BASE;
 		link->alh = res->mmio_base + SDW_ALH_BASE;
-
+		link->irq = res->irq;
 		link->ops = res->ops;
 		link->dev = res->dev;
+		link->clock_stop_quirks = res->clock_stop_quirks;
 
-		memset(&pdevinfo, 0, sizeof(pdevinfo));
+		md = sdw_master_device_add("intel-master",
+					   res->parent,
+					   acpi_fwnode_handle(adev),
+					   i,
+					   link);
 
-		pdevinfo.parent = res->parent;
-		pdevinfo.name = "int-sdw";
-		pdevinfo.id = i;
-		pdevinfo.fwnode = acpi_fwnode_handle(adev);
+		if (IS_ERR(md)) {
+			dev_err(&adev->dev, "Could not create link %d\n", i);
+			goto err;
+		}
 
-		pdev = platform_device_register_full(&pdevinfo);
-		if (IS_ERR(pdev)) {
-			dev_err(&adev->dev,
-				"platform device creation failed: %ld\n",
-				PTR_ERR(pdev));
-			goto pdev_err;
+		/*
+		 * we need to wait for the bus to be probed so that we
+		 * can report ACPI information to the upper layers
+		 */
+		time = wait_for_completion_timeout(&md->probe_complete,
+				msecs_to_jiffies(SDW_INTEL_MASTER_PROBE_TIMEOUT));
+		if (!time) {
+			dev_err(&adev->dev, "Master %d probe timed out\n", i);
+			goto err;
 		}
 
-		link->pdev = pdev;
-		link++;
+		link->md = md;
 	}
 
 	return ctx;
 
-pdev_err:
-	sdw_intel_cleanup_pdev(ctx);
+err:
+	sdw_intel_cleanup(ctx);
 link_err:
 	kfree(ctx);
 	return NULL;
 }
 
+static int
+sdw_intel_startup_controller(struct sdw_intel_ctx *ctx)
+{
+	struct acpi_device *adev;
+	struct sdw_intel_link_res *link;
+	struct sdw_master_device *md;
+	u32 caps;
+	u32 link_mask;
+	int i;
+
+	if (acpi_bus_get_device(ctx->handle, &adev))
+		return -EINVAL;
+
+	/* Check SNDWLCAP.LCOUNT */
+	caps = ioread32(ctx->mmio_base + SDW_SHIM_BASE + SDW_SHIM_LCAP);
+	caps &= GENMASK(2, 0);
+
+	/* Check HW supported vs property value */
+	if (caps < ctx->count) {
+		dev_err(&adev->dev,
+			"BIOS master count is larger than hardware capabilities\n");
+		return -EINVAL;
+	}
+
+	if (!ctx->links)
+		return -EINVAL;
+
+	link = ctx->links;
+	link_mask = ctx->link_mask;
+
+	/* Create SDW Master devices */
+	for (i = 0; i < ctx->count; i++, link++) {
+		if (link_mask && !(link_mask & BIT(i)))
+			continue;
+
+		md = link->md;
+
+		sdw_master_device_startup(md);
+	}
+
+	return 0;
+}
+
 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 				     void *cdata, void **return_value)
 {
-	struct sdw_intel_res *res = cdata;
+	struct sdw_intel_acpi_info *info = cdata;
 	struct acpi_device *adev;
 	acpi_status status;
 	u64 adr;
@@ -166,7 +290,7 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 		return AE_NOT_FOUND;
 	}
 
-	res->handle = handle;
+	info->handle = handle;
 
 	/*
 	 * On some Intel platforms, multiple children of the HDAS
@@ -183,36 +307,65 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 }
 
 /**
- * sdw_intel_init() - SoundWire Intel init routine
+ * sdw_intel_acpi_scan() - SoundWire Intel init routine
  * @parent_handle: ACPI parent handle
- * @res: resource data
+ * @info: description of what firmware/DSDT tables expose
  *
- * This scans the namespace and creates SoundWire link controller devices
- * based on the info queried.
+ * This scans the namespace and queries firmware to figure out which
+ * links to enable. A follow-up use of sdw_intel_probe() and
+ * sdw_intel_startup() is required for creation of devices and bus
+ * startup
  */
-void *sdw_intel_init(acpi_handle *parent_handle, struct sdw_intel_res *res)
+int sdw_intel_acpi_scan(acpi_handle *parent_handle,
+			struct sdw_intel_acpi_info *info)
 {
 	acpi_status status;
 
 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
 				     parent_handle, 1,
 				     sdw_intel_acpi_cb,
-				     NULL, res, NULL);
+				     NULL, info, NULL);
 	if (ACPI_FAILURE(status))
-		return NULL;
+		return -ENODEV;
 
-	return sdw_intel_add_controller(res);
+	return sdw_intel_scan_controller(info);
 }
+EXPORT_SYMBOL(sdw_intel_acpi_scan);
 
+/**
+ * sdw_intel_probe() - SoundWire Intel probe routine
+ * @res: resource data
+ *
+ * This creates SoundWire Master and Slave devices below the controller.
+ * All the information necessary is stored in the context, and the res
+ * argument pointer can be freed after this step.
+ */
+struct sdw_intel_ctx
+*sdw_intel_probe(struct sdw_intel_res *res)
+{
+	return sdw_intel_probe_controller(res);
+}
+EXPORT_SYMBOL(sdw_intel_probe);
+
+/**
+ * sdw_intel_startup() - SoundWire Intel startup
+ * @ctx: SoundWire context allocated in the probe
+ *
+ */
+int sdw_intel_startup(struct sdw_intel_ctx *ctx)
+{
+	return sdw_intel_startup_controller(ctx);
+}
+EXPORT_SYMBOL(sdw_intel_startup);
 /**
  * sdw_intel_exit() - SoundWire Intel exit
- * @arg: callback context
+ * @ctx: SoundWire context allocated in the probe
  *
  * Delete the controller instances created and cleanup
  */
 void sdw_intel_exit(struct sdw_intel_ctx *ctx)
 {
-	sdw_intel_cleanup_pdev(ctx);
+	sdw_intel_cleanup(ctx);
 	kfree(ctx);
 }
 EXPORT_SYMBOL(sdw_intel_exit);
-- 
2.20.1

Re: [RFC PATCH 0/2] soundwire: add master_device/driver support

[Greg KH]

On Fri, Jan 31, 2020 at 10:20:09PM -0600, Pierre-Louis Bossart wrote:
> The SoundWire master representation needs to evolve to take into account:
> 
> a) a May 2019 recommendation from Greg KH to remove platform devices
> 
> b) the need on Intel platforms to support hardware startup only once
> the power rail dependencies are settled. The SoundWire master is not
> an independent IP at all.
> 
> c) the need to deal with external wakes handled by the PCI subsystem
> in specific low-power modes
> 
> In case it wasn't clear, the SoundWire subsystem is currently unusable
> with v5.5 on devices hitting the shelves very soon (race conditions,
> power management, suspend/resume, etc). v5.6 will only provide
> interface changes and no functional improvement. We've circled on the
> same concepts since September 2019, and I hope this direction is now
> aligned with the suggestions from Vinod Koul and that we can target
> v5.7 as the 'SoundWire just works(tm)' version.
> 
> This series is provided as an RFC since it depends on patches already
> for review.

Both of these look sane to me, nice work!

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [alsa-devel] [RFC PATCH 0/2] soundwire: add master_device/driver support

[Pierre-Louis Bossart]

On 2/14/20 10:49 AM, Greg KH wrote:
> On Fri, Jan 31, 2020 at 10:20:09PM -0600, Pierre-Louis Bossart wrote:
>> The SoundWire master representation needs to evolve to take into account:
>>
>> a) a May 2019 recommendation from Greg KH to remove platform devices
>>
>> b) the need on Intel platforms to support hardware startup only once
>> the power rail dependencies are settled. The SoundWire master is not
>> an independent IP at all.
>>
>> c) the need to deal with external wakes handled by the PCI subsystem
>> in specific low-power modes
>>
>> In case it wasn't clear, the SoundWire subsystem is currently unusable
>> with v5.5 on devices hitting the shelves very soon (race conditions,
>> power management, suspend/resume, etc). v5.6 will only provide
>> interface changes and no functional improvement. We've circled on the
>> same concepts since September 2019, and I hope this direction is now
>> aligned with the suggestions from Vinod Koul and that we can target
>> v5.7 as the 'SoundWire just works(tm)' version.
>>
>> This series is provided as an RFC since it depends on patches already
>> for review.
> 
> Both of these look sane to me, nice work!
> 
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


Thanks Greg, I really appreciate the review and educational guidance on 
the use of platform devices!

If that's alright with Vinod and you, I'd like to defer the integration 
of these patches a bit so that we can improve them a bit e.g.

- I realized earlier this week there's a potential issue with the 
'shutdown' callback, what I did looks duplicated with 'shutdown' called 
from the device core and by the parent.

- it would make sense to add support for this 'master device' in the 
Qualcomm drivers as well, so that we are aligned with a similar device 
hierarchy (PCI -> sdw_master_device and DT/plaforms ->sdw_master_device).

- we probably want to add the sysfs patches that started this discussion 
on the platform devices. This would be very useful to debug new 
platforms, we depend on BIOS/firmware and we can't always know the 
actual settings just by looking at the DSDT static contents (multiple 
tests and overridden values).

My preference in terms of integration in drivers/soundwire would be

1. Intel DAI cleanup (only one kfree missing, will resubmit v3 today)

2. [PATCH 00/10] soundwire: bus: fix race conditions, add suspend-resume
this series solves a lot of issues and should go first.

3. ASoC/SOF integration (still with platform devices)
I narrowed this down to 6 patches, that would help me submit the rest of 
the ASoC/SOF patches in Mark Brown's tree. That would be Intel specific. 
This step would be the first where everything SoundWire-related can be 
enabled in a build, and while we've caught a lot of cross-compilation 
issues it's likely some bots will find corner cases to keep us busy.

4. master_device/driver transition: these updated patches removing 
platform devices + sysfs support + Qualcomm support (the last point 
would depend on the workload/support of Qualcomm/Linaro folks, I don't 
want to commit on their behalf).

5. New SoundWire functionality for Intel platforms (clock-stop/restart 
and synchronized links). The code would be only located in 
drivers/soundwire and be easier to handle. For the synchronized links we 
still have a bit of validation work to do so it should really come last.

Would this work for everyone?

Thanks,
-Pierre

Re: [alsa-devel] [RFC PATCH 0/2] soundwire: add master_device/driver support

[Greg KH]

On Fri, Feb 14, 2020 at 05:34:40PM -0600, Pierre-Louis Bossart wrote:
> 
> My preference in terms of integration in drivers/soundwire would be
> 
> 1. Intel DAI cleanup (only one kfree missing, will resubmit v3 today)
> 
> 2. [PATCH 00/10] soundwire: bus: fix race conditions, add suspend-resume
> this series solves a lot of issues and should go first.
> 
> 3. ASoC/SOF integration (still with platform devices)
> I narrowed this down to 6 patches, that would help me submit the rest of the
> ASoC/SOF patches in Mark Brown's tree. That would be Intel specific. This
> step would be the first where everything SoundWire-related can be enabled in
> a build, and while we've caught a lot of cross-compilation issues it's
> likely some bots will find corner cases to keep us busy.
> 
> 4. master_device/driver transition: these updated patches removing platform
> devices + sysfs support + Qualcomm support (the last point would depend on
> the workload/support of Qualcomm/Linaro folks, I don't want to commit on
> their behalf).
> 
> 5. New SoundWire functionality for Intel platforms (clock-stop/restart and
> synchronized links). The code would be only located in drivers/soundwire and
> be easier to handle. For the synchronized links we still have a bit of
> validation work to do so it should really come last.
> 
> Would this work for everyone?

Sounds reasonable to me, but patches would show it best to see if there
are any issues :)

thanks,

greg k-h