Add SDCA class driver

Merge series from Charles Keepax <[e-mail]>:

This series adds an initial SDCA class driver, this consists of a
primary driver attached to the SoundWire device, and auxiliary drivers
representing each of the functions of the SDCA device. These drivers all
use the APIs added over the past series's to provide the class
functionality, as such these final drivers themselves are quite thin.

Also a few fix ups at the start of the series that have gathered up
whilst the last SDCA series was in review.

include/linux/soundwire/sdw_registers.h

···
 /* Check the reserved and fixed bits in address */
 #define SDW_SDCA_VALID_CTL(reg) (((reg) & (GENMASK(31, 25) | BIT(18) | BIT(13))) == BIT(30))
 
+#define SDW_SDCA_MAX_REGISTER			0x47FFFFFF
+
 #endif /* __SDW_REGISTERS_H */

include/sound/sdca.h

···
 #include <linux/kconfig.h>
 
 struct acpi_table_swft;
+struct fwnode_handle;
 struct sdw_slave;
+struct sdca_dev;
 
 #define SDCA_MAX_FUNCTION_COUNT 8
 
 /**
  * struct sdca_function_desc - short descriptor for an SDCA Function
  * @node: firmware node for the Function.
+ * @func_dev: pointer to SDCA function device.
  * @name: Human-readable string.
  * @type: Function topology type.
  * @adr: ACPI address (used for SDCA register access).
  */
 struct sdca_function_desc {
 	struct fwnode_handle *node;
+	struct sdca_dev *func_dev;
 	const char *name;
 	u32 type;
 	u8 adr;
···
 void sdca_lookup_swft(struct sdw_slave *slave);
 void sdca_lookup_interface_revision(struct sdw_slave *slave);
 bool sdca_device_quirk_match(struct sdw_slave *slave, enum sdca_quirk quirk);
+int sdca_dev_register_functions(struct sdw_slave *slave);
+void sdca_dev_unregister_functions(struct sdw_slave *slave);
 
 #else
 
···
 {
 	return false;
 }
+
+static inline int sdca_dev_register_functions(struct sdw_slave *slave)
+{
+	return 0;
+}
+
+static inline void sdca_dev_unregister_functions(struct sdw_slave *slave) {}
+
 #endif
 
 #endif

include/sound/sdca_regmap.h

···
 
 int sdca_regmap_write_defaults(struct device *dev, struct regmap *regmap,
 			       struct sdca_function_data *function);
+int sdca_regmap_write_init(struct device *dev, struct regmap *regmap,
+			   struct sdca_function_data *function);
 
 #endif // __SDCA_REGMAP_H__

sound/soc/sdca/Kconfig

···
 config SND_SOC_SDCA
 	tristate
 	depends on ACPI
+	select AUXILIARY_BUS
 	help
 	  This option enables support for the MIPI SoundWire Device
 	  Class for Audio (SDCA).
···
 
 config SND_SOC_SDCA_OPTIONAL
 	def_tristate SND_SOC_SDCA || !SND_SOC_SDCA
+
+config SND_SOC_SDCA_CLASS
+	tristate "SDCA Class Driver"
+	depends on SND_SOC_SDCA
+	select SND_SOC_SDCA_CLASS_FUNCTION
+	select SND_SOC_SDCA_FDL
+	select SND_SOC_SDCA_HID
+	select SND_SOC_SDCA_IRQ
+	help
+	  This option enables support for the SDCA Class driver which should
+	  support any class compliant SDCA part.
+
+config SND_SOC_SDCA_CLASS_FUNCTION
+	tristate
+	help
+	  This option enables support for the SDCA Class Function drivers,
+	  these implement the individual functions of the SDCA Class driver.
 
 endmenu

sound/soc/sdca/Makefile

···
 # SPDX-License-Identifier: GPL-2.0-only
 
-snd-soc-sdca-y := sdca_functions.o sdca_device.o sdca_regmap.o sdca_asoc.o \
-		  sdca_ump.o
+snd-soc-sdca-y := sdca_functions.o sdca_device.o sdca_function_device.o \
+		  sdca_regmap.o sdca_asoc.o sdca_ump.o
 snd-soc-sdca-$(CONFIG_SND_SOC_SDCA_HID) += sdca_hid.o
 snd-soc-sdca-$(CONFIG_SND_SOC_SDCA_IRQ) += sdca_interrupts.o
 snd-soc-sdca-$(CONFIG_SND_SOC_SDCA_FDL) += sdca_fdl.o
 
+snd-soc-sdca-class-y := sdca_class.o
+snd-soc-sdca-class-function-y := sdca_class_function.o
+
 obj-$(CONFIG_SND_SOC_SDCA) += snd-soc-sdca.o
+
+obj-$(CONFIG_SND_SOC_SDCA_CLASS) += snd-soc-sdca-class.o
+obj-$(CONFIG_SND_SOC_SDCA_CLASS_FUNCTION) += snd-soc-sdca-class-function.o

sound/soc/sdca/sdca_class.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2025 Cirrus Logic, Inc. and
+//                    Cirrus Logic International Semiconductor Ltd.
+
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <linux/soundwire/sdw_type.h>
+#include <sound/sdca.h>
+#include <sound/sdca_function.h>
+#include <sound/sdca_interrupts.h>
+#include <sound/sdca_regmap.h>
+#include "sdca_class.h"
+
+#define CLASS_SDW_ATTACH_TIMEOUT_MS	5000
+
+static int class_read_prop(struct sdw_slave *sdw)
+{
+	struct sdw_slave_prop *prop = &sdw->prop;
+
+	sdw_slave_read_prop(sdw);
+
+	prop->use_domain_irq = true;
+	prop->scp_int1_mask = SDW_SCP_INT1_BUS_CLASH | SDW_SCP_INT1_PARITY |
+			      SDW_SCP_INT1_IMPL_DEF;
+
+	return 0;
+}
+
+static int class_sdw_update_status(struct sdw_slave *sdw, enum sdw_slave_status status)
+{
+	struct sdca_class_drv *drv = dev_get_drvdata(&sdw->dev);
+
+	switch (status) {
+	case SDW_SLAVE_ATTACHED:
+		dev_dbg(drv->dev, "device attach\n");
+
+		drv->attached = true;
+
+		complete(&drv->device_attach);
+		break;
+	case SDW_SLAVE_UNATTACHED:
+		dev_dbg(drv->dev, "device detach\n");
+
+		drv->attached = false;
+
+		reinit_completion(&drv->device_attach);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct sdw_slave_ops class_sdw_ops = {
+	.read_prop	= class_read_prop,
+	.update_status	= class_sdw_update_status,
+};
+
+static void class_regmap_lock(void *data)
+{
+	struct mutex *lock = data;
+
+	mutex_lock(lock);
+}
+
+static void class_regmap_unlock(void *data)
+{
+	struct mutex *lock = data;
+
+	mutex_unlock(lock);
+}
+
+static int class_wait_for_attach(struct sdca_class_drv *drv)
+{
+	if (!drv->attached) {
+		unsigned long timeout = msecs_to_jiffies(CLASS_SDW_ATTACH_TIMEOUT_MS);
+		unsigned long time;
+
+		time = wait_for_completion_timeout(&drv->device_attach, timeout);
+		if (!time) {
+			dev_err(drv->dev, "timed out waiting for device re-attach\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	regcache_cache_only(drv->dev_regmap, false);
+
+	return 0;
+}
+
+static bool class_dev_regmap_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case SDW_SCP_SDCA_INTMASK1 ... SDW_SCP_SDCA_INTMASK4:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static bool class_dev_regmap_precious(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case SDW_SCP_SDCA_INT1 ... SDW_SCP_SDCA_INT4:
+	case SDW_SCP_SDCA_INTMASK1 ... SDW_SCP_SDCA_INTMASK4:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config class_dev_regmap_config = {
+	.name			= "sdca-device",
+	.reg_bits		= 32,
+	.val_bits		= 8,
+
+	.max_register		= SDW_SDCA_MAX_REGISTER,
+	.volatile_reg		= class_dev_regmap_volatile,
+	.precious_reg		= class_dev_regmap_precious,
+
+	.cache_type		= REGCACHE_MAPLE,
+
+	.lock			= class_regmap_lock,
+	.unlock			= class_regmap_unlock,
+};
+
+static void class_boot_work(struct work_struct *work)
+{
+	struct sdca_class_drv *drv = container_of(work,
+						  struct sdca_class_drv,
+						  boot_work);
+	int ret;
+
+	ret = class_wait_for_attach(drv);
+	if (ret)
+		goto err;
+
+	drv->irq_info = sdca_irq_allocate(drv->dev, drv->dev_regmap,
+					  drv->sdw->irq);
+	if (IS_ERR(drv->irq_info))
+		goto err;
+
+	ret = sdca_dev_register_functions(drv->sdw);
+	if (ret)
+		goto err;
+
+	dev_dbg(drv->dev, "boot work complete\n");
+
+	pm_runtime_mark_last_busy(drv->dev);
+	pm_runtime_put_autosuspend(drv->dev);
+
+	return;
+
+err:
+	pm_runtime_put_sync(drv->dev);
+}
+
+static void class_dev_remove(void *data)
+{
+	struct sdca_class_drv *drv = data;
+
+	cancel_work_sync(&drv->boot_work);
+
+	sdca_dev_unregister_functions(drv->sdw);
+}
+
+static int class_sdw_probe(struct sdw_slave *sdw, const struct sdw_device_id *id)
+{
+	struct device *dev = &sdw->dev;
+	struct sdca_device_data *data = &sdw->sdca_data;
+	struct regmap_config *dev_config;
+	struct sdca_class_drv *drv;
+	int ret;
+
+	sdca_lookup_swft(sdw);
+
+	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	dev_config = devm_kmemdup(dev, &class_dev_regmap_config,
+				  sizeof(*dev_config), GFP_KERNEL);
+	if (!dev_config)
+		return -ENOMEM;
+
+	drv->functions = devm_kcalloc(dev, data->num_functions,
+				      sizeof(*drv->functions),
+				      GFP_KERNEL);
+	if (!drv->functions)
+		return -ENOMEM;
+
+	drv->dev = dev;
+	drv->sdw = sdw;
+	mutex_init(&drv->regmap_lock);
+
+	dev_set_drvdata(drv->dev, drv);
+
+	INIT_WORK(&drv->boot_work, class_boot_work);
+	init_completion(&drv->device_attach);
+
+	dev_config->lock_arg = &drv->regmap_lock;
+
+	drv->dev_regmap = devm_regmap_init_sdw(sdw, dev_config);
+	if (IS_ERR(drv->dev_regmap))
+		return dev_err_probe(drv->dev, PTR_ERR(drv->dev_regmap),
+				     "failed to create device regmap\n");
+
+	regcache_cache_only(drv->dev_regmap, true);
+
+	pm_runtime_set_autosuspend_delay(dev, 250);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_get_noresume(dev);
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, class_dev_remove, drv);
+	if (ret)
+		return ret;
+
+	queue_work(system_long_wq, &drv->boot_work);
+
+	return 0;
+}
+
+static int class_runtime_suspend(struct device *dev)
+{
+	struct sdca_class_drv *drv = dev_get_drvdata(dev);
+
+	/*
+	 * Whilst the driver doesn't power the chip down here, going into runtime
+	 * suspend lets the SoundWire bus power down, which means the driver
+	 * can't communicate with the device any more.
+	 */
+	regcache_cache_only(drv->dev_regmap, true);
+
+	return 0;
+}
+
+static int class_runtime_resume(struct device *dev)
+{
+	struct sdca_class_drv *drv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = class_wait_for_attach(drv);
+	if (ret)
+		goto err;
+
+	regcache_mark_dirty(drv->dev_regmap);
+
+	ret = regcache_sync(drv->dev_regmap);
+	if (ret) {
+		dev_err(drv->dev, "failed to restore cache: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	regcache_cache_only(drv->dev_regmap, true);
+
+	return ret;
+}
+
+static const struct dev_pm_ops class_pm_ops = {
+	RUNTIME_PM_OPS(class_runtime_suspend, class_runtime_resume, NULL)
+};
+
+static const struct sdw_device_id class_sdw_id[] = {
+	SDW_SLAVE_ENTRY(0x01FA, 0x4245, 0),
+	{}
+};
+MODULE_DEVICE_TABLE(sdw, class_sdw_id);
+
+static struct sdw_driver class_sdw_driver = {
+	.driver = {
+		.name		= "sdca_class",
+		.pm		= pm_ptr(&class_pm_ops),
+	},
+
+	.probe		= class_sdw_probe,
+	.id_table	= class_sdw_id,
+	.ops		= &class_sdw_ops,
+};
+module_sdw_driver(class_sdw_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SDCA Class Driver");
+MODULE_IMPORT_NS("SND_SOC_SDCA");

sound/soc/sdca/sdca_class.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright (C) 2025 Cirrus Logic, Inc. and
+ *                    Cirrus Logic International Semiconductor Ltd.
+ */
+
+#ifndef __SDCA_CLASS_H__
+#define __SDCA_CLASS_H__
+
+#include <linux/completion.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+struct device;
+struct regmap;
+struct sdw_slave;
+struct sdca_function_data;
+
+struct sdca_class_drv {
+	struct device *dev;
+	struct regmap *dev_regmap;
+	struct sdw_slave *sdw;
+
+	struct sdca_function_data *functions;
+	struct sdca_interrupt_info *irq_info;
+
+	struct mutex regmap_lock;
+	struct work_struct boot_work;
+	struct completion device_attach;
+
+	bool attached;
+};
+
+#endif /* __SDCA_CLASS_H__ */

sound/soc/sdca/sdca_class_function.c

···
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2025 Cirrus Logic, Inc. and
+//                    Cirrus Logic International Semiconductor Ltd.
+
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <sound/pcm.h>
+#include <sound/sdca_asoc.h>
+#include <sound/sdca_fdl.h>
+#include <sound/sdca_function.h>
+#include <sound/sdca_interrupts.h>
+#include <sound/sdca_regmap.h>
+#include <sound/sdw.h>
+#include <sound/soc-component.h>
+#include <sound/soc-dai.h>
+#include <sound/soc.h>
+#include "sdca_class.h"
+
+struct class_function_drv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct sdca_class_drv *core;
+
+	struct sdca_function_data *function;
+};
+
+static void class_function_regmap_lock(void *data)
+{
+	struct mutex *lock = data;
+
+	mutex_lock(lock);
+}
+
+static void class_function_regmap_unlock(void *data)
+{
+	struct mutex *lock = data;
+
+	mutex_unlock(lock);
+}
+
+static bool class_function_regmap_writeable(struct device *dev, unsigned int reg)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	return sdca_regmap_writeable(drv->function, reg);
+}
+
+static bool class_function_regmap_readable(struct device *dev, unsigned int reg)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	return sdca_regmap_readable(drv->function, reg);
+}
+
+static bool class_function_regmap_volatile(struct device *dev, unsigned int reg)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	return sdca_regmap_volatile(drv->function, reg);
+}
+
+static const struct regmap_config class_function_regmap_config = {
+	.name			= "sdca",
+	.reg_bits		= 32,
+	.val_bits		= 32,
+	.reg_format_endian	= REGMAP_ENDIAN_LITTLE,
+	.val_format_endian	= REGMAP_ENDIAN_LITTLE,
+
+	.max_register		= SDW_SDCA_MAX_REGISTER,
+	.readable_reg		= class_function_regmap_readable,
+	.writeable_reg		= class_function_regmap_writeable,
+	.volatile_reg		= class_function_regmap_volatile,
+
+	.cache_type		= REGCACHE_MAPLE,
+
+	.lock			= class_function_regmap_lock,
+	.unlock			= class_function_regmap_unlock,
+};
+
+static int class_function_regmap_mbq_size(struct device *dev, unsigned int reg)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	return sdca_regmap_mbq_size(drv->function, reg);
+}
+
+static bool class_function_regmap_deferrable(struct device *dev, unsigned int reg)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	return sdca_regmap_deferrable(drv->function, reg);
+}
+
+static const struct regmap_sdw_mbq_cfg class_function_mbq_config = {
+	.mbq_size		= class_function_regmap_mbq_size,
+	.deferrable		= class_function_regmap_deferrable,
+	.retry_us		= 1000,
+	.timeout_us		= 10000,
+};
+
+static int class_function_startup(struct snd_pcm_substream *substream,
+				  struct snd_soc_dai *dai)
+{
+	struct class_function_drv *drv = snd_soc_component_get_drvdata(dai->component);
+
+	return sdca_asoc_set_constraints(drv->dev, drv->regmap, drv->function,
+					 substream, dai);
+}
+
+static int class_function_sdw_add_peripheral(struct snd_pcm_substream *substream,
+					     struct snd_pcm_hw_params *params,
+					     struct snd_soc_dai *dai)
+{
+	struct class_function_drv *drv = snd_soc_component_get_drvdata(dai->component);
+	struct sdw_stream_runtime *sdw_stream = snd_soc_dai_get_dma_data(dai, substream);
+	struct sdw_slave *sdw = dev_to_sdw_dev(drv->dev->parent);
+	struct sdw_stream_config sconfig = {0};
+	struct sdw_port_config pconfig = {0};
+	int ret;
+
+	if (!sdw_stream)
+		return -EINVAL;
+
+	snd_sdw_params_to_config(substream, params, &sconfig, &pconfig);
+
+	/*
+	 * FIXME: As also noted in sdca_asoc_get_port(), currently only
+	 * a single unshared port is supported for each DAI.
+	 */
+	ret = sdca_asoc_get_port(drv->dev, drv->regmap, drv->function, dai);
+	if (ret < 0)
+		return ret;
+
+	pconfig.num = ret;
+
+	ret = sdw_stream_add_slave(sdw, &sconfig, &pconfig, 1, sdw_stream);
+	if (ret) {
+		dev_err(drv->dev, "failed to add sdw stream: %d\n", ret);
+		return ret;
+	}
+
+	return sdca_asoc_hw_params(drv->dev, drv->regmap, drv->function,
+				   substream, params, dai);
+}
+
+static int class_function_sdw_remove_peripheral(struct snd_pcm_substream *substream,
+						struct snd_soc_dai *dai)
+{
+	struct class_function_drv *drv = snd_soc_component_get_drvdata(dai->component);
+	struct sdw_stream_runtime *sdw_stream = snd_soc_dai_get_dma_data(dai, substream);
+	struct sdw_slave *sdw = dev_to_sdw_dev(drv->dev->parent);
+
+	if (!sdw_stream)
+		return -EINVAL;
+
+	return sdw_stream_remove_slave(sdw, sdw_stream);
+}
+
+static int class_function_sdw_set_stream(struct snd_soc_dai *dai, void *sdw_stream,
+					 int direction)
+{
+	snd_soc_dai_dma_data_set(dai, direction, sdw_stream);
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops class_function_sdw_ops = {
+	.startup	= class_function_startup,
+	.shutdown	= sdca_asoc_free_constraints,
+	.set_stream	= class_function_sdw_set_stream,
+	.hw_params	= class_function_sdw_add_peripheral,
+	.hw_free	= class_function_sdw_remove_peripheral,
+};
+
+static int class_function_component_probe(struct snd_soc_component *component)
+{
+	struct class_function_drv *drv = snd_soc_component_get_drvdata(component);
+	struct sdca_class_drv *core = drv->core;
+
+	return sdca_irq_populate(drv->function, component, core->irq_info);
+}
+
+static const struct snd_soc_component_driver class_function_component_drv = {
+	.probe			= class_function_component_probe,
+	.endianness		= 1,
+};
+
+static int class_function_boot(struct class_function_drv *drv)
+{
+	unsigned int reg = SDW_SDCA_CTL(drv->function->desc->adr,
+					SDCA_ENTITY_TYPE_ENTITY_0,
+					SDCA_CTL_ENTITY_0_FUNCTION_STATUS, 0);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(drv->regmap, reg, &val);
+	if (ret < 0) {
+		dev_err(drv->dev, "failed to read function status: %d\n", ret);
+		return ret;
+	}
+
+	if (!(val & SDCA_CTL_ENTITY_0_FUNCTION_HAS_BEEN_RESET)) {
+		dev_dbg(drv->dev, "reset function device\n");
+
+		ret = sdca_reset_function(drv->dev, drv->function, drv->regmap);
+		if (ret)
+			return ret;
+	}
+
+	if (val & SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION) {
+		dev_dbg(drv->dev, "write initialisation\n");
+
+		ret = sdca_regmap_write_init(drv->dev, drv->core->dev_regmap,
+					     drv->function);
+		if (ret)
+			return ret;
+
+		ret = regmap_write(drv->regmap, reg,
+				   SDCA_CTL_ENTITY_0_FUNCTION_NEEDS_INITIALIZATION);
+		if (ret < 0) {
+			dev_err(drv->dev,
+				"failed to clear function init status: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	/* Start FDL process */
+	ret = sdca_irq_populate_early(drv->dev, drv->regmap, drv->function,
+				      drv->core->irq_info);
+	if (ret)
+		return ret;
+
+	ret = sdca_fdl_sync(drv->dev, drv->function, drv->core->irq_info);
+	if (ret)
+		return ret;
+
+	ret = sdca_regmap_write_defaults(drv->dev, drv->regmap, drv->function);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(drv->regmap, reg, 0xFF);
+	if (ret < 0) {
+		dev_err(drv->dev, "failed to clear function status: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int class_function_probe(struct auxiliary_device *auxdev,
+				const struct auxiliary_device_id *aux_dev_id)
+{
+	struct device *dev = &auxdev->dev;
+	struct sdca_class_drv *core = dev_get_drvdata(dev->parent);
+	struct sdca_device_data *data = &core->sdw->sdca_data;
+	struct sdca_function_desc *desc;
+	struct snd_soc_component_driver *cmp_drv;
+	struct snd_soc_dai_driver *dais;
+	struct class_function_drv *drv;
+	struct regmap_sdw_mbq_cfg *mbq_config;
+	struct regmap_config *config;
+	struct reg_default *defaults;
+	int ndefaults;
+	int num_dais;
+	int ret;
+	int i;
+
+	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	cmp_drv = devm_kmemdup(dev, &class_function_component_drv, sizeof(*cmp_drv),
+			       GFP_KERNEL);
+	if (!cmp_drv)
+		return -ENOMEM;
+
+	config = devm_kmemdup(dev, &class_function_regmap_config, sizeof(*config),
+			      GFP_KERNEL);
+	if (!config)
+		return -ENOMEM;
+
+	mbq_config = devm_kmemdup(dev, &class_function_mbq_config, sizeof(*mbq_config),
+				  GFP_KERNEL);
+	if (!mbq_config)
+		return -ENOMEM;
+
+	drv->dev = dev;
+	drv->core = core;
+
+	for (i = 0; i < data->num_functions; i++) {
+		desc = &data->function[i];
+
+		if (desc->type == aux_dev_id->driver_data)
+			break;
+	}
+	if (i == core->sdw->sdca_data.num_functions) {
+		dev_err(dev, "failed to locate function\n");
+		return -EINVAL;
+	}
+
+	drv->function = &core->functions[i];
+
+	ret = sdca_parse_function(dev, core->sdw, desc, drv->function);
+	if (ret)
+		return ret;
+
+	ndefaults = sdca_regmap_count_constants(dev, drv->function);
+	if (ndefaults < 0)
+		return ndefaults;
+
+	defaults = devm_kcalloc(dev, ndefaults, sizeof(*defaults), GFP_KERNEL);
+	if (!defaults)
+		return -ENOMEM;
+
+	ret = sdca_regmap_populate_constants(dev, drv->function, defaults);
+	if (ret < 0)
+		return ret;
+
+	regcache_sort_defaults(defaults, ndefaults);
+
+	auxiliary_set_drvdata(auxdev, drv);
+
+	config->reg_defaults = defaults;
+	config->num_reg_defaults = ndefaults;
+	config->lock_arg = &core->regmap_lock;
+
+	if (drv->function->busy_max_delay) {
+		mbq_config->timeout_us = drv->function->busy_max_delay;
+		mbq_config->retry_us = umax(drv->function->busy_max_delay / 10,
+					    mbq_config->retry_us);
+	}
+
+	drv->regmap = devm_regmap_init_sdw_mbq_cfg(dev, core->sdw, config, mbq_config);
+	if (IS_ERR(drv->regmap))
+		return dev_err_probe(dev, PTR_ERR(drv->regmap),
+				     "failed to create regmap");
+
+	ret = sdca_asoc_populate_component(dev, drv->function, cmp_drv,
+					   &dais, &num_dais,
+					   &class_function_sdw_ops);
+	if (ret)
+		return ret;
+
+	pm_runtime_set_autosuspend_delay(dev, 200);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_get_noresume(dev);
+
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return ret;
+
+	ret = class_function_boot(drv);
+	if (ret)
+		return ret;
+
+	ret = devm_snd_soc_register_component(dev, cmp_drv, dais, num_dais);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register component\n");
+
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
+	return 0;
+}
+
+static int class_function_runtime_suspend(struct device *dev)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+
+	/*
+	 * Whilst the driver doesn't power the chip down here, going into
+	 * runtime suspend means the driver can't be sure the bus won't
+	 * power down which would prevent communication with the device.
+	 */
+	regcache_cache_only(drv->regmap, true);
+
+	return 0;
+}
+
+static int class_function_runtime_resume(struct device *dev)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct class_function_drv *drv = auxiliary_get_drvdata(auxdev);
+	int ret;
+
+	regcache_mark_dirty(drv->regmap);
+	regcache_cache_only(drv->regmap, false);
+
+	ret = regcache_sync(drv->regmap);
+	if (ret) {
+		dev_err(drv->dev, "failed to restore register cache: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	regcache_cache_only(drv->regmap, true);
+
+	return ret;
+}
+
+static const struct dev_pm_ops class_function_pm_ops = {
+	RUNTIME_PM_OPS(class_function_runtime_suspend,
+		       class_function_runtime_resume, NULL)
+};
+
+static const struct auxiliary_device_id class_function_id_table[] = {
+	{
+		.name = "snd_soc_sdca." SDCA_FUNCTION_TYPE_SMART_AMP_NAME,
+		.driver_data = SDCA_FUNCTION_TYPE_SMART_AMP,
+	},
+	{
+		.name = "snd_soc_sdca." SDCA_FUNCTION_TYPE_SMART_MIC_NAME,
+		.driver_data = SDCA_FUNCTION_TYPE_SMART_MIC,
+	},
+	{
+		.name = "snd_soc_sdca." SDCA_FUNCTION_TYPE_UAJ_NAME,
+		.driver_data = SDCA_FUNCTION_TYPE_UAJ,
+	},
+	{
+		.name = "snd_soc_sdca." SDCA_FUNCTION_TYPE_HID_NAME,
+		.driver_data = SDCA_FUNCTION_TYPE_HID,
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, class_function_id_table);
+
+static struct auxiliary_driver class_function_drv = {
+	.driver = {
+		.name		= "sdca_function",
+		.pm		= pm_ptr(&class_function_pm_ops),
+	},
+
+	.probe		= class_function_probe,
+	.id_table	= class_function_id_table
+};
+module_auxiliary_driver(class_function_drv);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SDCA Class Function Driver");
+MODULE_IMPORT_NS("SND_SOC_SDCA");

sound/soc/sdca/sdca_fdl.c

···
 		return -EINVAL;
 	}
 
+	/*
+	 * Poll up to 16 times but no more than once per ms, these are just
+	 * arbitrarily selected values, so may be fine tuned in future.
+	 */
 	poll_us = umin(function->reset_max_delay >> 4, 1000);
 
 	ret = regmap_read_poll_timeout(regmap, reg, val, !val, poll_us,
···
 	unsigned int reg, status;
 	int response, ret;
 
-	guard(mutex)(&fdl_state->lock);
-
 	ret = sdca_ump_get_owner_host(dev, interrupt->function_regmap,
 				      interrupt->function, interrupt->entity,
 				      interrupt->control);
···
 
 	sdca_ump_cancel_timeout(&fdl_state->timeout);
 
-	reg = SDW_SDCA_CTL(interrupt->function->desc->adr, interrupt->entity->id,
-			   SDCA_CTL_XU_FDL_STATUS, 0);
-	ret = regmap_read(interrupt->function_regmap, reg, &status);
-	if (ret < 0) {
-		dev_err(dev, "failed to read FDL status: %d\n", ret);
-		return ret;
-	}
-
-	dev_dbg(dev, "FDL status: %#x\n", status);
-
-	ret = fdl_status_process(interrupt, status);
-	if (ret < 0)
-		goto reset_function;
-
-	response = ret;
-
-	dev_dbg(dev, "FDL response: %#x\n", response);
-
-	ret = regmap_write(interrupt->function_regmap, reg,
-			   response | (status & ~SDCA_CTL_XU_FDLH_MASK));
-	if (ret < 0) {
-		dev_err(dev, "failed to set FDL status signal: %d\n", ret);
-		return ret;
-	}
-
-	ret = sdca_ump_set_owner_device(dev, interrupt->function_regmap,
-					interrupt->function, interrupt->entity,
-					interrupt->control);
-	if (ret)
-		return ret;
-
-	switch (response) {
-	case SDCA_CTL_XU_FDLH_RESET_ACK:
-		dev_dbg(dev, "FDL request reset\n");
-
-		switch (xu->reset_mechanism) {
-		default:
-			dev_warn(dev, "Requested reset mechanism not implemented\n");
-			fallthrough;
-		case SDCA_XU_RESET_FUNCTION:
-			goto reset_function;
+	scoped_guard(mutex, &fdl_state->lock) {
+		reg = SDW_SDCA_CTL(interrupt->function->desc->adr,
+				   interrupt->entity->id, SDCA_CTL_XU_FDL_STATUS, 0);
+		ret = regmap_read(interrupt->function_regmap, reg, &status);
+		if (ret < 0) {
+			dev_err(dev, "failed to read FDL status: %d\n", ret);
+			return ret;
 		}
-	case SDCA_CTL_XU_FDLH_COMPLETE:
-		if (status & SDCA_CTL_XU_FDLD_REQ_ABORT ||
-		    status == SDCA_CTL_XU_FDLD_COMPLETE)
+
+		dev_dbg(dev, "FDL status: %#x\n", status);
+
+		ret = fdl_status_process(interrupt, status);
+		if (ret < 0)
+			goto reset_function;
+
+		response = ret;
+
+		dev_dbg(dev, "FDL response: %#x\n", response);
+
+		ret = regmap_write(interrupt->function_regmap, reg,
+				   response | (status & ~SDCA_CTL_XU_FDLH_MASK));
+		if (ret < 0) {
+			dev_err(dev, "failed to set FDL status signal: %d\n", ret);
+			return ret;
+		}
+
+		ret = sdca_ump_set_owner_device(dev, interrupt->function_regmap,
+						interrupt->function,
+						interrupt->entity,
+						interrupt->control);
+		if (ret)
+			return ret;
+
+		switch (response) {
+		case SDCA_CTL_XU_FDLH_RESET_ACK:
+			dev_dbg(dev, "FDL request reset\n");
+
+			switch (xu->reset_mechanism) {
+			default:
+				dev_warn(dev, "Requested reset mechanism not implemented\n");
+				fallthrough;
+			case SDCA_XU_RESET_FUNCTION:
+				goto reset_function;
+			}
+		case SDCA_CTL_XU_FDLH_COMPLETE:
+			if (status & SDCA_CTL_XU_FDLD_REQ_ABORT ||
+			    status == SDCA_CTL_XU_FDLD_COMPLETE)
+				return 0;
+			fallthrough;
+		default:
+			sdca_ump_schedule_timeout(&fdl_state->timeout, xu->max_delay);
 			return 0;
-		fallthrough;
-	default:
-		sdca_ump_schedule_timeout(&fdl_state->timeout, xu->max_delay);
-		return 0;
+		}
 	}
 
 reset_function:

sound/soc/sdca/sdca_function_device.c

···
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2024 Intel Corporation.
+
+/*
+ * SDCA Function Device management
+ */
+
+#include <linux/acpi.h>
+#include <linux/module.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/soundwire/sdw.h>
+#include <sound/sdca.h>
+#include <sound/sdca_function.h>
+#include "sdca_function_device.h"
+
+/*
+ * A SoundWire device can have multiple SDCA functions identified by
+ * their type and ADR. there can be multiple SoundWire devices per
+ * link, or multiple devices spread across multiple links. An IDA is
+ * required to identify each instance.
+ */
+static DEFINE_IDA(sdca_function_ida);
+
+static void sdca_dev_release(struct device *dev)
+{
+	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
+	struct sdca_dev *sdev = auxiliary_dev_to_sdca_dev(auxdev);
+
+	ida_free(&sdca_function_ida, auxdev->id);
+	kfree(sdev);
+}
+
+/* alloc, init and add link devices */
+static struct sdca_dev *sdca_dev_register(struct device *parent,
+					  struct sdca_function_desc *function_desc)
+{
+	struct sdca_dev *sdev;
+	struct auxiliary_device *auxdev;
+	int ret;
+	int rc;
+
+	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+	if (!sdev)
+		return ERR_PTR(-ENOMEM);
+
+	auxdev = &sdev->auxdev;
+	auxdev->name = function_desc->name;
+	auxdev->dev.parent = parent;
+	auxdev->dev.fwnode = function_desc->node;
+	auxdev->dev.release = sdca_dev_release;
+
+	sdev->function.desc = function_desc;
+
+	rc = ida_alloc(&sdca_function_ida, GFP_KERNEL);
+	if (rc < 0) {
+		kfree(sdev);
+		return ERR_PTR(rc);
+	}
+	auxdev->id = rc;
+
+	/* now follow the two-step init/add sequence */
+	ret = auxiliary_device_init(auxdev);
+	if (ret < 0) {
+		dev_err(parent, "failed to initialize SDCA function dev %s\n",
+			function_desc->name);
+		ida_free(&sdca_function_ida, auxdev->id);
+		kfree(sdev);
+		return ERR_PTR(ret);
+	}
+
+	ret = auxiliary_device_add(auxdev);
+	if (ret < 0) {
+		dev_err(parent, "failed to add SDCA function dev %s\n",
+			sdev->auxdev.name);
+		/* sdev will be freed with the put_device() and .release sequence */
+		auxiliary_device_uninit(&sdev->auxdev);
+		return ERR_PTR(ret);
+	}
+
+	return sdev;
+}
+
+static void sdca_dev_unregister(struct sdca_dev *sdev)
+{
+	auxiliary_device_delete(&sdev->auxdev);
+	auxiliary_device_uninit(&sdev->auxdev);
+}
+
+int sdca_dev_register_functions(struct sdw_slave *slave)
+{
+	struct sdca_device_data *sdca_data = &slave->sdca_data;
+	int i;
+
+	for (i = 0; i < sdca_data->num_functions; i++) {
+		struct sdca_dev *func_dev;
+
+		func_dev = sdca_dev_register(&slave->dev,
+					     &sdca_data->function[i]);
+		if (!func_dev)
+			return -ENODEV;
+
+		sdca_data->function[i].func_dev = func_dev;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS(sdca_dev_register_functions, "SND_SOC_SDCA");
+
+void sdca_dev_unregister_functions(struct sdw_slave *slave)
+{
+	struct sdca_device_data *sdca_data = &slave->sdca_data;
+	int i;
+
+	for (i = 0; i < sdca_data->num_functions; i++)
+		sdca_dev_unregister(sdca_data->function[i].func_dev);
+}
+EXPORT_SYMBOL_NS(sdca_dev_unregister_functions, "SND_SOC_SDCA");

sound/soc/sdca/sdca_function_device.h

···
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/* Copyright(c) 2024 Intel Corporation. */
+
+#ifndef __SDCA_FUNCTION_DEVICE_H
+#define __SDCA_FUNCTION_DEVICE_H
+
+struct sdca_dev {
+	struct auxiliary_device auxdev;
+	struct sdca_function_data function;
+};
+
+#define auxiliary_dev_to_sdca_dev(auxiliary_dev)		\
+	container_of(auxiliary_dev, struct sdca_dev, auxdev)
+
+#endif

sound/soc/sdca/sdca_functions.c

···
  * https://www.mipi.org/mipi-sdca-v1-0-download
  */
 
-#define dev_fmt(fmt) "%s: " fmt, __func__
-
 #include <linux/acpi.h>
 #include <linux/byteorder/generic.h>
 #include <linux/cleanup.h>
···
 	control->type = find_sdca_control_datatype(entity, control);
 	control->nbits = find_sdca_control_bits(entity, control);
 
-	dev_info(dev, "%s: %s: control %#x mode %#x layers %#x cn %#llx int %d %s\n",
-		 entity->label, control->label, control->sel,
-		 control->mode, control->layers, control->cn_list,
-		 control->interrupt_position, control->deferrable ? "deferrable" : "");
+	dev_dbg(dev, "%s: %s: control %#x mode %#x layers %#x cn %#llx int %d %s\n",
+		entity->label, control->label, control->sel,
+		control->mode, control->layers, control->cn_list,
+		control->interrupt_position, control->deferrable ? "deferrable" : "");
 
 	return 0;
 }
···
 	if (!ret)
 		terminal->num_transducer = tmp;
 
-	dev_info(dev, "%s: terminal type %#x ref %#x conn %#x count %d\n",
-		 entity->label, terminal->type, terminal->reference,
-		 terminal->connector, terminal->num_transducer);
+	dev_dbg(dev, "%s: terminal type %#x ref %#x conn %#x count %d\n",
+		entity->label, terminal->type, terminal->reference,
+		terminal->connector, terminal->num_transducer);
 
 	return 0;
 }
···
 	if (!ret)
 		clock->max_delay = tmp;
 
-	dev_info(dev, "%s: clock type %#x delay %d\n", entity->label,
-		 clock->type, clock->max_delay);
+	dev_dbg(dev, "%s: clock type %#x delay %d\n", entity->label,
+		clock->type, clock->max_delay);
 
 	return 0;
 }
···
 		delays[i].to_ps = delay_list[j++];
 		delays[i].us = delay_list[j++];
 
-		dev_info(dev, "%s: from %#x to %#x delay %dus\n", entity->label,
-			 delays[i].from_ps, delays[i].to_ps, delays[i].us);
+		dev_dbg(dev, "%s: from %#x to %#x delay %dus\n", entity->label,
+			delays[i].from_ps, delays[i].to_ps, delays[i].us);
 	}
 
 	power->num_max_delay = num_delays;
···
 	unsigned char *report_desc = NULL;
 
 	ret = fwnode_property_read_u32(entity_node,
-				       "mipi-sdca-RxUMP-ownership-transition-maxdelay", &delay);
+				       "mipi-sdca-RxUMP-ownership-transition-max-delay", &delay);
 	if (!ret)
 		hide->max_delay = delay;
 
···
 
 	entity->type = tmp;
 
-	dev_info(dev, "%s: entity %#x type %#x\n",
-		 entity->label, entity->id, entity->type);
+	dev_dbg(dev, "%s: entity %#x type %#x\n",
+		entity->label, entity->id, entity->type);
 
 	switch (entity->type) {
 	case SDCA_ENTITY_TYPE_IT:
···
 
 	terminal->clock = clock_entity;
 
-	dev_info(dev, "%s -> %s\n", clock_entity->label, entity->label);
+	dev_dbg(dev, "%s -> %s\n", clock_entity->label, entity->label);
 
 	fwnode_handle_put(clock_node);
 	return 0;
···
 			return -EINVAL;
 		}
 
-		dev_info(dev, "%s -> %s\n", managed[i]->label, entity->label);
+		dev_dbg(dev, "%s -> %s\n", managed[i]->label, entity->label);
 	}
 
 	power->num_managed = num_managed;
···
 
 		pins[i] = connected_entity;
 
-		dev_info(dev, "%s -> %s\n", connected_entity->label, entity->label);
+		dev_dbg(dev, "%s -> %s\n", connected_entity->label, entity->label);
 
 		i++;
 		fwnode_handle_put(connected_node);
···
 
 	channel->relationship = tmp;
 
-	dev_info(dev, "cluster %#x: channel id %#x purpose %#x relationship %#x\n",
-		 cluster->id, channel->id, channel->purpose, channel->relationship);
+	dev_dbg(dev, "cluster %#x: channel id %#x purpose %#x relationship %#x\n",
+		cluster->id, channel->id, channel->purpose, channel->relationship);
 
 	return 0;
 }
···
 			return -EINVAL;
 		}
 
-		dev_info(dev, "fileset: %#x\n", filesets_list[i]);
+		dev_dbg(dev, "fileset: %#x\n", filesets_list[i]);
 
 		files = devm_kcalloc(dev, num_entries / mult_fileset,
 				     sizeof(struct sdca_fdl_file), GFP_KERNEL);
···
 			file->file_id = fileset_entries[j++];
 			file->fdl_offset = fileset_entries[j++];
 
-			dev_info(dev, "file: %#x, vendor: %#x, offset: %#x\n",
-				 file->file_id, file->vendor_id, file->fdl_offset);
+			dev_dbg(dev, "file: %#x, vendor: %#x, offset: %#x\n",
+				file->file_id, file->vendor_id, file->fdl_offset);
 		}
 
 		set->id = filesets_list[i];
···
 	if (!ret)
 		function->reset_max_delay = tmp;
 
-	dev_info(dev, "%pfwP: name %s busy delay %dus reset delay %dus\n",
-		 function->desc->node, function->desc->name,
-		 function->busy_max_delay, function->reset_max_delay);
+	dev_dbg(dev, "%pfwP: name %s busy delay %dus reset delay %dus\n",
+		function->desc->node, function->desc->name,
+		function->busy_max_delay, function->reset_max_delay);
 
 	ret = find_sdca_init_table(dev, function_desc->node, function);
 	if (ret)

sound/soc/sdca/sdca_hid.c

···
 	return 0;
 }
 EXPORT_SYMBOL_NS(sdca_hid_process_report, "SND_SOC_SDCA");
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_DESCRIPTION("SDCA HID library");

sound/soc/sdca/sdca_interrupts.c

···
 			else if (!interrupt)
 				continue;
 
-			switch (entity->type) {
-			case SDCA_ENTITY_TYPE_XU:
-				if (control->sel != SDCA_CTL_XU_FDL_CURRENTOWNER)
-					break;
-
+			switch (SDCA_CTL_TYPE(entity->type, control->sel)) {
+			case SDCA_CTL_TYPE_S(XU, FDL_CURRENTOWNER):
 				ret = sdca_irq_data_populate(dev, regmap, NULL,
 							     function, entity,
 							     control, interrupt);
···
 
 			handler = base_handler;
 
-			switch (entity->type) {
-			case SDCA_ENTITY_TYPE_ENTITY_0:
-				if (control->sel == SDCA_CTL_ENTITY_0_FUNCTION_STATUS)
-					handler = function_status_handler;
+			switch (SDCA_CTL_TYPE(entity->type, control->sel)) {
+			case SDCA_CTL_TYPE_S(ENTITY_0, FUNCTION_STATUS):
+				handler = function_status_handler;
 				break;
-			case SDCA_ENTITY_TYPE_GE:
-				if (control->sel == SDCA_CTL_GE_DETECTED_MODE)
-					handler = detected_mode_handler;
+			case SDCA_CTL_TYPE_S(GE, DETECTED_MODE):
+				handler = detected_mode_handler;
 				break;
-			case SDCA_ENTITY_TYPE_XU:
-				if (control->sel == SDCA_CTL_XU_FDL_CURRENTOWNER) {
-					ret = sdca_fdl_alloc_state(interrupt);
-					if (ret)
-						return ret;
+			case SDCA_CTL_TYPE_S(XU, FDL_CURRENTOWNER):
+				ret = sdca_fdl_alloc_state(interrupt);
+				if (ret)
+					return ret;
 
-					handler = fdl_owner_handler;
-				}
+				handler = fdl_owner_handler;
 				break;
-			case SDCA_ENTITY_TYPE_HIDE:
-				if (control->sel == SDCA_CTL_HIDE_HIDTX_CURRENTOWNER)
-					handler = hid_handler;
+			case SDCA_CTL_TYPE_S(HIDE, HIDTX_CURRENTOWNER):
+				handler = hid_handler;
 				break;
 			default:
 				break;
···
 	return info;
 }
 EXPORT_SYMBOL_NS_GPL(sdca_irq_allocate, "SND_SOC_SDCA");
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("SDCA IRQ library");

sound/soc/sdca/sdca_regmap.c

···
 }
 EXPORT_SYMBOL_NS(sdca_regmap_populate_constants, "SND_SOC_SDCA");
 
+static int populate_control_defaults(struct device *dev, struct regmap *regmap,
+				     struct sdca_function_data *function,
+				     struct sdca_entity *entity,
+				     struct sdca_control *control)
+{
+	int i, ret;
+	int cn;
+
+	if (control->mode == SDCA_ACCESS_MODE_DC)
+		return 0;
+
+	if (control->layers & SDCA_ACCESS_LAYER_DEVICE)
+		return 0;
+
+	i = 0;
+	for_each_set_bit(cn, (unsigned long *)&control->cn_list,
+			 BITS_PER_TYPE(control->cn_list)) {
+		unsigned int reg, val;
+
+		reg = SDW_SDCA_CTL(function->desc->adr, entity->id, control->sel, cn);
+
+		if (control->has_default || control->has_fixed) {
+			ret = regmap_write(regmap, reg, control->values[i]);
+			if (ret) {
+				dev_err(dev, "Failed to write default %#x: %d\n",
+					reg, ret);
+				return ret;
+			}
+
+			i++;
+		} else if (!control->is_volatile) {
+			ret = regmap_read(regmap, reg, &val);
+			if (ret) {
+				dev_err(dev, "Failed to read initial %#x: %d\n",
+					reg, ret);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
 /**
  * sdca_regmap_write_defaults - write out DisCo defaults to device
  * @dev: Pointer to the device.
···
  *
  * This function will write out to the hardware all the DisCo default and
  * fixed value controls. This will cause them to be populated into the cache,
- * and subsequent handling can be done through a cache sync.
+ * and subsequent handling can be done through a cache sync. It will also
+ * read any non-volatile registers that don't have defaults/fixed values to
+ * populate those into the cache, this ensures they are available for reads
+ * even when the device is runtime suspended.
  *
  * Return: Returns zero on success, and a negative error code on failure.
  */
 int sdca_regmap_write_defaults(struct device *dev, struct regmap *regmap,
 			       struct sdca_function_data *function)
 {
-	int i, j, k;
+	int i, j;
 	int ret;
 
 	for (i = 0; i < function->num_entities; i++) {
···
 
 		for (j = 0; j < entity->num_controls; j++) {
 			struct sdca_control *control = &entity->controls[j];
-			int cn;
 
-			if (control->mode == SDCA_ACCESS_MODE_DC)
-				continue;
-
-			if (!control->has_default && !control->has_fixed)
-				continue;
-
-			k = 0;
-			for_each_set_bit(cn, (unsigned long *)&control->cn_list,
-					 BITS_PER_TYPE(control->cn_list)) {
-				unsigned int reg;
-
-				reg = SDW_SDCA_CTL(function->desc->adr, entity->id,
-						   control->sel, cn);
-
-				ret = regmap_write(regmap, reg, control->values[k]);
-				if (ret)
-					return ret;
-
-				k++;
-			}
+			ret = populate_control_defaults(dev, regmap, function,
+							entity, control);
+			if (ret)
+				return ret;
 		}
 	}
 
 	return 0;
 }
 EXPORT_SYMBOL_NS(sdca_regmap_write_defaults, "SND_SOC_SDCA");
+
+int sdca_regmap_write_init(struct device *dev, struct regmap *regmap,
+			   struct sdca_function_data *function)
+{
+	struct sdca_init_write *init = function->init_table;
+	int ret, i;
+
+	for (i = 0; i < function->num_init_table; i++) {
+		ret = regmap_write(regmap, init[i].addr, init[i].val);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS(sdca_regmap_write_init, "SND_SOC_SDCA");