[PATCH v3 13/13] ASoC: SDCA: Add basic SDCA function driver

[Charles Keepax <ckeepax@opensource.cirrus.com>]

Add a driver to support the individual SDCA functions within the class
driver. Use the SDCA helpers to parse the DisCo information and register
a function driver based on those properties. Manage the boot of the
function, reset, FDL, defaults. Manage the function level register map.

Co-developed-by: Maciej Strozek <mstrozek@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v2:
 - Renamed suspend/resume functions to be a little less wordy.

 sound/soc/sdca/Kconfig               |   7 +
 sound/soc/sdca/Makefile              |   2 +
 sound/soc/sdca/sdca_class_function.c | 460 +++++++++++++++++++++++++++
 3 files changed, 469 insertions(+)
 create mode 100644 sound/soc/sdca/sdca_class_function.c

diff --git a/sound/soc/sdca/Kconfig b/sound/soc/sdca/Kconfig
index 56e3ff8448762..0a37e94a60302 100644
--- a/sound/soc/sdca/Kconfig
+++ b/sound/soc/sdca/Kconfig
@@ -39,6 +39,7 @@ config SND_SOC_SDCA_OPTIONAL
 
 config SND_SOC_SDCA_CLASS
 	tristate "SDCA Class Driver"
+	select SND_SOC_SDCA_CLASS_FUNCTION
 	select SND_SOC_SDCA
 	select SND_SOC_SDCA_FDL
 	select SND_SOC_SDCA_HID
@@ -47,4 +48,10 @@ config SND_SOC_SDCA_CLASS
 	  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
diff --git a/sound/soc/sdca/Makefile b/sound/soc/sdca/Makefile
index 95db4cef34833..f6b73275d9649 100644
--- a/sound/soc/sdca/Makefile
+++ b/sound/soc/sdca/Makefile
@@ -7,7 +7,9 @@ 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
diff --git a/sound/soc/sdca/sdca_class_function.c b/sound/soc/sdca/sdca_class_function.c
new file mode 100644
index 0000000000000..0028482a1e752
--- /dev/null
+++ b/sound/soc/sdca/sdca_class_function.c
@@ -0,0 +1,460 @@
+// 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");
-- 
2.47.3