1 files changed, 304 insertions, 0 deletions
diff --git a/sound/soc/sdca/sdca_class.c b/sound/soc/sdca/sdca_class.c
new file mode 100644
index 000000000000..349d32933ba8
--- /dev/null
+++ b/sound/soc/sdca/sdca_class.c
@@ -0,0 +1,304 @@
+// 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");