1 files changed, 114 insertions, 0 deletions
diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
new file mode 100644
index 000000000000..ac103bd0c176
--- /dev/null
+++ b/drivers/soundwire/slave.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2015-17 Intel Corporation.
+
+#include <linux/acpi.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
+#include "bus.h"
+
+static void sdw_slave_release(struct device *dev)
+{
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+
+	kfree(slave);
+}
+
+static int sdw_slave_add(struct sdw_bus *bus,
+		struct sdw_slave_id *id, struct fwnode_handle *fwnode)
+{
+	struct sdw_slave *slave;
+	int ret;
+
+	slave = kzalloc(sizeof(*slave), GFP_KERNEL);
+	if (!slave)
+		return -ENOMEM;
+
+	/* Initialize data structure */
+	memcpy(&slave->id, id, sizeof(*id));
+	slave->dev.parent = bus->dev;
+	slave->dev.fwnode = fwnode;
+
+	/* name shall be sdw:link:mfg:part:class:unique */
+	dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x:%x",
+			bus->link_id, id->mfg_id, id->part_id,
+			id->class_id, id->unique_id);
+
+	slave->dev.release = sdw_slave_release;
+	slave->dev.bus = &sdw_bus_type;
+	slave->bus = bus;
+	slave->status = SDW_SLAVE_UNATTACHED;
+	slave->dev_num = 0;
+
+	mutex_lock(&bus->bus_lock);
+	list_add_tail(&slave->node, &bus->slaves);
+	mutex_unlock(&bus->bus_lock);
+
+	ret = device_register(&slave->dev);
+	if (ret) {
+		dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
+
+		/*
+		 * On err, don't free but drop ref as this will be freed
+		 * when release method is invoked.
+		 */
+		mutex_lock(&bus->bus_lock);
+		list_del(&slave->node);
+		mutex_unlock(&bus->bus_lock);
+		put_device(&slave->dev);
+	}
+
+	return ret;
+}
+
+#if IS_ENABLED(CONFIG_ACPI)
+/*
+ * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
+ * @bus: SDW bus instance
+ *
+ * Scans Master ACPI node for SDW child Slave devices and registers it.
+ */
+int sdw_acpi_find_slaves(struct sdw_bus *bus)
+{
+	struct acpi_device *adev, *parent;
+
+	parent = ACPI_COMPANION(bus->dev);
+	if (!parent) {
+		dev_err(bus->dev, "Can't find parent for acpi bind\n");
+		return -ENODEV;
+	}
+
+	list_for_each_entry(adev, &parent->children, node) {
+		unsigned long long addr;
+		struct sdw_slave_id id;
+		unsigned int link_id;
+		acpi_status status;
+
+		status = acpi_evaluate_integer(adev->handle,
+					METHOD_NAME__ADR, NULL, &addr);
+
+		if (ACPI_FAILURE(status)) {
+			dev_err(bus->dev, "_ADR resolution failed: %x\n",
+							status);
+			return status;
+		}
+
+		/* Extract link id from ADR, Bit 51 to 48 (included) */
+		link_id = (addr >> 48) & GENMASK(3, 0);
+
+		/* Check for link_id match */
+		if (link_id != bus->link_id)
+			continue;
+
+		sdw_extract_slave_id(bus, addr, &id);
+
+		/*
+		 * don't error check for sdw_slave_add as we want to continue
+		 * adding Slaves
+		 */
+		sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
+	}
+
+	return 0;
+}
+
+#endif