i3c: Add core I3C infrastructure

Add core infrastructure to support I3C in Linux and document it.

This infrastructure adds basic I3C support. Advanced features will be
added afterwards.

There are a few design choices that are worth mentioning because they
impact the way I3C device drivers can interact with their devices:

- all functions used to send I3C/I2C frames must be called in
  non-atomic context. Mainly done this way to ease implementation, but
  this is not set in stone, and if anyone needs async support, new
  functions can be added later on.
- the bus element is a separate object, but it's tightly coupled with
  the master object. We thus have a 1:1 relationship between i3c_bus
  and i3c_master_controller objects, and if 2 master controllers are
  connected to the same bus and both exposed to the same Linux instance
  they will appear as two distinct busses, and devices on this bus will
  be exposed twice.
- I2C backward compatibility has been designed to be transparent to I2C
  drivers and the I2C subsystem. The I3C master just registers an I2C
  adapter which creates a new I2C bus. I'd say that, from a
  representation PoV it's not ideal because what should appear as a
  single I3C bus exposing I3C and I2C devices here appears as 2
  different buses connected to each other through the parenting (the
  I3C master is the parent of the I2C and I3C busses).
  On the other hand, I don't see a better solution if we want something
  that is not invasive.

Missing features:
- I3C HDR modes are not supported
- no support for multi-master and the associated concepts (mastership
  handover, support for secondary masters, ...)
- I2C devices can only be described using DT because this is the only
  use case I have. However, the framework can easily be extended with
  ACPI and board info support
- I3C slave framework. This has been completely omitted, but shouldn't
  have a huge impact on the I3C framework because I3C slaves don't see
  the whole bus, it's only about handling master requests and generating
  IBIs. Some of the struct, constant and enum definitions could be
  shared, but most of the I3C slave framework logic will be different

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

7 files changed, 2948 insertions, 0 deletions

diff --git a/drivers/i3c/Kconfig b/drivers/i3c/Kconfig
new file mode 100644
index 000000000000..30a441506f61
--- /dev/null
+++ b/drivers/i3c/Kconfig
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig I3C
+	tristate "I3C support"
+	select I2C
+	help
+	  I3C is a serial protocol standardized by the MIPI alliance.
+
+	  It's supposed to be backward compatible with I2C while providing
+	  support for high speed transfers and native interrupt support
+	  without the need for extra pins.
+
+	  The I3C protocol also standardizes the slave device types and is
+	  mainly designed to communicate with sensors.
+
+	  If you want I3C support, you should say Y here and also to the
+	  specific driver for your bus adapter(s) below.
+
+	  This I3C support can also be built as a module.  If so, the module
+	  will be called i3c.
+
+if I3C
+source "drivers/i3c/master/Kconfig"
+endif # I3C
diff --git a/drivers/i3c/Makefile b/drivers/i3c/Makefile
new file mode 100644
index 000000000000..11982efbc6d9
--- /dev/null
+++ b/drivers/i3c/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+i3c-y				:= device.o master.o
+obj-$(CONFIG_I3C)		+= i3c.o
+obj-$(CONFIG_I3C)		+= master/
diff --git a/drivers/i3c/device.c b/drivers/i3c/device.c
new file mode 100644
index 000000000000..69cc040c3a1c
--- /dev/null
+++ b/drivers/i3c/device.c
@@ -0,0 +1,233 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Cadence Design Systems Inc.
+ *
+ * Author: Boris Brezillon <boris.brezillon@bootlin.com>
+ */
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include "internals.h"
+
+/**
+ * i3c_device_do_priv_xfers() - do I3C SDR private transfers directed to a
+ *				specific device
+ *
+ * @dev: device with which the transfers should be done
+ * @xfers: array of transfers
+ * @nxfers: number of transfers
+ *
+ * Initiate one or several private SDR transfers with @dev.
+ *
+ * This function can sleep and thus cannot be called in atomic context.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+int i3c_device_do_priv_xfers(struct i3c_device *dev,
+			     struct i3c_priv_xfer *xfers,
+			     int nxfers)
+{
+	int ret, i;
+
+	if (nxfers < 1)
+		return 0;
+
+	for (i = 0; i < nxfers; i++) {
+		if (!xfers[i].len || !xfers[i].data.in)
+			return -EINVAL;
+	}
+
+	i3c_bus_normaluse_lock(dev->bus);
+	ret = i3c_dev_do_priv_xfers_locked(dev->desc, xfers, nxfers);
+	i3c_bus_normaluse_unlock(dev->bus);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i3c_device_do_priv_xfers);
+
+/**
+ * i3c_device_get_info() - get I3C device information
+ *
+ * @dev: device we want information on
+ * @info: the information object to fill in
+ *
+ * Retrieve I3C dev info.
+ */
+void i3c_device_get_info(struct i3c_device *dev,
+			 struct i3c_device_info *info)
+{
+	if (!info)
+		return;
+
+	i3c_bus_normaluse_lock(dev->bus);
+	if (dev->desc)
+		*info = dev->desc->info;
+	i3c_bus_normaluse_unlock(dev->bus);
+}
+EXPORT_SYMBOL_GPL(i3c_device_get_info);
+
+/**
+ * i3c_device_disable_ibi() - Disable IBIs coming from a specific device
+ * @dev: device on which IBIs should be disabled
+ *
+ * This function disable IBIs coming from a specific device and wait for
+ * all pending IBIs to be processed.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+int i3c_device_disable_ibi(struct i3c_device *dev)
+{
+	int ret = -ENOENT;
+
+	i3c_bus_normaluse_lock(dev->bus);
+	if (dev->desc) {
+		mutex_lock(&dev->desc->ibi_lock);
+		ret = i3c_dev_disable_ibi_locked(dev->desc);
+		mutex_unlock(&dev->desc->ibi_lock);
+	}
+	i3c_bus_normaluse_unlock(dev->bus);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i3c_device_disable_ibi);
+
+/**
+ * i3c_device_enable_ibi() - Enable IBIs coming from a specific device
+ * @dev: device on which IBIs should be enabled
+ *
+ * This function enable IBIs coming from a specific device and wait for
+ * all pending IBIs to be processed. This should be called on a device
+ * where i3c_device_request_ibi() has succeeded.
+ *
+ * Note that IBIs from this device might be received before this function
+ * returns to its caller.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+int i3c_device_enable_ibi(struct i3c_device *dev)
+{
+	int ret = -ENOENT;
+
+	i3c_bus_normaluse_lock(dev->bus);
+	if (dev->desc) {
+		mutex_lock(&dev->desc->ibi_lock);
+		ret = i3c_dev_enable_ibi_locked(dev->desc);
+		mutex_unlock(&dev->desc->ibi_lock);
+	}
+	i3c_bus_normaluse_unlock(dev->bus);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i3c_device_enable_ibi);
+
+/**
+ * i3c_device_request_ibi() - Request an IBI
+ * @dev: device for which we should enable IBIs
+ * @req: setup requested for this IBI
+ *
+ * This function is responsible for pre-allocating all resources needed to
+ * process IBIs coming from @dev. When this function returns, the IBI is not
+ * enabled until i3c_device_enable_ibi() is called.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+int i3c_device_request_ibi(struct i3c_device *dev,
+			   const struct i3c_ibi_setup *req)
+{
+	int ret = -ENOENT;
+
+	if (!req->handler || !req->num_slots)
+		return -EINVAL;
+
+	i3c_bus_normaluse_lock(dev->bus);
+	if (dev->desc) {
+		mutex_lock(&dev->desc->ibi_lock);
+		ret = i3c_dev_request_ibi_locked(dev->desc, req);
+		mutex_unlock(&dev->desc->ibi_lock);
+	}
+	i3c_bus_normaluse_unlock(dev->bus);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(i3c_device_request_ibi);
+
+/**
+ * i3c_device_free_ibi() - Free all resources needed for IBI handling
+ * @dev: device on which you want to release IBI resources
+ *
+ * This function is responsible for de-allocating resources previously
+ * allocated by i3c_device_request_ibi(). It should be called after disabling
+ * IBIs with i3c_device_disable_ibi().
+ */
+void i3c_device_free_ibi(struct i3c_device *dev)
+{
+	i3c_bus_normaluse_lock(dev->bus);
+	if (dev->desc) {
+		mutex_lock(&dev->desc->ibi_lock);
+		i3c_dev_free_ibi_locked(dev->desc);
+		mutex_unlock(&dev->desc->ibi_lock);
+	}
+	i3c_bus_normaluse_unlock(dev->bus);
+}
+EXPORT_SYMBOL_GPL(i3c_device_free_ibi);
+
+/**
+ * i3cdev_to_dev() - Returns the device embedded in @i3cdev
+ * @i3cdev: I3C device
+ *
+ * Return: a pointer to a device object.
+ */
+struct device *i3cdev_to_dev(struct i3c_device *i3cdev)
+{
+	return &i3cdev->dev;
+}
+EXPORT_SYMBOL_GPL(i3cdev_to_dev);
+
+/**
+ * dev_to_i3cdev() - Returns the I3C device containing @dev
+ * @dev: device object
+ *
+ * Return: a pointer to an I3C device object.
+ */
+struct i3c_device *dev_to_i3cdev(struct device *dev)
+{
+	return container_of(dev, struct i3c_device, dev);
+}
+EXPORT_SYMBOL_GPL(dev_to_i3cdev);
+
+/**
+ * i3c_driver_register_with_owner() - register an I3C device driver
+ *
+ * @drv: driver to register
+ * @owner: module that owns this driver
+ *
+ * Register @drv to the core.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+int i3c_driver_register_with_owner(struct i3c_driver *drv, struct module *owner)
+{
+	drv->driver.owner = owner;
+	drv->driver.bus = &i3c_bus_type;
+
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(i3c_driver_register_with_owner);
+
+/**
+ * i3c_driver_unregister() - unregister an I3C device driver
+ *
+ * @drv: driver to unregister
+ *
+ * Unregister @drv.
+ */
+void i3c_driver_unregister(struct i3c_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(i3c_driver_unregister);
diff --git a/drivers/i3c/internals.h b/drivers/i3c/internals.h
new file mode 100644
index 000000000000..86b7b44cfca2
--- /dev/null
+++ b/drivers/i3c/internals.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 Cadence Design Systems Inc.
+ *
+ * Author: Boris Brezillon <boris.brezillon@bootlin.com>
+ */
+
+#ifndef I3C_INTERNALS_H
+#define I3C_INTERNALS_H
+
+#include <linux/i3c/master.h>
+
+extern struct bus_type i3c_bus_type;
+
+void i3c_bus_normaluse_lock(struct i3c_bus *bus);
+void i3c_bus_normaluse_unlock(struct i3c_bus *bus);
+
+int i3c_dev_do_priv_xfers_locked(struct i3c_dev_desc *dev,
+				 struct i3c_priv_xfer *xfers,
+				 int nxfers);
+int i3c_dev_disable_ibi_locked(struct i3c_dev_desc *dev);
+int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev);
+int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
+			       const struct i3c_ibi_setup *req);
+void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev);
+#endif /* I3C_INTERNAL_H */
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
new file mode 100644
index 000000000000..0ea7bb045fad
--- /dev/null
+++ b/drivers/i3c/master.c
@@ -0,0 +1,2661 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Cadence Design Systems Inc.
+ *
+ * Author: Boris Brezillon <boris.brezillon@bootlin.com>
+ */
+
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+
+#include "internals.h"
+
+static DEFINE_IDR(i3c_bus_idr);
+static DEFINE_MUTEX(i3c_core_lock);
+
+/**
+ * i3c_bus_maintenance_lock - Lock the bus for a maintenance operation
+ * @bus: I3C bus to take the lock on
+ *
+ * This function takes the bus lock so that no other operations can occur on
+ * the bus. This is needed for all kind of bus maintenance operation, like
+ * - enabling/disabling slave events
+ * - re-triggering DAA
+ * - changing the dynamic address of a device
+ * - relinquishing mastership
+ * - ...
+ *
+ * The reason for this kind of locking is that we don't want drivers and core
+ * logic to rely on I3C device information that could be changed behind their
+ * back.
+ */
+static void i3c_bus_maintenance_lock(struct i3c_bus *bus)
+{
+	down_write(&bus->lock);
+}
+
+/**
+ * i3c_bus_maintenance_unlock - Release the bus lock after a maintenance
+ *			      operation
+ * @bus: I3C bus to release the lock on
+ *
+ * Should be called when the bus maintenance operation is done. See
+ * i3c_bus_maintenance_lock() for more details on what these maintenance
+ * operations are.
+ */
+static void i3c_bus_maintenance_unlock(struct i3c_bus *bus)
+{
+	up_write(&bus->lock);
+}
+
+/**
+ * i3c_bus_normaluse_lock - Lock the bus for a normal operation
+ * @bus: I3C bus to take the lock on
+ *
+ * This function takes the bus lock for any operation that is not a maintenance
+ * operation (see i3c_bus_maintenance_lock() for a non-exhaustive list of
+ * maintenance operations). Basically all communications with I3C devices are
+ * normal operations (HDR, SDR transfers or CCC commands that do not change bus
+ * state or I3C dynamic address).
+ *
+ * Note that this lock is not guaranteeing serialization of normal operations.
+ * In other words, transfer requests passed to the I3C master can be submitted
+ * in parallel and I3C master drivers have to use their own locking to make
+ * sure two different communications are not inter-mixed, or access to the
+ * output/input queue is not done while the engine is busy.
+ */
+void i3c_bus_normaluse_lock(struct i3c_bus *bus)
+{
+	down_read(&bus->lock);
+}
+
+/**
+ * i3c_bus_normaluse_unlock - Release the bus lock after a normal operation
+ * @bus: I3C bus to release the lock on
+ *
+ * Should be called when a normal operation is done. See
+ * i3c_bus_normaluse_lock() for more details on what these normal operations
+ * are.
+ */
+void i3c_bus_normaluse_unlock(struct i3c_bus *bus)
+{
+	up_read(&bus->lock);
+}
+
+static struct i3c_master_controller *dev_to_i3cmaster(struct device *dev)
+{
+	return container_of(dev, struct i3c_master_controller, dev);
+}
+
+static const struct device_type i3c_device_type;
+
+static struct i3c_bus *dev_to_i3cbus(struct device *dev)
+{
+	struct i3c_master_controller *master;
+
+	if (dev->type == &i3c_device_type)
+		return dev_to_i3cdev(dev)->bus;
+
+	master = dev_to_i3cmaster(dev);
+
+	return &master->bus;
+}
+
+static struct i3c_dev_desc *dev_to_i3cdesc(struct device *dev)
+{
+	struct i3c_master_controller *master;
+
+	if (dev->type == &i3c_device_type)
+		return dev_to_i3cdev(dev)->desc;
+
+	master = container_of(dev, struct i3c_master_controller, dev);
+
+	return master->this;
+}
+
+static ssize_t bcr_show(struct device *dev,
+			struct device_attribute *da,
+			char *buf)
+{
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+	struct i3c_dev_desc *desc;
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(bus);
+	desc = dev_to_i3cdesc(dev);
+	ret = sprintf(buf, "%x\n", desc->info.bcr);
+	i3c_bus_normaluse_unlock(bus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(bcr);
+
+static ssize_t dcr_show(struct device *dev,
+			struct device_attribute *da,
+			char *buf)
+{
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+	struct i3c_dev_desc *desc;
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(bus);
+	desc = dev_to_i3cdesc(dev);
+	ret = sprintf(buf, "%x\n", desc->info.dcr);
+	i3c_bus_normaluse_unlock(bus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(dcr);
+
+static ssize_t pid_show(struct device *dev,
+			struct device_attribute *da,
+			char *buf)
+{
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+	struct i3c_dev_desc *desc;
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(bus);
+	desc = dev_to_i3cdesc(dev);
+	ret = sprintf(buf, "%llx\n", desc->info.pid);
+	i3c_bus_normaluse_unlock(bus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(pid);
+
+static ssize_t dynamic_address_show(struct device *dev,
+				    struct device_attribute *da,
+				    char *buf)
+{
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+	struct i3c_dev_desc *desc;
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(bus);
+	desc = dev_to_i3cdesc(dev);
+	ret = sprintf(buf, "%02x\n", desc->info.dyn_addr);
+	i3c_bus_normaluse_unlock(bus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(dynamic_address);
+
+static const char * const hdrcap_strings[] = {
+	"hdr-ddr", "hdr-tsp", "hdr-tsl",
+};
+
+static ssize_t hdrcap_show(struct device *dev,
+			   struct device_attribute *da,
+			   char *buf)
+{
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+	struct i3c_dev_desc *desc;
+	ssize_t offset = 0, ret;
+	unsigned long caps;
+	int mode;
+
+	i3c_bus_normaluse_lock(bus);
+	desc = dev_to_i3cdesc(dev);
+	caps = desc->info.hdr_cap;
+	for_each_set_bit(mode, &caps, 8) {
+		if (mode >= ARRAY_SIZE(hdrcap_strings))
+			break;
+
+		if (!hdrcap_strings[mode])
+			continue;
+
+		ret = sprintf(buf + offset, offset ? " %s" : "%s",
+			      hdrcap_strings[mode]);
+		if (ret < 0)
+			goto out;
+
+		offset += ret;
+	}
+
+	ret = sprintf(buf + offset, "\n");
+	if (ret < 0)
+		goto out;
+
+	ret = offset + ret;
+
+out:
+	i3c_bus_normaluse_unlock(bus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(hdrcap);
+
+static struct attribute *i3c_device_attrs[] = {
+	&dev_attr_bcr.attr,
+	&dev_attr_dcr.attr,
+	&dev_attr_pid.attr,
+	&dev_attr_dynamic_address.attr,
+	&dev_attr_hdrcap.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(i3c_device);
+
+static int i3c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
+	struct i3c_device_info devinfo;
+	u16 manuf, part, ext;
+
+	i3c_device_get_info(i3cdev, &devinfo);
+	manuf = I3C_PID_MANUF_ID(devinfo.pid);
+	part = I3C_PID_PART_ID(devinfo.pid);
+	ext = I3C_PID_EXTRA_INFO(devinfo.pid);
+
+	if (I3C_PID_RND_LOWER_32BITS(devinfo.pid))
+		return add_uevent_var(env, "MODALIAS=i3c:dcr%02Xmanuf%04X",
+				      devinfo.dcr, manuf);
+
+	return add_uevent_var(env,
+			      "MODALIAS=i3c:dcr%02Xmanuf%04Xpart%04xext%04x",
+			      devinfo.dcr, manuf, part, ext);
+}
+
+static const struct device_type i3c_device_type = {
+	.groups	= i3c_device_groups,
+	.uevent = i3c_device_uevent,
+};
+
+static const struct i3c_device_id *
+i3c_device_match_id(struct i3c_device *i3cdev,
+		    const struct i3c_device_id *id_table)
+{
+	struct i3c_device_info devinfo;
+	const struct i3c_device_id *id;
+
+	i3c_device_get_info(i3cdev, &devinfo);
+
+	/*
+	 * The lower 32bits of the provisional ID is just filled with a random
+	 * value, try to match using DCR info.
+	 */
+	if (!I3C_PID_RND_LOWER_32BITS(devinfo.pid)) {
+		u16 manuf = I3C_PID_MANUF_ID(devinfo.pid);
+		u16 part = I3C_PID_PART_ID(devinfo.pid);
+		u16 ext_info = I3C_PID_EXTRA_INFO(devinfo.pid);
+
+		/* First try to match by manufacturer/part ID. */
+		for (id = id_table; id->match_flags != 0; id++) {
+			if ((id->match_flags & I3C_MATCH_MANUF_AND_PART) !=
+			    I3C_MATCH_MANUF_AND_PART)
+				continue;
+
+			if (manuf != id->manuf_id || part != id->part_id)
+				continue;
+
+			if ((id->match_flags & I3C_MATCH_EXTRA_INFO) &&
+			    ext_info != id->extra_info)
+				continue;
+
+			return id;
+		}
+	}
+
+	/* Fallback to DCR match. */
+	for (id = id_table; id->match_flags != 0; id++) {
+		if ((id->match_flags & I3C_MATCH_DCR) &&
+		    id->dcr == devinfo.dcr)
+			return id;
+	}
+
+	return NULL;
+}
+
+static int i3c_device_match(struct device *dev, struct device_driver *drv)
+{
+	struct i3c_device *i3cdev;
+	struct i3c_driver *i3cdrv;
+
+	if (dev->type != &i3c_device_type)
+		return 0;
+
+	i3cdev = dev_to_i3cdev(dev);
+	i3cdrv = drv_to_i3cdrv(drv);
+	if (i3c_device_match_id(i3cdev, i3cdrv->id_table))
+		return 1;
+
+	return 0;
+}
+
+static int i3c_device_probe(struct device *dev)
+{
+	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
+	struct i3c_driver *driver = drv_to_i3cdrv(dev->driver);
+
+	return driver->probe(i3cdev);
+}
+
+static int i3c_device_remove(struct device *dev)
+{
+	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
+	struct i3c_driver *driver = drv_to_i3cdrv(dev->driver);
+	int ret;
+
+	ret = driver->remove(i3cdev);
+	if (ret)
+		return ret;
+
+	i3c_device_free_ibi(i3cdev);
+
+	return ret;
+}
+
+struct bus_type i3c_bus_type = {
+	.name = "i3c",
+	.match = i3c_device_match,
+	.probe = i3c_device_probe,
+	.remove = i3c_device_remove,
+};
+
+static enum i3c_addr_slot_status
+i3c_bus_get_addr_slot_status(struct i3c_bus *bus, u16 addr)
+{
+	int status, bitpos = addr * 2;
+
+	if (addr > I2C_MAX_ADDR)
+		return I3C_ADDR_SLOT_RSVD;
+
+	status = bus->addrslots[bitpos / BITS_PER_LONG];
+	status >>= bitpos % BITS_PER_LONG;
+
+	return status & I3C_ADDR_SLOT_STATUS_MASK;
+}
+
+static void i3c_bus_set_addr_slot_status(struct i3c_bus *bus, u16 addr,
+					 enum i3c_addr_slot_status status)
+{
+	int bitpos = addr * 2;
+	unsigned long *ptr;
+
+	if (addr > I2C_MAX_ADDR)
+		return;
+
+	ptr = bus->addrslots + (bitpos / BITS_PER_LONG);
+	*ptr &= ~(I3C_ADDR_SLOT_STATUS_MASK << (bitpos % BITS_PER_LONG));
+	*ptr |= status << (bitpos % BITS_PER_LONG);
+}
+
+static bool i3c_bus_dev_addr_is_avail(struct i3c_bus *bus, u8 addr)
+{
+	enum i3c_addr_slot_status status;
+
+	status = i3c_bus_get_addr_slot_status(bus, addr);
+
+	return status == I3C_ADDR_SLOT_FREE;
+}
+
+static int i3c_bus_get_free_addr(struct i3c_bus *bus, u8 start_addr)
+{
+	enum i3c_addr_slot_status status;
+	u8 addr;
+
+	for (addr = start_addr; addr < I3C_MAX_ADDR; addr++) {
+		status = i3c_bus_get_addr_slot_status(bus, addr);
+		if (status == I3C_ADDR_SLOT_FREE)
+			return addr;
+	}
+
+	return -ENOMEM;
+}
+
+static void i3c_bus_init_addrslots(struct i3c_bus *bus)
+{
+	int i;
+
+	/* Addresses 0 to 7 are reserved. */
+	for (i = 0; i < 8; i++)
+		i3c_bus_set_addr_slot_status(bus, i, I3C_ADDR_SLOT_RSVD);
+
+	/*
+	 * Reserve broadcast address and all addresses that might collide
+	 * with the broadcast address when facing a single bit error.
+	 */
+	i3c_bus_set_addr_slot_status(bus, I3C_BROADCAST_ADDR,
+				     I3C_ADDR_SLOT_RSVD);
+	for (i = 0; i < 7; i++)
+		i3c_bus_set_addr_slot_status(bus, I3C_BROADCAST_ADDR ^ BIT(i),
+					     I3C_ADDR_SLOT_RSVD);
+}
+
+static void i3c_bus_cleanup(struct i3c_bus *i3cbus)
+{
+	mutex_lock(&i3c_core_lock);
+	idr_remove(&i3c_bus_idr, i3cbus->id);
+	mutex_unlock(&i3c_core_lock);
+}
+
+static int i3c_bus_init(struct i3c_bus *i3cbus)
+{
+	int ret;
+
+	init_rwsem(&i3cbus->lock);
+	INIT_LIST_HEAD(&i3cbus->devs.i2c);
+	INIT_LIST_HEAD(&i3cbus->devs.i3c);
+	i3c_bus_init_addrslots(i3cbus);
+	i3cbus->mode = I3C_BUS_MODE_PURE;
+
+	mutex_lock(&i3c_core_lock);
+	ret = idr_alloc(&i3c_bus_idr, i3cbus, 0, 0, GFP_KERNEL);
+	mutex_unlock(&i3c_core_lock);
+
+	if (ret < 0)
+		return ret;
+
+	i3cbus->id = ret;
+
+	return 0;
+}
+
+static const char * const i3c_bus_mode_strings[] = {
+	[I3C_BUS_MODE_PURE] = "pure",
+	[I3C_BUS_MODE_MIXED_FAST] = "mixed-fast",
+	[I3C_BUS_MODE_MIXED_SLOW] = "mixed-slow",
+};
+
+static ssize_t mode_show(struct device *dev,
+			 struct device_attribute *da,
+			 char *buf)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	if (i3cbus->mode < 0 ||
+	    i3cbus->mode > ARRAY_SIZE(i3c_bus_mode_strings) ||
+	    !i3c_bus_mode_strings[i3cbus->mode])
+		ret = sprintf(buf, "unknown\n");
+	else
+		ret = sprintf(buf, "%s\n", i3c_bus_mode_strings[i3cbus->mode]);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(mode);
+
+static ssize_t current_master_show(struct device *dev,
+				   struct device_attribute *da,
+				   char *buf)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sprintf(buf, "%d-%llx\n", i3cbus->id,
+		      i3cbus->cur_master->info.pid);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(current_master);
+
+static ssize_t i3c_scl_frequency_show(struct device *dev,
+				      struct device_attribute *da,
+				      char *buf)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sprintf(buf, "%ld\n", i3cbus->scl_rate.i3c);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(i3c_scl_frequency);
+
+static ssize_t i2c_scl_frequency_show(struct device *dev,
+				      struct device_attribute *da,
+				      char *buf)
+{
+	struct i3c_bus *i3cbus = dev_to_i3cbus(dev);
+	ssize_t ret;
+
+	i3c_bus_normaluse_lock(i3cbus);
+	ret = sprintf(buf, "%ld\n", i3cbus->scl_rate.i2c);
+	i3c_bus_normaluse_unlock(i3cbus);
+
+	return ret;
+}
+static DEVICE_ATTR_RO(i2c_scl_frequency);
+
+static struct attribute *i3c_masterdev_attrs[] = {
+	&dev_attr_mode.attr,
+	&dev_attr_current_master.attr,
+	&dev_attr_i3c_scl_frequency.attr,
+	&dev_attr_i2c_scl_frequency.attr,
+	&dev_attr_bcr.attr,
+	&dev_attr_dcr.attr,
+	&dev_attr_pid.attr,
+	&dev_attr_dynamic_address.attr,
+	&dev_attr_hdrcap.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(i3c_masterdev);
+
+static void i3c_masterdev_release(struct device *dev)
+{
+	struct i3c_master_controller *master = dev_to_i3cmaster(dev);
+	struct i3c_bus *bus = dev_to_i3cbus(dev);
+
+	if (master->wq)
+		destroy_workqueue(master->wq);
+
+	WARN_ON(!list_empty(&bus->devs.i2c) || !list_empty(&bus->devs.i3c));
+	i3c_bus_cleanup(bus);
+
+	of_node_put(dev->of_node);
+}
+
+static const struct device_type i3c_masterdev_type = {
+	.groups	= i3c_masterdev_groups,
+};
+
+int i3c_bus_set_mode(struct i3c_bus *i3cbus, enum i3c_bus_mode mode)
+{
+	i3cbus->mode = mode;
+
+	if (!i3cbus->scl_rate.i3c)
+		i3cbus->scl_rate.i3c = I3C_BUS_TYP_I3C_SCL_RATE;
+
+	if (!i3cbus->scl_rate.i2c) {
+		if (i3cbus->mode == I3C_BUS_MODE_MIXED_SLOW)
+			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_SCL_RATE;
+		else
+			i3cbus->scl_rate.i2c = I3C_BUS_I2C_FM_PLUS_SCL_RATE;
+	}
+
+	/*
+	 * I3C/I2C frequency may have been overridden, check that user-provided
+	 * values are not exceeding max possible frequency.
+	 */
+	if (i3cbus->scl_rate.i3c > I3C_BUS_MAX_I3C_SCL_RATE ||
+	    i3cbus->scl_rate.i2c > I3C_BUS_I2C_FM_PLUS_SCL_RATE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct i3c_master_controller *
+i2c_adapter_to_i3c_master(struct i2c_adapter *adap)
+{
+	return container_of(adap, struct i3c_master_controller, i2c);
+}
+
+static struct i2c_adapter *
+i3c_master_to_i2c_adapter(struct i3c_master_controller *master)
+{
+	return &master->i2c;
+}
+
+static void i3c_master_free_i2c_dev(struct i2c_dev_desc *dev)
+{
+	kfree(dev);
+}
+
+static struct i2c_dev_desc *
+i3c_master_alloc_i2c_dev(struct i3c_master_controller *master,
+			 const struct i2c_dev_boardinfo *boardinfo)
+{
+	struct i2c_dev_desc *dev;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->common.master = master;
+	dev->boardinfo = boardinfo;
+
+	return dev;
+}
+
+static void *i3c_ccc_cmd_dest_init(struct i3c_ccc_cmd_dest *dest, u8 addr,
+				   u16 payloadlen)
+{
+	dest->addr = addr;
+	dest->payload.len = payloadlen;
+	if (payloadlen)
+		dest->payload.data = kzalloc(payloadlen, GFP_KERNEL);
+	else
+		dest->payload.data = NULL;
+
+	return dest->payload.data;
+}
+
+static void i3c_ccc_cmd_dest_cleanup(struct i3c_ccc_cmd_dest *dest)
+{
+	kfree(dest->payload.data);
+}
+
+static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id,
+			     struct i3c_ccc_cmd_dest *dests,
+			     unsigned int ndests)
+{
+	cmd->rnw = rnw ? 1 : 0;
+	cmd->id = id;
+	cmd->dests = dests;
+	cmd->ndests = ndests;
+	cmd->err = I3C_ERROR_UNKNOWN;
+}
+
+static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master,
+					  struct i3c_ccc_cmd *cmd)
+{
+	int ret;
+
+	if (!cmd || !master)
+		return -EINVAL;
+
+	if (WARN_ON(master->init_done &&
+		    !rwsem_is_locked(&master->bus.lock)))
+		return -EINVAL;
+
+	if (!master->ops->send_ccc_cmd)
+		return -ENOTSUPP;
+
+	if ((cmd->id & I3C_CCC_DIRECT) && (!cmd->dests || !cmd->ndests))
+		return -EINVAL;
+
+	if (master->ops->supports_ccc_cmd &&
+	    !master->ops->supports_ccc_cmd(master, cmd))
+		return -ENOTSUPP;
+
+	ret = master->ops->send_ccc_cmd(master, cmd);
+	if (ret) {
+		if (cmd->err != I3C_ERROR_UNKNOWN)
+			return cmd->err;
+
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct i2c_dev_desc *
+i3c_master_find_i2c_dev_by_addr(const struct i3c_master_controller *master,
+				u16 addr)
+{
+	struct i2c_dev_desc *dev;
+
+	i3c_bus_for_each_i2cdev(&master->bus, dev) {
+		if (dev->boardinfo->base.addr == addr)
+			return dev;
+	}
+
+	return NULL;
+}
+
+/**
+ * i3c_master_get_free_addr() - get a free address on the bus
+ * @master: I3C master object
+ * @start_addr: where to start searching
+ *
+ * This function must be called with the bus lock held in write mode.
+ *
+ * Return: the first free address starting at @start_addr (included) or -ENOMEM
+ * if there's no more address available.
+ */
+int i3c_master_get_free_addr(struct i3c_master_controller *master,
+			     u8 start_addr)
+{
+	return i3c_bus_get_free_addr(&master->bus, start_addr);
+}
+EXPORT_SYMBOL_GPL(i3c_master_get_free_addr);
+
+static void i3c_device_release(struct device *dev)
+{
+	struct i3c_device *i3cdev = dev_to_i3cdev(dev);
+
+	WARN_ON(i3cdev->desc);
+
+	of_node_put(i3cdev->dev.of_node);
+	kfree(i3cdev);
+}
+
+static void i3c_master_free_i3c_dev(struct i3c_dev_desc *dev)
+{
+	kfree(dev);
+}
+
+static struct i3c_dev_desc *
+i3c_master_alloc_i3c_dev(struct i3c_master_controller *master,
+			 const struct i3c_device_info *info)
+{
+	struct i3c_dev_desc *dev;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	dev->common.master = master;
+	dev->info = *info;
+	mutex_init(&dev->ibi_lock);
+
+	return dev;
+}
+
+static int i3c_master_rstdaa_locked(struct i3c_master_controller *master,
+				    u8 addr)
+{
+	enum i3c_addr_slot_status addrstat;
+	struct i3c_ccc_cmd_dest dest;
+	struct i3c_ccc_cmd cmd;
+	int ret;
+
+	if (!master)
+		return -EINVAL;
+
+	addrstat = i3c_bus_get_addr_slot_status(&master->bus, addr);
+	if (addr != I3C_BROADCAST_ADDR && addrstat != I3C_ADDR_SLOT_I3C_DEV)
+		return -EINVAL;
+
+	i3c_ccc_cmd_dest_init(&dest, addr, 0);
+	i3c_ccc_cmd_init(&cmd, false,
+			 I3C_CCC_RSTDAA(addr == I3C_BROADCAST_ADDR),
+			 &dest, 1);
+	ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
+	i3c_ccc_cmd_dest_cleanup(&dest);
+
+	return ret;
+}
+
+/**
+ * i3c_master_entdaa_locked() - start a DAA (Dynamic Address Assignment)
+ *				procedure
+ * @master: master used to send frames on the bus
+ *
+ * Send a ENTDAA CCC command to start a DAA procedure.
+ *
+ * Note that this function only sends the ENTDAA CCC command, all the logic
+ * behind dynamic address assignment has to be handled in the I3C master
+ * driver.
+ *
+ * This function must be called with the bus lock held in write mode.
+ *
+ * Return: 0 in case of success, a positive I3C error code if the error is
+ * one of the official Mx error codes, and a negative error code otherwise.