diff mbox series

[v7,1/6] usb: Add support for Intel LJCA device

Message ID 20230325154711.2419569-2-xiang.ye@intel.com
State Superseded
Headers show
Series Add Intel LJCA device driver | expand

Commit Message

Ye Xiang March 25, 2023, 3:47 p.m. UTC
This patch implements the USB part of Intel USB-I2C/GPIO/SPI adapter
device named "La Jolla Cove Adapter" (LJCA).

The communication between the various LJCA module drivers and the
hardware will be muxed/demuxed by this driver. Three modules (
I2C, GPIO, and SPI) are supported currently.

Each sub-module of LJCA device is identified by type field within
the LJCA message header.

The minimum code in ASL that covers this board is
Scope (\_SB.PCI0.DWC3.RHUB.HS01)
    {
        Device (GPIO)
        {
            Name (_ADR, Zero)
            Name (_STA, 0x0F)
        }

        Device (I2C)
        {
            Name (_ADR, One)
            Name (_STA, 0x0F)
        }

        Device (SPI)
        {
            Name (_ADR, 0x02)
            Name (_STA, 0x0F)
        }
    }

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
---
 drivers/usb/misc/Kconfig    |  13 +
 drivers/usb/misc/Makefile   |   1 +
 drivers/usb/misc/usb-ljca.c | 966 ++++++++++++++++++++++++++++++++++++
 include/linux/usb/ljca.h    |  43 ++
 4 files changed, 1023 insertions(+)
 create mode 100644 drivers/usb/misc/usb-ljca.c
 create mode 100644 include/linux/usb/ljca.h

Comments

Greg KH March 25, 2023, 4:20 p.m. UTC | #1
On Sat, Mar 25, 2023 at 11:47:06PM +0800, Ye Xiang wrote:
> This patch implements the USB part of Intel USB-I2C/GPIO/SPI adapter
> device named "La Jolla Cove Adapter" (LJCA).
> 
> The communication between the various LJCA module drivers and the
> hardware will be muxed/demuxed by this driver. Three modules (
> I2C, GPIO, and SPI) are supported currently.
> 
> Each sub-module of LJCA device is identified by type field within
> the LJCA message header.
> 
> The minimum code in ASL that covers this board is

As this requires ACPI, why are you not saying so in your Kconfig entry?
What good would this driver be without ACPI enabled?

thanks,

greg k-h
Ye Xiang March 25, 2023, 5:26 p.m. UTC | #2
Hi Greg,

Thanks for the review.
On Sat, Mar 25, 2023 at 05:20:09PM +0100, Greg Kroah-Hartman wrote:
> On Sat, Mar 25, 2023 at 11:47:06PM +0800, Ye Xiang wrote:
> > This patch implements the USB part of Intel USB-I2C/GPIO/SPI adapter
> > device named "La Jolla Cove Adapter" (LJCA).
> > 
> > The communication between the various LJCA module drivers and the
> > hardware will be muxed/demuxed by this driver. Three modules (
> > I2C, GPIO, and SPI) are supported currently.
> > 
> > Each sub-module of LJCA device is identified by type field within
> > the LJCA message header.
> > 
> > The minimum code in ASL that covers this board is
> 
> As this requires ACPI, why are you not saying so in your Kconfig entry?
I would add a `depends on ACPI` item on the Kconfig entry so that the
CONFI_ACPI macro can be removed from usb-ljca, because our use case with
LJCA currently needs the ACPI binding.
> What good would this driver be without ACPI enabled?
Before, I just tried to make it compatible with other platforms that
don't support ACPI but want to use LJCA device. But, We don't have
this use case until now.

Thanks
Ye Xiang
Greg KH March 25, 2023, 5:35 p.m. UTC | #3
On Sun, Mar 26, 2023 at 01:26:55AM +0800, Ye, Xiang wrote:
> Hi Greg,
> 
> Thanks for the review.
> On Sat, Mar 25, 2023 at 05:20:09PM +0100, Greg Kroah-Hartman wrote:
> > On Sat, Mar 25, 2023 at 11:47:06PM +0800, Ye Xiang wrote:
> > > This patch implements the USB part of Intel USB-I2C/GPIO/SPI adapter
> > > device named "La Jolla Cove Adapter" (LJCA).
> > > 
> > > The communication between the various LJCA module drivers and the
> > > hardware will be muxed/demuxed by this driver. Three modules (
> > > I2C, GPIO, and SPI) are supported currently.
> > > 
> > > Each sub-module of LJCA device is identified by type field within
> > > the LJCA message header.
> > > 
> > > The minimum code in ASL that covers this board is
> > 
> > As this requires ACPI, why are you not saying so in your Kconfig entry?
> I would add a `depends on ACPI` item on the Kconfig entry so that the
> CONFI_ACPI macro can be removed from usb-ljca, because our use case with
> LJCA currently needs the ACPI binding.

That would make more sense.

thanks,

greg k-h
Mark Brown March 25, 2023, 6:05 p.m. UTC | #4
On Sun, Mar 26, 2023 at 01:26:55AM +0800, Ye, Xiang wrote:
> On Sat, Mar 25, 2023 at 05:20:09PM +0100, Greg Kroah-Hartman wrote:

> > As this requires ACPI, why are you not saying so in your Kconfig entry?

> I would add a `depends on ACPI` item on the Kconfig entry so that the
> CONFI_ACPI macro can be removed from usb-ljca, because our use case with

> LJCA currently needs the ACPI binding.

> > What good would this driver be without ACPI enabled?
> Before, I just tried to make it compatible with other platforms that
> don't support ACPI but want to use LJCA device. But, We don't have
> this use case until now.

If it builds without ACPI then making the dependency ACPI ||
COMPILE_TEST will help improve build coverage for people doing
treewide or subsystem work.
Greg KH March 25, 2023, 10:27 p.m. UTC | #5
On Sat, Mar 25, 2023 at 11:47:06PM +0800, Ye Xiang wrote:
> +static void ljca_aux_release(struct device *dev) {}

Sorry, but creating an empty release function just to shut the kernel up
is NOT how to properly do this, you all know better.  This is totally
broken.  The kernel was telling you what you had to do, don't think that
you are being smarter than it by doing this, otherwise we would have
never had the kernel spit out that error in the first place, right?

Now I will ask you to follow the proper Intel kernel review rules and
get proper approval for the patchset before submitting it to us again,
as basic things like this are not supposed to be caught by us, but by
your internal review process first.

good luck!

greg k-h
Ye Xiang March 26, 2023, 9:04 a.m. UTC | #6
On Sat, Mar 25, 2023 at 11:27:03PM +0100, Greg Kroah-Hartman wrote:
> On Sat, Mar 25, 2023 at 11:47:06PM +0800, Ye Xiang wrote:
> > +static void ljca_aux_release(struct device *dev) {}
> 
> Sorry, but creating an empty release function just to shut the kernel up
> is NOT how to properly do this, you all know better.  This is totally
> broken.  The kernel was telling you what you had to do, don't think that
> you are being smarter than it by doing this, otherwise we would have
> never had the kernel spit out that error in the first place, right?
Got it. Will use the release callback to free memory used by the auxiliary
device instead.
> 
> Now I will ask you to follow the proper Intel kernel review rules and
> get proper approval for the patchset before submitting it to us again,
> as basic things like this are not supposed to be caught by us, but by
> your internal review process first.
Thanks. I will get approval on Intel's internal review first before sending
the next version out for review.

--
Thanks
Ye Xiang
Oliver Neukum March 27, 2023, 11:08 a.m. UTC | #7
On 25.03.23 16:47, Ye Xiang wrote:

Hi,

> +static int ljca_parse(struct ljca_dev *dev, struct ljca_msg *header)
> +{
> +	struct ljca_stub *stub;
> +
> +	stub = ljca_stub_find(dev, header->type);
> +	if (IS_ERR(stub))
> +		return PTR_ERR(stub);
> +
> +	if (!(header->flags & LJCA_ACK_FLAG)) {
> +		ljca_stub_notify(stub, header->cmd, header->data, header->len);
> +		return 0;
> +	}
> +
> +	if (stub->cur_cmd != header->cmd) {
> +		dev_err(&dev->intf->dev, "header and stub current command mismatch (%x vs %x)\n",
> +			header->cmd, stub->cur_cmd);
> +		return -EINVAL;
> +	}
> +
> +	if (stub->ipacket.ibuf && stub->ipacket.ibuf_len) {

Here you read those values from ipacket.

> +		unsigned int newlen;
> +
> +		newlen = min_t(unsigned int, header->len, *stub->ipacket.ibuf_len);

Here you read them again.

> +
> +		*stub->ipacket.ibuf_len = newlen;
> +		memcpy(stub->ipacket.ibuf, header->data, newlen);

And here you read them again. The compiler is free to generate a memory access for
ipacket.ibuf, which may read a new value from RAM. That means here you have a window
in which you can no longer guarantee stub->ipacket.ibuf != NULL,
if you set it to NULL elsewhere.

> +	}
> +
> +	stub->acked = true;
> +	wake_up(&dev->ack_wq);
> +
> +	return 0;
> +}
> +
> +static int ljca_stub_write(struct ljca_stub *stub, u8 cmd, const void *obuf, unsigned int obuf_len,
> +			   void *ibuf, unsigned int *ibuf_len, bool wait_ack, unsigned long timeout)
> +{
> +	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
> +	u8 flags = LJCA_CMPL_FLAG;
> +	struct ljca_msg *header;
> +	unsigned int msg_len = sizeof(*header) + obuf_len;
> +	int actual;
> +	int ret;
> +
> +	if (msg_len > LJCA_MAX_PACKET_SIZE)
> +		return -EINVAL;
> +
> +	if (wait_ack)
> +		flags |= LJCA_ACK_FLAG;
> +
> +	header = kmalloc(msg_len, GFP_KERNEL);
> +	if (!header)
> +		return -ENOMEM;
> +
> +	header->type = stub->type;
> +	header->cmd = cmd;
> +	header->flags = flags;
> +	header->len = obuf_len;
> +
> +	if (obuf)
> +		memcpy(header->data, obuf, obuf_len);
> +
> +	dev_dbg(&dev->intf->dev, "send: type:%d cmd:%d flags:%d len:%d\n", header->type,
> +		header->cmd, header->flags, header->len);
> +
> +	usb_autopm_get_interface(dev->intf);
> +	if (!dev->started) {
> +		kfree(header);
> +		ret = -ENODEV;
> +		goto error_put;
> +	}
> +
> +	mutex_lock(&dev->mutex);
> +	stub->cur_cmd = cmd;
> +	stub->ipacket.ibuf = ibuf;
> +	stub->ipacket.ibuf_len = ibuf_len;
> +	stub->acked = false;
> +	ret = usb_bulk_msg(interface_to_usbdev(dev->intf),
> +			   usb_sndbulkpipe(interface_to_usbdev(dev->intf), dev->out_ep), header,
> +			   msg_len, &actual, LJCA_USB_WRITE_TIMEOUT_MS);
> +	kfree(header);
> +	if (ret) {
> +		dev_err(&dev->intf->dev, "bridge write failed ret:%d\n", ret);
> +		goto error_unlock;
> +	}
> +
> +	if (actual != msg_len) {
> +		dev_err(&dev->intf->dev, "bridge write length mismatch (%d vs %d)\n", msg_len,
> +			actual);
> +		ret = -EINVAL;
> +		goto error_unlock;
> +	}
> +
> +	if (wait_ack) {
> +		ret = wait_event_timeout(dev->ack_wq, stub->acked, msecs_to_jiffies(timeout));
> +		if (!ret) {
> +			dev_err(&dev->intf->dev, "acked wait timeout\n");
> +			ret = -ETIMEDOUT;
> +			goto error_unlock;
> +		}
> +	}
> +
> +	ret = 0;
> +error_unlock:
> +	stub->ipacket.ibuf = NULL;
> +	stub->ipacket.ibuf_len = NULL;

And here you set stub->ipacket.ibuf to NULL.
If you do that and want consistency, you'll need to use READ_ONCE
and a local variable if you read this in interrupt.

> +	mutex_unlock(&dev->mutex);
> +error_put:
> +	usb_autopm_put_interface(dev->intf);
> +
> +	return ret;
> +}
> +

	HTH,
		Oliver
diff mbox series

Patch

diff --git a/drivers/usb/misc/Kconfig b/drivers/usb/misc/Kconfig
index a5f7652db7da..6566039b3e1c 100644
--- a/drivers/usb/misc/Kconfig
+++ b/drivers/usb/misc/Kconfig
@@ -273,6 +273,19 @@  config USB_LINK_LAYER_TEST
 	  Layer Test Device. Say Y only when you want to conduct USB Super Speed
 	  Link Layer Test for host controllers.
 
+config USB_LJCA
+	tristate "Intel La Jolla Cove Adapter support"
+	select AUXILIARY_BUS
+	depends on USB
+	help
+	  This adds support for Intel La Jolla Cove USB-I2C/SPI/GPIO
+	  Master Adapter (LJCA). Additional drivers such as I2C_LJCA,
+	  GPIO_LJCA and SPI_LJCA must be enabled in order to use the
+	  functionality of the device.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called usb-ljca.
+
 config USB_CHAOSKEY
 	tristate "ChaosKey random number generator driver support"
 	depends on HW_RANDOM
diff --git a/drivers/usb/misc/Makefile b/drivers/usb/misc/Makefile
index 93581baec3a8..a41d02cc4f3e 100644
--- a/drivers/usb/misc/Makefile
+++ b/drivers/usb/misc/Makefile
@@ -29,6 +29,7 @@  obj-$(CONFIG_USB_HUB_USB251XB)		+= usb251xb.o
 obj-$(CONFIG_USB_HSIC_USB3503)		+= usb3503.o
 obj-$(CONFIG_USB_HSIC_USB4604)		+= usb4604.o
 obj-$(CONFIG_USB_CHAOSKEY)		+= chaoskey.o
+obj-$(CONFIG_USB_LJCA)			+= usb-ljca.o
 
 obj-$(CONFIG_USB_SISUSBVGA)		+= sisusbvga/
 obj-$(CONFIG_USB_LINK_LAYER_TEST)	+= lvstest.o
diff --git a/drivers/usb/misc/usb-ljca.c b/drivers/usb/misc/usb-ljca.c
new file mode 100644
index 000000000000..96e2b8c43c58
--- /dev/null
+++ b/drivers/usb/misc/usb-ljca.c
@@ -0,0 +1,966 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel La Jolla Cove Adapter USB driver
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/dev_printk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/usb.h>
+#include <linux/usb/ljca.h>
+
+enum ljca_acpi_match_adr {
+	LJCA_ACPI_MATCH_GPIO,
+	LJCA_ACPI_MATCH_I2C1,
+	LJCA_ACPI_MATCH_I2C2,
+	LJCA_ACPI_MATCH_SPI1,
+	LJCA_ACPI_MATCH_SPI2,
+	LJCA_ACPI_MATCH_MAX,
+};
+
+struct ljca_msg {
+	u8 type;
+	u8 cmd;
+	u8 flags;
+	u8 len;
+	u8 data[];
+} __packed;
+
+struct fw_version {
+	u8 major;
+	u8 minor;
+	__le16 patch;
+	__le16 build;
+} __packed;
+
+/**
+ * enum ljca_stub_type - Stub type supported by LJCA.
+ * @LJCA_MNG_STUB: Provides Management messages.
+ * @LJCA_DIAG_STUB: provides Diagnose messages.
+ * @LJCA_GPIO_STUB: provides GPIO functionality.
+ * @LJCA_I2C_STUB: provides I2C functionality.
+ * @LJCA_SPI_STUB: provides SPI functionality.
+ */
+enum ljca_stub_type {
+	LJCA_MNG_STUB = 1,
+	LJCA_DIAG_STUB,
+	LJCA_GPIO_STUB,
+	LJCA_I2C_STUB,
+	LJCA_SPI_STUB,
+};
+
+/* command Flags */
+#define LJCA_ACK_FLAG	BIT(0)
+#define LJCA_RESP_FLAG	BIT(1)
+#define LJCA_CMPL_FLAG	BIT(2)
+
+/* MNG stub commands */
+enum ljca_mng_cmd {
+	LJCA_MNG_GET_VERSION = 1,
+	LJCA_MNG_RESET_NOTIFY,
+	LJCA_MNG_RESET,
+	LJCA_MNG_ENUM_GPIO,
+	LJCA_MNG_ENUM_I2C,
+	LJCA_MNG_POWER_STATE_CHANGE,
+	LJCA_MNG_SET_DFU_MODE,
+	LJCA_MNG_ENUM_SPI,
+};
+
+/* DIAG commands */
+enum ljca_diag_cmd {
+	LJCA_DIAG_GET_STATE = 1,
+	LJCA_DIAG_GET_STATISTIC,
+	LJCA_DIAG_SET_TRACE_LEVEL,
+	LJCA_DIAG_SET_ECHO_MODE,
+	LJCA_DIAG_GET_FW_LOG,
+	LJCA_DIAG_GET_FW_COREDUMP,
+	LJCA_DIAG_TRIGGER_WDT,
+	LJCA_DIAG_TRIGGER_FAULT,
+	LJCA_DIAG_FEED_WDT,
+	LJCA_DIAG_GET_SECURE_STATE,
+};
+
+struct ljca_i2c_ctr_info {
+	u8 id;
+	u8 capacity;
+	u8 intr_pin;
+} __packed;
+
+struct ljca_i2c_descriptor {
+	u8 num;
+	struct ljca_i2c_ctr_info info[];
+} __packed;
+
+struct ljca_spi_ctr_info {
+	u8 id;
+	u8 capacity;
+} __packed;
+
+struct ljca_spi_descriptor {
+	u8 num;
+	struct ljca_spi_ctr_info info[];
+} __packed;
+
+struct ljca_bank_descriptor {
+	u8 bank_id;
+	u8 pin_num;
+
+	/* 1 bit for each gpio, 1 means valid */
+	u32 valid_pins;
+} __packed;
+
+struct ljca_gpio_descriptor {
+	u8 pins_per_bank;
+	u8 bank_num;
+	struct ljca_bank_descriptor bank_desc[];
+} __packed;
+
+#define LJCA_MAX_PACKET_SIZE		64
+#define LJCA_MAX_PAYLOAD_SIZE		(LJCA_MAX_PACKET_SIZE - sizeof(struct ljca_msg))
+#define LJCA_USB_WRITE_TIMEOUT_MS	200
+#define LJCA_USB_WRITE_ACK_TIMEOUT_MS	500
+#define LJCA_USB_ENUM_STUB_TIMEOUT_MS	20
+
+struct ljca_event_cb_entry {
+	ljca_event_cb_t notify;
+	void *context;
+};
+
+struct ljca_dev {
+	struct usb_interface *intf;
+	u8 in_ep; /* the address of the bulk in endpoint */
+	u8 out_ep; /* the address of the bulk out endpoint */
+
+	/* the urb/buffer for read */
+	struct urb *in_urb;
+	unsigned char *ibuf;
+	size_t ibuf_len;
+
+	/* mutex to protect all fields in this structure */
+	struct mutex mutex;
+	bool started;
+	struct list_head stubs_list;
+
+	/* to wait for an ongoing write ack */
+	wait_queue_head_t ack_wq;
+
+	struct auxiliary_device auxdevs[LJCA_ACPI_MATCH_MAX];
+	int auxdev_count;
+};
+
+struct ljca {
+	u8 type;
+	struct ljca_dev *dev;
+};
+
+struct ljca_stub_packet {
+	unsigned int *ibuf_len;
+	u8 *ibuf;
+};
+
+struct ljca_stub {
+	struct list_head list;
+	struct usb_interface *intf;
+	struct ljca_stub_packet ipacket;
+	u8 type;
+
+	/* for identify ack */
+	bool acked;
+	int cur_cmd;
+
+	struct ljca_event_cb_entry event_entry;
+	/* lock to protect event_entry */
+	spinlock_t event_cb_lock;
+
+	struct ljca ljca;
+	unsigned long priv[];
+};
+
+static inline void *ljca_priv(struct ljca_stub *stub)
+{
+	return stub->priv;
+}
+
+static bool ljca_validate(struct ljca_msg *header, u32 data_len)
+{
+	return header->len + sizeof(*header) == data_len;
+}
+
+static struct ljca_stub *ljca_stub_alloc(struct ljca_dev *dev, u8 type, int priv_size)
+{
+	struct ljca_stub *stub;
+
+	stub = kzalloc(struct_size(stub, priv, priv_size), GFP_KERNEL);
+	if (!stub)
+		return ERR_PTR(-ENOMEM);
+
+	stub->type = type;
+	stub->intf = usb_get_intf(dev->intf);
+	stub->ljca.dev = dev;
+	stub->ljca.type = stub->type;
+	spin_lock_init(&stub->event_cb_lock);
+	list_add_tail(&stub->list, &dev->stubs_list);
+
+	return stub;
+}
+
+static void ljca_stub_destroy(struct ljca_stub *stub)
+{
+	usb_put_intf(stub->intf);
+	list_del_init(&stub->list);
+	kfree(stub);
+}
+
+static void ljca_stub_cleanup(struct ljca_dev *dev)
+{
+	struct ljca_stub *stub, *next;
+
+	list_for_each_entry_safe(stub, next, &dev->stubs_list, list) {
+		ljca_stub_destroy(stub);
+	}
+}
+
+static struct ljca_stub *ljca_stub_find(struct ljca_dev *dev, u8 type)
+{
+	struct ljca_stub *stub;
+
+	list_for_each_entry(stub, &dev->stubs_list, list) {
+		if (stub->type == type)
+			return stub;
+	}
+
+	dev_err(&dev->intf->dev, "USB stub not found, type:%d\n", type);
+
+	return ERR_PTR(-ENODEV);
+}
+
+static void ljca_stub_notify(struct ljca_stub *stub, u8 cmd, const void *evt_data, int len)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&stub->event_cb_lock, flags);
+	if (stub->event_entry.notify && stub->event_entry.context)
+		stub->event_entry.notify(stub->event_entry.context, cmd, evt_data, len);
+	spin_unlock_irqrestore(&stub->event_cb_lock, flags);
+}
+
+static int ljca_parse(struct ljca_dev *dev, struct ljca_msg *header)
+{
+	struct ljca_stub *stub;
+
+	stub = ljca_stub_find(dev, header->type);
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	if (!(header->flags & LJCA_ACK_FLAG)) {
+		ljca_stub_notify(stub, header->cmd, header->data, header->len);
+		return 0;
+	}
+
+	if (stub->cur_cmd != header->cmd) {
+		dev_err(&dev->intf->dev, "header and stub current command mismatch (%x vs %x)\n",
+			header->cmd, stub->cur_cmd);
+		return -EINVAL;
+	}
+
+	if (stub->ipacket.ibuf && stub->ipacket.ibuf_len) {
+		unsigned int newlen;
+
+		newlen = min_t(unsigned int, header->len, *stub->ipacket.ibuf_len);
+
+		*stub->ipacket.ibuf_len = newlen;
+		memcpy(stub->ipacket.ibuf, header->data, newlen);
+	}
+
+	stub->acked = true;
+	wake_up(&dev->ack_wq);
+
+	return 0;
+}
+
+static int ljca_stub_write(struct ljca_stub *stub, u8 cmd, const void *obuf, unsigned int obuf_len,
+			   void *ibuf, unsigned int *ibuf_len, bool wait_ack, unsigned long timeout)
+{
+	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
+	u8 flags = LJCA_CMPL_FLAG;
+	struct ljca_msg *header;
+	unsigned int msg_len = sizeof(*header) + obuf_len;
+	int actual;
+	int ret;
+
+	if (msg_len > LJCA_MAX_PACKET_SIZE)
+		return -EINVAL;
+
+	if (wait_ack)
+		flags |= LJCA_ACK_FLAG;
+
+	header = kmalloc(msg_len, GFP_KERNEL);
+	if (!header)
+		return -ENOMEM;
+
+	header->type = stub->type;
+	header->cmd = cmd;
+	header->flags = flags;
+	header->len = obuf_len;
+
+	if (obuf)
+		memcpy(header->data, obuf, obuf_len);
+
+	dev_dbg(&dev->intf->dev, "send: type:%d cmd:%d flags:%d len:%d\n", header->type,
+		header->cmd, header->flags, header->len);
+
+	usb_autopm_get_interface(dev->intf);
+	if (!dev->started) {
+		kfree(header);
+		ret = -ENODEV;
+		goto error_put;
+	}
+
+	mutex_lock(&dev->mutex);
+	stub->cur_cmd = cmd;
+	stub->ipacket.ibuf = ibuf;
+	stub->ipacket.ibuf_len = ibuf_len;
+	stub->acked = false;
+	ret = usb_bulk_msg(interface_to_usbdev(dev->intf),
+			   usb_sndbulkpipe(interface_to_usbdev(dev->intf), dev->out_ep), header,
+			   msg_len, &actual, LJCA_USB_WRITE_TIMEOUT_MS);
+	kfree(header);
+	if (ret) {
+		dev_err(&dev->intf->dev, "bridge write failed ret:%d\n", ret);
+		goto error_unlock;
+	}
+
+	if (actual != msg_len) {
+		dev_err(&dev->intf->dev, "bridge write length mismatch (%d vs %d)\n", msg_len,
+			actual);
+		ret = -EINVAL;
+		goto error_unlock;
+	}
+
+	if (wait_ack) {
+		ret = wait_event_timeout(dev->ack_wq, stub->acked, msecs_to_jiffies(timeout));
+		if (!ret) {
+			dev_err(&dev->intf->dev, "acked wait timeout\n");
+			ret = -ETIMEDOUT;
+			goto error_unlock;
+		}
+	}
+
+	ret = 0;
+error_unlock:
+	stub->ipacket.ibuf = NULL;
+	stub->ipacket.ibuf_len = NULL;
+	mutex_unlock(&dev->mutex);
+error_put:
+	usb_autopm_put_interface(dev->intf);
+
+	return ret;
+}
+
+static void ljca_read_complete(struct urb *urb)
+{
+	struct ljca_msg *header = urb->transfer_buffer;
+	struct ljca_dev *dev = urb->context;
+	int len = urb->actual_length;
+	int ret;
+
+	WARN_ON_ONCE(!dev);
+	WARN_ON_ONCE(!header);
+
+	if (urb->status) {
+		/* sync/async unlink faults aren't errors */
+		if (urb->status == -ENOENT || urb->status == -ECONNRESET ||
+		    urb->status == -ESHUTDOWN)
+			return;
+
+		dev_err(&dev->intf->dev, "read bulk urb transfer failed: %d\n", urb->status);
+		goto resubmit;
+	}
+
+	dev_dbg(&dev->intf->dev, "receive: type:%d cmd:%d flags:%d len:%d\n", header->type,
+		header->cmd, header->flags, header->len);
+
+	if (!ljca_validate(header, len)) {
+		dev_err(&dev->intf->dev, "data not correct header->len:%d payload_len:%d\n ",
+			header->len, len);
+		goto resubmit;
+	}
+
+	ret = ljca_parse(dev, header);
+	if (ret)
+		dev_err(&dev->intf->dev, "failed to parse data: ret:%d type:%d len:%d\n", ret,
+			header->type, header->len);
+
+resubmit:
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret)
+		dev_err(&dev->intf->dev, "failed submitting read urb, error %d\n", ret);
+}
+
+static int ljca_start(struct ljca_dev *dev)
+{
+	int ret;
+
+	usb_fill_bulk_urb(dev->in_urb, interface_to_usbdev(dev->intf),
+			  usb_rcvbulkpipe(interface_to_usbdev(dev->intf), dev->in_ep), dev->ibuf,
+			  dev->ibuf_len, ljca_read_complete, dev);
+
+	ret = usb_submit_urb(dev->in_urb, GFP_KERNEL);
+	if (ret) {
+		dev_err(&dev->intf->dev, "failed submitting read urb, error %d\n", ret);
+		return ret;
+	}
+
+	mutex_lock(&dev->mutex);
+	dev->started = true;
+	mutex_unlock(&dev->mutex);
+
+	return 0;
+}
+
+struct ljca_mng_priv {
+	u32 reset_id;
+};
+
+static int ljca_mng_reset_handshake(struct ljca_stub *stub)
+{
+	struct ljca_mng_priv *priv;
+	__le32 reset_id;
+	__le32 reset_id_ret = 0;
+	unsigned int ilen = sizeof(__le32);
+	int ret;
+
+	priv = ljca_priv(stub);
+	reset_id = cpu_to_le32(priv->reset_id++);
+	ret = ljca_stub_write(stub, LJCA_MNG_RESET_NOTIFY, &reset_id, sizeof(reset_id),
+			      &reset_id_ret, &ilen, true, LJCA_USB_WRITE_ACK_TIMEOUT_MS);
+	if (ret)
+		return ret;
+
+	if (ilen != sizeof(reset_id_ret) || reset_id_ret != reset_id) {
+		dev_err(&stub->intf->dev, "mng reset notify failed reset_id:%u/%u\n",
+			le32_to_cpu(reset_id_ret), le32_to_cpu(reset_id));
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void ljca_aux_release(struct device *dev) {}
+
+#ifdef CONFIG_ACPI
+static void ljca_aux_dev_acpi_bind(struct ljca_dev *dev, struct auxiliary_device *auxdev,
+				   unsigned int adr)
+{
+	struct acpi_device *parent;
+	struct acpi_device *adev = NULL;
+
+	/* new auxiliary device bind to acpi device */
+	parent = ACPI_COMPANION(&dev->intf->dev);
+	adev = acpi_find_child_device(parent, adr, false);
+	ACPI_COMPANION_SET(&auxdev->dev, adev ?: parent);
+}
+#else
+static void ljca_aux_dev_acpi_bind(struct ljca_dev *dev, struct auxiliary_device *auxdev,
+				   unsigned int adr)
+{
+}
+#endif
+
+static int ljca_add_aux_dev(struct ljca_dev *dev, char *name, unsigned int id, unsigned int adr,
+			    void *data)
+{
+	struct auxiliary_device *auxdev;
+	int ret;
+
+	if (dev->auxdev_count >= ARRAY_SIZE(dev->auxdevs))
+		return -EINVAL;
+
+	auxdev = &dev->auxdevs[dev->auxdev_count];
+	auxdev->name = name;
+	auxdev->id = id;
+	auxdev->dev.platform_data = data;
+	auxdev->dev.parent = &dev->intf->dev;
+	auxdev->dev.release = ljca_aux_release;
+
+	ret = auxiliary_device_init(auxdev);
+	if (ret)
+		return ret;
+
+	ljca_aux_dev_acpi_bind(dev, auxdev, adr);
+
+	ret = auxiliary_device_add(auxdev);
+	if (ret) {
+		dev_err(&dev->intf->dev, "failed to add auxiliary dev %s.%d\n", name, id);
+		auxiliary_device_uninit(auxdev);
+		return ret;
+	}
+
+	dev->auxdev_count++;
+
+	return 0;
+}
+
+static void ljca_cleanup_aux_dev(struct ljca_dev *dev)
+{
+	int i;
+
+	for (i = 0; i < dev->auxdev_count; i++) {
+		auxiliary_device_delete(&dev->auxdevs[i]);
+		auxiliary_device_uninit(&dev->auxdevs[i]);
+	}
+}
+
+static int ljca_gpio_stub_init(struct ljca_dev *dev, struct ljca_gpio_descriptor *desc)
+{
+	u32 valid_pin[LJCA_MAX_GPIO_NUM / BITS_PER_TYPE(u32)];
+	struct ljca_gpio_info *gpio_info;
+	struct ljca_stub *stub;
+	int gpio_num;
+	int i;
+	int ret;
+
+	gpio_num = desc->pins_per_bank * desc->bank_num;
+	if (gpio_num > LJCA_MAX_GPIO_NUM)
+		return -EINVAL;
+
+	stub = ljca_stub_alloc(dev, LJCA_GPIO_STUB, sizeof(*gpio_info));
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	gpio_info = ljca_priv(stub);
+	gpio_info->ljca = &stub->ljca;
+	gpio_info->num = gpio_num;
+
+	for (i = 0; i < desc->bank_num; i++)
+		valid_pin[i] = desc->bank_desc[i].valid_pins;
+
+	bitmap_from_arr32(gpio_info->valid_pin_map, valid_pin, gpio_num);
+
+	ret = ljca_add_aux_dev(dev, "ljca-gpio", 0, LJCA_ACPI_MATCH_GPIO, gpio_info);
+	if (ret)
+		ljca_stub_destroy(stub);
+
+	return ret;
+}
+
+static int ljca_mng_enum_gpio(struct ljca_stub *stub)
+{
+	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
+	char buf[LJCA_MAX_PAYLOAD_SIZE];
+	struct ljca_gpio_descriptor *desc;
+	unsigned int len = LJCA_MAX_PAYLOAD_SIZE;
+	int ret;
+
+	ret = ljca_stub_write(stub, LJCA_MNG_ENUM_GPIO, NULL, 0, buf, &len, true,
+			      LJCA_USB_ENUM_STUB_TIMEOUT_MS);
+	if (ret)
+		return ret;
+
+	desc = (struct ljca_gpio_descriptor *)buf;
+	if (len != struct_size(desc, bank_desc, desc->bank_num)) {
+		dev_err(&stub->intf->dev, "GPIO enumeration failed, len:%u bank_num:%u\n", len,
+			desc->bank_num);
+		return -EINVAL;
+	}
+
+	return ljca_gpio_stub_init(dev, desc);
+}
+
+static int ljca_i2c_stub_init(struct ljca_dev *dev, struct ljca_i2c_descriptor *desc)
+{
+	struct ljca_i2c_info *i2c_info;
+	struct ljca_stub *stub;
+	int ret;
+	int i;
+
+	stub = ljca_stub_alloc(dev, LJCA_I2C_STUB, size_mul(desc->num, sizeof(*i2c_info)));
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	i2c_info = ljca_priv(stub);
+
+	for (i = 0; i < desc->num; i++) {
+		i2c_info[i].ljca = &stub->ljca;
+		i2c_info[i].id = desc->info[i].id;
+		i2c_info[i].capacity = desc->info[i].capacity;
+		i2c_info[i].intr_pin = desc->info[i].intr_pin;
+
+		ret = ljca_add_aux_dev(dev, "ljca-i2c", i, LJCA_ACPI_MATCH_I2C1 + i,
+				       &i2c_info[i]);
+		if (ret) {
+			ljca_stub_destroy(stub);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ljca_mng_enum_i2c(struct ljca_stub *stub)
+{
+	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
+	char buf[LJCA_MAX_PAYLOAD_SIZE];
+	struct ljca_i2c_descriptor *desc;
+	unsigned int len = LJCA_MAX_PAYLOAD_SIZE;
+	int ret;
+
+	ret = ljca_stub_write(stub, LJCA_MNG_ENUM_I2C, NULL, 0, buf, &len, true,
+			      LJCA_USB_ENUM_STUB_TIMEOUT_MS);
+	if (ret) {
+		dev_err(&stub->intf->dev, "I2C enumeration failed, ret:%d len:%u\n", ret, len);
+		return ret;
+	}
+
+	desc = (struct ljca_i2c_descriptor *)buf;
+	return ljca_i2c_stub_init(dev, desc);
+}
+
+static int ljca_spi_stub_init(struct ljca_dev *dev, struct ljca_spi_descriptor *desc)
+{
+	struct ljca_spi_info *spi_info;
+	struct ljca_stub *stub;
+	int i;
+	int ret;
+
+	stub = ljca_stub_alloc(dev, LJCA_SPI_STUB, size_mul(desc->num, sizeof(*spi_info)));
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	spi_info = ljca_priv(stub);
+	for (i = 0; i < desc->num; i++) {
+		spi_info[i].ljca = &stub->ljca;
+		spi_info[i].id = desc->info[i].id;
+		spi_info[i].capacity = desc->info[i].capacity;
+
+		ret = ljca_add_aux_dev(dev, "ljca-spi", i, LJCA_ACPI_MATCH_SPI1 + i,
+				       &spi_info[i]);
+		if (ret) {
+			ljca_stub_destroy(stub);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ljca_mng_enum_spi(struct ljca_stub *stub)
+{
+	struct ljca_dev *dev = usb_get_intfdata(stub->intf);
+	char buf[LJCA_MAX_PAYLOAD_SIZE];
+	struct ljca_spi_descriptor *desc;
+	unsigned int len = LJCA_MAX_PAYLOAD_SIZE;
+	int ret;
+
+	ret = ljca_stub_write(stub, LJCA_MNG_ENUM_SPI, NULL, 0, buf, &len, true,
+			      LJCA_USB_ENUM_STUB_TIMEOUT_MS);
+	if (ret) {
+		dev_err(&stub->intf->dev, "SPI enumeration failed, ret:%d len:%d\n", ret, len);
+		return ret;
+	}
+
+	desc = (struct ljca_spi_descriptor *)buf;
+	return ljca_spi_stub_init(dev, desc);
+}
+
+static int ljca_mng_get_version(struct ljca_stub *stub, char *buf)
+{
+	struct fw_version version = {};
+	unsigned int len = sizeof(version);
+	int ret;
+
+	ret = ljca_stub_write(stub, LJCA_MNG_GET_VERSION, NULL, 0, &version, &len, true,
+			      LJCA_USB_WRITE_ACK_TIMEOUT_MS);
+	if (ret)
+		return ret;
+
+	if (len != sizeof(version)) {
+		dev_err(&stub->intf->dev, "get version failed, len:%d\n", len);
+		return -EINVAL;
+	}
+
+	return sysfs_emit(buf, "%d.%d.%d.%d\n", version.major, version.minor,
+			  le16_to_cpu(version.patch), le16_to_cpu(version.build));
+}
+
+static inline int ljca_mng_set_dfu_mode(struct ljca_stub *stub)
+{
+	return ljca_stub_write(stub, LJCA_MNG_SET_DFU_MODE, NULL, 0, NULL, NULL, true,
+			       LJCA_USB_WRITE_ACK_TIMEOUT_MS);
+}
+
+static int ljca_mng_link(struct ljca_dev *dev, struct ljca_stub *stub)
+{
+	int ret;
+
+	ret = ljca_mng_reset_handshake(stub);
+	if (ret)
+		return ret;
+
+	/* try to enum all the stubs */
+	ret = ljca_mng_enum_gpio(stub);
+	if (ret)
+		dev_warn(&dev->intf->dev, "GPIO function does not support yet\n");
+
+	ret = ljca_mng_enum_i2c(stub);
+	if (ret)
+		dev_warn(&dev->intf->dev, "I2C function does not support yet\n");
+
+	ret = ljca_mng_enum_spi(stub);
+	if (ret)
+		dev_warn(&dev->intf->dev, "SPI function does not support yet\n");
+
+	return 0;
+}
+
+static int ljca_mng_init(struct ljca_dev *dev)
+{
+	struct ljca_stub *stub;
+	struct ljca_mng_priv *priv;
+	int ret;
+
+	stub = ljca_stub_alloc(dev, LJCA_MNG_STUB, sizeof(*priv));
+	if (IS_ERR(stub))
+		return PTR_ERR(stub);
+
+	priv = ljca_priv(stub);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->reset_id = 0;
+
+	ret = ljca_mng_link(dev, stub);
+	if (ret)
+		dev_err(&dev->intf->dev, "mng stub link failed, ret:%d\n", ret);
+
+	return ret;
+}
+
+static inline int ljca_diag_set_trace_level(struct ljca_stub *stub, u8 level)
+{
+	return ljca_stub_write(stub, LJCA_DIAG_SET_TRACE_LEVEL, &level, sizeof(level), NULL, NULL,
+			       true, LJCA_USB_WRITE_ACK_TIMEOUT_MS);
+}
+
+static int ljca_diag_init(struct ljca_dev *dev)
+{
+	struct ljca_stub *stub;
+
+	stub = ljca_stub_alloc(dev, LJCA_DIAG_STUB, 0);
+
+	return PTR_ERR_OR_ZERO(stub);
+}
+
+static void ljca_delete(struct ljca_dev *dev)
+{
+	mutex_destroy(&dev->mutex);
+	usb_free_urb(dev->in_urb);
+	usb_put_intf(dev->intf);
+}
+
+static int ljca_init(struct ljca_dev *dev)
+{
+	mutex_init(&dev->mutex);
+	init_waitqueue_head(&dev->ack_wq);
+	INIT_LIST_HEAD(&dev->stubs_list);
+
+	return 0;
+}
+
+static void ljca_stop(struct ljca_dev *dev)
+{
+	mutex_lock(&dev->mutex);
+	dev->started = false;
+	mutex_unlock(&dev->mutex);
+	usb_kill_urb(dev->in_urb);
+}
+
+static ssize_t ljca_enable_dfu_store(struct device *dev, struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct ljca_dev *ljca_dev = usb_get_intfdata(intf);
+	struct ljca_stub *mng_stub = ljca_stub_find(ljca_dev, LJCA_MNG_STUB);
+	bool enable;
+	int ret;
+
+	ret = kstrtobool(buf, &enable);
+	if (ret)
+		return ret;
+
+	if (enable) {
+		ret = ljca_mng_set_dfu_mode(mng_stub);
+		if (ret)
+			return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(ljca_enable_dfu);
+
+static ssize_t ljca_trace_level_store(struct device *dev, struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct ljca_dev *ljca_dev = usb_get_intfdata(intf);
+	struct ljca_stub *diag_stub = ljca_stub_find(ljca_dev, LJCA_DIAG_STUB);
+	u8 level;
+	int ret;
+
+	if (kstrtou8(buf, 0, &level))
+		return -EINVAL;
+
+	ret = ljca_diag_set_trace_level(diag_stub, level);
+	if (ret)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(ljca_trace_level);
+
+static ssize_t ljca_version_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct ljca_dev *ljca_dev = usb_get_intfdata(intf);
+	struct ljca_stub *stub = ljca_stub_find(ljca_dev, LJCA_MNG_STUB);
+
+	return ljca_mng_get_version(stub, buf);
+}
+static DEVICE_ATTR_RO(ljca_version);
+
+static struct attribute *ljca_attrs[] = {
+	&dev_attr_ljca_version.attr,
+	&dev_attr_ljca_enable_dfu.attr,
+	&dev_attr_ljca_trace_level.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(ljca);
+
+static int ljca_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct ljca_dev *dev;
+	struct usb_endpoint_descriptor *bulk_in, *bulk_out;
+	int ret;
+
+	/* allocate memory for our device state and initialize it */
+	dev = devm_kzalloc(&intf->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	ljca_init(dev);
+	dev->intf = usb_get_intf(intf);
+
+	/* set up the endpoint information use only the first bulk-in and bulk-out endpoints */
+	ret = usb_find_common_endpoints(intf->cur_altsetting, &bulk_in, &bulk_out, NULL, NULL);
+	if (ret) {
+		dev_err(&intf->dev, "could not find both bulk-in and bulk-out endpoints\n");
+		goto error;
+	}
+
+	dev->ibuf_len = usb_endpoint_maxp(bulk_in);
+	dev->in_ep = bulk_in->bEndpointAddress;
+	dev->ibuf = devm_kzalloc(&intf->dev, dev->ibuf_len, GFP_KERNEL);
+	if (!dev->ibuf) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	dev->in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->in_urb) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	dev->out_ep = bulk_out->bEndpointAddress;
+	/* save our data pointer in this intf device */
+	usb_set_intfdata(intf, dev);
+	ret = ljca_start(dev);
+	if (ret) {
+		dev_err(&intf->dev, "bridge read start failed ret %d\n", ret);
+		goto error;
+	}
+
+	ret = ljca_mng_init(dev);
+	if (ret) {
+		dev_err(&intf->dev, "register mng stub failed ret %d\n", ret);
+		goto error_stop;
+	}
+
+	ret = ljca_diag_init(dev);
+	if (ret) {
+		dev_err(&intf->dev, "register diag stub failed ret %d\n", ret);
+		goto error_stop;
+	}
+
+	usb_enable_autosuspend(interface_to_usbdev(dev->intf));
+
+	return 0;
+
+error_stop:
+	ljca_stop(dev);
+	ljca_cleanup_aux_dev(dev);
+	ljca_stub_cleanup(dev);
+error:
+	dev_err(&intf->dev, "LJCA USB device init failed\n");
+	ljca_delete(dev);
+
+	return ret;
+}
+
+static void ljca_disconnect(struct usb_interface *intf)
+{
+	struct ljca_dev *dev = usb_get_intfdata(intf);
+
+	ljca_stop(dev);
+	ljca_cleanup_aux_dev(dev);
+	ljca_stub_cleanup(dev);
+	ljca_delete(dev);
+}
+
+static int ljca_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct ljca_dev *dev = usb_get_intfdata(intf);
+
+	ljca_stop(dev);
+
+	return 0;
+}
+
+static int ljca_resume(struct usb_interface *intf)
+{
+	struct ljca_dev *dev = usb_get_intfdata(intf);
+
+	return ljca_start(dev);
+}
+
+static const struct usb_device_id ljca_table[] = {
+	{USB_DEVICE(0x8086, 0x0b63)},
+	{}
+};
+MODULE_DEVICE_TABLE(usb, ljca_table);
+
+static struct usb_driver ljca_driver = {
+	.name = "ljca",
+	.probe = ljca_probe,
+	.disconnect = ljca_disconnect,
+	.suspend = ljca_suspend,
+	.resume = ljca_resume,
+	.id_table = ljca_table,
+	.dev_groups = ljca_groups,
+	.supports_autosuspend = 1,
+};
+module_usb_driver(ljca_driver);
+
+MODULE_AUTHOR("Ye Xiang <xiang.ye@intel.com>");
+MODULE_AUTHOR("Wang Zhifeng <zhifeng.wang@intel.com>");
+MODULE_AUTHOR("Zhang Lixu <lixu.zhang@intel.com>");
+MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/usb/ljca.h b/include/linux/usb/ljca.h
new file mode 100644
index 000000000000..843d9f79865a
--- /dev/null
+++ b/include/linux/usb/ljca.h
@@ -0,0 +1,43 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _LINUX_USB_LJCA_H_
+#define _LINUX_USB_LJCA_H_
+
+#include <linux/types.h>
+
+struct ljca;
+
+#define LJCA_MAX_GPIO_NUM 64
+struct ljca_gpio_info {
+	struct ljca *ljca;
+	unsigned int num;
+	DECLARE_BITMAP(valid_pin_map, LJCA_MAX_GPIO_NUM);
+};
+
+struct ljca_i2c_info {
+	struct ljca *ljca;
+	u8 id;
+	u8 capacity;
+	u8 intr_pin;
+};
+
+struct ljca_spi_info {
+	struct ljca *ljca;
+	u8 id;
+	u8 capacity;
+};
+
+/**
+ * typedef ljca_event_cb_t - event callback function signature
+ *
+ * @context: the execution context of who registered this callback
+ * @cmd: the command from device for this event
+ * @evt_data: the event data payload
+ * @len: the event data payload length
+ *
+ * The callback function is called in interrupt context and the data payload is
+ * only valid during the call. If the user needs later access of the data, it
+ * must copy it.
+ */
+typedef void (*ljca_event_cb_t)(void *context, u8 cmd, const void *evt_data, int len);
+
+#endif