Date:	Wed, 11 Sep 2013 15:13:28 -0500
From:	David Barksdale <dbarksdale@...ogix.com>
To:	David Herrmann <dh.herrmann@...il.com>
CC:	David Barksdale <dbarksdale@...ogix.com>,
	Jiri Kosina <jkosina@...e.cz>,
	Benjamin Tissoires <benjamin.tissoires@...hat.com>,
	Oliver Neukum <oliver@...kum.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v2] HID: New hid-cp2112 driver.

This patch adds support for the Silicon Labs CP2112
"Single-Chip HID USB to SMBus Master Bridge."

I wrote this to support a USB temperature and humidity
sensor I've been working on. It's been tested by using
SMBus byte-read, byte-data-read/write, and word-data-read
transfer modes to talk to an I2C sensor. The other
transfer modes have not been tested.

Signed-off-by: David Barksdale <dbarksdale@...ogix.com>

--
Changes since v1:
* Prefix symbols to avoid name collision.
* Define CP2112 device ID.
* Missing break.
* Use module_hid_driver().
* Fix cp2122 typo.
* Fix probe and remove functions.
* Remove #if in hid_have_special_driver[].
* Improve symbolic constants for timeouts.
* Wrap DMA functions to kmalloc buffers.
* Added a short description of the device.
* Add request formatting functions for readability.
* Whitespace changes.
* Fix endianess of word transfers.

However this version doesn't work. Adding the hid_hw_open/hid_hw_close
calls to cp2112_probe() as suggested by David Herrmann seems to have
stopped events being delivered to cp2112_raw_event(). Why is that?

---
 drivers/hid/Kconfig      |   6 +
 drivers/hid/Makefile     |   1 +
 drivers/hid/hid-core.c   |   1 +
 drivers/hid/hid-cp2112.c | 559 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h    |   1 +
 5 files changed, 568 insertions(+)

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 14ef6ab..1833948 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -175,6 +175,12 @@ config HID_PRODIKEYS
 	  multimedia keyboard, but will lack support for the musical keyboard
 	  and some additional multimedia keys.
 
+config HID_CP2112
+	tristate "Silicon Labs CP2112 HID USB-to-SMBus Bridge support"
+	depends on USB_HID
+	---help---
+	Support for Silicon Labs CP2112 HID USB to SMBus Master Bridge.
+
 config HID_CYPRESS
 	tristate "Cypress mouse and barcode readers" if EXPERT
 	depends on HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 6f68728..a88a5c4 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_HID_AUREAL)        += hid-aureal.o
 obj-$(CONFIG_HID_BELKIN)	+= hid-belkin.o
 obj-$(CONFIG_HID_CHERRY)	+= hid-cherry.o
 obj-$(CONFIG_HID_CHICONY)	+= hid-chicony.o
+obj-$(CONFIG_HID_CP2112)	+= hid-cp2112.o
 obj-$(CONFIG_HID_CYPRESS)	+= hid-cypress.o
 obj-$(CONFIG_HID_DRAGONRISE)	+= hid-dr.o
 obj-$(CONFIG_HID_EMS_FF)	+= hid-emsff.o
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 36668d1..69e5f39 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1568,6 +1568,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_CHICONY_WIRELESS2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_CHICONY_AK1D) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CREATIVELABS, USB_DEVICE_ID_PRODIKEYS_PCMIDI) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_CP2112) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_1) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_2) },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_3) },
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
new file mode 100644
index 0000000..5c6d294
--- /dev/null
+++ b/drivers/hid/hid-cp2112.c
@@ -0,0 +1,559 @@
+/*
+  hid-cp2112.c - Silicon Labs HID USB to SMBus master bridge
+  Copyright (c) 2013 Uplogix, Inc.
+  David Barksdale <dbarksdale@...ogix.com>
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+  The Silicon Labs CP2112 chip is a USB HID device which provides an
+  SMBus controller for talking to slave devices. The host communicates
+  with the CP2112 via raw HID reports.
+ */
+
+#include <linux/hid.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+enum {
+	CP2112_GET_VERSION_INFO = 0x05,
+	CP2112_SMBUS_CONFIG = 0x06,
+	CP2112_DATA_READ_REQUEST = 0x10,
+	CP2112_DATA_WRITE_READ_REQUEST = 0x11,
+	CP2112_DATA_READ_FORCE_SEND = 0x12,
+	CP2112_DATA_READ_RESPONSE = 0x13,
+	CP2112_DATA_WRITE_REQUEST = 0x14,
+	CP2112_TRANSFER_STATUS_REQUEST = 0x15,
+	CP2112_TRANSFER_STATUS_RESPONSE = 0x16,
+	CP2112_CANCEL_TRANSFER = 0x17,
+};
+
+enum {
+	STATUS0_IDLE = 0x00,
+	STATUS0_BUSY = 0x01,
+	STATUS0_COMPLETE = 0x02,
+	STATUS0_ERROR = 0x03,
+};
+
+enum {
+	STATUS1_TIMEOUT_NACK = 0x00,
+	STATUS1_TIMEOUT_BUS = 0x01,
+	STATUS1_ARBITRATION_LOST = 0x02,
+	STATUS1_READ_INCOMPLETE = 0x03,
+	STATUS1_WRITE_INCOMPLETE = 0x04,
+	STATUS1_SUCCESS = 0x05,
+};
+
+/* All values are in big-endian */
+struct __attribute__ ((__packed__)) cp2112_smbus_config {
+	uint32_t clock_speed; /* Hz */
+	uint8_t device_address; /* Stored in the upper 7 bits */
+	uint8_t auto_send_read; /* 1 = enabled, 0 = disabled */
+	uint16_t write_timeout; /* ms, 0 = no timeout */
+	uint16_t read_timeout; /* ms, 0 = no timeout */
+	uint8_t scl_low_timeout; /* 1 = enabled, 0 = disabled */
+	uint16_t retry_time; /* # of retries, 0 = no limit */
+};
+
+/* Number of times to request transfer status before giving up waiting for a
+   transfer to complete. */
+static const int XFER_TIMEOUT = 100;
+
+/* Time in ms to wait for a CP2112_DATA_READ_RESPONSE or
+   CP2112_TRANSFER_STATUS_RESPONSE. */
+static const int RESPONSE_TIMEOUT = 50;
+
+static const struct hid_device_id cp2112_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_CP2112) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, cp2112_devices);
+
+struct cp2112_device {
+	struct i2c_adapter adap;
+	struct hid_device *hdev;
+	wait_queue_head_t wait;
+	uint8_t read_data[61];
+	uint8_t read_length;
+	int xfer_status;
+	atomic_t read_avail;
+	atomic_t xfer_avail;
+};
+
+static int cp2112_wait(struct cp2112_device *dev, atomic_t *avail)
+{
+	int ret = 0;
+
+	ret = wait_event_interruptible_timeout(dev->wait,
+		atomic_read(avail), msecs_to_jiffies(RESPONSE_TIMEOUT));
+	if (-ERESTARTSYS == ret)
+		return ret;
+	if (!ret)
+		return -ETIMEDOUT;
+	atomic_set(avail, 0);
+	return 0;
+}
+
+static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
+			  uint8_t *data, size_t count,
+			  unsigned char report_type)
+{
+	uint8_t *buf;
+	int ret;
+
+	buf = kmalloc(count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	ret = hdev->hid_get_raw_report(hdev, report_number, buf, count,
+				       report_type);
+	memcpy(data, buf, count);
+	kfree(buf);
+	return ret;
+}
+
+static int cp2112_hid_output(struct hid_device *hdev, uint8_t *data,
+			     size_t count, unsigned char report_type)
+{
+	uint8_t *buf;
+	int ret;
+
+	buf = kmemdup(data, count, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	ret = hdev->hid_output_raw_report(hdev, buf, count, report_type);
+	kfree(buf);
+	return ret;
+}
+
+static int cp2112_xfer_status(struct cp2112_device *dev)
+{
+	struct hid_device *hdev = dev->hdev;
+	uint8_t buf[2];
+	int ret;
+
+	buf[0] = CP2112_TRANSFER_STATUS_REQUEST;
+	buf[1] = 0x01;
+	atomic_set(&dev->xfer_avail, 0);
+	ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
+	if (ret < 0) {
+		hid_warn(hdev, "Error requesting status: %d\n", ret);
+		return ret;
+	}
+	ret = cp2112_wait(dev, &dev->xfer_avail);
+	if (ret)
+		return ret;
+	return dev->xfer_status;
+}
+
+static int cp2112_read(struct cp2112_device *dev, uint8_t *data, size_t size)
+{
+	struct hid_device *hdev = dev->hdev;
+	uint8_t buf[3];
+	int ret;
+
+	buf[0] = CP2112_DATA_READ_FORCE_SEND;
+	*(uint16_t *)&buf[1] = htons(size);
+	atomic_set(&dev->read_avail, 0);
+	ret = cp2112_hid_output(hdev, buf, 3, HID_OUTPUT_REPORT);
+	if (ret < 0) {
+		hid_warn(hdev, "Error requesting data: %d\n", ret);
+		return ret;
+	}
+	ret = cp2112_wait(dev, &dev->read_avail);
+	if (ret)
+		return ret;
+	hid_dbg(hdev, "read %d of %d bytes requested\n",
+		dev->read_length, size);
+	if (size > dev->read_length)
+		size = dev->read_length;
+	memcpy(data, dev->read_data, size);
+	return dev->read_length;
+}
+
+static int cp2112_read_req(uint8_t *buf, uint8_t slave_address, uint16_t length)
+{
+	if (length < 1 || length > 512)
+		return -EINVAL;
+	buf[0] = CP2112_DATA_READ_REQUEST;
+	buf[1] = slave_address << 1;
+	*(uint16_t *)&buf[2] = htons(length);
+	return 4;
+}
+
+static int cp2112_write_read_req(uint8_t *buf, uint8_t slave_address,
+				 uint16_t length, uint8_t command,
+				 uint8_t *data, uint8_t data_length)
+{
+	if (length < 1 || length > 512 || data_length > 15)
+		return -EINVAL;
+	buf[0] = CP2112_DATA_WRITE_READ_REQUEST;
+	buf[1] = slave_address << 1;
+	*(uint16_t *)&buf[2] = htons(length);
+	buf[4] = data_length + 1;
+	buf[5] = command;
+	memcpy(&buf[6], data, data_length);
+	return data_length + 6;
+}
+
+static int cp2112_write_req(uint8_t *buf, uint8_t slave_address,
+			    uint8_t command, uint8_t *data, uint8_t data_length)
+{
+	if (data_length > 60)
+		return -EINVAL;
+	buf[0] = CP2112_DATA_WRITE_REQUEST;
+	buf[1] = slave_address << 1;
+	buf[2] = data_length + 1;
+	buf[3] = command;
+	memcpy(&buf[4], data, data_length);
+	return data_length + 4;
+}
+
+static int cp2112_xfer(struct i2c_adapter *adap, uint16_t addr,
+		       unsigned short flags, char read_write, uint8_t command,
+		       int size, union i2c_smbus_data *data)
+{
+	struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
+	struct hid_device *hdev = dev->hdev;
+	uint8_t buf[64];
+	uint16_t word;
+	size_t count;
+	size_t read_length = 0;
+	size_t timeout;
+	int ret;
+
+	hid_dbg(hdev, "%s addr 0x%x flags 0x%x cmd 0x%x size %d\n",
+		read_write == I2C_SMBUS_WRITE ? "write" : "read",
+		addr, flags, command, size);
+	switch (size) {
+	case I2C_SMBUS_BYTE:
+		read_length = 1;
+		if (I2C_SMBUS_READ == read_write)
+			count = cp2112_read_req(buf, addr, read_length);
+		else
+			count = cp2112_write_req(buf, addr, data->byte, NULL,
+						 0);
+		break;
+	case I2C_SMBUS_BYTE_DATA:
+		read_length = 1;
+		if (I2C_SMBUS_READ == read_write)
+			count = cp2112_write_read_req(buf, addr, read_length,
+						      command, NULL, 0);
+		else
+			count = cp2112_write_req(buf, addr, command,
+						 &data->byte, 1);
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		read_length = 2;
+		word = htons(data->word);
+		if (I2C_SMBUS_READ == read_write)
+			count = cp2112_write_read_req(buf, addr, read_length,
+						      command, NULL, 0);
+		else
+			count = cp2112_write_req(buf, addr, command,
+						 (uint8_t *)&word, 2);
+		break;
+	case I2C_SMBUS_PROC_CALL:
+		size = I2C_SMBUS_WORD_DATA;
+		read_write = I2C_SMBUS_READ;
+		read_length = 2;
+		word = htons(data->word);
+		count = cp2112_write_read_req(buf, addr, read_length, command,
+					      (uint8_t *)&word, 2);
+		break;
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		size = I2C_SMBUS_BLOCK_DATA;
+		/* fallthrough */
+	case I2C_SMBUS_BLOCK_DATA:
+		if (I2C_SMBUS_READ == read_write) {
+			count = cp2112_write_read_req(buf, addr,
+						      I2C_SMBUS_BLOCK_MAX,
+						      command, NULL, 0);
+		} else {
+			count = cp2112_write_req(buf, addr, command,
+						 data->block,
+						 data->block[0] + 1);
+		}
+		break;
+	case I2C_SMBUS_BLOCK_PROC_CALL:
+		size = I2C_SMBUS_BLOCK_DATA;
+		read_write = I2C_SMBUS_READ;
+		count = cp2112_write_read_req(buf, addr, I2C_SMBUS_BLOCK_MAX,
+					      command, data->block,
+					      data->block[0] + 1);
+		break;
+	default:
+		hid_warn(hdev, "Unsupported transaction %d\n", size);
+		return -EOPNOTSUPP;
+	}
+	if (count < 0)
+		return count;
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		hid_err(hdev, "hw open failed\n");
+		return ret;
+	}
+	ret = hid_hw_power(hdev, PM_HINT_FULLON);
+	if (ret < 0) {
+		hid_err(hdev, "power management error: %d\n", ret);
+		goto hid_close;
+	}
+	ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
+	if (ret < 0) {
+		hid_warn(hdev, "Error starting transaction: %d\n", ret);
+		goto power_normal;
+	}
+	for (timeout = 0; timeout < XFER_TIMEOUT; ++timeout) {
+		ret = cp2112_xfer_status(dev);
+		if (-EBUSY == ret)
+			continue;
+		if (ret < 0)
+			goto power_normal;
+		break;
+	}
+	if (XFER_TIMEOUT <= timeout) {
+		hid_warn(hdev, "Transfer timed out, cancelling.\n");
+		buf[0] = CP2112_CANCEL_TRANSFER;
+		buf[1] = 0x01;
+		ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
+		if (ret < 0) {
+			hid_warn(hdev, "Error cancelling transaction: %d\n",
+				 ret);
+		}
+		ret = -ETIMEDOUT;
+		goto power_normal;
+	}
+	if (I2C_SMBUS_WRITE == read_write) {
+		ret = 0;
+		goto power_normal;
+	}
+	if (I2C_SMBUS_BLOCK_DATA == size)
+		read_length = ret;
+	ret = cp2112_read(dev, buf, read_length);
+	if (ret < 0)
+		goto power_normal;
+	if (ret != read_length) {
+		hid_warn(hdev, "short read: %d < %d\n", ret, read_length);
+		ret = -EIO;
+		goto power_normal;
+	}
+	switch (size) {
+	case I2C_SMBUS_BYTE:
+	case I2C_SMBUS_BYTE_DATA:
+		data->byte = buf[0];
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		data->word = ntohs(*(uint16_t *)buf);
+		break;
+	case I2C_SMBUS_BLOCK_DATA:
+		if (read_length > I2C_SMBUS_BLOCK_MAX) {
+			ret = -EPROTO;
+			goto power_normal;
+		}
+		memcpy(data->block, buf, read_length);
+		break;
+	}
+	ret = 0;
+power_normal:
+	hid_hw_power(hdev, PM_HINT_NORMAL);
+hid_close:
+	hid_hw_close(hdev);
+	hid_dbg(hdev, "transfer finished: %d\n", ret);
+	return ret;
+}
+
+static uint32_t cp2112_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_SMBUS_BYTE |
+		I2C_FUNC_SMBUS_BYTE_DATA |
+		I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_BLOCK_DATA |
+		I2C_FUNC_SMBUS_I2C_BLOCK |
+		I2C_FUNC_SMBUS_PROC_CALL |
+		I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
+}
+
+static const struct i2c_algorithm smbus_algorithm = {
+	.smbus_xfer	= cp2112_xfer,
+	.functionality	= cp2112_functionality,
+};
+
+static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct cp2112_device *dev;
+	uint8_t buf[64];
+	struct cp2112_smbus_config *config;
+	int ret;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		return ret;
+	}
+	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		return ret;
+	}
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		hid_err(hdev, "hw open failed\n");
+		goto hid_stop;
+	}
+	ret = hid_hw_power(hdev, PM_HINT_FULLON);
+	if (ret < 0) {
+		hid_err(hdev, "power management error: %d\n", ret);
+		goto hid_close;
+	}
+	ret = cp2112_hid_get(hdev, CP2112_GET_VERSION_INFO, buf, 3,
+			     HID_FEATURE_REPORT);
+	if (ret != 3) {
+		hid_err(hdev, "error requesting version\n");
+		if (ret >= 0)
+			ret = -EIO;
+		goto power_normal;
+	}
+	hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
+		 buf[1], buf[2]);
+	ret = cp2112_hid_get(hdev, CP2112_SMBUS_CONFIG, buf,
+			     sizeof(*config) + 1, HID_FEATURE_REPORT);
+	if (ret != sizeof(*config) + 1) {
+		hid_err(hdev, "error requesting SMBus config\n");
+		if (ret >= 0)
+			ret = -EIO;
+		goto power_normal;
+	}
+	config = (struct cp2112_smbus_config *)&buf[1];
+	config->retry_time = htons(1);
+	ret = cp2112_hid_output(hdev, buf, sizeof(*config) + 1,
+				HID_FEATURE_REPORT);
+	if (ret != sizeof(*config) + 1) {
+		hid_err(hdev, "error setting SMBus config\n");
+		if (ret >= 0)
+			ret = -EIO;
+		goto power_normal;
+	}
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		hid_err(hdev, "out of memory\n");
+		ret = -ENOMEM;
+		goto power_normal;
+	}
+	dev->hdev = hdev;
+	hid_set_drvdata(hdev, (void *)dev);
+	dev->adap.owner		= THIS_MODULE;
+	dev->adap.class		= I2C_CLASS_HWMON;
+	dev->adap.algo		= &smbus_algorithm;
+	dev->adap.algo_data	= dev;
+	dev->adap.dev.parent	= &hdev->dev;
+	snprintf(dev->adap.name, sizeof(dev->adap.name),
+		 "CP2112 SMBus Bridge on hiddev%d", hdev->minor);
+	init_waitqueue_head(&dev->wait);
+	hid_device_io_start(hdev);
+	ret = i2c_add_adapter(&dev->adap);
+	hid_device_io_stop(hdev);
+	hid_hw_power(hdev, PM_HINT_NORMAL);
+	hid_hw_close(hdev);
+	if (ret) {
+		hid_err(hdev, "error registering i2c adapter\n");
+		kfree(dev);
+		goto hid_stop;
+	}
+	hid_dbg(hdev, "adapter registered\n");
+	return ret;
+power_normal:
+	hid_hw_power(hdev, PM_HINT_NORMAL);
+hid_close:
+	hid_hw_close(hdev);
+hid_stop:
+	hid_hw_stop(hdev);
+	return ret;
+}
+
+static void cp2112_remove(struct hid_device *hdev)
+{
+	struct cp2112_device *dev = hid_get_drvdata(hdev);
+
+	hid_hw_stop(hdev);
+	i2c_del_adapter(&dev->adap);
+	kfree(dev);
+}
+
+static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
+			    uint8_t *data, int size)
+{
+	struct cp2112_device *dev = hid_get_drvdata(hdev);
+
+	switch (data[0]) {
+	case CP2112_TRANSFER_STATUS_RESPONSE:
+		hid_dbg(hdev, "xfer status: %02x %02x %04x %04x\n",
+			data[1], data[2], htons(*(uint16_t *)&data[3]),
+			htons(*(uint16_t *)&data[5]));
+		switch (data[1]) {
+		case STATUS0_IDLE:
+			dev->xfer_status = -EAGAIN;
+			break;
+		case STATUS0_BUSY:
+			dev->xfer_status = -EBUSY;
+			break;
+		case STATUS0_COMPLETE:
+			dev->xfer_status = ntohs(*(uint16_t *)&data[5]);
+			break;
+		case STATUS0_ERROR:
+			switch (data[2]) {
+			case STATUS1_TIMEOUT_NACK:
+			case STATUS1_TIMEOUT_BUS:
+				dev->xfer_status = -ETIMEDOUT;
+				break;
+			default:
+				dev->xfer_status = -EIO;
+			}
+			break;
+		default:
+			dev->xfer_status = -EINVAL;
+			break;
+		}
+		atomic_set(&dev->xfer_avail, 1);
+		break;
+	case CP2112_DATA_READ_RESPONSE:
+		hid_dbg(hdev, "read response: %02x %02x\n", data[1], data[2]);
+		dev->read_length = data[2];
+		if (dev->read_length > sizeof(dev->read_data))
+			dev->read_length = sizeof(dev->read_data);
+		memcpy(dev->read_data, &data[3], dev->read_length);
+		atomic_set(&dev->read_avail, 1);
+		break;
+	default:
+		hid_err(hdev, "unknown report\n");
+		return 0;
+	}
+	wake_up_interruptible(&dev->wait);
+	return 1;
+}
+
+static struct hid_driver cp2112_driver = {
+	.name = "cp2112",
+	.id_table = cp2112_devices,
+	.probe = cp2112_probe,
+	.remove = cp2112_remove,
+	.raw_event = cp2112_raw_event,
+};
+
+module_hid_driver(cp2112_driver);
+MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
+MODULE_AUTHOR("David Barksdale <dbarksdale@...ogix.com>");
+MODULE_LICENSE("GPL");
+
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index ffe4c7a..3a9dd5d 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -240,6 +240,7 @@
 
 #define USB_VENDOR_ID_CYGNAL		0x10c4
 #define USB_DEVICE_ID_CYGNAL_RADIO_SI470X	0x818a
+#define USB_DEVICE_ID_CYGNAL_CP2112	0xEA90
 
 #define USB_VENDOR_ID_CYPRESS		0x04b4
 #define USB_DEVICE_ID_CYPRESS_MOUSE	0x0001
-- 
tg: (584d88b..) upstream/hid-cp2112 (depends on: upstream/master)
--
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