Date:	Tue, 13 Aug 2013 10:25:39 -0500
From:	David Barksdale <dbarksdale@...ogix.com>
To:	Jiri Kosina <jkosina@...e.cz>
CC:	<linux-kernel@...r.kernel.org>, Mark Ferrell <mferrell@...ogix.com>
Subject: [PATCH] HID: New hid-cp2112 driver.

From: David Barksdale <dbarksdale@...ogix.com>

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 byte-word-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>

---
  drivers/hid/Kconfig      |   6 +
  drivers/hid/Makefile     |   1 +
  drivers/hid/hid-core.c   |   3 +
  drivers/hid/hid-cp2112.c | 504 +++++++++++++++++++++++++++++++++++++++++++++++
  4 files changed, 514 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..b472a0d 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1568,6 +1568,9 @@ 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) },
+#if IS_ENABLED(CONFIG_HID_CP2112)
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, 0xEA90) },
+#endif
  	{ 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..8737d18
--- /dev/null
+++ b/drivers/hid/hid-cp2112.c
@@ -0,0 +1,504 @@
+/*
+  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.
+ */
+
+#include <linux/hid.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+enum {
+	GET_VERSION_INFO = 0x05,
+	SMBUS_CONFIG = 0x06,
+	DATA_READ_REQUEST = 0x10,
+	DATA_WRITE_READ_REQUEST = 0x11,
+	DATA_READ_FORCE_SEND = 0x12,
+	DATA_READ_RESPONSE = 0x13,
+	DATA_WRITE_REQUEST = 0x14,
+	TRANSFER_STATUS_REQUEST = 0x15,
+	TRANSFER_STATUS_RESPONSE = 0x16,
+	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__)) 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 */
+};
+
+static const int MAX_TIMEOUT = 100;
+
+static const struct hid_device_id cp2112_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, 0xEA90) },
+	{ }
+};
+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(50));
+	if (-ERESTARTSYS == ret)
+		return ret;
+	if (!ret)
+		return -ETIMEDOUT;
+	atomic_set(avail, 0);
+	return 0;
+}
+
+static int cp2112_xfer_status(struct cp2112_device *dev)
+{
+	struct hid_device *hdev = dev->hdev;
+	uint8_t buf[2];
+	int ret;
+
+	buf[0] = TRANSFER_STATUS_REQUEST;
+	buf[1] = 0x01;
+	atomic_set(&dev->xfer_avail, 0);
+	ret = hdev->hid_output_raw_report(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] = DATA_READ_FORCE_SEND;
+	*(uint16_t *)&buf[1] = htons(size);
+	atomic_set(&dev->read_avail, 0);
+	ret = hdev->hid_output_raw_report(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_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];
+	size_t count;
+	size_t read_length = 0;
+	size_t write_length;
+	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);
+	buf[1] = addr << 1;
+	switch (size) {
+	case I2C_SMBUS_BYTE:
+		if (I2C_SMBUS_READ == read_write) {
+			read_length = 1;
+			buf[0] = DATA_READ_REQUEST;
+			*(uint16_t *)&buf[2] = htons(read_length);
+			count = 4;
+		} else {
+			write_length = 1;
+			buf[0] = DATA_WRITE_REQUEST;
+			buf[2] = write_length;
+			buf[3] = data->byte;
+			count = 4;
+		}
+		break;
+	case I2C_SMBUS_BYTE_DATA:
+		if (I2C_SMBUS_READ == read_write) {
+			read_length = 1;
+			buf[0] = DATA_WRITE_READ_REQUEST;
+			*(uint16_t *)&buf[2] = htons(read_length);
+			buf[4] = 1;
+			buf[5] = command;
+			count = 6;
+		} else {
+			write_length = 2;
+			buf[0] = DATA_WRITE_REQUEST;
+			buf[2] = write_length;
+			buf[3] = command;
+			buf[4] = data->byte;
+			count = 5;
+		}
+		break;
+	case I2C_SMBUS_WORD_DATA:
+		if (I2C_SMBUS_READ == read_write) {
+			read_length = 2;
+			buf[0] = DATA_WRITE_READ_REQUEST;
+			*(uint16_t *)&buf[2] = htons(read_length);
+			buf[4] = 1;
+			buf[5] = command;
+			count = 6;
+		} else {
+			write_length = 3;
+			buf[0] = DATA_WRITE_REQUEST;
+			buf[2] = write_length;
+			buf[3] = command;
+			*(uint16_t *)&buf[4] = htons(data->word);
+			count = 6;
+		}
+		break;
+	case I2C_SMBUS_PROC_CALL:
+		size = I2C_SMBUS_WORD_DATA;
+		read_write = I2C_SMBUS_READ;
+		read_length = 2;
+		write_length = 3;
+		buf[0] = DATA_WRITE_READ_REQUEST;
+		*(uint16_t *)&buf[2] = htons(read_length);
+		buf[4] = write_length;
+		buf[5] = command;
+		*(uint16_t *)&buf[6] = data->word;
+		count = 8;
+		break;
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		size = I2C_SMBUS_BLOCK_DATA;
+		/* fallthrough */
+	case I2C_SMBUS_BLOCK_DATA:
+		if (I2C_SMBUS_READ == read_write) {
+			buf[0] = DATA_WRITE_READ_REQUEST;
+			*(uint16_t *)&buf[2] = htons(I2C_SMBUS_BLOCK_MAX);
+			buf[4] = 1;
+			buf[5] = command;
+			count = 6;
+		} else {
+			write_length = data->block[0];
+			if (write_length > 61 - 2)
+				return -EINVAL;
+			buf[0] = DATA_WRITE_REQUEST;
+			buf[2] = write_length + 2;
+			buf[3] = command;
+			memcpy(&buf[4], data->block, write_length + 1);
+			count = 5 + write_length;
+		}
+		break;
+	case I2C_SMBUS_BLOCK_PROC_CALL:
+		size = I2C_SMBUS_BLOCK_DATA;
+		read_write = I2C_SMBUS_READ;
+		write_length = data->block[0];
+		if (write_length > 16 - 2)
+			return -EINVAL;
+		buf[0] = DATA_WRITE_READ_REQUEST;
+		*(uint16_t *)&buf[2] = htons(I2C_SMBUS_BLOCK_MAX);
+		buf[4] = write_length + 2;
+		buf[5] = command;
+		memcpy(&buf[6], data->block, write_length + 1);
+		count = 7 + write_length;
+	default:
+		hid_warn(hdev, "Unsupported transaction %d\n", size);
+		return -EOPNOTSUPP;
+	}
+	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 = hdev->hid_output_raw_report(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 < MAX_TIMEOUT; ++timeout) {
+		ret = cp2112_xfer_status(dev);
+		if (-EBUSY == ret)
+			continue;
+		if (ret < 0)
+			goto power_normal;
+		break;
+	}
+	if (MAX_TIMEOUT <= timeout) {
+		hid_warn(hdev, "Transfer timed out, cancelling.\n");
+		buf[0] = CANCEL_TRANSFER;
+		buf[1] = 0x01;
+		ret = hdev->hid_output_raw_report(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 cp2122_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	= cp2122_functionality,
+};
+
+static int
+cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	struct cp2112_device *dev;
+	uint8_t buf[64];
+	struct 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_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		return ret;
+	}
+	ret = hdev->hid_get_raw_report(hdev, GET_VERSION_INFO, buf, 3,
+		HID_FEATURE_REPORT);
+	if (ret != 3) {
+		hid_err(hdev, "error requesting version\n");
+		return ret;
+	}
+	hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
+		buf[1], buf[2]);
+	ret = hdev->hid_get_raw_report(hdev, SMBUS_CONFIG, buf,
+		sizeof(*config) + 1, HID_FEATURE_REPORT);
+	if (ret != sizeof(*config) + 1) {
+		hid_err(hdev, "error requesting SMBus config\n");
+		return ret;
+	}
+	config = (struct smbus_config *)&buf[1];
+	config->retry_time = htons(1);
+	ret = hdev->hid_output_raw_report(hdev, buf,
+		sizeof(*config) + 1, HID_FEATURE_REPORT);
+	if (ret != sizeof(*config) + 1) {
+		hid_err(hdev, "error setting SMBus config\n");
+		return ret;
+	}
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		hid_err(hdev, "out of memory\n");
+		return -ENOMEM;
+	}
+	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;
+	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);
+	if (ret) {
+		hid_err(hdev, "error registering i2c adapter\n");
+		kfree(dev);
+		hid_set_drvdata(hdev, NULL);
+	}
+	hid_dbg(hdev, "adapter registered\n");
+	return ret;
+}
+
+static void cp2112_remove(struct hid_device *hdev)
+{
+	struct cp2112_device *dev = hid_get_drvdata(hdev);
+
+	if (dev) {
+		i2c_del_adapter(&dev->adap);
+		wake_up_interruptible(&dev->wait);
+		kfree(dev);
+		hid_set_drvdata(hdev, NULL);
+	}
+	hid_hw_stop(hdev);
+}
+
+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 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 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,
+};
+
+static int __init cp2112_init(void)
+{
+	return hid_register_driver(&cp2112_driver);
+}
+
+static void __exit cp2112_exit(void)
+{
+	hid_unregister_driver(&cp2112_driver);
+}
+
+module_init(cp2112_init);
+module_exit(cp2112_exit);
+MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
+MODULE_AUTHOR("David Barksdale <dbarksdale@...ogix.com>");
+MODULE_LICENSE("GPL");
+
-- 
tg: (584d88b..) upstream/hid-cp2112 (depends on: upstream/master)
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