Date:	Wed, 3 Nov 2010 17:26:29 -0700
From:	Guenter Roeck <guenter.roeck@...csson.com>
To:	Jean Delvare <khali@...ux-fr.org>
CC:	Ben Dooks <ben-linux@...ff.org>, <linux-i2c@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	Guenter Roeck <guenter.roeck@...csson.com>
Subject: [RFC/PATCH] i2c/busses: Add support for Diolan U2C-12 USB/I2C adapter

Signed-off-by: Guenter Roeck <guenter.roeck@...csson.com>
---
This is an usb-i2c adapter I am using to connect to i2c evaluation and test
boards. Not sure if it is worth adding it into the kernel. If yes, I'll be
happy to add myself as maintainer.

 drivers/i2c/busses/Kconfig          |   10 +
 drivers/i2c/busses/Makefile         |    1 +
 drivers/i2c/busses/i2c-diolan-u2c.c |  455 +++++++++++++++++++++++++++++++++++
 3 files changed, 466 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-diolan-u2c.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3a6321c..d73be36 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -640,6 +640,16 @@ config I2C_XILINX
 
 comment "External I2C/SMBus adapter drivers"
 
+config I2C_DIOLAN_U2C
+	tristate "Diolan U2C-12 USB adapter"
+	depends on USB
+	help
+	  If you say yes to this option, support will be included for Diolan
+	  U2C-12, a USB to I2C interface.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-diolan-u2c.
+
 config I2C_PARPORT
 	tristate "Parallel port adapter"
 	depends on PARPORT
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 84cb16a..46315db 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_I2C_OCTEON)	+= i2c-octeon.o
 obj-$(CONFIG_I2C_XILINX)	+= i2c-xiic.o
 
 # External I2C/SMBus adapter drivers
+obj-$(CONFIG_I2C_DIOLAN_U2C)	+= i2c-diolan-u2c.o
 obj-$(CONFIG_I2C_PARPORT)	+= i2c-parport.o
 obj-$(CONFIG_I2C_PARPORT_LIGHT)	+= i2c-parport-light.o
 obj-$(CONFIG_I2C_TAOS_EVM)	+= i2c-taos-evm.o
diff --git a/drivers/i2c/busses/i2c-diolan-u2c.c b/drivers/i2c/busses/i2c-diolan-u2c.c
new file mode 100644
index 0000000..5f4fb74
--- /dev/null
+++ b/drivers/i2c/busses/i2c-diolan-u2c.c
@@ -0,0 +1,455 @@
+/*
+ * driver for the Diolan u2c-12 usb adapter
+ *
+ * Copyright (c) 2010 Ericsson AB
+ *
+ * Derived from:
+ *  i2c-tiny-usb.c
+ *  Copyright (C) 2006-2007 Till Harbaum (Till@...baum.org)
+ *
+ * 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, version 2.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/i2c.h>
+
+#define USB_VENDOR_ID_DIOLAN		0x0abf
+#define USB_DEVICE_ID_DIOLAN_U2C	0x3370
+
+#define DIOLAN_OUT_EP		0x02
+#define DIOLAN_IN_EP		0x84
+
+/* commands via USB, must match command ids in the firmware */
+#define CMD_I2C_READ		0x01
+#define CMD_I2C_WRITE		0x02
+#define CMD_I2C_SCAN		0x03	/* Returns list of detected devices */
+#define CMD_I2C_RELEASE_SDA	0x04
+#define CMD_I2C_RELEASE_SCL	0x05
+#define CMD_I2C_DROP_SDA	0x06
+#define CMD_I2C_DROP_SCL	0x07
+#define CMD_I2C_READ_SDA	0x08
+#define CMD_I2C_READ_SCL	0x09
+#define CMD_GET_FW_VERSION	0x0a
+#define CMD_GET_SERIAL		0x0b
+#define CMD_I2C_START		0x0c
+#define CMD_I2C_STOP		0x0d
+#define CMD_I2C_REPEATED_START	0x0e
+#define CMD_I2C_PUT_BYTE	0x0f
+#define CMD_I2C_GET_BYTE	0x10
+#define CMD_I2C_PUT_ACK		0x11
+#define CMD_I2C_GET_ACK		0x12
+#define CMD_I2C_PUT_BYTE_ACK	0x13
+#define CMD_I2C_GET_BYTE_ACK	0x14
+#define CMD_I2C_SET_SPEED	0x1b
+#define CMD_I2C_GET_SPEED	0x1c
+#define CMD_SET_CLOCK_SYNCH	0x24
+#define CMD_GET_CLOCK_SYNCH	0x25
+#define CMD_SET_CLOCK_SYNCH_TO	0x26
+#define CMD_GET_CLOCK_SYNCH_TO	0x27
+
+#define RESP_OK			0x00
+#define RESP_FAILED		0x01
+#define RESP_BAD_MEMADDR	0x04
+#define RESP_DATA_ERR		0x05
+#define RESP_NOT_IMPLEMENTED	0x06
+#define RESP_NACK		0x07
+
+#define U2C_I2C_FREQ_FAST	0	/* 400 kHz  */
+#define U2C_I2C_FREQ_STD	1	/* 100 kHz  */
+#define U2C_I2C_FREQ_83KHZ	2
+#define U2C_I2C_FREQ_71KHZ	3
+#define U2C_I2C_FREQ_62KHZ	4
+#define U2C_I2C_FREQ_50KHZ	6
+#define U2C_I2C_FREQ_25KHZ	16
+#define U2C_I2C_FREQ_10KHZ	46
+#define U2C_I2C_FREQ_5KHZ	96
+#define U2C_I2C_FREQ_2KHZ	242
+
+#define DIOLAN_USB_TIMEOUT	100
+
+/* Structure to hold all of our device specific stuff */
+struct i2c_diolan_u2c {
+	struct usb_device *usb_dev;	/* the usb device for this device */
+	struct usb_interface *interface;/* the interface for this device */
+	struct i2c_adapter adapter;	/* i2c related things */
+};
+
+/* usb layer */
+
+static int diolan_usb_transfer(struct i2c_adapter *adapter, u8 * obuffer,
+			       int olen, u8 *ibuffer, int ilen)
+{
+	struct i2c_diolan_u2c *dev = adapter->algo_data;
+	int ret = 0;
+	int actual;
+	unsigned char inbuffer[257];
+
+	if (olen) {
+		ret = usb_bulk_msg(dev->usb_dev,
+				   usb_sndbulkpipe(dev->usb_dev, DIOLAN_OUT_EP),
+				   obuffer, olen, &actual, DIOLAN_USB_TIMEOUT);
+	}
+	if (!ret) {
+		ret = usb_bulk_msg(dev->usb_dev,
+				   usb_rcvbulkpipe(dev->usb_dev, DIOLAN_IN_EP),
+				   inbuffer, sizeof(inbuffer), &actual,
+				   DIOLAN_USB_TIMEOUT);
+		if (ret == 0 && actual > 0) {
+			ret = min(actual, ilen);
+			switch (inbuffer[actual - 1]) {
+			case RESP_NACK:
+				ret = -EINVAL;
+				goto abort;
+			case RESP_OK:
+				break;
+			default:
+				ret = -EIO;
+				goto abort;
+			}
+			if (ret)
+				memcpy(ibuffer, inbuffer, ret);
+		}
+	}
+abort:
+	return ret;
+}
+
+/*
+ * Flush input queue.
+ * If we don't do this at startup and the controller has queued up
+ * messages which were not retrieved, it will stop responding
+ * at some point.
+ */
+static void diolan_flush_input(struct usb_device *dev)
+{
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		int actual = 0;
+		int ret;
+		u8 inbuffer[257];
+
+		ret = usb_bulk_msg(dev, usb_rcvbulkpipe(dev, DIOLAN_IN_EP),
+				   inbuffer, sizeof(inbuffer), &actual,
+				   DIOLAN_USB_TIMEOUT);
+		if (ret < 0 || actual == 0)
+			break;
+	}
+}
+
+static int diolan_i2c_start(struct i2c_adapter *adapter)
+{
+	u8 buffer[1];
+
+	buffer[0] = CMD_I2C_START;
+
+	return diolan_usb_transfer(adapter, buffer, 1, buffer, 1);
+}
+
+static int diolan_i2c_repeated_start(struct i2c_adapter *adapter)
+{
+	u8 buffer[1];
+
+	buffer[0] = CMD_I2C_REPEATED_START;
+
+	return diolan_usb_transfer(adapter, buffer, 1, buffer, 1);
+}
+
+static int diolan_i2c_stop(struct i2c_adapter *adapter)
+{
+	u8 buffer[1];
+
+	buffer[0] = CMD_I2C_STOP;
+
+	return diolan_usb_transfer(adapter, buffer, 1, buffer, 1);
+}
+
+static int diolan_i2c_get_byte_ack(struct i2c_adapter *adapter, bool ack,
+				   u8 *byte)
+{
+	u8 buffer[2];
+	int rv;
+
+	buffer[0] = CMD_I2C_GET_BYTE_ACK;
+	buffer[1] = ack;
+
+	rv = diolan_usb_transfer(adapter, buffer, 2, buffer, 2);
+	if (rv > 0)
+		*byte = buffer[0];
+	else if (rv == 0)
+		rv = -EIO;
+
+	return rv;
+}
+
+static int diolan_i2c_put_byte_ack(struct i2c_adapter *adapter, u8 byte)
+{
+	u8 buffer[2];
+
+	buffer[0] = CMD_I2C_PUT_BYTE_ACK;
+	buffer[1] = byte;
+
+	return diolan_usb_transfer(adapter, buffer, 2, buffer, 1);
+}
+
+static int diolan_set_speed(struct i2c_adapter *adapter, u8 speed)
+{
+	u8 buffer[2];
+
+	buffer[0] = CMD_I2C_SET_SPEED;
+	buffer[1] = speed;
+
+	return diolan_usb_transfer(adapter, buffer, 2, buffer, 1);
+}
+
+static int diolan_fw_version(struct i2c_adapter *adapter)
+{
+	u8 buffer[3];
+	int ret;
+
+	buffer[0] = CMD_GET_FW_VERSION;
+	ret = diolan_usb_transfer(adapter, buffer, 1, buffer, 3);
+	if (ret == 3)
+		dev_info(&adapter->dev,
+			 "Diolan U2C firmware version %d.%d\n",
+			 buffer[0], buffer[1]);
+	return ret;
+}
+
+static int diolan_get_serial(struct i2c_adapter *adapter)
+{
+	u8 buffer[5];
+	int ret;
+
+	buffer[0] = CMD_GET_SERIAL;
+	ret = diolan_usb_transfer(adapter, buffer, 1, buffer, 5);
+	if (ret == 5)
+		dev_info(&adapter->dev,
+			 "Diolan U2C serial number %d\n", *(u32 *) &buffer[0]);
+	return ret;
+}
+
+static int diolan_scan(struct i2c_adapter *adapter)
+{
+	u8 buffer[257];
+	int i, ret;
+
+	buffer[0] = CMD_I2C_SCAN;
+	ret = diolan_usb_transfer(adapter, buffer, 1, buffer, 257);
+	if (ret > 0) {
+		for (i = 0; i < ret - 1; i++) {
+			if (buffer[i])
+				dev_info(&adapter->dev,
+					 "Found I2C device at address 0x%x\n",
+					 buffer[i] >> 1);
+		}
+	}
+	return ret;
+}
+
+/* i2c layer */
+
+static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
+{
+	struct i2c_msg *pmsg;
+	int i, j;
+	int rc = 0;
+
+	rc = diolan_i2c_start(adapter);
+	if (rc < 0)
+		return rc;
+
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+		if (i) {
+			rc = diolan_i2c_repeated_start(adapter);
+			if (rc < 0)
+				goto abort;
+		}
+		if (pmsg->flags & I2C_M_RD) {
+			rc = diolan_i2c_put_byte_ack(adapter,
+						((pmsg->addr & 0x7f) << 1) | 1);
+			if (rc < 0)
+				goto abort;
+			for (j = 0; j < pmsg->len; j++) {
+				u8 byte;
+				bool ack = j < pmsg->len - 1;
+
+				/*
+				 * Don't send NACK if this is the first byte
+				 * of a SMBUS_BLOCK message.
+				 */
+				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
+					ack = true;
+
+				rc = diolan_i2c_get_byte_ack(adapter, ack,
+							     &byte);
+				if (rc < 0)
+					goto abort;
+				/*
+				 * Adjust count if first received byte is length
+				 */
+				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
+					if (byte == 0
+					    || byte > I2C_SMBUS_BLOCK_MAX) {
+						rc = -EREMOTEIO;
+						goto abort;
+					}
+					pmsg->len += byte;
+				}
+				pmsg->buf[j] = byte;
+			}
+		} else {
+			rc = diolan_i2c_put_byte_ack(adapter,
+						     (pmsg->addr & 0x7f) << 1);
+			if (rc < 0)
+				goto abort;
+			for (j = 0; j < pmsg->len; j++) {
+				rc = diolan_i2c_put_byte_ack(adapter,
+							     pmsg->buf[j]);
+				if (rc < 0)
+					goto abort;
+			}
+		}
+	}
+abort:
+	diolan_i2c_stop(adapter);
+	return rc;
+}
+
+/*
+ * Return list of supported functionality.
+ */
+static u32 usb_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+	    I2C_FUNC_SMBUS_READ_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm usb_algorithm = {
+	.master_xfer = usb_xfer,
+	.functionality = usb_func,
+};
+
+/* device layer */
+
+static struct usb_device_id i2c_diolan_u2c_table[] = {
+	{USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C)},
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, i2c_diolan_u2c_table);
+
+static void i2c_diolan_u2c_free(struct i2c_diolan_u2c *dev)
+{
+	usb_put_dev(dev->usb_dev);
+	kfree(dev);
+}
+
+static int i2c_diolan_u2c_probe(struct usb_interface *interface,
+				const struct usb_device_id *id)
+{
+	struct i2c_diolan_u2c *dev;
+	int retval = -ENOMEM;
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (dev == NULL) {
+		dev_err(&interface->dev, "Out of memory\n");
+		goto error;
+	}
+
+	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	dev->interface = interface;
+
+	/* save our data pointer in this interface device */
+	usb_set_intfdata(interface, dev);
+
+	dev_info(&interface->dev,
+		 "Diolan U2C at bus %03d address %03d\n",
+		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
+
+	/* setup i2c adapter description */
+	dev->adapter.owner = THIS_MODULE;
+	dev->adapter.class = I2C_CLASS_HWMON;
+	dev->adapter.algo = &usb_algorithm;
+	dev->adapter.algo_data = dev;
+	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
+		 "i2c-u2c-usb at bus %03d device %03d",
+		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
+
+	dev->adapter.dev.parent = &dev->interface->dev;
+
+	diolan_flush_input(dev->usb_dev);
+
+	/* and finally attach to i2c layer */
+	i2c_add_adapter(&dev->adapter);
+
+	diolan_fw_version(&dev->adapter);
+
+	retval = diolan_set_speed(&dev->adapter, U2C_I2C_FREQ_STD);
+	if (retval < 0) {
+		dev_err(&dev->adapter.dev,
+			"failure %d setting I2C bus frequency\n", retval);
+		goto error_del;
+	}
+	diolan_get_serial(&dev->adapter);
+	diolan_scan(&dev->adapter);
+
+	dev_dbg(&dev->adapter.dev, "connected i2c-u2c-usb device\n");
+
+	return 0;
+
+error_del:
+	i2c_del_adapter(&dev->adapter);
+	i2c_diolan_u2c_free(dev);
+error:
+	return retval;
+}
+
+static void i2c_diolan_u2c_disconnect(struct usb_interface *interface)
+{
+	struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
+
+	i2c_del_adapter(&dev->adapter);
+	usb_set_intfdata(interface, NULL);
+	i2c_diolan_u2c_free(dev);
+
+	dev_dbg(&interface->dev, "disconnected\n");
+}
+
+static struct usb_driver i2c_diolan_u2c_driver = {
+	.name = "i2c-u2c-usb",
+	.probe = i2c_diolan_u2c_probe,
+	.disconnect = i2c_diolan_u2c_disconnect,
+	.id_table = i2c_diolan_u2c_table,
+};
+
+static int __init usb_i2c_diolan_u2c_init(void)
+{
+	/* register this driver with the USB subsystem */
+	return usb_register(&i2c_diolan_u2c_driver);
+}
+
+static void __exit usb_i2c_diolan_u2c_exit(void)
+{
+	/* deregister this driver with the USB subsystem */
+	usb_deregister(&i2c_diolan_u2c_driver);
+}
+
+module_init(usb_i2c_diolan_u2c_init);
+module_exit(usb_i2c_diolan_u2c_exit);
+
+/* ----- end of usb layer ------------------------------------------------ */
+
+MODULE_AUTHOR("Guenter Roeck <guenter.roeck@...csson.com>");
+MODULE_DESCRIPTION("i2c-u2c-usb driver");
+MODULE_LICENSE("GPL");
-- 
1.7.3.1

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