drivers/i2c/busses/i2c-tiny-usb.c - maze/linux - Git at Google

 /*
  * driver for the i2c-tiny-usb adapter - 1.0
  * http://www.harbaum.org/till/i2c_tiny_usb
  *
  * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.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 interfaces to usb layer */
 #include <linux/usb.h>

 /* include interface to i2c layer */
 #include <linux/i2c.h>

 /* commands via USB, must match command ids in the firmware */
 #define CMD_ECHO		0
 #define CMD_GET_FUNC		1
 #define CMD_SET_DELAY		2
 #define CMD_GET_STATUS		3

 #define CMD_I2C_IO		4
 #define CMD_I2C_IO_BEGIN	(1<<0)
 #define CMD_I2C_IO_END		(1<<1)

 /* i2c bit delay, default is 10us -> 100kHz max
    (in practice, due to additional delays in the i2c bitbanging
    code this results in a i2c clock of about 50kHz) */
 static unsigned short delay = 10;
 module_param(delay, ushort, 0);
 MODULE_PARM_DESC(delay, "bit delay in microseconds "
 		 "(default is 10us for 100kHz max)");

 static int usb_read(struct i2c_adapter *adapter, int cmd,
 		    int value, int index, void *data, int len);

 static int usb_write(struct i2c_adapter *adapter, int cmd,
 		     int value, int index, void *data, int len);

 /* ----- begin of i2c layer ---------------------------------------------- */

 #define STATUS_IDLE		0
 #define STATUS_ADDRESS_ACK	1
 #define STATUS_ADDRESS_NAK	2

 static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
 {
 	unsigned char status;
 	struct i2c_msg *pmsg;
 	int i;

 	dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);

 	for (i = 0 ; i < num ; i++) {
 		int cmd = CMD_I2C_IO;

 		if (i == 0)
 			cmd |= CMD_I2C_IO_BEGIN;

 		if (i == num-1)
 			cmd |= CMD_I2C_IO_END;

 		pmsg = &msgs[i];

 		dev_dbg(&adapter->dev,
 			"  %d: %s (flags %d) %d bytes to 0x%02x\n",
 			i, pmsg->flags & I2C_M_RD ? "read" : "write",
 			pmsg->flags, pmsg->len, pmsg->addr);

 		/* and directly send the message */
 		if (pmsg->flags & I2C_M_RD) {
 			/* read data */
 			if (usb_read(adapter, cmd,
 				     pmsg->flags, pmsg->addr,
 				     pmsg->buf, pmsg->len) != pmsg->len) {
 				dev_err(&adapter->dev,
 					"failure reading data\n");
 				return -EREMOTEIO;
 			}
 		} else {
 			/* write data */
 			if (usb_write(adapter, cmd,
 				      pmsg->flags, pmsg->addr,
 				      pmsg->buf, pmsg->len) != pmsg->len) {
 				dev_err(&adapter->dev,
 					"failure writing data\n");
 				return -EREMOTEIO;
 			}
 		}

 		/* read status */
 		if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
 			dev_err(&adapter->dev, "failure reading status\n");
 			return -EREMOTEIO;
 		}

 		dev_dbg(&adapter->dev, "  status = %d\n", status);
 		if (status == STATUS_ADDRESS_NAK)
 			return -EREMOTEIO;
 	}

 	return i;
 }

 static u32 usb_func(struct i2c_adapter *adapter)
 {
 	__le32 func;

 	/* get functionality from adapter */
 	if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
 	    sizeof(func)) {
 		dev_err(&adapter->dev, "failure reading functionality\n");
 		return 0;
 	}

 	return le32_to_cpu(func);
 }

 /* This is the actual algorithm we define */
 static const struct i2c_algorithm usb_algorithm = {
 	.master_xfer	= usb_xfer,
 	.functionality	= usb_func,
 };

 /* ----- end of i2c layer ------------------------------------------------ */

 /* ----- begin of usb layer ---------------------------------------------- */

 /*
  * Initially the usb i2c interface uses a vid/pid pair donated by
  * Future Technology Devices International Ltd., later a pair was
  * bought from EZPrototypes
  */
 static const struct usb_device_id i2c_tiny_usb_table[] = {
 	{ USB_DEVICE(0x0403, 0xc631) },   /* FTDI */
 	{ USB_DEVICE(0x1c40, 0x0534) },   /* EZPrototypes */
 	{ }                               /* Terminating entry */
 };

 MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);

 /* Structure to hold all of our device specific stuff */
 struct i2c_tiny_usb {
 	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 */
 };

 static int usb_read(struct i2c_adapter *adapter, int cmd,
 		    int value, int index, void *data, int len)
 {
 	struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;

 	/* do control transfer */
 	return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
 			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
 			       USB_DIR_IN, value, index, data, len, 2000);
 }

 static int usb_write(struct i2c_adapter *adapter, int cmd,
 		     int value, int index, void *data, int len)
 {
 	struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;

 	/* do control transfer */
 	return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
 			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
 			       value, index, data, len, 2000);
 }

 static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
 {
 	usb_put_dev(dev->usb_dev);
 	kfree(dev);
 }

 static int i2c_tiny_usb_probe(struct usb_interface *interface,
 			      const struct usb_device_id *id)
 {
 	struct i2c_tiny_usb *dev;
 	int retval = -ENOMEM;
 	u16 version;

 	dev_dbg(&interface->dev, "probing usb device\n");

 	/* 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);

 	version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
 	dev_info(&interface->dev,
 		 "version %x.%02x found at bus %03d address %03d\n",
 		 version >> 8, version & 0xff,
 		 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-tiny-usb at bus %03d device %03d",
 		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);

 	if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
 		dev_err(&dev->adapter.dev,
 			"failure setting delay to %dus\n", delay);
 		retval = -EIO;
 		goto error;
 	}

 	dev->adapter.dev.parent = &dev->interface->dev;

 	/* and finally attach to i2c layer */
 	i2c_add_adapter(&dev->adapter);

 	/* inform user about successful attachment to i2c layer */
 	dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");

 	return 0;

  error:
 	if (dev)
 		i2c_tiny_usb_free(dev);

 	return retval;
 }

 static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
 {
 	struct i2c_tiny_usb *dev = usb_get_intfdata(interface);

 	i2c_del_adapter(&dev->adapter);
 	usb_set_intfdata(interface, NULL);
 	i2c_tiny_usb_free(dev);

 	dev_dbg(&interface->dev, "disconnected\n");
 }

 static struct usb_driver i2c_tiny_usb_driver = {
 	.name		= "i2c-tiny-usb",
 	.probe		= i2c_tiny_usb_probe,
 	.disconnect	= i2c_tiny_usb_disconnect,
 	.id_table	= i2c_tiny_usb_table,
 };

 static int __init usb_i2c_tiny_usb_init(void)
 {
 	/* register this driver with the USB subsystem */
 	return usb_register(&i2c_tiny_usb_driver);
 }

 static void __exit usb_i2c_tiny_usb_exit(void)
 {
 	/* deregister this driver with the USB subsystem */
 	usb_deregister(&i2c_tiny_usb_driver);
 }

 module_init(usb_i2c_tiny_usb_init);
 module_exit(usb_i2c_tiny_usb_exit);

 /* ----- end of usb layer ------------------------------------------------ */

 MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
 MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
 MODULE_LICENSE("GPL");
	/*
	* driver for the i2c-tiny-usb adapter - 1.0
	* http://www.harbaum.org/till/i2c_tiny_usb
	*
	* Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.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 interfaces to usb layer */
	#include <linux/usb.h>

	/* include interface to i2c layer */
	#include <linux/i2c.h>

	/* commands via USB, must match command ids in the firmware */
	#define CMD_ECHO 0
	#define CMD_GET_FUNC 1
	#define CMD_SET_DELAY 2
	#define CMD_GET_STATUS 3

	#define CMD_I2C_IO 4
	#define CMD_I2C_IO_BEGIN (1<<0)
	#define CMD_I2C_IO_END (1<<1)

	/* i2c bit delay, default is 10us -> 100kHz max
	(in practice, due to additional delays in the i2c bitbanging
	code this results in a i2c clock of about 50kHz) */
	static unsigned short delay = 10;
	module_param(delay, ushort, 0);
	MODULE_PARM_DESC(delay, "bit delay in microseconds "
	"(default is 10us for 100kHz max)");

	static int usb_read(struct i2c_adapter *adapter, int cmd,
	int value, int index, void *data, int len);

	static int usb_write(struct i2c_adapter *adapter, int cmd,
	int value, int index, void *data, int len);

	/* ----- begin of i2c layer ---------------------------------------------- */

	#define STATUS_IDLE 0
	#define STATUS_ADDRESS_ACK 1
	#define STATUS_ADDRESS_NAK 2

	static int usb_xfer(struct i2c_adapter adapter, struct i2c_msg msgs, int num)
	{
	unsigned char status;
	struct i2c_msg *pmsg;
	int i;

	dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);

	for (i = 0 ; i < num ; i++) {
	int cmd = CMD_I2C_IO;

	if (i == 0)
	cmd \|= CMD_I2C_IO_BEGIN;

	if (i == num-1)
	cmd \|= CMD_I2C_IO_END;

	pmsg = &msgs[i];

	dev_dbg(&adapter->dev,
	" %d: %s (flags %d) %d bytes to 0x%02x\n",
	i, pmsg->flags & I2C_M_RD ? "read" : "write",
	pmsg->flags, pmsg->len, pmsg->addr);

	/* and directly send the message */
	if (pmsg->flags & I2C_M_RD) {
	/* read data */
	if (usb_read(adapter, cmd,
	pmsg->flags, pmsg->addr,
	pmsg->buf, pmsg->len) != pmsg->len) {
	dev_err(&adapter->dev,
	"failure reading data\n");
	return -EREMOTEIO;
	}
	} else {
	/* write data */
	if (usb_write(adapter, cmd,
	pmsg->flags, pmsg->addr,
	pmsg->buf, pmsg->len) != pmsg->len) {
	dev_err(&adapter->dev,
	"failure writing data\n");
	return -EREMOTEIO;
	}
	}

	/* read status */
	if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
	dev_err(&adapter->dev, "failure reading status\n");
	return -EREMOTEIO;
	}

	dev_dbg(&adapter->dev, " status = %d\n", status);
	if (status == STATUS_ADDRESS_NAK)
	return -EREMOTEIO;
	}

	return i;
	}

	static u32 usb_func(struct i2c_adapter *adapter)
	{
	__le32 func;

	/* get functionality from adapter */
	if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
	sizeof(func)) {
	dev_err(&adapter->dev, "failure reading functionality\n");
	return 0;
	}

	return le32_to_cpu(func);
	}

	/* This is the actual algorithm we define */
	static const struct i2c_algorithm usb_algorithm = {
	.master_xfer = usb_xfer,
	.functionality = usb_func,
	};

	/* ----- end of i2c layer ------------------------------------------------ */

	/* ----- begin of usb layer ---------------------------------------------- */

	/*
	* Initially the usb i2c interface uses a vid/pid pair donated by
	* Future Technology Devices International Ltd., later a pair was
	* bought from EZPrototypes
	*/
	static const struct usb_device_id i2c_tiny_usb_table[] = {
	{ USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
	{ USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
	{ } /* Terminating entry */
	};

	MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);

	/* Structure to hold all of our device specific stuff */
	struct i2c_tiny_usb {
	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 */
	};

	static int usb_read(struct i2c_adapter *adapter, int cmd,
	int value, int index, void *data, int len)
	{
	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;

	/* do control transfer */
	return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE \|
	USB_DIR_IN, value, index, data, len, 2000);
	}

	static int usb_write(struct i2c_adapter *adapter, int cmd,
	int value, int index, void *data, int len)
	{
	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;

	/* do control transfer */
	return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE,
	value, index, data, len, 2000);
	}

	static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
	{
	usb_put_dev(dev->usb_dev);
	kfree(dev);
	}

	static int i2c_tiny_usb_probe(struct usb_interface *interface,
	const struct usb_device_id *id)
	{
	struct i2c_tiny_usb *dev;
	int retval = -ENOMEM;
	u16 version;

	dev_dbg(&interface->dev, "probing usb device\n");

	/* 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);

	version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
	dev_info(&interface->dev,
	"version %x.%02x found at bus %03d address %03d\n",
	version >> 8, version & 0xff,
	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-tiny-usb at bus %03d device %03d",
	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);

	if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
	dev_err(&dev->adapter.dev,
	"failure setting delay to %dus\n", delay);
	retval = -EIO;
	goto error;
	}

	dev->adapter.dev.parent = &dev->interface->dev;

	/* and finally attach to i2c layer */
	i2c_add_adapter(&dev->adapter);

	/* inform user about successful attachment to i2c layer */
	dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");

	return 0;

	error:
	if (dev)
	i2c_tiny_usb_free(dev);

	return retval;
	}

	static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
	{
	struct i2c_tiny_usb *dev = usb_get_intfdata(interface);

	i2c_del_adapter(&dev->adapter);
	usb_set_intfdata(interface, NULL);
	i2c_tiny_usb_free(dev);

	dev_dbg(&interface->dev, "disconnected\n");
	}

	static struct usb_driver i2c_tiny_usb_driver = {
	.name = "i2c-tiny-usb",
	.probe = i2c_tiny_usb_probe,
	.disconnect = i2c_tiny_usb_disconnect,
	.id_table = i2c_tiny_usb_table,
	};

	static int __init usb_i2c_tiny_usb_init(void)
	{
	/* register this driver with the USB subsystem */
	return usb_register(&i2c_tiny_usb_driver);
	}

	static void __exit usb_i2c_tiny_usb_exit(void)
	{
	/* deregister this driver with the USB subsystem */
	usb_deregister(&i2c_tiny_usb_driver);
	}

	module_init(usb_i2c_tiny_usb_init);
	module_exit(usb_i2c_tiny_usb_exit);

	/* ----- end of usb layer ------------------------------------------------ */

	MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
	MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
	MODULE_LICENSE("GPL");