[linux-2.6-block.git] / drivers / i2c / busses / i2c-tiny-usb.c

/*
 * 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 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 */
static int delay = 10;
module_param(delay, int, 0);
MODULE_PARM_DESC(delay, "bit delay in microseconds, "
		 "e.g. 10 for 100kHz (default is 100kHz)");

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)
{
	u32 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 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 ---------------------------------------------- */

/* The usb i2c interface uses a vid/pid pair donated by */
/* Future Technology Devices International Ltd. */
static struct usb_device_id i2c_tiny_usb_table [] = {
	{ USB_DEVICE(0x0403, 0xc631) },
	{ }			/* 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,
		      cpu_to_le16(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");
Commit	Line	Data
e8c76eed TH	1	/*
	2	* driver for the i2c-tiny-usb adapter - 1.0
	3	* http://www.harbaum.org/till/i2c_tiny_usb
	4	*
	5	* Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
	6	*
	7	* This program is free software; you can redistribute it and/or
	8	* modify it under the terms of the GNU General Public License as
	9	* published by the Free Software Foundation, version 2.
	10	*
	11	*/
	12
	13	#include <linux/kernel.h>
	14	#include <linux/errno.h>
	15	#include <linux/module.h>
	16
	17	/* include interfaces to usb layer */
	18	#include <linux/usb.h>
	19
	20	/* include interface to i2c layer */
	21	#include <linux/i2c.h>
	22
	23	/* commands via USB, must match command ids in the firmware */
	24	#define CMD_ECHO 0
	25	#define CMD_GET_FUNC 1
	26	#define CMD_SET_DELAY 2
	27	#define CMD_GET_STATUS 3
	28
	29	#define CMD_I2C_IO 4
	30	#define CMD_I2C_IO_BEGIN (1<<0)
	31	#define CMD_I2C_IO_END (1<<1)
	32
	33	/* i2c bit delay, default is 10us -> 100kHz */
	34	static int delay = 10;
	35	module_param(delay, int, 0);
	36	MODULE_PARM_DESC(delay, "bit delay in microseconds, "
	37	"e.g. 10 for 100kHz (default is 100kHz)");
	38
	39	static int usb_read(struct i2c_adapter *adapter, int cmd,
	40	int value, int index, void *data, int len);
	41
	42	static int usb_write(struct i2c_adapter *adapter, int cmd,
	43	int value, int index, void *data, int len);
	44
	45	/* ----- begin of i2c layer ---------------------------------------------- */
	46
	47	#define STATUS_IDLE 0
	48	#define STATUS_ADDRESS_ACK 1
	49	#define STATUS_ADDRESS_NAK 2
	50
	51	static int usb_xfer(struct i2c_adapter adapter, struct i2c_msg msgs, int num)
	52	{
	53	unsigned char status;
	54	struct i2c_msg *pmsg;
	55	int i;
	56
	57	dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
	58
	59	for (i = 0 ; i < num ; i++) {
	60	int cmd = CMD_I2C_IO;
	61
	62	if (i == 0)
	63	cmd \|= CMD_I2C_IO_BEGIN;
	64
65	if (i == num-1)
66	cmd \|= CMD_I2C_IO_END;
67
68	pmsg = &msgs[i];
69
70	dev_dbg(&adapter->dev,
71	" %d: %s (flags %d) %d bytes to 0x%02x\n",
72	i, pmsg->flags & I2C_M_RD ? "read" : "write",
73	pmsg->flags, pmsg->len, pmsg->addr);
74
75	/* and directly send the message */
76	if (pmsg->flags & I2C_M_RD) {
77	/* read data */
78	if (usb_read(adapter, cmd,
79	pmsg->flags, pmsg->addr,
80	pmsg->buf, pmsg->len) != pmsg->len) {
81	dev_err(&adapter->dev,
82	"failure reading data\n");
83	return -EREMOTEIO;
84	}
85	} else {
86	/* write data */
87	if (usb_write(adapter, cmd,
88	pmsg->flags, pmsg->addr,
89	pmsg->buf, pmsg->len) != pmsg->len) {
90	dev_err(&adapter->dev,
91	"failure writing data\n");
92	return -EREMOTEIO;
93	}
94	}
95
96	/* read status */
97	if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
98	dev_err(&adapter->dev, "failure reading status\n");
99	return -EREMOTEIO;
100	}
101
102	dev_dbg(&adapter->dev, " status = %d\n", status);
103	if (status == STATUS_ADDRESS_NAK)
104	return -EREMOTEIO;
105	}
106
107	return i;
108	}
109
110	static u32 usb_func(struct i2c_adapter *adapter)
111	{
112	u32 func;
113
114	/* get functionality from adapter */
115	if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
116	sizeof(func)) {
117	dev_err(&adapter->dev, "failure reading functionality\n");
118	return 0;
119	}
120
121	return func;
122	}
123
124	/* This is the actual algorithm we define */
125	static const struct i2c_algorithm usb_algorithm = {
126	.master_xfer = usb_xfer,
127	.functionality = usb_func,
128	};
129
130	/* ----- end of i2c layer ------------------------------------------------ */
131
132	/* ----- begin of usb layer ---------------------------------------------- */
133
134	/* The usb i2c interface uses a vid/pid pair donated by */
135	/* Future Technology Devices International Ltd. */
136	static struct usb_device_id i2c_tiny_usb_table [] = {
137	{ USB_DEVICE(0x0403, 0xc631) },
138	{ } /* Terminating entry */
139	};
140
141	MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
142
143	/* Structure to hold all of our device specific stuff */
144	struct i2c_tiny_usb {
145	struct usb_device usb_dev; / the usb device for this device */
146	struct usb_interface interface; / the interface for this device */
147	struct i2c_adapter adapter; /* i2c related things */
148	};
149
150	static int usb_read(struct i2c_adapter *adapter, int cmd,
151	int value, int index, void *data, int len)
152	{
153	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;
154
155	/* do control transfer */
156	return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
157	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE \|
158	USB_DIR_IN, value, index, data, len, 2000);
159	}
160
161	static int usb_write(struct i2c_adapter *adapter, int cmd,
162	int value, int index, void *data, int len)
163	{
164	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;
165
166	/* do control transfer */
167	return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
168	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE,
169	value, index, data, len, 2000);
170	}
171
172	static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
173	{
174	usb_put_dev(dev->usb_dev);
175	kfree(dev);
176	}
177
178	static int i2c_tiny_usb_probe(struct usb_interface *interface,
179	const struct usb_device_id *id)
180	{
181	struct i2c_tiny_usb *dev;
182	int retval = -ENOMEM;
183	u16 version;
184
185	dev_dbg(&interface->dev, "probing usb device\n");
186
187	/* allocate memory for our device state and initialize it */
188	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
189	if (dev == NULL) {
190	dev_err(&interface->dev, "Out of memory\n");
191	goto error;
192	}
193
194	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
195	dev->interface = interface;
196
197	/* save our data pointer in this interface device */
198	usb_set_intfdata(interface, dev);
199
200	version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
201	dev_info(&interface->dev,
202	"version %x.%02x found at bus %03d address %03d\n",
203	version >> 8, version & 0xff,
204	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
205
206	/* setup i2c adapter description */
207	dev->adapter.owner = THIS_MODULE;
208	dev->adapter.class = I2C_CLASS_HWMON;
209	dev->adapter.algo = &usb_algorithm;
210	dev->adapter.algo_data = dev;
6a7ce82f	211	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
e8c76eed TH	212	"i2c-tiny-usb at bus %03d device %03d",
	213	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
	214
	215	if (usb_write(&dev->adapter, CMD_SET_DELAY,
	216	cpu_to_le16(delay), 0, NULL, 0) != 0) {
	217	dev_err(&dev->adapter.dev,
	218	"failure setting delay to %dus\n", delay);
	219	retval = -EIO;
	220	goto error;
	221	}
	222
	223	dev->adapter.dev.parent = &dev->interface->dev;
	224
	225	/* and finally attach to i2c layer */
	226	i2c_add_adapter(&dev->adapter);
	227
	228	/* inform user about successful attachment to i2c layer */
	229	dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
	230
	231	return 0;
	232
	233	error:
	234	if (dev)
	235	i2c_tiny_usb_free(dev);
	236
	237	return retval;
	238	}
	239
	240	static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
	241	{
	242	struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
	243
	244	i2c_del_adapter(&dev->adapter);
	245	usb_set_intfdata(interface, NULL);
	246	i2c_tiny_usb_free(dev);
	247
	248	dev_dbg(&interface->dev, "disconnected\n");
	249	}
	250
	251	static struct usb_driver i2c_tiny_usb_driver = {
	252	.name = "i2c-tiny-usb",
	253	.probe = i2c_tiny_usb_probe,
	254	.disconnect = i2c_tiny_usb_disconnect,
	255	.id_table = i2c_tiny_usb_table,
	256	};
	257
	258	static int __init usb_i2c_tiny_usb_init(void)
	259	{
	260	/* register this driver with the USB subsystem */
	261	return usb_register(&i2c_tiny_usb_driver);
	262	}
	263
	264	static void __exit usb_i2c_tiny_usb_exit(void)
	265	{
	266	/* deregister this driver with the USB subsystem */
	267	usb_deregister(&i2c_tiny_usb_driver);
	268	}
	269
	270	module_init(usb_i2c_tiny_usb_init);
	271	module_exit(usb_i2c_tiny_usb_exit);
	272
	273	/* ----- end of usb layer ------------------------------------------------ */
	274
	275	MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
276	MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
277	MODULE_LICENSE("GPL");