[mirror_ubuntu-artful-kernel.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 <linux/slab.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 *pstatus;
	struct i2c_msg *pmsg;
	int i, ret;

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

	pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
	if (!pstatus)
		return -ENOMEM;

	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");
				ret = -EREMOTEIO;
				goto out;
			}
		} 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");
				ret = -EREMOTEIO;
				goto out;
			}
		}

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

		dev_dbg(&adapter->dev, "  status = %d\n", *pstatus);
		if (*pstatus == STATUS_ADDRESS_NAK) {
			ret = -EREMOTEIO;
			goto out;
		}
	}

	ret = i;
out:
	kfree(pstatus);
	return ret;
}

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

	pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);

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

	ret = le32_to_cpup(pfunc);
out:
	kfree(pfunc);
	return ret;
}

/* 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;
	void *dmadata = kmalloc(len, GFP_KERNEL);
	int ret;

	if (!dmadata)
		return -ENOMEM;

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

	memcpy(data, dmadata, len);
	kfree(dmadata);
	return ret;
}

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;
	void *dmadata = kmemdup(data, len, GFP_KERNEL);
	int ret;

	if (!dmadata)
		return -ENOMEM;

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

	kfree(dmadata);
	return ret;
}

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,
};

module_usb_driver(i2c_tiny_usb_driver);

/* ----- 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>
5a0e3ad6	16	#include <linux/slab.h>
1c010ff8	17	#include <linux/types.h>
e8c76eed TH	18
	19	/* include interfaces to usb layer */
	20	#include <linux/usb.h>
	21
	22	/* include interface to i2c layer */
	23	#include <linux/i2c.h>
	24
	25	/* commands via USB, must match command ids in the firmware */
	26	#define CMD_ECHO 0
	27	#define CMD_GET_FUNC 1
	28	#define CMD_SET_DELAY 2
	29	#define CMD_GET_STATUS 3
	30
	31	#define CMD_I2C_IO 4
	32	#define CMD_I2C_IO_BEGIN (1<<0)
	33	#define CMD_I2C_IO_END (1<<1)
	34
c05d4902 JD	35	/* i2c bit delay, default is 10us -> 100kHz max
	36	(in practice, due to additional delays in the i2c bitbanging
	37	code this results in a i2c clock of about 50kHz) */
1c010ff8 JD	38	static unsigned short delay = 10;
1c010ff8 JD	39	module_param(delay, ushort, 0);
c05d4902 JD	40	MODULE_PARM_DESC(delay, "bit delay in microseconds "
c05d4902 JD	41	"(default is 10us for 100kHz max)");
e8c76eed TH	42
	43	static int usb_read(struct i2c_adapter *adapter, int cmd,
	44	int value, int index, void *data, int len);
	45
	46	static int usb_write(struct i2c_adapter *adapter, int cmd,
	47	int value, int index, void *data, int len);
	48
	49	/* ----- begin of i2c layer ---------------------------------------------- */
	50
	51	#define STATUS_IDLE 0
	52	#define STATUS_ADDRESS_ACK 1
	53	#define STATUS_ADDRESS_NAK 2
	54
	55	static int usb_xfer(struct i2c_adapter adapter, struct i2c_msg msgs, int num)
	56	{
243ec090	57	unsigned char *pstatus;
e8c76eed	58	struct i2c_msg *pmsg;
243ec090	59	int i, ret;
e8c76eed TH	60
	61	dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
	62
243ec090 JK	63	pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
	64	if (!pstatus)
	65	return -ENOMEM;
	66
e8c76eed TH	67	for (i = 0 ; i < num ; i++) {
	68	int cmd = CMD_I2C_IO;
	69
	70	if (i == 0)
	71	cmd \|= CMD_I2C_IO_BEGIN;
	72
	73	if (i == num-1)
	74	cmd \|= CMD_I2C_IO_END;
	75
	76	pmsg = &msgs[i];
	77
	78	dev_dbg(&adapter->dev,
	79	" %d: %s (flags %d) %d bytes to 0x%02x\n",
	80	i, pmsg->flags & I2C_M_RD ? "read" : "write",
	81	pmsg->flags, pmsg->len, pmsg->addr);
	82
	83	/* and directly send the message */
	84	if (pmsg->flags & I2C_M_RD) {
	85	/* read data */
	86	if (usb_read(adapter, cmd,
	87	pmsg->flags, pmsg->addr,
	88	pmsg->buf, pmsg->len) != pmsg->len) {
	89	dev_err(&adapter->dev,
	90	"failure reading data\n");
243ec090 JK	91	ret = -EREMOTEIO;
243ec090 JK	92	goto out;
e8c76eed TH	93	}
	94	} else {
	95	/* write data */
	96	if (usb_write(adapter, cmd,
	97	pmsg->flags, pmsg->addr,
	98	pmsg->buf, pmsg->len) != pmsg->len) {
	99	dev_err(&adapter->dev,
	100	"failure writing data\n");
243ec090 JK	101	ret = -EREMOTEIO;
243ec090 JK	102	goto out;
e8c76eed TH	103	}
	104	}
	105
	106	/* read status */
243ec090	107	if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
e8c76eed	108	dev_err(&adapter->dev, "failure reading status\n");
243ec090 JK	109	ret = -EREMOTEIO;
243ec090 JK	110	goto out;
e8c76eed TH	111	}
e8c76eed TH	112
243ec090 JK	113	dev_dbg(&adapter->dev, " status = %d\n", *pstatus);
	114	if (*pstatus == STATUS_ADDRESS_NAK) {
	115	ret = -EREMOTEIO;
	116	goto out;
	117	}
e8c76eed TH	118	}
e8c76eed TH	119
243ec090 JK	120	ret = i;
	121	out:
	122	kfree(pstatus);
	123	return ret;
e8c76eed TH	124	}
	125
	126	static u32 usb_func(struct i2c_adapter *adapter)
	127	{
243ec090 JK	128	__le32 *pfunc;
	129	u32 ret;
	130
	131	pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
e8c76eed TH	132
e8c76eed TH	133	/* get functionality from adapter */
243ec090 JK	134	if (!pfunc \|\| usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
243ec090 JK	135	sizeof(pfunc)) != sizeof(pfunc)) {
e8c76eed	136	dev_err(&adapter->dev, "failure reading functionality\n");
243ec090 JK	137	ret = 0;
243ec090 JK	138	goto out;
e8c76eed TH	139	}
e8c76eed TH	140
243ec090 JK	141	ret = le32_to_cpup(pfunc);
	142	out:
	143	kfree(pfunc);
	144	return ret;
e8c76eed TH	145	}
	146
	147	/* This is the actual algorithm we define */
	148	static const struct i2c_algorithm usb_algorithm = {
	149	.master_xfer = usb_xfer,
	150	.functionality = usb_func,
	151	};
	152
	153	/* ----- end of i2c layer ------------------------------------------------ */
	154
	155	/* ----- begin of usb layer ---------------------------------------------- */
	156
fa16eefd TH	157	/*
	158	* Initially the usb i2c interface uses a vid/pid pair donated by
	159	* Future Technology Devices International Ltd., later a pair was
	160	* bought from EZPrototypes
	161	*/
4111ecd2	162	static const struct usb_device_id i2c_tiny_usb_table[] = {
fa16eefd TH	163	{ USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
	164	{ USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
	165	{ } /* Terminating entry */
e8c76eed TH	166	};
	167
	168	MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
	169
	170	/* Structure to hold all of our device specific stuff */
	171	struct i2c_tiny_usb {
	172	struct usb_device usb_dev; / the usb device for this device */
	173	struct usb_interface interface; / the interface for this device */
	174	struct i2c_adapter adapter; /* i2c related things */
	175	};
	176
	177	static int usb_read(struct i2c_adapter *adapter, int cmd,
	178	int value, int index, void *data, int len)
	179	{
	180	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;
5165da59 SR	181	void *dmadata = kmalloc(len, GFP_KERNEL);
	182	int ret;
	183
	184	if (!dmadata)
	185	return -ENOMEM;
e8c76eed TH	186
e8c76eed TH	187	/* do control transfer */
5165da59	188	ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
e8c76eed	189	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE \|
5165da59 SR	190	USB_DIR_IN, value, index, dmadata, len, 2000);
	191
	192	memcpy(data, dmadata, len);
	193	kfree(dmadata);
	194	return ret;
e8c76eed TH	195	}
	196
	197	static int usb_write(struct i2c_adapter *adapter, int cmd,
	198	int value, int index, void *data, int len)
	199	{
	200	struct i2c_tiny_usb dev = (struct i2c_tiny_usb )adapter->algo_data;
5165da59 SR	201	void *dmadata = kmemdup(data, len, GFP_KERNEL);
	202	int ret;
	203
	204	if (!dmadata)
	205	return -ENOMEM;
e8c76eed TH	206
e8c76eed TH	207	/* do control transfer */
5165da59	208	ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
e8c76eed	209	cmd, USB_TYPE_VENDOR \| USB_RECIP_INTERFACE,
5165da59 SR	210	value, index, dmadata, len, 2000);
	211
	212	kfree(dmadata);
	213	return ret;
e8c76eed TH	214	}
	215
	216	static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
	217	{
	218	usb_put_dev(dev->usb_dev);
	219	kfree(dev);
	220	}
	221
	222	static int i2c_tiny_usb_probe(struct usb_interface *interface,
	223	const struct usb_device_id *id)
	224	{
	225	struct i2c_tiny_usb *dev;
	226	int retval = -ENOMEM;
	227	u16 version;
	228
	229	dev_dbg(&interface->dev, "probing usb device\n");
	230
	231	/* allocate memory for our device state and initialize it */
	232	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	233	if (dev == NULL) {
	234	dev_err(&interface->dev, "Out of memory\n");
	235	goto error;
	236	}
	237
	238	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
	239	dev->interface = interface;
	240
	241	/* save our data pointer in this interface device */
	242	usb_set_intfdata(interface, dev);
	243
	244	version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
	245	dev_info(&interface->dev,
	246	"version %x.%02x found at bus %03d address %03d\n",
	247	version >> 8, version & 0xff,
	248	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
	249
	250	/* setup i2c adapter description */
	251	dev->adapter.owner = THIS_MODULE;
	252	dev->adapter.class = I2C_CLASS_HWMON;
	253	dev->adapter.algo = &usb_algorithm;
	254	dev->adapter.algo_data = dev;
6a7ce82f	255	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
e8c76eed TH	256	"i2c-tiny-usb at bus %03d device %03d",
	257	dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
	258
1c010ff8	259	if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
e8c76eed TH	260	dev_err(&dev->adapter.dev,
	261	"failure setting delay to %dus\n", delay);
	262	retval = -EIO;
	263	goto error;
	264	}
	265
	266	dev->adapter.dev.parent = &dev->interface->dev;
	267
	268	/* and finally attach to i2c layer */
	269	i2c_add_adapter(&dev->adapter);
	270
	271	/* inform user about successful attachment to i2c layer */
	272	dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
	273
	274	return 0;
	275
	276	error:
	277	if (dev)
	278	i2c_tiny_usb_free(dev);
	279
	280	return retval;
	281	}
	282
	283	static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
	284	{
	285	struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
	286
	287	i2c_del_adapter(&dev->adapter);
	288	usb_set_intfdata(interface, NULL);
	289	i2c_tiny_usb_free(dev);
	290
	291	dev_dbg(&interface->dev, "disconnected\n");
	292	}
	293
	294	static struct usb_driver i2c_tiny_usb_driver = {
	295	.name = "i2c-tiny-usb",
	296	.probe = i2c_tiny_usb_probe,
	297	.disconnect = i2c_tiny_usb_disconnect,
	298	.id_table = i2c_tiny_usb_table,
	299	};
	300
fe748483	301	module_usb_driver(i2c_tiny_usb_driver);
e8c76eed TH	302
	303	/* ----- end of usb layer ------------------------------------------------ */
	304
	305	MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
	306	MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
	307	MODULE_LICENSE("GPL");