2 * driver for the i2c-tiny-usb adapter - 1.0
3 * http://www.harbaum.org/till/i2c_tiny_usb
5 * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
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.
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
19 /* include interfaces to usb layer */
20 #include <linux/usb.h>
22 /* include interface to i2c layer */
23 #include <linux/i2c.h>
25 /* commands via USB, must match command ids in the firmware */
27 #define CMD_GET_FUNC 1
28 #define CMD_SET_DELAY 2
29 #define CMD_GET_STATUS 3
32 #define CMD_I2C_IO_BEGIN (1<<0)
33 #define CMD_I2C_IO_END (1<<1)
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) */
38 static unsigned short delay = 10;
39 module_param(delay, ushort, 0);
40 MODULE_PARM_DESC(delay, "bit delay in microseconds "
41 "(default is 10us for 100kHz max)");
43 static int usb_read(struct i2c_adapter *adapter, int cmd,
44 int value, int index, void *data, int len);
46 static int usb_write(struct i2c_adapter *adapter, int cmd,
47 int value, int index, void *data, int len);
49 /* ----- begin of i2c layer ---------------------------------------------- */
52 #define STATUS_ADDRESS_ACK 1
53 #define STATUS_ADDRESS_NAK 2
55 static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
61 dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
63 for (i = 0 ; i < num ; i++) {
67 cmd |= CMD_I2C_IO_BEGIN;
70 cmd |= CMD_I2C_IO_END;
74 dev_dbg(&adapter->dev,
75 " %d: %s (flags %d) %d bytes to 0x%02x\n",
76 i, pmsg->flags & I2C_M_RD ? "read" : "write",
77 pmsg->flags, pmsg->len, pmsg->addr);
79 /* and directly send the message */
80 if (pmsg->flags & I2C_M_RD) {
82 if (usb_read(adapter, cmd,
83 pmsg->flags, pmsg->addr,
84 pmsg->buf, pmsg->len) != pmsg->len) {
85 dev_err(&adapter->dev,
86 "failure reading data\n");
91 if (usb_write(adapter, cmd,
92 pmsg->flags, pmsg->addr,
93 pmsg->buf, pmsg->len) != pmsg->len) {
94 dev_err(&adapter->dev,
95 "failure writing data\n");
101 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
102 dev_err(&adapter->dev, "failure reading status\n");
106 dev_dbg(&adapter->dev, " status = %d\n", status);
107 if (status == STATUS_ADDRESS_NAK)
114 static u32 usb_func(struct i2c_adapter *adapter)
118 /* get functionality from adapter */
119 if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
121 dev_err(&adapter->dev, "failure reading functionality\n");
125 return le32_to_cpu(func);
128 /* This is the actual algorithm we define */
129 static const struct i2c_algorithm usb_algorithm = {
130 .master_xfer = usb_xfer,
131 .functionality = usb_func,
134 /* ----- end of i2c layer ------------------------------------------------ */
136 /* ----- begin of usb layer ---------------------------------------------- */
139 * Initially the usb i2c interface uses a vid/pid pair donated by
140 * Future Technology Devices International Ltd., later a pair was
141 * bought from EZPrototypes
143 static const struct usb_device_id i2c_tiny_usb_table[] = {
144 { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
145 { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
146 { } /* Terminating entry */
149 MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
151 /* Structure to hold all of our device specific stuff */
152 struct i2c_tiny_usb {
153 struct usb_device *usb_dev; /* the usb device for this device */
154 struct usb_interface *interface; /* the interface for this device */
155 struct i2c_adapter adapter; /* i2c related things */
158 static int usb_read(struct i2c_adapter *adapter, int cmd,
159 int value, int index, void *data, int len)
161 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
162 void *dmadata = kmalloc(len, GFP_KERNEL);
168 /* do control transfer */
169 ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
170 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
171 USB_DIR_IN, value, index, dmadata, len, 2000);
173 memcpy(data, dmadata, len);
178 static int usb_write(struct i2c_adapter *adapter, int cmd,
179 int value, int index, void *data, int len)
181 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
182 void *dmadata = kmemdup(data, len, GFP_KERNEL);
188 /* do control transfer */
189 ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
190 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
191 value, index, dmadata, len, 2000);
197 static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
199 usb_put_dev(dev->usb_dev);
203 static int i2c_tiny_usb_probe(struct usb_interface *interface,
204 const struct usb_device_id *id)
206 struct i2c_tiny_usb *dev;
207 int retval = -ENOMEM;
210 dev_dbg(&interface->dev, "probing usb device\n");
212 /* allocate memory for our device state and initialize it */
213 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
215 dev_err(&interface->dev, "Out of memory\n");
219 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
220 dev->interface = interface;
222 /* save our data pointer in this interface device */
223 usb_set_intfdata(interface, dev);
225 version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
226 dev_info(&interface->dev,
227 "version %x.%02x found at bus %03d address %03d\n",
228 version >> 8, version & 0xff,
229 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
231 /* setup i2c adapter description */
232 dev->adapter.owner = THIS_MODULE;
233 dev->adapter.class = I2C_CLASS_HWMON;
234 dev->adapter.algo = &usb_algorithm;
235 dev->adapter.algo_data = dev;
236 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
237 "i2c-tiny-usb at bus %03d device %03d",
238 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
240 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
241 dev_err(&dev->adapter.dev,
242 "failure setting delay to %dus\n", delay);
247 dev->adapter.dev.parent = &dev->interface->dev;
249 /* and finally attach to i2c layer */
250 i2c_add_adapter(&dev->adapter);
252 /* inform user about successful attachment to i2c layer */
253 dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
259 i2c_tiny_usb_free(dev);
264 static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
266 struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
268 i2c_del_adapter(&dev->adapter);
269 usb_set_intfdata(interface, NULL);
270 i2c_tiny_usb_free(dev);
272 dev_dbg(&interface->dev, "disconnected\n");
275 static struct usb_driver i2c_tiny_usb_driver = {
276 .name = "i2c-tiny-usb",
277 .probe = i2c_tiny_usb_probe,
278 .disconnect = i2c_tiny_usb_disconnect,
279 .id_table = i2c_tiny_usb_table,
282 static int __init usb_i2c_tiny_usb_init(void)
284 /* register this driver with the USB subsystem */
285 return usb_register(&i2c_tiny_usb_driver);
288 static void __exit usb_i2c_tiny_usb_exit(void)
290 /* deregister this driver with the USB subsystem */
291 usb_deregister(&i2c_tiny_usb_driver);
294 module_init(usb_i2c_tiny_usb_init);
295 module_exit(usb_i2c_tiny_usb_exit);
297 /* ----- end of usb layer ------------------------------------------------ */
299 MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
300 MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
301 MODULE_LICENSE("GPL");