x86/xen: resume timer irqs early
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-tiny-usb.c
blobe7d3b755af3bb3771359fcb4110310a8d6359a90
1 /*
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 */
26 #define CMD_ECHO 0
27 #define CMD_GET_FUNC 1
28 #define CMD_SET_DELAY 2
29 #define CMD_GET_STATUS 3
31 #define CMD_I2C_IO 4
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 ---------------------------------------------- */
51 #define STATUS_IDLE 0
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)
57 unsigned char *pstatus;
58 struct i2c_msg *pmsg;
59 int i, ret;
61 dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
63 pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
64 if (!pstatus)
65 return -ENOMEM;
67 for (i = 0 ; i < num ; i++) {
68 int cmd = CMD_I2C_IO;
70 if (i == 0)
71 cmd |= CMD_I2C_IO_BEGIN;
73 if (i == num-1)
74 cmd |= CMD_I2C_IO_END;
76 pmsg = &msgs[i];
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);
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");
91 ret = -EREMOTEIO;
92 goto out;
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");
101 ret = -EREMOTEIO;
102 goto out;
106 /* read status */
107 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
108 dev_err(&adapter->dev, "failure reading status\n");
109 ret = -EREMOTEIO;
110 goto out;
113 dev_dbg(&adapter->dev, " status = %d\n", *pstatus);
114 if (*pstatus == STATUS_ADDRESS_NAK) {
115 ret = -EREMOTEIO;
116 goto out;
120 ret = i;
121 out:
122 kfree(pstatus);
123 return ret;
126 static u32 usb_func(struct i2c_adapter *adapter)
128 __le32 *pfunc;
129 u32 ret;
131 pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
133 /* get functionality from adapter */
134 if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
135 sizeof(*pfunc)) != sizeof(*pfunc)) {
136 dev_err(&adapter->dev, "failure reading functionality\n");
137 ret = 0;
138 goto out;
141 ret = le32_to_cpup(pfunc);
142 out:
143 kfree(pfunc);
144 return ret;
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,
153 /* ----- end of i2c layer ------------------------------------------------ */
155 /* ----- begin of usb layer ---------------------------------------------- */
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
162 static const struct usb_device_id i2c_tiny_usb_table[] = {
163 { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
164 { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
165 { USB_DEVICE(0x1964, 0x0001) }, /* Robofuzz OSIF */
166 { } /* Terminating entry */
169 MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
171 /* Structure to hold all of our device specific stuff */
172 struct i2c_tiny_usb {
173 struct usb_device *usb_dev; /* the usb device for this device */
174 struct usb_interface *interface; /* the interface for this device */
175 struct i2c_adapter adapter; /* i2c related things */
178 static int usb_read(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;
183 /* do control transfer */
184 return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
185 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
186 USB_DIR_IN, value, index, data, len, 2000);
189 static int usb_write(struct i2c_adapter *adapter, int cmd,
190 int value, int index, void *data, int len)
192 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
194 /* do control transfer */
195 return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
196 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
197 value, index, data, len, 2000);
200 static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
202 usb_put_dev(dev->usb_dev);
203 kfree(dev);
206 static int i2c_tiny_usb_probe(struct usb_interface *interface,
207 const struct usb_device_id *id)
209 struct i2c_tiny_usb *dev;
210 int retval = -ENOMEM;
211 u16 version;
213 dev_dbg(&interface->dev, "probing usb device\n");
215 /* allocate memory for our device state and initialize it */
216 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
217 if (dev == NULL) {
218 dev_err(&interface->dev, "Out of memory\n");
219 goto error;
222 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
223 dev->interface = interface;
225 /* save our data pointer in this interface device */
226 usb_set_intfdata(interface, dev);
228 version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
229 dev_info(&interface->dev,
230 "version %x.%02x found at bus %03d address %03d\n",
231 version >> 8, version & 0xff,
232 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
234 /* setup i2c adapter description */
235 dev->adapter.owner = THIS_MODULE;
236 dev->adapter.class = I2C_CLASS_HWMON;
237 dev->adapter.algo = &usb_algorithm;
238 dev->adapter.algo_data = dev;
239 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
240 "i2c-tiny-usb at bus %03d device %03d",
241 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
243 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
244 dev_err(&dev->adapter.dev,
245 "failure setting delay to %dus\n", delay);
246 retval = -EIO;
247 goto error;
250 dev->adapter.dev.parent = &dev->interface->dev;
252 /* and finally attach to i2c layer */
253 i2c_add_adapter(&dev->adapter);
255 /* inform user about successful attachment to i2c layer */
256 dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
258 return 0;
260 error:
261 if (dev)
262 i2c_tiny_usb_free(dev);
264 return retval;
267 static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
269 struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
271 i2c_del_adapter(&dev->adapter);
272 usb_set_intfdata(interface, NULL);
273 i2c_tiny_usb_free(dev);
275 dev_dbg(&interface->dev, "disconnected\n");
278 static struct usb_driver i2c_tiny_usb_driver = {
279 .name = "i2c-tiny-usb",
280 .probe = i2c_tiny_usb_probe,
281 .disconnect = i2c_tiny_usb_disconnect,
282 .id_table = i2c_tiny_usb_table,
285 module_usb_driver(i2c_tiny_usb_driver);
287 /* ----- end of usb layer ------------------------------------------------ */
289 MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
290 MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
291 MODULE_LICENSE("GPL");