summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-robotfuzz-osif.c
blob: 66dfa211e736b1a8a7d0e9392f8dfad95eeac569 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for RobotFuzz OSIF
 *
 * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
 * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
 *
 * Based on the i2c-tiny-usb by
 *
 * Copyright (C) 2006 Til Harbaum (Till@Harbaum.org)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/usb.h>

#define OSIFI2C_READ		20
#define OSIFI2C_WRITE		21
#define OSIFI2C_STOP		22
#define OSIFI2C_STATUS		23
#define OSIFI2C_SET_BIT_RATE	24

#define STATUS_ADDRESS_ACK	0
#define STATUS_ADDRESS_NAK	2

struct osif_priv {
	struct usb_device *usb_dev;
	struct usb_interface *interface;
	struct i2c_adapter adapter;
	unsigned char status;
};

static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
			 int value, int index, void *data, int len)
{
	struct osif_priv *priv = adapter->algo_data;

	return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
			       USB_DIR_IN, value, index, data, len, 2000);
}

static int osif_usb_write(struct i2c_adapter *adapter, int cmd,
			  int value, int index, void *data, int len)
{

	struct osif_priv *priv = adapter->algo_data;

	return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
			       value, index, data, len, 2000);
}

static int osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
			 int num)
{
	struct osif_priv *priv = adapter->algo_data;
	struct i2c_msg *pmsg;
	int ret;
	int i;

	for (i = 0; i < num; i++) {
		pmsg = &msgs[i];

		if (pmsg->flags & I2C_M_RD) {
			ret = osif_usb_read(adapter, OSIFI2C_READ,
					    pmsg->flags, pmsg->addr,
					    pmsg->buf, pmsg->len);
			if (ret != pmsg->len) {
				dev_err(&adapter->dev, "failure reading data\n");
				return -EREMOTEIO;
			}
		} else {
			ret = osif_usb_write(adapter, OSIFI2C_WRITE,
					     pmsg->flags, pmsg->addr,
					     pmsg->buf, pmsg->len);
			if (ret != pmsg->len) {
				dev_err(&adapter->dev, "failure writing data\n");
				return -EREMOTEIO;
			}
		}

		ret = osif_usb_write(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
		if (ret) {
			dev_err(&adapter->dev, "failure sending STOP\n");
			return -EREMOTEIO;
		}

		/* read status */
		ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
				    &priv->status, 1);
		if (ret != 1) {
			dev_err(&adapter->dev, "failure reading status\n");
			return -EREMOTEIO;
		}

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

	return i;
}

static u32 osif_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static const struct i2c_algorithm osif_algorithm = {
	.master_xfer	= osif_xfer,
	.functionality	= osif_func,
};

#define USB_OSIF_VENDOR_ID	0x1964
#define USB_OSIF_PRODUCT_ID	0x0001

static const struct usb_device_id osif_table[] = {
	{ USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
	{ }
};
MODULE_DEVICE_TABLE(usb, osif_table);

static int osif_probe(struct usb_interface *interface,
			     const struct usb_device_id *id)
{
	int ret;
	struct osif_priv *priv;
	u16 version;

	priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
	priv->interface = interface;

	usb_set_intfdata(interface, priv);

	priv->adapter.owner = THIS_MODULE;
	priv->adapter.class = I2C_CLASS_HWMON;
	priv->adapter.algo = &osif_algorithm;
	priv->adapter.algo_data = priv;
	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
		 "OSIF at bus %03d device %03d",
		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);

	/*
	 * Set bus frequency. The frequency is:
	 * 120,000,000 / ( 16 + 2 * div * 4^prescale).
	 * Using dev = 52, prescale = 0 give 100KHz */
	ret = osif_usb_write(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
			    NULL, 0);
	if (ret) {
		dev_err(&interface->dev, "failure sending bit rate");
		usb_put_dev(priv->usb_dev);
		return ret;
	}

	i2c_add_adapter(&(priv->adapter));

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

	return 0;
}

static void osif_disconnect(struct usb_interface *interface)
{
	struct osif_priv *priv = usb_get_intfdata(interface);

	i2c_del_adapter(&(priv->adapter));
	usb_set_intfdata(interface, NULL);
	usb_put_dev(priv->usb_dev);
}

static struct usb_driver osif_driver = {
	.name		= "RobotFuzz Open Source InterFace, OSIF",
	.probe		= osif_probe,
	.disconnect	= osif_disconnect,
	.id_table	= osif_table,
};

module_usb_driver(osif_driver);

MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
MODULE_DESCRIPTION("RobotFuzz OSIF driver");
MODULE_LICENSE("GPL v2");