i2c-robotfuzz-osif.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for RobotFuzz OSIF
  4 *
  5 * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
  6 * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
  7 *
  8 * Based on the i2c-tiny-usb by
  9 *
 10 * Copyright (C) 2006 Til Harbaum (Till@Harbaum.org)
 11 */
 12
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/errno.h>
 16#include <linux/i2c.h>
 17#include <linux/slab.h>
 18#include <linux/usb.h>
 19
 20#define OSIFI2C_READ		20
 21#define OSIFI2C_WRITE		21
 22#define OSIFI2C_STOP		22
 23#define OSIFI2C_STATUS		23
 24#define OSIFI2C_SET_BIT_RATE	24
 25
 26#define STATUS_ADDRESS_ACK	0
 27#define STATUS_ADDRESS_NAK	2
 28
 29struct osif_priv {
 30	struct usb_device *usb_dev;
 31	struct usb_interface *interface;
 32	struct i2c_adapter adapter;
 33	unsigned char status;
 34};
 35
 36static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
 37			 int value, int index, void *data, int len)
 38{
 39	struct osif_priv *priv = adapter->algo_data;
 40
 41	return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
 42			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
 43			       USB_DIR_IN, value, index, data, len, 2000);
 44}
 45
 46static int osif_usb_write(struct i2c_adapter *adapter, int cmd,
 47			  int value, int index, void *data, int len)
 48{
 49
 50	struct osif_priv *priv = adapter->algo_data;
 51
 52	return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
 53			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
 54			       value, index, data, len, 2000);
 55}
 56
 57static int osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 58			 int num)
 59{
 60	struct osif_priv *priv = adapter->algo_data;
 61	struct i2c_msg *pmsg;
 62	int ret;
 63	int i;
 64
 65	for (i = 0; i < num; i++) {
 66		pmsg = &msgs[i];
 67
 68		if (pmsg->flags & I2C_M_RD) {
 69			ret = osif_usb_read(adapter, OSIFI2C_READ,
 70					    pmsg->flags, pmsg->addr,
 71					    pmsg->buf, pmsg->len);
 72			if (ret != pmsg->len) {
 73				dev_err(&adapter->dev, "failure reading data\n");
 74				return -EREMOTEIO;
 75			}
 76		} else {
 77			ret = osif_usb_write(adapter, OSIFI2C_WRITE,
 78					     pmsg->flags, pmsg->addr,
 79					     pmsg->buf, pmsg->len);
 80			if (ret != pmsg->len) {
 81				dev_err(&adapter->dev, "failure writing data\n");
 82				return -EREMOTEIO;
 83			}
 84		}
 85
 86		ret = osif_usb_write(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
 87		if (ret) {
 88			dev_err(&adapter->dev, "failure sending STOP\n");
 89			return -EREMOTEIO;
 90		}
 91
 92		/* read status */
 93		ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
 94				    &priv->status, 1);
 95		if (ret != 1) {
 96			dev_err(&adapter->dev, "failure reading status\n");
 97			return -EREMOTEIO;
 98		}
 99
100		if (priv->status != STATUS_ADDRESS_ACK) {
101			dev_dbg(&adapter->dev, "status = %d\n", priv->status);
102			return -EREMOTEIO;
103		}
104	}
105
106	return i;
107}
108
109static u32 osif_func(struct i2c_adapter *adapter)
110{
111	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
112}
113
114/* prevent invalid 0-length usb_control_msg */
115static const struct i2c_adapter_quirks osif_quirks = {
116	.flags = I2C_AQ_NO_ZERO_LEN_READ,
117};
118
119static const struct i2c_algorithm osif_algorithm = {
120	.xfer = osif_xfer,
121	.functionality = osif_func,
122};
123
124#define USB_OSIF_VENDOR_ID	0x1964
125#define USB_OSIF_PRODUCT_ID	0x0001
126
127static const struct usb_device_id osif_table[] = {
128	{ USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
129	{ }
130};
131MODULE_DEVICE_TABLE(usb, osif_table);
132
133static int osif_probe(struct usb_interface *interface,
134			     const struct usb_device_id *id)
135{
136	int ret;
137	struct osif_priv *priv;
138	u16 version;
139
140	priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
141	if (!priv)
142		return -ENOMEM;
143
144	priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
145	priv->interface = interface;
146
147	usb_set_intfdata(interface, priv);
148
149	priv->adapter.owner = THIS_MODULE;
150	priv->adapter.class = I2C_CLASS_HWMON;
151	priv->adapter.quirks = &osif_quirks;
152	priv->adapter.algo = &osif_algorithm;
153	priv->adapter.algo_data = priv;
154	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
155		 "OSIF at bus %03d device %03d",
156		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
157
158	/*
159	 * Set bus frequency. The frequency is:
160	 * 120,000,000 / ( 16 + 2 * div * 4^prescale).
161	 * Using dev = 52, prescale = 0 give 100KHz */
162	ret = osif_usb_write(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
163			    NULL, 0);
164	if (ret) {
165		dev_err(&interface->dev, "failure sending bit rate");
166		usb_put_dev(priv->usb_dev);
167		return ret;
168	}
169
170	i2c_add_adapter(&(priv->adapter));
171
172	version = le16_to_cpu(priv->usb_dev->descriptor.bcdDevice);
173	dev_info(&interface->dev,
174		 "version %x.%02x found at bus %03d address %03d",
175		 version >> 8, version & 0xff,
176		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
177
178	return 0;
179}
180
181static void osif_disconnect(struct usb_interface *interface)
182{
183	struct osif_priv *priv = usb_get_intfdata(interface);
184
185	i2c_del_adapter(&(priv->adapter));
186	usb_set_intfdata(interface, NULL);
187	usb_put_dev(priv->usb_dev);
188}
189
190static struct usb_driver osif_driver = {
191	.name		= "RobotFuzz Open Source InterFace, OSIF",
192	.probe		= osif_probe,
193	.disconnect	= osif_disconnect,
194	.id_table	= osif_table,
195};
196
197module_usb_driver(osif_driver);
198
199MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
200MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
201MODULE_DESCRIPTION("RobotFuzz OSIF driver");
202MODULE_LICENSE("GPL v2");