i2c/busses/i2c-robotfuzz-osif.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Driver for RobotFuzz OSIF
0004  *
0005  * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
0006  * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
0007  *
0008  * Based on the i2c-tiny-usb by
0009  *
0010  * Copyright (C) 2006 Til Harbaum (Till@Harbaum.org)
0011  */
0012
0013 #include <linux/kernel.h>
0014 #include <linux/module.h>
0015 #include <linux/errno.h>
0016 #include <linux/i2c.h>
0017 #include <linux/slab.h>
0018 #include <linux/usb.h>
0019
0020 #define OSIFI2C_READ        20
0021 #define OSIFI2C_WRITE       21
0022 #define OSIFI2C_STOP        22
0023 #define OSIFI2C_STATUS      23
0024 #define OSIFI2C_SET_BIT_RATE    24
0025
0026 #define STATUS_ADDRESS_ACK  0
0027 #define STATUS_ADDRESS_NAK  2
0028
0029 struct osif_priv {
0030     struct usb_device *usb_dev;
0031     struct usb_interface *interface;
0032     struct i2c_adapter adapter;
0033     unsigned char status;
0034 };
0035
0036 static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
0037              int value, int index, void *data, int len)
0038 {
0039     struct osif_priv *priv = adapter->algo_data;
0040
0041     return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
0042                    cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
0043                    USB_DIR_IN, value, index, data, len, 2000);
0044 }
0045
0046 static int osif_usb_write(struct i2c_adapter *adapter, int cmd,
0047               int value, int index, void *data, int len)
0048 {
0049
0050     struct osif_priv *priv = adapter->algo_data;
0051
0052     return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
0053                    cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
0054                    value, index, data, len, 2000);
0055 }
0056
0057 static int osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
0058              int num)
0059 {
0060     struct osif_priv *priv = adapter->algo_data;
0061     struct i2c_msg *pmsg;
0062     int ret;
0063     int i;
0064
0065     for (i = 0; i < num; i++) {
0066         pmsg = &msgs[i];
0067
0068         if (pmsg->flags & I2C_M_RD) {
0069             ret = osif_usb_read(adapter, OSIFI2C_READ,
0070                         pmsg->flags, pmsg->addr,
0071                         pmsg->buf, pmsg->len);
0072             if (ret != pmsg->len) {
0073                 dev_err(&adapter->dev, "failure reading data\n");
0074                 return -EREMOTEIO;
0075             }
0076         } else {
0077             ret = osif_usb_write(adapter, OSIFI2C_WRITE,
0078                          pmsg->flags, pmsg->addr,
0079                          pmsg->buf, pmsg->len);
0080             if (ret != pmsg->len) {
0081                 dev_err(&adapter->dev, "failure writing data\n");
0082                 return -EREMOTEIO;
0083             }
0084         }
0085
0086         ret = osif_usb_write(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
0087         if (ret) {
0088             dev_err(&adapter->dev, "failure sending STOP\n");
0089             return -EREMOTEIO;
0090         }
0091
0092         /* read status */
0093         ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
0094                     &priv->status, 1);
0095         if (ret != 1) {
0096             dev_err(&adapter->dev, "failure reading status\n");
0097             return -EREMOTEIO;
0098         }
0099
0100         if (priv->status != STATUS_ADDRESS_ACK) {
0101             dev_dbg(&adapter->dev, "status = %d\n", priv->status);
0102             return -EREMOTEIO;
0103         }
0104     }
0105
0106     return i;
0107 }
0108
0109 static u32 osif_func(struct i2c_adapter *adapter)
0110 {
0111     return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
0112 }
0113
0114 static const struct i2c_algorithm osif_algorithm = {
0115     .master_xfer    = osif_xfer,
0116     .functionality  = osif_func,
0117 };
0118
0119 #define USB_OSIF_VENDOR_ID  0x1964
0120 #define USB_OSIF_PRODUCT_ID 0x0001
0121
0122 static const struct usb_device_id osif_table[] = {
0123     { USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
0124     { }
0125 };
0126 MODULE_DEVICE_TABLE(usb, osif_table);
0127
0128 static int osif_probe(struct usb_interface *interface,
0129                  const struct usb_device_id *id)
0130 {
0131     int ret;
0132     struct osif_priv *priv;
0133     u16 version;
0134
0135     priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
0136     if (!priv)
0137         return -ENOMEM;
0138
0139     priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
0140     priv->interface = interface;
0141
0142     usb_set_intfdata(interface, priv);
0143
0144     priv->adapter.owner = THIS_MODULE;
0145     priv->adapter.class = I2C_CLASS_HWMON;
0146     priv->adapter.algo = &osif_algorithm;
0147     priv->adapter.algo_data = priv;
0148     snprintf(priv->adapter.name, sizeof(priv->adapter.name),
0149          "OSIF at bus %03d device %03d",
0150          priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
0151
0152     /*
0153      * Set bus frequency. The frequency is:
0154      * 120,000,000 / ( 16 + 2 * div * 4^prescale).
0155      * Using dev = 52, prescale = 0 give 100KHz */
0156     ret = osif_usb_write(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
0157                 NULL, 0);
0158     if (ret) {
0159         dev_err(&interface->dev, "failure sending bit rate");
0160         usb_put_dev(priv->usb_dev);
0161         return ret;
0162     }
0163
0164     i2c_add_adapter(&(priv->adapter));
0165
0166     version = le16_to_cpu(priv->usb_dev->descriptor.bcdDevice);
0167     dev_info(&interface->dev,
0168          "version %x.%02x found at bus %03d address %03d",
0169          version >> 8, version & 0xff,
0170          priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
0171
0172     return 0;
0173 }
0174
0175 static void osif_disconnect(struct usb_interface *interface)
0176 {
0177     struct osif_priv *priv = usb_get_intfdata(interface);
0178
0179     i2c_del_adapter(&(priv->adapter));
0180     usb_set_intfdata(interface, NULL);
0181     usb_put_dev(priv->usb_dev);
0182 }
0183
0184 static struct usb_driver osif_driver = {
0185     .name       = "RobotFuzz Open Source InterFace, OSIF",
0186     .probe      = osif_probe,
0187     .disconnect = osif_disconnect,
0188     .id_table   = osif_table,
0189 };
0190
0191 module_usb_driver(osif_driver);
0192
0193 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
0194 MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
0195 MODULE_DESCRIPTION("RobotFuzz OSIF driver");
0196 MODULE_LICENSE("GPL v2");