drivers/i2c/busses/i2c-robotfuzz-osif.c

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