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 = 0;
  66         int i, cmd;
  67
  68         for (i = 0; ret >= 0 && i < num; i++) {
  69                 pmsg = &msgs[i];
  70
  71                 if (pmsg->flags & I2C_M_RD) {
  72                         cmd = OSIFI2C_READ;
  73
  74                         ret = osif_usb_read(adapter, cmd, pmsg->flags,
  75                                             pmsg->addr, pmsg->buf,
  76                                             pmsg->len);
  77                         if (ret != pmsg->len) {
  78                                 dev_err(&adapter->dev, "failure reading data\n");
  79                                 return -EREMOTEIO;
  80                         }
  81                 } else {
  82                         cmd = OSIFI2C_WRITE;
  83
  84                         ret = osif_usb_write(adapter, cmd, pmsg->flags,
  85                                              pmsg->addr, pmsg->buf, pmsg->len);
  86                         if (ret != pmsg->len) {
  87                                 dev_err(&adapter->dev, "failure writing data\n");
  88                                 return -EREMOTEIO;
  89                         }
  90                 }
  91
  92                 ret = osif_usb_read(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
  93                 if (ret) {
  94                         dev_err(&adapter->dev, "failure sending STOP\n");
  95                         return -EREMOTEIO;
  96                 }
  97
  98                 /* read status */
  99                 ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
 100                                     &priv->status, 1);
 101                 if (ret != 1) {
 102                         dev_err(&adapter->dev, "failure reading status\n");
 103                         return -EREMOTEIO;
 104                 }
 105
 106                 if (priv->status != STATUS_ADDRESS_ACK) {
 107                         dev_dbg(&adapter->dev, "status = %d\n", priv->status);
 108                         return -EREMOTEIO;
 109                 }
 110         }
 111
 112         return i;
 113 }
 114
 115 static u32 osif_func(struct i2c_adapter *adapter)
 116 {
 117         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 118 }
 119
 120 static struct i2c_algorithm osif_algorithm = {
 121         .master_xfer    = osif_xfer,
 122         .functionality  = osif_func,
 123 };
 124
 125 #define USB_OSIF_VENDOR_ID      0x1964
 126 #define USB_OSIF_PRODUCT_ID     0x0001
 127
 128 static const struct usb_device_id osif_table[] = {
 129         { USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
 130         { }
 131 };
 132 MODULE_DEVICE_TABLE(usb, osif_table);
 133
 134 static int osif_probe(struct usb_interface *interface,
 135                              const struct usb_device_id *id)
 136 {
 137         int ret;
 138         struct osif_priv *priv;
 139         u16 version;
 140
 141         priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
 142         if (!priv)
 143                 return -ENOMEM;
 144
 145         priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 146         priv->interface = interface;
 147
 148         usb_set_intfdata(interface, priv);
 149
 150         priv->adapter.owner = THIS_MODULE;
 151         priv->adapter.class = I2C_CLASS_HWMON;
 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_read(&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
 181 static 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
 190 static 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
 197 module_usb_driver(osif_driver);
 198
 199 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 200 MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
 201 MODULE_DESCRIPTION("RobotFuzz OSIF driver");
 202 MODULE_LICENSE("GPL v2");