drivers/i2c/busses/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
  29 struct osif_priv {
  30         struct usb_device *usb_dev;
  31         struct usb_interface *interface;
  32         struct i2c_adapter adapter;
  33         unsigned char status;
  34 };
  35
  36 static 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
  46 static 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
  57 static 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
 109 static u32 osif_func(struct i2c_adapter *adapter)
 110 {
 111         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 112 }
 113
 114 static const struct i2c_algorithm osif_algorithm = {
 115         .xfer = osif_xfer,
 116         .functionality = osif_func,
 117 };
 118
 119 #define USB_OSIF_VENDOR_ID      0x1964
 120 #define USB_OSIF_PRODUCT_ID     0x0001
 121
 122 static const struct usb_device_id osif_table[] = {
 123         { USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
 124         { }
 125 };
 126 MODULE_DEVICE_TABLE(usb, osif_table);
 127
 128 static int osif_probe(struct usb_interface *interface,
 129                              const struct usb_device_id *id)
 130 {
 131         int ret;
 132         struct osif_priv *priv;
 133         u16 version;
 134
 135         priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
 136         if (!priv)
 137                 return -ENOMEM;
 138
 139         priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 140         priv->interface = interface;
 141
 142         usb_set_intfdata(interface, priv);
 143
 144         priv->adapter.owner = THIS_MODULE;
 145         priv->adapter.class = I2C_CLASS_HWMON;
 146         priv->adapter.algo = &osif_algorithm;
 147         priv->adapter.algo_data = priv;
 148         snprintf(priv->adapter.name, sizeof(priv->adapter.name),
 149                  "OSIF at bus %03d device %03d",
 150                  priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
 151
 152         /*
 153          * Set bus frequency. The frequency is:
 154          * 120,000,000 / ( 16 + 2 * div * 4^prescale).
 155          * Using dev = 52, prescale = 0 give 100KHz */
 156         ret = osif_usb_write(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
 157                             NULL, 0);
 158         if (ret) {
 159                 dev_err(&interface->dev, "failure sending bit rate");
 160                 usb_put_dev(priv->usb_dev);
 161                 return ret;
 162         }
 163
 164         i2c_add_adapter(&(priv->adapter));
 165
 166         version = le16_to_cpu(priv->usb_dev->descriptor.bcdDevice);
 167         dev_info(&interface->dev,
 168                  "version %x.%02x found at bus %03d address %03d",
 169                  version >> 8, version & 0xff,
 170                  priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
 171
 172         return 0;
 173 }
 174
 175 static void osif_disconnect(struct usb_interface *interface)
 176 {
 177         struct osif_priv *priv = usb_get_intfdata(interface);
 178
 179         i2c_del_adapter(&(priv->adapter));
 180         usb_set_intfdata(interface, NULL);
 181         usb_put_dev(priv->usb_dev);
 182 }
 183
 184 static struct usb_driver osif_driver = {
 185         .name           = "RobotFuzz Open Source InterFace, OSIF",
 186         .probe          = osif_probe,
 187         .disconnect     = osif_disconnect,
 188         .id_table       = osif_table,
 189 };
 190
 191 module_usb_driver(osif_driver);
 192
 193 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 194 MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
 195 MODULE_DESCRIPTION("RobotFuzz OSIF driver");
 196 MODULE_LICENSE("GPL v2");