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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * driver for the i2c-tiny-usb adapter - 1.04 * http://www.harbaum.org/till/i2c_tiny_usb5 *6 * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)7 */8 9#include <linux/kernel.h>10#include <linux/errno.h>11#include <linux/module.h>12#include <linux/slab.h>13#include <linux/types.h>14 15/* include interfaces to usb layer */16#include <linux/usb.h>17 18/* include interface to i2c layer */19#include <linux/i2c.h>20 21/* commands via USB, must match command ids in the firmware */22#define CMD_ECHO 023#define CMD_GET_FUNC 124#define CMD_SET_DELAY 225#define CMD_GET_STATUS 326 27#define CMD_I2C_IO 428#define CMD_I2C_IO_BEGIN (1<<0)29#define CMD_I2C_IO_END (1<<1)30 31/* i2c bit delay, default is 10us -> 100kHz max32 (in practice, due to additional delays in the i2c bitbanging33 code this results in a i2c clock of about 50kHz) */34static unsigned short delay = 10;35module_param(delay, ushort, 0);36MODULE_PARM_DESC(delay, "bit delay in microseconds "37 "(default is 10us for 100kHz max)");38 39static int usb_read(struct i2c_adapter *adapter, int cmd,40 int value, int index, void *data, int len);41 42static int usb_write(struct i2c_adapter *adapter, int cmd,43 int value, int index, void *data, int len);44 45/* ----- begin of i2c layer ---------------------------------------------- */46 47#define STATUS_IDLE 048#define STATUS_ADDRESS_ACK 149#define STATUS_ADDRESS_NAK 250 51static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)52{53 unsigned char *pstatus;54 struct i2c_msg *pmsg;55 int i, ret;56 57 pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);58 if (!pstatus)59 return -ENOMEM;60 61 for (i = 0 ; i < num ; i++) {62 int cmd = CMD_I2C_IO;63 64 if (i == 0)65 cmd |= CMD_I2C_IO_BEGIN;66 67 if (i == num-1)68 cmd |= CMD_I2C_IO_END;69 70 pmsg = &msgs[i];71 72 dev_dbg(&adapter->dev,73 " %d: %s (flags %d) %d bytes to 0x%02x\n",74 i, pmsg->flags & I2C_M_RD ? "read" : "write",75 pmsg->flags, pmsg->len, pmsg->addr);76 77 /* and directly send the message */78 if (pmsg->flags & I2C_M_RD) {79 /* read data */80 if (usb_read(adapter, cmd,81 pmsg->flags, pmsg->addr,82 pmsg->buf, pmsg->len) != pmsg->len) {83 dev_err(&adapter->dev,84 "failure reading data\n");85 ret = -EIO;86 goto out;87 }88 } else {89 /* write data */90 if (usb_write(adapter, cmd,91 pmsg->flags, pmsg->addr,92 pmsg->buf, pmsg->len) != pmsg->len) {93 dev_err(&adapter->dev,94 "failure writing data\n");95 ret = -EIO;96 goto out;97 }98 }99 100 /* read status */101 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {102 dev_err(&adapter->dev, "failure reading status\n");103 ret = -EIO;104 goto out;105 }106 107 dev_dbg(&adapter->dev, " status = %d\n", *pstatus);108 if (*pstatus == STATUS_ADDRESS_NAK) {109 ret = -ENXIO;110 goto out;111 }112 }113 114 ret = i;115out:116 kfree(pstatus);117 return ret;118}119 120static u32 usb_func(struct i2c_adapter *adapter)121{122 __le32 *pfunc;123 u32 ret;124 125 pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);126 127 /* get functionality from adapter */128 if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,129 sizeof(*pfunc)) != sizeof(*pfunc)) {130 dev_err(&adapter->dev, "failure reading functionality\n");131 ret = 0;132 goto out;133 }134 135 ret = le32_to_cpup(pfunc);136out:137 kfree(pfunc);138 return ret;139}140 141/* This is the actual algorithm we define */142static const struct i2c_algorithm usb_algorithm = {143 .xfer = usb_xfer,144 .functionality = usb_func,145};146 147/* ----- end of i2c layer ------------------------------------------------ */148 149/* ----- begin of usb layer ---------------------------------------------- */150 151/*152 * Initially the usb i2c interface uses a vid/pid pair donated by153 * Future Technology Devices International Ltd., later a pair was154 * bought from EZPrototypes155 */156static const struct usb_device_id i2c_tiny_usb_table[] = {157 { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */158 { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */159 { } /* Terminating entry */160};161 162MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);163 164/* Structure to hold all of our device specific stuff */165struct i2c_tiny_usb {166 struct usb_device *usb_dev; /* the usb device for this device */167 struct usb_interface *interface; /* the interface for this device */168 struct i2c_adapter adapter; /* i2c related things */169};170 171static int usb_read(struct i2c_adapter *adapter, int cmd,172 int value, int index, void *data, int len)173{174 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;175 void *dmadata = kmalloc(len, GFP_KERNEL);176 int ret;177 178 if (!dmadata)179 return -ENOMEM;180 181 /* do control transfer */182 ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),183 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |184 USB_DIR_IN, value, index, dmadata, len, 2000);185 186 memcpy(data, dmadata, len);187 kfree(dmadata);188 return ret;189}190 191static int usb_write(struct i2c_adapter *adapter, int cmd,192 int value, int index, void *data, int len)193{194 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;195 void *dmadata = kmemdup(data, len, GFP_KERNEL);196 int ret;197 198 if (!dmadata)199 return -ENOMEM;200 201 /* do control transfer */202 ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),203 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,204 value, index, dmadata, len, 2000);205 206 kfree(dmadata);207 return ret;208}209 210static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)211{212 usb_put_dev(dev->usb_dev);213 kfree(dev);214}215 216static int i2c_tiny_usb_probe(struct usb_interface *interface,217 const struct usb_device_id *id)218{219 struct i2c_tiny_usb *dev;220 int retval = -ENOMEM;221 u16 version;222 223 if (interface->intf_assoc &&224 interface->intf_assoc->bFunctionClass != USB_CLASS_VENDOR_SPEC)225 return -ENODEV;226 227 dev_dbg(&interface->dev, "probing usb device\n");228 229 /* allocate memory for our device state and initialize it */230 dev = kzalloc(sizeof(*dev), GFP_KERNEL);231 if (!dev)232 goto error;233 234 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));235 dev->interface = interface;236 237 /* save our data pointer in this interface device */238 usb_set_intfdata(interface, dev);239 240 version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);241 dev_info(&interface->dev,242 "version %x.%02x found at bus %03d address %03d\n",243 version >> 8, version & 0xff,244 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);245 246 /* setup i2c adapter description */247 dev->adapter.owner = THIS_MODULE;248 dev->adapter.class = I2C_CLASS_HWMON;249 dev->adapter.algo = &usb_algorithm;250 dev->adapter.algo_data = dev;251 snprintf(dev->adapter.name, sizeof(dev->adapter.name),252 "i2c-tiny-usb at bus %03d device %03d",253 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);254 255 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {256 dev_err(&dev->adapter.dev,257 "failure setting delay to %dus\n", delay);258 retval = -EIO;259 goto error;260 }261 262 dev->adapter.dev.parent = &dev->interface->dev;263 264 /* and finally attach to i2c layer */265 i2c_add_adapter(&dev->adapter);266 267 /* inform user about successful attachment to i2c layer */268 dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");269 270 return 0;271 272 error:273 if (dev)274 i2c_tiny_usb_free(dev);275 276 return retval;277}278 279static void i2c_tiny_usb_disconnect(struct usb_interface *interface)280{281 struct i2c_tiny_usb *dev = usb_get_intfdata(interface);282 283 i2c_del_adapter(&dev->adapter);284 usb_set_intfdata(interface, NULL);285 i2c_tiny_usb_free(dev);286 287 dev_dbg(&interface->dev, "disconnected\n");288}289 290static struct usb_driver i2c_tiny_usb_driver = {291 .name = "i2c-tiny-usb",292 .probe = i2c_tiny_usb_probe,293 .disconnect = i2c_tiny_usb_disconnect,294 .id_table = i2c_tiny_usb_table,295};296 297module_usb_driver(i2c_tiny_usb_driver);298 299/* ----- end of usb layer ------------------------------------------------ */300 301MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");302MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");303MODULE_LICENSE("GPL");304