diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-tiny-usb.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-tiny-usb.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-tiny-usb.c b/drivers/i2c/busses/i2c-tiny-usb.c new file mode 100644 index 0000000..b1c050f --- /dev/null +++ b/drivers/i2c/busses/i2c-tiny-usb.c @@ -0,0 +1,281 @@ +/* + * driver for the i2c-tiny-usb adapter - 1.0 + * http://www.harbaum.org/till/i2c_tiny_usb + * + * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2. + * + */ + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/module.h> + +/* include interfaces to usb layer */ +#include <linux/usb.h> + +/* include interface to i2c layer */ +#include <linux/i2c.h> + +/* commands via USB, must match command ids in the firmware */ +#define CMD_ECHO 0 +#define CMD_GET_FUNC 1 +#define CMD_SET_DELAY 2 +#define CMD_GET_STATUS 3 + +#define CMD_I2C_IO 4 +#define CMD_I2C_IO_BEGIN (1<<0) +#define CMD_I2C_IO_END (1<<1) + +/* i2c bit delay, default is 10us -> 100kHz */ +static int delay = 10; +module_param(delay, int, 0); +MODULE_PARM_DESC(delay, "bit delay in microseconds, " + "e.g. 10 for 100kHz (default is 100kHz)"); + +static int usb_read(struct i2c_adapter *adapter, int cmd, + int value, int index, void *data, int len); + +static int usb_write(struct i2c_adapter *adapter, int cmd, + int value, int index, void *data, int len); + +/* ----- begin of i2c layer ---------------------------------------------- */ + +#define STATUS_IDLE 0 +#define STATUS_ADDRESS_ACK 1 +#define STATUS_ADDRESS_NAK 2 + +static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) +{ + unsigned char status; + struct i2c_msg *pmsg; + int i; + + dev_dbg(&adapter->dev, "master xfer %d messages:\n", num); + + for (i = 0 ; i < num ; i++) { + int cmd = CMD_I2C_IO; + + if (i == 0) + cmd |= CMD_I2C_IO_BEGIN; + + if (i == num-1) + cmd |= CMD_I2C_IO_END; + + pmsg = &msgs[i]; + + dev_dbg(&adapter->dev, + " %d: %s (flags %d) %d bytes to 0x%02x\n", + i, pmsg->flags & I2C_M_RD ? "read" : "write", + pmsg->flags, pmsg->len, pmsg->addr); + + /* and directly send the message */ + if (pmsg->flags & I2C_M_RD) { + /* read data */ + if (usb_read(adapter, cmd, + pmsg->flags, pmsg->addr, + pmsg->buf, pmsg->len) != pmsg->len) { + dev_err(&adapter->dev, + "failure reading data\n"); + return -EREMOTEIO; + } + } else { + /* write data */ + if (usb_write(adapter, cmd, + pmsg->flags, pmsg->addr, + pmsg->buf, pmsg->len) != pmsg->len) { + dev_err(&adapter->dev, + "failure writing data\n"); + return -EREMOTEIO; + } + } + + /* read status */ + if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) { + dev_err(&adapter->dev, "failure reading status\n"); + return -EREMOTEIO; + } + + dev_dbg(&adapter->dev, " status = %d\n", status); + if (status == STATUS_ADDRESS_NAK) + return -EREMOTEIO; + } + + return i; +} + +static u32 usb_func(struct i2c_adapter *adapter) +{ + u32 func; + + /* get functionality from adapter */ + if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) != + sizeof(func)) { + dev_err(&adapter->dev, "failure reading functionality\n"); + return 0; + } + + return func; +} + +/* This is the actual algorithm we define */ +static const struct i2c_algorithm usb_algorithm = { + .master_xfer = usb_xfer, + .functionality = usb_func, +}; + +/* ----- end of i2c layer ------------------------------------------------ */ + +/* ----- begin of usb layer ---------------------------------------------- */ + +/* + * Initially the usb i2c interface uses a vid/pid pair donated by + * Future Technology Devices International Ltd., later a pair was + * bought from EZPrototypes + */ +static struct usb_device_id i2c_tiny_usb_table [] = { + { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */ + { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */ + { } /* Terminating entry */ +}; + +MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table); + +/* Structure to hold all of our device specific stuff */ +struct i2c_tiny_usb { + struct usb_device *usb_dev; /* the usb device for this device */ + struct usb_interface *interface; /* the interface for this device */ + struct i2c_adapter adapter; /* i2c related things */ +}; + +static int usb_read(struct i2c_adapter *adapter, int cmd, + int value, int index, void *data, int len) +{ + struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; + + /* do control transfer */ + return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), + cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | + USB_DIR_IN, value, index, data, len, 2000); +} + +static int usb_write(struct i2c_adapter *adapter, int cmd, + int value, int index, void *data, int len) +{ + struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; + + /* do control transfer */ + return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), + cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, + value, index, data, len, 2000); +} + +static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev) +{ + usb_put_dev(dev->usb_dev); + kfree(dev); +} + +static int i2c_tiny_usb_probe(struct usb_interface *interface, + const struct usb_device_id *id) +{ + struct i2c_tiny_usb *dev; + int retval = -ENOMEM; + u16 version; + + dev_dbg(&interface->dev, "probing usb device\n"); + + /* allocate memory for our device state and initialize it */ + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (dev == NULL) { + dev_err(&interface->dev, "Out of memory\n"); + goto error; + } + + dev->usb_dev = usb_get_dev(interface_to_usbdev(interface)); + dev->interface = interface; + + /* save our data pointer in this interface device */ + usb_set_intfdata(interface, dev); + + version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice); + dev_info(&interface->dev, + "version %x.%02x found at bus %03d address %03d\n", + version >> 8, version & 0xff, + dev->usb_dev->bus->busnum, dev->usb_dev->devnum); + + /* setup i2c adapter description */ + dev->adapter.owner = THIS_MODULE; + dev->adapter.class = I2C_CLASS_HWMON; + dev->adapter.algo = &usb_algorithm; + dev->adapter.algo_data = dev; + snprintf(dev->adapter.name, sizeof(dev->adapter.name), + "i2c-tiny-usb at bus %03d device %03d", + dev->usb_dev->bus->busnum, dev->usb_dev->devnum); + + if (usb_write(&dev->adapter, CMD_SET_DELAY, + cpu_to_le16(delay), 0, NULL, 0) != 0) { + dev_err(&dev->adapter.dev, + "failure setting delay to %dus\n", delay); + retval = -EIO; + goto error; + } + + dev->adapter.dev.parent = &dev->interface->dev; + + /* and finally attach to i2c layer */ + i2c_add_adapter(&dev->adapter); + + /* inform user about successful attachment to i2c layer */ + dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n"); + + return 0; + + error: + if (dev) + i2c_tiny_usb_free(dev); + + return retval; +} + +static void i2c_tiny_usb_disconnect(struct usb_interface *interface) +{ + struct i2c_tiny_usb *dev = usb_get_intfdata(interface); + + i2c_del_adapter(&dev->adapter); + usb_set_intfdata(interface, NULL); + i2c_tiny_usb_free(dev); + + dev_dbg(&interface->dev, "disconnected\n"); +} + +static struct usb_driver i2c_tiny_usb_driver = { + .name = "i2c-tiny-usb", + .probe = i2c_tiny_usb_probe, + .disconnect = i2c_tiny_usb_disconnect, + .id_table = i2c_tiny_usb_table, +}; + +static int __init usb_i2c_tiny_usb_init(void) +{ + /* register this driver with the USB subsystem */ + return usb_register(&i2c_tiny_usb_driver); +} + +static void __exit usb_i2c_tiny_usb_exit(void) +{ + /* deregister this driver with the USB subsystem */ + usb_deregister(&i2c_tiny_usb_driver); +} + +module_init(usb_i2c_tiny_usb_init); +module_exit(usb_i2c_tiny_usb_exit); + +/* ----- end of usb layer ------------------------------------------------ */ + +MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>"); +MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0"); +MODULE_LICENSE("GPL"); |
