forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
303 lines
7.7 KiB
303 lines
7.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* driver for the i2c-tiny-usb adapter - 1.0 |
|
* http://www.harbaum.org/till/i2c_tiny_usb |
|
* |
|
* Copyright (C) 2006-2007 Till Harbaum ([email protected]) |
|
*/ |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/errno.h> |
|
#include <linux/module.h> |
|
#include <linux/slab.h> |
|
#include <linux/types.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 max |
|
(in practice, due to additional delays in the i2c bitbanging |
|
code this results in a i2c clock of about 50kHz) */ |
|
static unsigned short delay = 10; |
|
module_param(delay, ushort, 0); |
|
MODULE_PARM_DESC(delay, "bit delay in microseconds " |
|
"(default is 10us for 100kHz max)"); |
|
|
|
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 *pstatus; |
|
struct i2c_msg *pmsg; |
|
int i, ret; |
|
|
|
dev_dbg(&adapter->dev, "master xfer %d messages:\n", num); |
|
|
|
pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL); |
|
if (!pstatus) |
|
return -ENOMEM; |
|
|
|
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"); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
} 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"); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
} |
|
|
|
/* read status */ |
|
if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) { |
|
dev_err(&adapter->dev, "failure reading status\n"); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
dev_dbg(&adapter->dev, " status = %d\n", *pstatus); |
|
if (*pstatus == STATUS_ADDRESS_NAK) { |
|
ret = -ENXIO; |
|
goto out; |
|
} |
|
} |
|
|
|
ret = i; |
|
out: |
|
kfree(pstatus); |
|
return ret; |
|
} |
|
|
|
static u32 usb_func(struct i2c_adapter *adapter) |
|
{ |
|
__le32 *pfunc; |
|
u32 ret; |
|
|
|
pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL); |
|
|
|
/* get functionality from adapter */ |
|
if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc, |
|
sizeof(*pfunc)) != sizeof(*pfunc)) { |
|
dev_err(&adapter->dev, "failure reading functionality\n"); |
|
ret = 0; |
|
goto out; |
|
} |
|
|
|
ret = le32_to_cpup(pfunc); |
|
out: |
|
kfree(pfunc); |
|
return ret; |
|
} |
|
|
|
/* 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 const 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; |
|
void *dmadata = kmalloc(len, GFP_KERNEL); |
|
int ret; |
|
|
|
if (!dmadata) |
|
return -ENOMEM; |
|
|
|
/* do control transfer */ |
|
ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), |
|
cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | |
|
USB_DIR_IN, value, index, dmadata, len, 2000); |
|
|
|
memcpy(data, dmadata, len); |
|
kfree(dmadata); |
|
return ret; |
|
} |
|
|
|
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; |
|
void *dmadata = kmemdup(data, len, GFP_KERNEL); |
|
int ret; |
|
|
|
if (!dmadata) |
|
return -ENOMEM; |
|
|
|
/* do control transfer */ |
|
ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), |
|
cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, |
|
value, index, dmadata, len, 2000); |
|
|
|
kfree(dmadata); |
|
return ret; |
|
} |
|
|
|
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, 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, |
|
}; |
|
|
|
module_usb_driver(i2c_tiny_usb_driver); |
|
|
|
/* ----- end of usb layer ------------------------------------------------ */ |
|
|
|
MODULE_AUTHOR("Till Harbaum <[email protected]>"); |
|
MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0"); |
|
MODULE_LICENSE("GPL");
|
|
|