| // 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 (Till@Harbaum.org) |
| */ |
| |
| #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 = -EREMOTEIO; |
| 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 = -EREMOTEIO; |
| 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 = -EREMOTEIO; |
| goto out; |
| } |
| |
| dev_dbg(&adapter->dev, " status = %d\n", *pstatus); |
| if (*pstatus == STATUS_ADDRESS_NAK) { |
| ret = -EREMOTEIO; |
| 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 <Till@Harbaum.org>"); |
| MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0"); |
| MODULE_LICENSE("GPL"); |