--- /dev/null
+/*
+ * 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 <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;
+
+ /* 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, 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");
Code Review / kvmfornfv.git / blobdiff