text: /*
     em28xx-i2c.c - driver for Empia EM2800/EM2820/2840 USB video capture devices
  
     Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
  		      Markus Rechberger <mrechberger@gmail.com>
  		      Mauro Carvalho Chehab <mchehab@infradead.org>
  		      Sascha Sommer <saschasommer@freenet.de>
     Copyright (C) 2013 Frank Schäfer <fschaefer.oss@googlemail.com>
  
     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; either version 2 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include "em28xx.h"
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/usb.h>
  #include <linux/i2c.h>
  #include <linux/jiffies.h>
  
  #include "tuner-xc2028.h"
  #include <media/v4l2-common.h>
  #include <media/tuner.h>
  
  /* ----------------------------------------------------------- */
  
  static unsigned int i2c_scan;
  module_param(i2c_scan, int, 0444);
  MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  
  static unsigned int i2c_debug;
  module_param(i2c_debug, int, 0644);
  MODULE_PARM_DESC(i2c_debug, "i2c debug message level (1: normal debug, 2: show I2C transfers)");
  
  #define dprintk(level, fmt, arg...) do {				\
  	if (i2c_debug > level)						\
  		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
  			   "i2c: %s: " fmt, __func__, ## arg);		\
  } while (0)
  
  
  /*
   * em2800_i2c_send_bytes()
   * send up to 4 bytes to the em2800 i2c device
   */
  static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
  {
  	unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT);
  	int ret;
  	u8 b2[6];
  
  	if (len < 1 || len > 4)
  		return -EOPNOTSUPP;
  
  	BUG_ON(len < 1 || len > 4);
  	b2[5] = 0x80 + len - 1;
  	b2[4] = addr;
  	b2[3] = buf[0];
  	if (len > 1)
  		b2[2] = buf[1];
  	if (len > 2)
  		b2[1] = buf[2];
  	if (len > 3)
  		b2[0] = buf[3];
  
  	/* trigger write */
  	ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len);
  	if (ret != 2 + len) {
  		dev_warn(&dev->intf->dev,
  			 "failed to trigger write to i2c address 0x%x (error=%i)\n",
  			    addr, ret);
  		return (ret < 0) ? ret : -EIO;
  	}
  	/* wait for completion */
  	while (time_is_after_jiffies(timeout)) {
  		ret = dev->em28xx_read_reg(dev, 0x05);
  		if (ret == 0x80 + len - 1)
  			return len;
  		if (ret == 0x94 + len - 1) {
  			dprintk(1, "R05 returned 0x%02x: I2C ACK error\n", ret);
  			return -ENXIO;
  		}
  		if (ret < 0) {
  			dev_warn(&dev->intf->dev,
  				 "failed to get i2c transfer status from bridge register (error=%i)\n",
  				ret);
  			return ret;
  		}
  		msleep(5);
  	}
  	dprintk(0, "write to i2c device at 0x%x timed out\n", addr);
  	return -ETIMEDOUT;
  }
  
  /*
   * em2800_i2c_recv_bytes()
   * read up to 4 bytes from the em2800 i2c device
   */
  static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
  {
  	unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT);
  	u8 buf2[4];
  	int ret;
  	int i;
  
  	if (len < 1 || len > 4)
  		return -EOPNOTSUPP;
  
  	/* trigger read */
  	buf2[1] = 0x84 + len - 1;
  	buf2[0] = addr;
  	ret = dev->em28xx_write_regs(dev, 0x04, buf2, 2);
  	if (ret != 2) {
  		dev_warn(&dev->intf->dev,
  			 "failed to trigger read from i2c address 0x%x (error=%i)\n",
  			 addr, ret);
  		return (ret < 0) ? ret : -EIO;
  	}
  
  	/* wait for completion */
  	while (time_is_after_jiffies(timeout)) {
  		ret = dev->em28xx_read_reg(dev, 0x05);
  		if (ret == 0x84 + len - 1)
  			break;
  		if (ret == 0x94 + len - 1) {
  			dprintk(1, "R05 returned 0x%02x: I2C ACK error\n",
  				ret);
  			return -ENXIO;
  		}
  		if (ret < 0) {
  			dev_warn(&dev->intf->dev,
  				 "failed to get i2c transfer status from bridge register (error=%i)\n",
  				 ret);
  			return ret;
  		}
  		msleep(5);
  	}
  	if (ret != 0x84 + len - 1) {
  		dprintk(0, "read from i2c device at 0x%x timed out\n", addr);
  	}
  
  	/* get the received message */
  	ret = dev->em28xx_read_reg_req_len(dev, 0x00, 4-len, buf2, len);
  	if (ret != len) {
  		dev_warn(&dev->intf->dev,
  			 "reading from i2c device at 0x%x failed: couldn't get the received message from the bridge (error=%i)\n",
  			 addr, ret);
  		return (ret < 0) ? ret : -EIO;
  	}
  	for (i = 0; i < len; i++)
  		buf[i] = buf2[len - 1 - i];
  
  	return ret;
  }
  
  /*
   * em2800_i2c_check_for_device()
   * check if there is an i2c device at the supplied address
   */
  static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr)
  {
  	u8 buf;
  	int ret;
  
  	ret = em2800_i2c_recv_bytes(dev, addr, &buf, 1);
  	if (ret == 1)
  		return 0;
  	return (ret < 0) ? ret : -EIO;
  }
  
  /*
   * em28xx_i2c_send_bytes()
   */
  static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
  				 u16 len, int stop)
  {
  	unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_I2C_XFER_TIMEOUT);
  	int ret;
  
  	if (len < 1 || len > 64)
  		return -EOPNOTSUPP;
  	/*
  	 * NOTE: limited by the USB ctrl message constraints
  	 * Zero length reads always succeed, even if no device is connected
  	 */
  
  	/* Write to i2c device */
  	ret = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);
  	if (ret != len) {
  		if (ret < 0) {
  			dev_warn(&dev->intf->dev,
  				 "writing to i2c device at 0x%x failed (error=%i)\n",
  				 addr, ret);
  			return ret;
  		} else {
  			dev_warn(&dev->intf->dev,
  				 "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
  				 len, addr, ret);
  			return -EIO;
  		}
  	}
  
  	/* wait for completion */
  	while (time_is_after_jiffies(timeout)) {
  		ret = dev->em28xx_read_reg(dev, 0x05);
  		if (ret == 0) /* success */
  			return len;
  		if (ret == 0x10) {
  			dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
  				addr);
  			return -ENXIO;
  		}
  		if (ret < 0) {
  			dev_warn(&dev->intf->dev,
  				 "failed to get i2c transfer status from bridge register (error=%i)\n",
  				 ret);
  			return ret;
  		}
  		msleep(5);
  		/*
  		 * NOTE: do we really have to wait for success ?
  		 * Never seen anything else than 0x00 or 0x10
  		 * (even with high payload) ...
  		 */
  	}
  
  	if (ret == 0x02 || ret == 0x04) {
  		/* NOTE: these errors seem to be related to clock stretching */
  		dprintk(0,
  			"write to i2c device at 0x%x timed out (status=%i)\n",
  			addr, ret);
  		return -ETIMEDOUT;
  	}
  
  	dev_warn(&dev->intf->dev,
  		 "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
  		 addr, ret);
  	return -EIO;
  }
  
  /*
   * em28xx_i2c_recv_bytes()
   * read a byte from the i2c device
   */
  static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
  {
  	int ret;
  
  	if (len < 1 || len > 64)
  		return -EOPNOTSUPP;
  	/*
  	 * NOTE: limited by the USB ctrl message constraints
  	 * Zero length reads always succeed, even if no device is connected
  	 */
  
  	/* Read data from i2c device */
  	ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
  	if (ret < 0) {
  		dev_warn(&dev->intf->dev,
  			 "reading from i2c device at 0x%x failed (error=%i)\n",
  			 addr, ret);
  		return ret;
  	}
  	/*
  	 * NOTE: some devices with two i2c busses have the bad habit to return 0
  	 * bytes if we are on bus B AND there was no write attempt to the
  	 * specified slave address before AND no device is present at the
  	 * requested slave address.
  	 * Anyway, the next check will fail with -ENXIO in this case, so avoid
  	 * spamming the system log on device probing and do nothing here.
  	 */
  
  	/* Check success of the i2c operation */
  	ret = dev->em28xx_read_reg(dev, 0x05);
  	if (ret == 0) /* success */
  		return len;
  	if (ret < 0) {
  		dev_warn(&dev->intf->dev,
  			 "failed to get i2c transfer status from bridge register (error=%i)\n",
  			 ret);
  		return ret;
  	}
  	if (ret == 0x10) {
  		dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
  			addr);
  		return -ENXIO;
  	}
  
  	if (ret == 0x02 || ret == 0x04) {
  		/* NOTE: these errors seem to be related to clock stretching */
  		dprintk(0,
  			"write to i2c device at 0x%x timed out (status=%i)\n",
  			addr, ret);
  		return -ETIMEDOUT;
  	}
  
  	dev_warn(&dev->intf->dev,
  		 "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
  		 addr, ret);
  	return -EIO;
  }
  
  /*
   * em28xx_i2c_check_for_device()
   * check if there is a i2c_device at the supplied address
   */
  static int em28xx_i2c_check_for_device(struct em28xx *dev, u16 addr)
  {
  	int ret;
  	u8 buf;
  
  	ret = em28xx_i2c_recv_bytes(dev, addr, &buf, 1);
  	if (ret == 1)
  		return 0;
  	return (ret < 0) ? ret : -EIO;
  }
  
  /*
   * em25xx_bus_B_send_bytes
   * write bytes to the i2c device
   */
  static int em25xx_bus_B_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
  				   u16 len)
  {
  	int ret;
  
  	if (len < 1 || len > 64)
  		return -EOPNOTSUPP;
  	/*
  	 * NOTE: limited by the USB ctrl message constraints
  	 * Zero length reads always succeed, even if no device is connected
  	 */
  
  	/* Set register and write value */
  	ret = dev->em28xx_write_regs_req(dev, 0x06, addr, buf, len);
  	if (ret != len) {
  		if (ret < 0) {
  			dev_warn(&dev->intf->dev,
  				 "writing to i2c device at 0x%x failed (error=%i)\n",
  				 addr, ret);
  			return ret;
  		} else {
  			dev_warn(&dev->intf->dev,
  				 "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
  				 len, addr, ret);
  			return -EIO;
  		}
  	}
  	/* Check success */
  	ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
  	/*
  	 * NOTE: the only error we've seen so far is
  	 * 0x01 when the slave device is not present
  	 */
  	if (!ret)
  		return len;
  	else if (ret > 0) {
  		dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
  		return -ENXIO;
  	}
  
  	return ret;
  	/*
  	 * NOTE: With chip types (other chip IDs) which actually don't support
  	 * this operation, it seems to succeed ALWAYS ! (even if there is no
  	 * slave device or even no second i2c bus provided)
  	 */
  }
  
  /*
   * em25xx_bus_B_recv_bytes
   * read bytes from the i2c device
   */
  static int em25xx_bus_B_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf,
  				   u16 len)
  {
  	int ret;
  
  	if (len < 1 || len > 64)
  		return -EOPNOTSUPP;
  	/*
  	 * NOTE: limited by the USB ctrl message constraints
  	 * Zero length reads always succeed, even if no device is connected
  	 */
  
  	/* Read value */
  	ret = dev->em28xx_read_reg_req_len(dev, 0x06, addr, buf, len);
  	if (ret < 0) {
  		dev_warn(&dev->intf->dev,
  			 "reading from i2c device at 0x%x failed (error=%i)\n",
  			 addr, ret);
  		return ret;
  	}
  	/*
  	 * NOTE: some devices with two i2c busses have the bad habit to return 0
  	 * bytes if we are on bus B AND there was no write attempt to the
  	 * specified slave address before AND no device is present at the
  	 * requested slave address.
  	 * Anyway, the next check will fail with -ENXIO in this case, so avoid
  	 * spamming the system log on device probing and do nothing here.
  	 */
  
  	/* Check success */
  	ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
  	/*
  	 * NOTE: the only error we've seen so far is
  	 * 0x01 when the slave device is not present
  	 */
  	if (!ret)
  		return len;
  	else if (ret > 0) {
  		dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
  		return -ENXIO;
  	}
  
  	return ret;
  	/*
  	 * NOTE: With chip types (other chip IDs) which actually don't support
  	 * this operation, it seems to succeed ALWAYS ! (even if there is no
  	 * slave device or even no second i2c bus provided)
  	 */
  }
  
  /*
   * em25xx_bus_B_check_for_device()
   * check if there is a i2c device at the supplied address
   */
  static int em25xx_bus_B_check_for_device(struct em28xx *dev, u16 addr)
  {
  	u8 buf;
  	int ret;
  
  	ret = em25xx_bus_B_recv_bytes(dev, addr, &buf, 1);
  	if (ret < 0)
  		return ret;
  
  	return 0;
  	/*
  	 * NOTE: With chips which do not support this operation,
  	 * it seems to succeed ALWAYS ! (even if no device connected)
  	 */
  }
  
  static inline int i2c_check_for_device(struct em28xx_i2c_bus *i2c_bus, u16 addr)
  {
  	struct em28xx *dev = i2c_bus->dev;
  	int rc = -EOPNOTSUPP;
  
  	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
  		rc = em28xx_i2c_check_for_device(dev, addr);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
  		rc = em2800_i2c_check_for_device(dev, addr);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
  		rc = em25xx_bus_B_check_for_device(dev, addr);
  	return rc;
  }
  
  static inline int i2c_recv_bytes(struct em28xx_i2c_bus *i2c_bus,
  				 struct i2c_msg msg)
  {
  	struct em28xx *dev = i2c_bus->dev;
  	u16 addr = msg.addr << 1;
  	int rc = -EOPNOTSUPP;
  
  	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
  		rc = em28xx_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
  		rc = em2800_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
  		rc = em25xx_bus_B_recv_bytes(dev, addr, msg.buf, msg.len);
  	return rc;
  }
  
  static inline int i2c_send_bytes(struct em28xx_i2c_bus *i2c_bus,
  				 struct i2c_msg msg, int stop)
  {
  	struct em28xx *dev = i2c_bus->dev;
  	u16 addr = msg.addr << 1;
  	int rc = -EOPNOTSUPP;
  
  	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
  		rc = em28xx_i2c_send_bytes(dev, addr, msg.buf, msg.len, stop);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
  		rc = em2800_i2c_send_bytes(dev, addr, msg.buf, msg.len);
  	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
  		rc = em25xx_bus_B_send_bytes(dev, addr, msg.buf, msg.len);
  	return rc;
  }
  
  /*
   * em28xx_i2c_xfer()
   * the main i2c transfer function
   */
  static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
  			   struct i2c_msg msgs[], int num)
  {
  	struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;
  	struct em28xx *dev = i2c_bus->dev;
  	unsigned bus = i2c_bus->bus;
  	int addr, rc, i;
  	u8 reg;
  
  	/* prevent i2c xfer attempts after device is disconnected
  	   some fe's try to do i2c writes/reads from their release
  	   interfaces when called in disconnect path */
  	if (dev->disconnected)
  		return -ENODEV;
  
  	if (!rt_mutex_trylock(&dev->i2c_bus_lock))
  		return -EAGAIN;
  
  	/* Switch I2C bus if needed */
  	if (bus != dev->cur_i2c_bus &&
  	    i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX) {
  		if (bus == 1)
  			reg = EM2874_I2C_SECONDARY_BUS_SELECT;
  		else
  			reg = 0;
  		em28xx_write_reg_bits(dev, EM28XX_R06_I2C_CLK, reg,
  				      EM2874_I2C_SECONDARY_BUS_SELECT);
  		dev->cur_i2c_bus = bus;
  	}
  
  	if (num <= 0) {
  		rt_mutex_unlock(&dev->i2c_bus_lock);
  		return 0;
  	}
  	for (i = 0; i < num; i++) {
  		addr = msgs[i].addr << 1;
  		if (!msgs[i].len) {
  			/*
  			 * no len: check only for device presence
  			 * This code is only called during device probe.
  			 */
  			rc = i2c_check_for_device(i2c_bus, addr);
  
  			if (rc == -ENXIO)
  				rc = -ENODEV;
  		} else if (msgs[i].flags & I2C_M_RD) {
  			/* read bytes */
  			rc = i2c_recv_bytes(i2c_bus, msgs[i]);
  		} else {
  			/* write bytes */
  			rc = i2c_send_bytes(i2c_bus, msgs[i], i == num - 1);
  		}
  
  		if (rc < 0)
  			goto error;
  
  		dprintk(2, "%s %s addr=%02x len=%d: %*ph\n",
  			(msgs[i].flags & I2C_M_RD) ? "read" : "write",
  			i == num - 1 ? "stop" : "nonstop",
  			addr, msgs[i].len,
  			msgs[i].len, msgs[i].buf);
  	}
  
  	rt_mutex_unlock(&dev->i2c_bus_lock);
  	return num;
  
  error:
  	dprintk(2, "%s %s addr=%02x len=%d: %sERROR: %i\n",
  		(msgs[i].flags & I2C_M_RD) ? "read" : "write",
  		i == num - 1 ? "stop" : "nonstop",
  		addr, msgs[i].len,
  		(rc == -ENODEV) ? "no device " : "",
  		rc);
  
  	rt_mutex_unlock(&dev->i2c_bus_lock);
  	return rc;
  }
  
  /*
   * based on linux/sunrpc/svcauth.h and linux/hash.h
   * The original hash function returns a different value, if arch is x86_64
   * or i386.
   */
  static inline unsigned long em28xx_hash_mem(char *buf, int length, int bits)
  {
  	unsigned long hash = 0;
  	unsigned long l = 0;
  	int len = 0;
  	unsigned char c;
  
  	do {
  		if (len == length) {
  			c = (char)len;
  			len = -1;
  		} else
  			c = *buf++;
  		l = (l << 8) | c;
  		len++;
  		if ((len & (32 / 8 - 1)) == 0)
  			hash = ((hash^l) * 0x9e370001UL);
  	} while (len);
  
  	return (hash >> (32 - bits)) & 0xffffffffUL;
  }
  
  /*
   * Helper function to read data blocks from i2c clients with 8 or 16 bit
   * address width, 8 bit register width and auto incrementation been activated
   */
  static int em28xx_i2c_read_block(struct em28xx *dev, unsigned bus, u16 addr,
  				 bool addr_w16, u16 len, u8 *data)
  {
  	int remain = len, rsize, rsize_max, ret;
  	u8 buf[2];
  
  	/* Sanity check */
  	if (addr + remain > (addr_w16 * 0xff00 + 0xff + 1))
  		return -EINVAL;
  	/* Select address */
  	buf[0] = addr >> 8;
  	buf[1] = addr & 0xff;
  	ret = i2c_master_send(&dev->i2c_client[bus], buf + !addr_w16, 1 + addr_w16);
  	if (ret < 0)
  		return ret;
  	/* Read data */
  	if (dev->board.is_em2800)
  		rsize_max = 4;
  	else
  		rsize_max = 64;
  	while (remain > 0) {
  		if (remain > rsize_max)
  			rsize = rsize_max;
  		else
  			rsize = remain;
  
  		ret = i2c_master_recv(&dev->i2c_client[bus], data, rsize);
  		if (ret < 0)
  			return ret;
  
  		remain -= rsize;
  		data += rsize;
  	}
  
  	return len;
  }
  
  static int em28xx_i2c_eeprom(struct em28xx *dev, unsigned bus,
  			     u8 **eedata, u16 *eedata_len)
  {
  	const u16 len = 256;
  	/*
  	 * FIXME common length/size for bytes to read, to display, hash
  	 * calculation and returned device dataset. Simplifies the code a lot,
  	 * but we might have to deal with multiple sizes in the future !
  	 */
  	int err;
  	struct em28xx_eeprom *dev_config;
  	u8 buf, *data;
  
  	*eedata = NULL;
  	*eedata_len = 0;
  
  	/* EEPROM is always on i2c bus 0 on all known devices. */
  
  	dev->i2c_client[bus].addr = 0xa0 >> 1;
  
  	/* Check if board has eeprom */
  	err = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
  	if (err < 0) {
  		dev_info(&dev->intf->dev, "board has no eeprom\n");
  		return -ENODEV;
  	}
  
  	data = kzalloc(len, GFP_KERNEL);
  	if (data == NULL)
  		return -ENOMEM;
  
  	/* Read EEPROM content */
  	err = em28xx_i2c_read_block(dev, bus, 0x0000,
  				    dev->eeprom_addrwidth_16bit,
  				    len, data);
  	if (err != len) {
  		dev_err(&dev->intf->dev,
  			"failed to read eeprom (err=%d)\n", err);
  		goto error;
  	}
  
  	if (i2c_debug) {
  		/* Display eeprom content */
  		print_hex_dump(KERN_DEBUG, "em28xx eeprom ", DUMP_PREFIX_OFFSET,
  			       16, 1, data, len, true);
  
  		if (dev->eeprom_addrwidth_16bit)
  			dev_info(&dev->intf->dev,
  				 "eeprom %06x: ... (skipped)\n", 256);
  	}
  
  	if (dev->eeprom_addrwidth_16bit &&
  	    data[0] == 0x26 && data[3] == 0x00) {
  		/* new eeprom format; size 4-64kb */
  		u16 mc_start;
  		u16 hwconf_offset;
  
  		dev->hash = em28xx_hash_mem(data, len, 32);
  		mc_start = (data[1] << 8) + 4;	/* usually 0x0004 */
  
  		dev_info(&dev->intf->dev,
  			 "EEPROM ID = %02x %02x %02x %02x, EEPROM hash = 0x%08lx\n",
  			 data[0], data[1], data[2], data[3], dev->hash);
  		dev_info(&dev->intf->dev,
  			 "EEPROM info:\n");
  		dev_info(&dev->intf->dev,
  			 "\tmicrocode start address = 0x%04x, boot configuration = 0x%02x\n",
  			 mc_start, data[2]);
  		/*
  		 * boot configuration (address 0x0002):
  		 * [0]   microcode download speed: 1 = 400 kHz; 0 = 100 kHz
  		 * [1]   always selects 12 kb RAM
  		 * [2]   USB device speed: 1 = force Full Speed; 0 = auto detect
  		 * [4]   1 = force fast mode and no suspend for device testing
  		 * [5:7] USB PHY tuning registers; determined by device
  		 *       characterization
  		 */
  
  		/*
  		 * Read hardware config dataset offset from address
  		 * (microcode start + 46)
  		 */
  		err = em28xx_i2c_read_block(dev, bus, mc_start + 46, 1, 2,
  					    data);
  		if (err != 2) {
  			dev_err(&dev->intf->dev,
  				"failed to read hardware configuration data from eeprom (err=%d)\n",
  				err);
  			goto error;
  		}
  
  		/* Calculate hardware config dataset start address */
  		hwconf_offset = mc_start + data[0] + (data[1] << 8);
  
  		/* Read hardware config dataset */
  		/*
  		 * NOTE: the microcode copy can be multiple pages long, but
  		 * we assume the hardware config dataset is the same as in
  		 * the old eeprom and not longer than 256 bytes.
  		 * tveeprom is currently also limited to 256 bytes.
  		 */
  		err = em28xx_i2c_read_block(dev, bus, hwconf_offset, 1, len,
  					    data);
  		if (err != len) {
  			dev_err(&dev->intf->dev,
  				"failed to read hardware configuration data from eeprom (err=%d)\n",
  				err);
  			goto error;
  		}
  
  		/* Verify hardware config dataset */
  		/* NOTE: not all devices provide this type of dataset */
  		if (data[0] != 0x1a || data[1] != 0xeb ||
  		    data[2] != 0x67 || data[3] != 0x95) {
  			dev_info(&dev->intf->dev,
  				 "\tno hardware configuration dataset found in eeprom\n");
  			kfree(data);
  			return 0;
  		}
  
  		/* TODO: decrypt eeprom data for camera bridges (em25xx, em276x+) */
  
  	} else if (!dev->eeprom_addrwidth_16bit &&
  		   data[0] == 0x1a && data[1] == 0xeb &&
  		   data[2] == 0x67 && data[3] == 0x95) {
  		dev->hash = em28xx_hash_mem(data, len, 32);
  		dev_info(&dev->intf->dev,
  			 "EEPROM ID = %02x %02x %02x %02x, EEPROM hash = 0x%08lx\n",
  			 data[0], data[1], data[2], data[3], dev->hash);
  		dev_info(&dev->intf->dev,
  			 "EEPROM info:\n");
  	} else {
  		dev_info(&dev->intf->dev,
  			 "unknown eeprom format or eeprom corrupted !\n");
  		err = -ENODEV;
  		goto error;
  	}
  
  	*eedata = data;
  	*eedata_len = len;
  	dev_config = (void *)*eedata;
  
  	switch (le16_to_cpu(dev_config->chip_conf) >> 4 & 0x3) {
  	case 0:
  		dev_info(&dev->intf->dev, "\tNo audio on board.\n");
  		break;
  	case 1:
  		dev_info(&dev->intf->dev, "\tAC97 audio (5 sample rates)\n");
  		break;
  	case 2:
  		if (dev->chip_id < CHIP_ID_EM2860)
  			dev_info(&dev->intf->dev,
  				 "\tI2S audio, sample rate=32k\n");
  		else
  			dev_info(&dev->intf->dev,
  				 "\tI2S audio, 3 sample rates\n");
  		break;
  	case 3:
  		if (dev->chip_id < CHIP_ID_EM2860)
  			dev_info(&dev->intf->dev,
  				 "\tI2S audio, 3 sample rates\n");
  		else
  			dev_info(&dev->intf->dev,
  				 "\tI2S audio, 5 sample rates\n");
  		break;
  	}
  
  	if (le16_to_cpu(dev_config->chip_conf) & 1 << 3)
  		dev_info(&dev->intf->dev, "\tUSB Remote wakeup capable\n");
  
  	if (le16_to_cpu(dev_config->chip_conf) & 1 << 2)
  		dev_info(&dev->intf->dev, "\tUSB Self power capable\n");
  
  	switch (le16_to_cpu(dev_config->chip_conf) & 0x3) {
  	case 0:
  		dev_info(&dev->intf->dev, "\t500mA max power\n");
  		break;
  	case 1:
  		dev_info(&dev->intf->dev, "\t400mA max power\n");
  		break;
  	case 2:
  		dev_info(&dev->intf->dev, "\t300mA max power\n");
  		break;
  	case 3:
  		dev_info(&dev->intf->dev, "\t200mA max power\n");
  		break;
  	}
  	dev_info(&dev->intf->dev,
  		 "\tTable at offset 0x%02x, strings=0x%04x, 0x%04x, 0x%04x\n",
  		 dev_config->string_idx_table,
  		 le16_to_cpu(dev_config->string1),
  		 le16_to_cpu(dev_config->string2),
  		 le16_to_cpu(dev_config->string3));
  
  	return 0;
  
  error:
  	kfree(data);
  	return err;
  }
  
  /* ----------------------------------------------------------- */
  
  /*
   * functionality()
   */
  static u32 functionality(struct i2c_adapter *i2c_adap)
  {
  	struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;
  
  	if ((i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX) ||
  	    (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)) {
  		return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
  	} else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)  {
  		return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL) &
  			~I2C_FUNC_SMBUS_WRITE_BLOCK_DATA;
  	}
  
  	WARN(1, "Unknown i2c bus algorithm.\n");
  	return 0;
  }
  
  static const struct i2c_algorithm em28xx_algo = {
  	.master_xfer   = em28xx_i2c_xfer,
  	.functionality = functionality,
  };
  
  static const struct i2c_adapter em28xx_adap_template = {
  	.owner = THIS_MODULE,
  	.name = "em28xx",
  	.algo = &em28xx_algo,
  };
  
  static struct i2c_client em28xx_client_template = {
  	.name = "em28xx internal",
  };
  
  /* ----------------------------------------------------------- */
  
  /*
   * i2c_devs
   * incomplete list of known devices
   */
  static char *i2c_devs[128] = {
         [0x1c >> 1] = "lgdt330x",
  	[0x3e >> 1] = "remote IR sensor",
  	[0x4a >> 1] = "saa7113h",
  	[0x52 >> 1] = "drxk",
  	[0x60 >> 1] = "remote IR sensor",
  	[0x8e >> 1] = "remote IR sensor",
  	[0x86 >> 1] = "tda9887",
  	[0x80 >> 1] = "msp34xx",
  	[0x88 >> 1] = "msp34xx",
  	[0xa0 >> 1] = "eeprom",
  	[0xb0 >> 1] = "tda9874",
  	[0xb8 >> 1] = "tvp5150a",
  	[0xba >> 1] = "webcam sensor or tvp5150a",
  	[0xc0 >> 1] = "tuner (analog)",
  	[0xc2 >> 1] = "tuner (analog)",
  	[0xc4 >> 1] = "tuner (analog)",
  	[0xc6 >> 1] = "tuner (analog)",
  };
  
  /*
   * do_i2c_scan()
   * check i2c address range for devices
   */
  void em28xx_do_i2c_scan(struct em28xx *dev, unsigned bus)
  {
  	u8 i2c_devicelist[128];
  	unsigned char buf;
  	int i, rc;
  
  	memset(i2c_devicelist, 0, ARRAY_SIZE(i2c_devicelist));
  
  	for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
  		dev->i2c_client[bus].addr = i;
  		rc = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
  		if (rc < 0)
  			continue;
  		i2c_devicelist[i] = i;
  		dev_info(&dev->intf->dev,
  			 "found i2c device @ 0x%x on bus %d [%s]\n",
  			 i << 1, bus, i2c_devs[i] ? i2c_devs[i] : "???");
  	}
  
  	if (bus == dev->def_i2c_bus)
  		dev->i2c_hash = em28xx_hash_mem(i2c_devicelist,
  						ARRAY_SIZE(i2c_devicelist), 32);
  }
  
  /*
   * em28xx_i2c_register()
   * register i2c bus
   */
  int em28xx_i2c_register(struct em28xx *dev, unsigned bus,
  			enum em28xx_i2c_algo_type algo_type)
  {
  	int retval;
  
  	BUG_ON(!dev->em28xx_write_regs || !dev->em28xx_read_reg);
  	BUG_ON(!dev->em28xx_write_regs_req || !dev->em28xx_read_reg_req);
  
  	if (bus >= NUM_I2C_BUSES)
  		return -ENODEV;
  
  	dev->i2c_adap[bus] = em28xx_adap_template;
  	dev->i2c_adap[bus].dev.parent = &dev->intf->dev;
  	strcpy(dev->i2c_adap[bus].name, dev_name(&dev->intf->dev));
  
  	dev->i2c_bus[bus].bus = bus;
  	dev->i2c_bus[bus].algo_type = algo_type;
  	dev->i2c_bus[bus].dev = dev;
  	dev->i2c_adap[bus].algo_data = &dev->i2c_bus[bus];
  
  	retval = i2c_add_adapter(&dev->i2c_adap[bus]);
  	if (retval < 0) {
  		dev_err(&dev->intf->dev,
  			"%s: i2c_add_adapter failed! retval [%d]\n",
  			__func__, retval);
  		return retval;
  	}
  
  	dev->i2c_client[bus] = em28xx_client_template;
  	dev->i2c_client[bus].adapter = &dev->i2c_adap[bus];
  
  	/* Up to now, all eeproms are at bus 0 */
  	if (!bus) {
  		retval = em28xx_i2c_eeprom(dev, bus, &dev->eedata, &dev->eedata_len);
  		if ((retval < 0) && (retval != -ENODEV)) {
  			dev_err(&dev->intf->dev,
  				"%s: em28xx_i2_eeprom failed! retval [%d]\n",
  				__func__, retval);
  		}
  	}
  
  	if (i2c_scan)
  		em28xx_do_i2c_scan(dev, bus);
  
  	return 0;
  }
  
  /*
   * em28xx_i2c_unregister()
   * unregister i2c_bus
   */
  int em28xx_i2c_unregister(struct em28xx *dev, unsigned bus)
  {
  	if (bus >= NUM_I2C_BUSES)
  		return -ENODEV;
  
  	i2c_del_adapter(&dev->i2c_adap[bus]);
  	return 0;
  }
  