text: /*
   *  Driver for the Auvitek AU0828 USB bridge
   *
   *  Copyright (c) 2008 Steven Toth <stoth@linuxtv.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; 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 <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/init.h>
  #include <linux/delay.h>
  #include <linux/io.h>
  
  #include "au0828.h"
  
  #include <media/v4l2-common.h>
  
  static int i2c_scan;
  module_param(i2c_scan, int, 0444);
  MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
  
  #define I2C_WAIT_DELAY 512
  #define I2C_WAIT_RETRY 64
  
  static inline int i2c_slave_did_write_ack(struct i2c_adapter *i2c_adap)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	return au0828_read(dev, AU0828_I2C_STATUS_201) &
  		AU0828_I2C_STATUS_NO_WRITE_ACK ? 0 : 1;
  }
  
  static inline int i2c_slave_did_read_ack(struct i2c_adapter *i2c_adap)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	return au0828_read(dev, AU0828_I2C_STATUS_201) &
  		AU0828_I2C_STATUS_NO_READ_ACK ? 0 : 1;
  }
  
  static int i2c_wait_read_ack(struct i2c_adapter *i2c_adap)
  {
  	int count;
  
  	for (count = 0; count < I2C_WAIT_RETRY; count++) {
  		if (!i2c_slave_did_read_ack(i2c_adap))
  			break;
  		udelay(I2C_WAIT_DELAY);
  	}
  
  	if (I2C_WAIT_RETRY == count)
  		return 0;
  
  	return 1;
  }
  
  static inline int i2c_is_read_busy(struct i2c_adapter *i2c_adap)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	return au0828_read(dev, AU0828_I2C_STATUS_201) &
  		AU0828_I2C_STATUS_READ_DONE ? 0 : 1;
  }
  
  static int i2c_wait_read_done(struct i2c_adapter *i2c_adap)
  {
  	int count;
  
  	for (count = 0; count < I2C_WAIT_RETRY; count++) {
  		if (!i2c_is_read_busy(i2c_adap))
  			break;
  		udelay(I2C_WAIT_DELAY);
  	}
  
  	if (I2C_WAIT_RETRY == count)
  		return 0;
  
  	return 1;
  }
  
  static inline int i2c_is_write_done(struct i2c_adapter *i2c_adap)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	return au0828_read(dev, AU0828_I2C_STATUS_201) &
  		AU0828_I2C_STATUS_WRITE_DONE ? 1 : 0;
  }
  
  static int i2c_wait_write_done(struct i2c_adapter *i2c_adap)
  {
  	int count;
  
  	for (count = 0; count < I2C_WAIT_RETRY; count++) {
  		if (i2c_is_write_done(i2c_adap))
  			break;
  		udelay(I2C_WAIT_DELAY);
  	}
  
  	if (I2C_WAIT_RETRY == count)
  		return 0;
  
  	return 1;
  }
  
  static inline int i2c_is_busy(struct i2c_adapter *i2c_adap)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	return au0828_read(dev, AU0828_I2C_STATUS_201) &
  		AU0828_I2C_STATUS_BUSY ? 1 : 0;
  }
  
  static int i2c_wait_done(struct i2c_adapter *i2c_adap)
  {
  	int count;
  
  	for (count = 0; count < I2C_WAIT_RETRY; count++) {
  		if (!i2c_is_busy(i2c_adap))
  			break;
  		udelay(I2C_WAIT_DELAY);
  	}
  
  	if (I2C_WAIT_RETRY == count)
  		return 0;
  
  	return 1;
  }
  
  /* FIXME: Implement join handling correctly */
  static int i2c_sendbytes(struct i2c_adapter *i2c_adap,
  	const struct i2c_msg *msg, int joined_rlen)
  {
  	int i, strobe = 0;
  	struct au0828_dev *dev = i2c_adap->algo_data;
  
  	dprintk(4, "%s()\n", __func__);
  
  	au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
  
  	/* Set the I2C clock */
  	au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
  		     dev->board.i2c_clk_divider);
  
  	/* Hardware needs 8 bit addresses */
  	au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
  
  	dprintk(4, "SEND: %02x\n", msg->addr);
  
  	/* Deal with i2c_scan */
  	if (msg->len == 0) {
  		/* The analog tuner detection code makes use of the SMBUS_QUICK
  		   message (which involves a zero length i2c write).  To avoid
  		   checking the status register when we didn't strobe out any
  		   actual bytes to the bus, just do a read check.  This is
  		   consistent with how I saw i2c device checking done in the
  		   USB trace of the Windows driver */
  		au0828_write(dev, AU0828_I2C_TRIGGER_200,
  			     AU0828_I2C_TRIGGER_READ);
  
  		if (!i2c_wait_done(i2c_adap))
  			return -EIO;
  
  		if (i2c_wait_read_ack(i2c_adap))
  			return -EIO;
  
  		return 0;
  	}
  
  	for (i = 0; i < msg->len;) {
  
  		dprintk(4, " %02x\n", msg->buf[i]);
  
  		au0828_write(dev, AU0828_I2C_WRITE_FIFO_205, msg->buf[i]);
  
  		strobe++;
  		i++;
  
  		if ((strobe >= 4) || (i >= msg->len)) {
  
  			/* Strobe the byte into the bus */
  			if (i < msg->len)
  				au0828_write(dev, AU0828_I2C_TRIGGER_200,
  					     AU0828_I2C_TRIGGER_WRITE |
  					     AU0828_I2C_TRIGGER_HOLD);
  			else
  				au0828_write(dev, AU0828_I2C_TRIGGER_200,
  					     AU0828_I2C_TRIGGER_WRITE);
  
  			/* Reset strobe trigger */
  			strobe = 0;
  
  			if (!i2c_wait_write_done(i2c_adap))
  				return -EIO;
  
  		}
  
  	}
  	if (!i2c_wait_done(i2c_adap))
  		return -EIO;
  
  	dprintk(4, "\n");
  
  	return msg->len;
  }
  
  /* FIXME: Implement join handling correctly */
  static int i2c_readbytes(struct i2c_adapter *i2c_adap,
  	const struct i2c_msg *msg, int joined)
  {
  	struct au0828_dev *dev = i2c_adap->algo_data;
  	int i;
  
  	dprintk(4, "%s()\n", __func__);
  
  	au0828_write(dev, AU0828_I2C_MULTIBYTE_MODE_2FF, 0x01);
  
  	/* Set the I2C clock */
  	au0828_write(dev, AU0828_I2C_CLK_DIVIDER_202,
  		     dev->board.i2c_clk_divider);
  
  	/* Hardware needs 8 bit addresses */
  	au0828_write(dev, AU0828_I2C_DEST_ADDR_203, msg->addr << 1);
  
  	dprintk(4, " RECV:\n");
  
  	/* Deal with i2c_scan */
  	if (msg->len == 0) {
  		au0828_write(dev, AU0828_I2C_TRIGGER_200,
  			     AU0828_I2C_TRIGGER_READ);
  
  		if (i2c_wait_read_ack(i2c_adap))
  			return -EIO;
  		return 0;
  	}
  
  	for (i = 0; i < msg->len;) {
  
  		i++;
  
  		if (i < msg->len)
  			au0828_write(dev, AU0828_I2C_TRIGGER_200,
  				     AU0828_I2C_TRIGGER_READ |
  				     AU0828_I2C_TRIGGER_HOLD);
  		else
  			au0828_write(dev, AU0828_I2C_TRIGGER_200,
  				     AU0828_I2C_TRIGGER_READ);
  
  		if (!i2c_wait_read_done(i2c_adap))
  			return -EIO;
  
  		msg->buf[i-1] = au0828_read(dev, AU0828_I2C_READ_FIFO_209) &
  			0xff;
  
  		dprintk(4, " %02x\n", msg->buf[i-1]);
  	}
  	if (!i2c_wait_done(i2c_adap))
  		return -EIO;
  
  	dprintk(4, "\n");
  
  	return msg->len;
  }
  
  static int i2c_xfer(struct i2c_adapter *i2c_adap,
  		    struct i2c_msg *msgs, int num)
  {
  	int i, retval = 0;
  
  	dprintk(4, "%s(num = %d)\n", __func__, num);
  
  	for (i = 0; i < num; i++) {
  		dprintk(4, "%s(num = %d) addr = 0x%02x  len = 0x%x\n",
  			__func__, num, msgs[i].addr, msgs[i].len);
  		if (msgs[i].flags & I2C_M_RD) {
  			/* read */
  			retval = i2c_readbytes(i2c_adap, &msgs[i], 0);
  		} else if (i + 1 < num && (msgs[i + 1].flags & I2C_M_RD) &&
  			   msgs[i].addr == msgs[i + 1].addr) {
  			/* write then read from same address */
  			retval = i2c_sendbytes(i2c_adap, &msgs[i],
  					       msgs[i + 1].len);
  			if (retval < 0)
  				goto err;
  			i++;
  			retval = i2c_readbytes(i2c_adap, &msgs[i], 1);
  		} else {
  			/* write */
  			retval = i2c_sendbytes(i2c_adap, &msgs[i], 0);
  		}
  		if (retval < 0)
  			goto err;
  	}
  	return num;
  
  err:
  	return retval;
  }
  
  static u32 au0828_functionality(struct i2c_adapter *adap)
  {
  	return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
  }
  
  static struct i2c_algorithm au0828_i2c_algo_template = {
  	.master_xfer	= i2c_xfer,
  	.functionality	= au0828_functionality,
  };
  
  /* ----------------------------------------------------------------------- */
  
  static struct i2c_adapter au0828_i2c_adap_template = {
  	.name              = DRIVER_NAME,
  	.owner             = THIS_MODULE,
  	.algo              = &au0828_i2c_algo_template,
  };
  
  static struct i2c_client au0828_i2c_client_template = {
  	.name	= "au0828 internal",
  };
  
  static char *i2c_devs[128] = {
  	[0x8e >> 1] = "au8522",
  	[0xa0 >> 1] = "eeprom",
  	[0xc2 >> 1] = "tuner/xc5000",
  };
  
  static void do_i2c_scan(char *name, struct i2c_client *c)
  {
  	unsigned char buf;
  	int i, rc;
  
  	for (i = 0; i < 128; i++) {
  		c->addr = i;
  		rc = i2c_master_recv(c, &buf, 0);
  		if (rc < 0)
  			continue;
  		printk(KERN_INFO "%s: i2c scan: found device @ 0x%x  [%s]\n",
  		       name, i << 1, i2c_devs[i] ? i2c_devs[i] : "???");
  	}
  }
  
  /* init + register i2c algo-bit adapter */
  int au0828_i2c_register(struct au0828_dev *dev)
  {
  	dprintk(1, "%s()\n", __func__);
  
  	memcpy(&dev->i2c_adap, &au0828_i2c_adap_template,
  	       sizeof(dev->i2c_adap));
  	memcpy(&dev->i2c_algo, &au0828_i2c_algo_template,
  	       sizeof(dev->i2c_algo));
  	memcpy(&dev->i2c_client, &au0828_i2c_client_template,
  	       sizeof(dev->i2c_client));
  
  	dev->i2c_adap.dev.parent = &dev->usbdev->dev;
  
  	strlcpy(dev->i2c_adap.name, DRIVER_NAME,
  		sizeof(dev->i2c_adap.name));
  
  	dev->i2c_adap.algo = &dev->i2c_algo;
  	dev->i2c_adap.algo_data = dev;
  	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
  	i2c_add_adapter(&dev->i2c_adap);
  
  	dev->i2c_client.adapter = &dev->i2c_adap;
  
  	if (0 == dev->i2c_rc) {
  		printk(KERN_INFO "%s: i2c bus registered\n", DRIVER_NAME);
  		if (i2c_scan)
  			do_i2c_scan(DRIVER_NAME, &dev->i2c_client);
  	} else
  		printk(KERN_INFO "%s: i2c bus register FAILED\n", DRIVER_NAME);
  
  	return dev->i2c_rc;
  }
  
  int au0828_i2c_unregister(struct au0828_dev *dev)
  {
  	i2c_del_adapter(&dev->i2c_adap);
  	return 0;
  }
  