text: /*
   * L3 code
   *
   *  Copyright (C) 2008, Christian Pellegrin <chripell@evolware.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   *
   * based on:
   *
   * L3 bus algorithm module.
   *
   *  Copyright (C) 2001 Russell King, All Rights Reserved.
   *
   *
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  
  #include <sound/l3.h>
  
  /*
   * Send one byte of data to the chip.  Data is latched into the chip on
   * the rising edge of the clock.
   */
  static void sendbyte(struct l3_pins *adap, unsigned int byte)
  {
  	int i;
  
  	for (i = 0; i < 8; i++) {
  		adap->setclk(0);
  		udelay(adap->data_hold);
  		adap->setdat(byte & 1);
  		udelay(adap->data_setup);
  		adap->setclk(1);
  		udelay(adap->clock_high);
  		byte >>= 1;
  	}
  }
  
  /*
   * Send a set of bytes to the chip.  We need to pulse the MODE line
   * between each byte, but never at the start nor at the end of the
   * transfer.
   */
  static void sendbytes(struct l3_pins *adap, const u8 *buf,
  		      int len)
  {
  	int i;
  
  	for (i = 0; i < len; i++) {
  		if (i) {
  			udelay(adap->mode_hold);
  			adap->setmode(0);
  			udelay(adap->mode);
  		}
  		adap->setmode(1);
  		udelay(adap->mode_setup);
  		sendbyte(adap, buf[i]);
  	}
  }
  
  int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
  {
  	adap->setclk(1);
  	adap->setdat(1);
  	adap->setmode(1);
  	udelay(adap->mode);
  
  	adap->setmode(0);
  	udelay(adap->mode_setup);
  	sendbyte(adap, addr);
  	udelay(adap->mode_hold);
  
  	sendbytes(adap, data, len);
  
  	adap->setclk(1);
  	adap->setdat(1);
  	adap->setmode(0);
  
  	return len;
  }
  EXPORT_SYMBOL_GPL(l3_write);
  
  MODULE_DESCRIPTION("L3 bit-banging driver");
  MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
  MODULE_LICENSE("GPL");
  