Logo Search packages:      
Sourcecode: alsa-driver version File versions  Download package

l3.c

/*
 * 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");

Generated by  Doxygen 1.6.0   Back to index