l3.c
1.77 KB
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/*
* 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");