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https://github.com/torvalds/linux
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1cad1de1b2
Signed-off-by: Christian Pellegrin <chripell@fsfe.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/*
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* L3 code
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*
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* Copyright (C) 2008, Christian Pellegrin <chripell@evolware.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*
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* based on:
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*
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* L3 bus algorithm module.
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*
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* Copyright (C) 2001 Russell King, All Rights Reserved.
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*
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <sound/l3.h>
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/*
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* Send one byte of data to the chip. Data is latched into the chip on
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* the rising edge of the clock.
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*/
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static void sendbyte(struct l3_pins *adap, unsigned int byte)
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{
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int i;
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for (i = 0; i < 8; i++) {
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adap->setclk(0);
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udelay(adap->data_hold);
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adap->setdat(byte & 1);
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udelay(adap->data_setup);
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adap->setclk(1);
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udelay(adap->clock_high);
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byte >>= 1;
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}
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}
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/*
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* Send a set of bytes to the chip. We need to pulse the MODE line
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* between each byte, but never at the start nor at the end of the
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* transfer.
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*/
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static void sendbytes(struct l3_pins *adap, const u8 *buf,
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int len)
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{
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int i;
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for (i = 0; i < len; i++) {
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if (i) {
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udelay(adap->mode_hold);
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adap->setmode(0);
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udelay(adap->mode);
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}
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adap->setmode(1);
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udelay(adap->mode_setup);
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sendbyte(adap, buf[i]);
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}
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}
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int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
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{
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adap->setclk(1);
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adap->setdat(1);
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adap->setmode(1);
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udelay(adap->mode);
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adap->setmode(0);
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udelay(adap->mode_setup);
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sendbyte(adap, addr);
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udelay(adap->mode_hold);
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sendbytes(adap, data, len);
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adap->setclk(1);
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adap->setdat(1);
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adap->setmode(0);
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return len;
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}
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EXPORT_SYMBOL_GPL(l3_write);
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MODULE_DESCRIPTION("L3 bit-banging driver");
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MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
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MODULE_LICENSE("GPL");
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