295 lines
7.9 KiB
C
295 lines
7.9 KiB
C
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/* ------------------------------------------------------------------------- */
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/* i2c-elektor.c i2c-hw access for PCF8584 style isa bus adaptes */
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/* ------------------------------------------------------------------------- */
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/* Copyright (C) 1995-97 Simon G. Vogl
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1998-99 Hans Berglund
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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 as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* ------------------------------------------------------------------------- */
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/* With some changes from Ky<4B>sti M<>lkki <kmalkki@cc.hut.fi> and even
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Frodo Looijaard <frodol@dds.nl> */
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/* Partialy rewriten by Oleg I. Vdovikin for mmapped support of
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for Alpha Processor Inc. UP-2000(+) boards */
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#include <linux/kernel.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/pci.h>
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#include <linux/wait.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-pcf.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include "../algos/i2c-algo-pcf.h"
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#define DEFAULT_BASE 0x330
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static int base;
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static int irq;
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static int clock = 0x1c;
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static int own = 0x55;
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static int mmapped;
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/* vdovikin: removed static struct i2c_pcf_isa gpi; code -
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this module in real supports only one device, due to missing arguments
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in some functions, called from the algo-pcf module. Sometimes it's
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need to be rewriten - but for now just remove this for simpler reading */
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static wait_queue_head_t pcf_wait;
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static int pcf_pending;
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static spinlock_t lock;
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/* ----- local functions ---------------------------------------------- */
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static void pcf_isa_setbyte(void *data, int ctl, int val)
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{
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int address = ctl ? (base + 1) : base;
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/* enable irq if any specified for serial operation */
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if (ctl && irq && (val & I2C_PCF_ESO)) {
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val |= I2C_PCF_ENI;
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}
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pr_debug("i2c-elektor: Write 0x%X 0x%02X\n", address, val & 255);
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switch (mmapped) {
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case 0: /* regular I/O */
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outb(val, address);
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break;
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case 2: /* double mapped I/O needed for UP2000 board,
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I don't know why this... */
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writeb(val, (void *)address);
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/* fall */
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case 1: /* memory mapped I/O */
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writeb(val, (void *)address);
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break;
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}
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}
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static int pcf_isa_getbyte(void *data, int ctl)
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{
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int address = ctl ? (base + 1) : base;
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int val = mmapped ? readb((void *)address) : inb(address);
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pr_debug("i2c-elektor: Read 0x%X 0x%02X\n", address, val);
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return (val);
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}
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static int pcf_isa_getown(void *data)
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{
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return (own);
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}
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static int pcf_isa_getclock(void *data)
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{
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return (clock);
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}
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static void pcf_isa_waitforpin(void) {
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DEFINE_WAIT(wait);
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int timeout = 2;
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unsigned long flags;
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if (irq > 0) {
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spin_lock_irqsave(&lock, flags);
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if (pcf_pending == 0) {
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spin_unlock_irqrestore(&lock, flags);
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prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
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if (schedule_timeout(timeout*HZ)) {
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spin_lock_irqsave(&lock, flags);
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if (pcf_pending == 1) {
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pcf_pending = 0;
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}
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spin_unlock_irqrestore(&lock, flags);
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}
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finish_wait(&pcf_wait, &wait);
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} else {
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pcf_pending = 0;
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spin_unlock_irqrestore(&lock, flags);
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}
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} else {
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udelay(100);
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}
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}
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static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id, struct pt_regs *regs) {
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spin_lock(&lock);
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pcf_pending = 1;
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spin_unlock(&lock);
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wake_up_interruptible(&pcf_wait);
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return IRQ_HANDLED;
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}
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static int pcf_isa_init(void)
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{
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spin_lock_init(&lock);
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if (!mmapped) {
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if (!request_region(base, 2, "i2c (isa bus adapter)")) {
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printk(KERN_ERR
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"i2c-elektor: requested I/O region (0x%X:2) "
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"is in use.\n", base);
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return -ENODEV;
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}
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}
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if (irq > 0) {
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if (request_irq(irq, pcf_isa_handler, 0, "PCF8584", NULL) < 0) {
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printk(KERN_ERR "i2c-elektor: Request irq%d failed\n", irq);
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irq = 0;
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} else
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enable_irq(irq);
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}
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return 0;
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}
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/* ------------------------------------------------------------------------
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* Encapsulate the above functions in the correct operations structure.
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* This is only done when more than one hardware adapter is supported.
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*/
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static struct i2c_algo_pcf_data pcf_isa_data = {
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.setpcf = pcf_isa_setbyte,
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.getpcf = pcf_isa_getbyte,
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.getown = pcf_isa_getown,
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.getclock = pcf_isa_getclock,
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.waitforpin = pcf_isa_waitforpin,
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.udelay = 10,
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.mdelay = 10,
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.timeout = 100,
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};
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static struct i2c_adapter pcf_isa_ops = {
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.owner = THIS_MODULE,
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.class = I2C_CLASS_HWMON,
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.id = I2C_HW_P_ELEK,
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.algo_data = &pcf_isa_data,
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.name = "PCF8584 ISA adapter",
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};
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static int __init i2c_pcfisa_init(void)
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{
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#ifdef __alpha__
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/* check to see we have memory mapped PCF8584 connected to the
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Cypress cy82c693 PCI-ISA bridge as on UP2000 board */
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if (base == 0) {
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struct pci_dev *cy693_dev;
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cy693_dev = pci_get_device(PCI_VENDOR_ID_CONTAQ,
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PCI_DEVICE_ID_CONTAQ_82C693, NULL);
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if (cy693_dev) {
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char config;
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/* yeap, we've found cypress, let's check config */
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if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
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pr_debug("i2c-elektor: found cy82c693, config register 0x47 = 0x%02x.\n", config);
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/* UP2000 board has this register set to 0xe1,
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but the most significant bit as seems can be
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reset during the proper initialisation
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sequence if guys from API decides to do that
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(so, we can even enable Tsunami Pchip
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window for the upper 1 Gb) */
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/* so just check for ROMCS at 0xe0000,
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ROMCS enabled for writes
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and external XD Bus buffer in use. */
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if ((config & 0x7f) == 0x61) {
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/* seems to be UP2000 like board */
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base = 0xe0000;
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/* I don't know why we need to
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write twice */
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mmapped = 2;
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/* UP2000 drives ISA with
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8.25 MHz (PCI/4) clock
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(this can be read from cypress) */
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clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
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printk(KERN_INFO "i2c-elektor: found API UP2000 like board, will probe PCF8584 later.\n");
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}
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}
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pci_dev_put(cy693_dev);
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}
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}
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#endif
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/* sanity checks for mmapped I/O */
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if (mmapped && base < 0xc8000) {
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printk(KERN_ERR "i2c-elektor: incorrect base address (0x%0X) specified for mmapped I/O.\n", base);
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return -ENODEV;
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}
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printk(KERN_INFO "i2c-elektor: i2c pcf8584-isa adapter driver\n");
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if (base == 0) {
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base = DEFAULT_BASE;
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}
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init_waitqueue_head(&pcf_wait);
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if (pcf_isa_init())
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return -ENODEV;
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if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
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goto fail;
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printk(KERN_ERR "i2c-elektor: found device at %#x.\n", base);
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return 0;
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fail:
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if (irq > 0) {
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disable_irq(irq);
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free_irq(irq, NULL);
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}
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if (!mmapped)
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release_region(base , 2);
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return -ENODEV;
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}
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static void i2c_pcfisa_exit(void)
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{
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i2c_pcf_del_bus(&pcf_isa_ops);
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if (irq > 0) {
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disable_irq(irq);
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free_irq(irq, NULL);
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}
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if (!mmapped)
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release_region(base , 2);
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}
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MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
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MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
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MODULE_LICENSE("GPL");
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module_param(base, int, 0);
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module_param(irq, int, 0);
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module_param(clock, int, 0);
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module_param(own, int, 0);
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module_param(mmapped, int, 0);
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module_init(i2c_pcfisa_init);
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module_exit(i2c_pcfisa_exit);
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