i2c-elektor.c 8.78 KB
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/* ------------------------------------------------------------------------- */
/* i2c-elektor.c i2c-hw access for PCF8584 style isa bus adaptes             */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-97 Simon G. Vogl
                   1998-99 Hans Berglund

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.		     */
/* ------------------------------------------------------------------------- */

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/* With some changes from Kyösti Mälkki <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 */

#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/wait.h>

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#include <linux/isa.h>
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#include <linux/i2c.h>
#include <linux/i2c-algo-pcf.h>

#include <asm/io.h>
#include <asm/irq.h>

#include "../algos/i2c-algo-pcf.h"

#define DEFAULT_BASE 0x330

static int base;
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static u8 __iomem *base_iomem;

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static int irq;
static int clock  = 0x1c;
static int own    = 0x55;
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
  in some functions, called from the algo-pcf module. Sometimes it's
  need to be rewriten - but for now just remove this for simpler reading */

static wait_queue_head_t pcf_wait;
static int pcf_pending;
static spinlock_t lock;

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static struct i2c_adapter pcf_isa_ops;

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/* ----- local functions ----------------------------------------------	*/

static void pcf_isa_setbyte(void *data, int ctl, int val)
{
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	u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
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	/* enable irq if any specified for serial operation */
	if (ctl && irq && (val & I2C_PCF_ESO)) {
		val |= I2C_PCF_ENI;
	}

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	pr_debug("%s: Write %p 0x%02X\n", pcf_isa_ops.name, address, val);
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	iowrite8(val, address);
#ifdef __alpha__
	/* API UP2000 needs some hardware fudging to make the write stick */
	iowrite8(val, address);
#endif
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}

static int pcf_isa_getbyte(void *data, int ctl)
{
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	u8 __iomem *address = ctl ? (base_iomem + 1) : base_iomem;
	int val = ioread8(address);
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	pr_debug("%s: Read %p 0x%02X\n", pcf_isa_ops.name, address, val);
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	return (val);
}

static int pcf_isa_getown(void *data)
{
	return (own);
}


static int pcf_isa_getclock(void *data)
{
	return (clock);
}

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static void pcf_isa_waitforpin(void *data)
{
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	DEFINE_WAIT(wait);
	int timeout = 2;
	unsigned long flags;

	if (irq > 0) {
		spin_lock_irqsave(&lock, flags);
		if (pcf_pending == 0) {
			spin_unlock_irqrestore(&lock, flags);
			prepare_to_wait(&pcf_wait, &wait, TASK_INTERRUPTIBLE);
			if (schedule_timeout(timeout*HZ)) {
				spin_lock_irqsave(&lock, flags);
				if (pcf_pending == 1) {
					pcf_pending = 0;
				}
				spin_unlock_irqrestore(&lock, flags);
			}
			finish_wait(&pcf_wait, &wait);
		} else {
			pcf_pending = 0;
			spin_unlock_irqrestore(&lock, flags);
		}
	} else {
		udelay(100);
	}
}


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static irqreturn_t pcf_isa_handler(int this_irq, void *dev_id) {
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	spin_lock(&lock);
	pcf_pending = 1;
	spin_unlock(&lock);
	wake_up_interruptible(&pcf_wait);
	return IRQ_HANDLED;
}


static int pcf_isa_init(void)
{
	spin_lock_init(&lock);
	if (!mmapped) {
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		if (!request_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested I/O region (%#x:2) is "
			       "in use\n", pcf_isa_ops.name, base);
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			return -ENODEV;
		}
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		base_iomem = ioport_map(base, 2);
		if (!base_iomem) {
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			printk(KERN_ERR "%s: remap of I/O region %#x failed\n",
			       pcf_isa_ops.name, base);
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			release_region(base, 2);
			return -ENODEV;
		}
	} else {
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		if (!request_mem_region(base, 2, pcf_isa_ops.name)) {
			printk(KERN_ERR "%s: requested memory region (%#x:2) "
			       "is in use\n", pcf_isa_ops.name, base);
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			return -ENODEV;
		}
		base_iomem = ioremap(base, 2);
		if (base_iomem == NULL) {
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			printk(KERN_ERR "%s: remap of memory region %#x "
			       "failed\n", pcf_isa_ops.name, base);
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			release_mem_region(base, 2);
			return -ENODEV;
		}
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	}
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	pr_debug("%s: registers %#x remapped to %p\n", pcf_isa_ops.name, base,
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		 base_iomem);

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	if (irq > 0) {
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		if (request_irq(irq, pcf_isa_handler, 0, pcf_isa_ops.name,
				NULL) < 0) {
			printk(KERN_ERR "%s: Request irq%d failed\n",
			       pcf_isa_ops.name, irq);
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			irq = 0;
		} else
			enable_irq(irq);
	}
	return 0;
}

/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */
static struct i2c_algo_pcf_data pcf_isa_data = {
	.setpcf	    = pcf_isa_setbyte,
	.getpcf	    = pcf_isa_getbyte,
	.getown	    = pcf_isa_getown,
	.getclock   = pcf_isa_getclock,
	.waitforpin = pcf_isa_waitforpin,
};

static struct i2c_adapter pcf_isa_ops = {
	.owner		= THIS_MODULE,
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	.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
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	.algo_data	= &pcf_isa_data,
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	.name		= "i2c-elektor",
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};

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static int __devinit elektor_match(struct device *dev, unsigned int id)
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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 */
	if (base == 0) {
		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);
		if (cy693_dev) {
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			unsigned char config;
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			/* yeap, we've found cypress, let's check config */
			if (!pci_read_config_byte(cy693_dev, 0x47, &config)) {
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				dev_dbg(dev, "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
				   (so, we can even enable Tsunami Pchip
				   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. */
				if ((config & 0x7f) == 0x61) {
					/* seems to be UP2000 like board */
					base = 0xe0000;
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					mmapped = 1;
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					/* UP2000 drives ISA with
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					   8.25 MHz (PCI/4) clock
					   (this can be read from cypress) */
					clock = I2C_PCF_CLK | I2C_PCF_TRNS90;
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					dev_info(dev, "found API UP2000 like "
						 "board, will probe PCF8584 "
						 "later\n");
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				}
			}
			pci_dev_put(cy693_dev);
		}
	}
#endif

	/* sanity checks for mmapped I/O */
	if (mmapped && base < 0xc8000) {
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		dev_err(dev, "incorrect base address (%#x) specified "
		       "for mmapped I/O\n", base);
		return 0;
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	}

	if (base == 0) {
		base = DEFAULT_BASE;
	}
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	return 1;
}
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static int __devinit elektor_probe(struct device *dev, unsigned int id)
{
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	init_waitqueue_head(&pcf_wait);
	if (pcf_isa_init())
		return -ENODEV;
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	pcf_isa_ops.dev.parent = dev;
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	if (i2c_pcf_add_bus(&pcf_isa_ops) < 0)
		goto fail;
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	dev_info(dev, "found device at %#x\n", base);
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	return 0;

 fail:
	if (irq > 0) {
		disable_irq(irq);
		free_irq(irq, NULL);
	}

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	if (!mmapped) {
		ioport_unmap(base_iomem);
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		release_region(base, 2);
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	} else {
		iounmap(base_iomem);
		release_mem_region(base, 2);
	}
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	return -ENODEV;
}

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static int __devexit elektor_remove(struct device *dev, unsigned int id)
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{
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	i2c_del_adapter(&pcf_isa_ops);
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	if (irq > 0) {
		disable_irq(irq);
		free_irq(irq, NULL);
	}

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	if (!mmapped) {
		ioport_unmap(base_iomem);
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		release_region(base, 2);
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	} else {
		iounmap(base_iomem);
		release_mem_region(base, 2);
	}
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	return 0;
}

static struct isa_driver i2c_elektor_driver = {
	.match		= elektor_match,
	.probe		= elektor_probe,
	.remove		= __devexit_p(elektor_remove),
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "i2c-elektor",
	},
};

static int __init i2c_pcfisa_init(void)
{
	return isa_register_driver(&i2c_elektor_driver, 1);
}

static void __exit i2c_pcfisa_exit(void)
{
	isa_unregister_driver(&i2c_elektor_driver);
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}

MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for PCF8584 ISA bus adapter");
MODULE_LICENSE("GPL");

module_param(base, int, 0);
module_param(irq, int, 0);
module_param(clock, int, 0);
module_param(own, int, 0);
module_param(mmapped, int, 0);

module_init(i2c_pcfisa_init);
module_exit(i2c_pcfisa_exit);