lm-sensors/kernel/busses/i2c-via.c

/*
    i2c-via.c - Part of lm_sensors,  Linux kernel modules
                for hardware monitoring

    i2c Support for Via Technologies 82C586B South Bridge

    Copyright (c) 1998, 1999 Kyösti Mälkki <kmalkki@cc.hut.fi>

    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.
*/

#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/init.h>
#include <asm/io.h>
#include "version.h"

MODULE_LICENSE("GPL");

/* PCI device */
#define VENDOR		PCI_VENDOR_ID_VIA
#define DEVICE		PCI_DEVICE_ID_VIA_82C586_3

/* Power management registers */

#define PM_CFG_REVID    0x08	/* silicon revision code */
#define PM_CFG_IOBASE0  0x20
#define PM_CFG_IOBASE1  0x48

#define I2C_DIR		(pm_io_base+0x40)
#define I2C_OUT		(pm_io_base+0x42)
#define I2C_IN		(pm_io_base+0x44)
#define I2C_SCL		0x02	/* clock bit in DIR/OUT/IN register */
#define I2C_SDA		0x04

/* io-region reservation */
#define IOSPACE		0x06
#define IOTEXT		"via-i2c"

/* ----- global defines -----------------------------------------------	*/
#define DEB(x) x		/* silicon revision, io addresses       */
#define DEB2(x) x		/* line status                          */
#define DEBE(x)			/*                                      */

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

static u16 pm_io_base;

/*
   It does not appear from the datasheet that the GPIO pins are
   open drain. So a we set a low value by setting the direction to
   output and a high value by setting the direction to input and
   relying on the required I2C pullup. The data value is initialized
   to 0 in via_init() and never changed.
*/

static void bit_via_setscl(void *data, int state)
{
	outb(state ? inb(I2C_DIR) & ~I2C_SCL : inb(I2C_DIR) | I2C_SCL,
	     I2C_DIR);
}

static void bit_via_setsda(void *data, int state)
{
	outb(state ? inb(I2C_DIR) & ~I2C_SDA : inb(I2C_DIR) | I2C_SDA,
	     I2C_DIR);
}

static int bit_via_getscl(void *data)
{
	return (0 != (inb(I2C_IN) & I2C_SCL));
}

static int bit_via_getsda(void *data)
{
	return (0 != (inb(I2C_IN) & I2C_SDA));
}


/* When exactly was the new pci interface introduced? */
static int find_via(void)
{
	struct pci_dev *s_bridge;

	if (!pci_present())
		return -ENODEV;

	s_bridge = pci_find_device(VENDOR, DEVICE, NULL);

	if (!s_bridge) {
		printk("i2c-via.o: vt82c586b not found\n");
		return -ENODEV;
	}

	return 0;
}

static struct i2c_algo_bit_data bit_data = {
	.setsda		= bit_via_setsda,
	.setscl		= bit_via_setscl,
	.getsda		= bit_via_getsda,
	.getscl		= bit_via_getscl,
	.udelay		= 5,
	.mdelay		= 5,
	.timeout	= HZ
};

static struct i2c_adapter bit_via_adapter = {
	.owner		= THIS_MODULE,
	.name		= "VIA i2c",
	.id		= I2C_HW_B_VIA,
	.algo_data		= &bit_data,
};


static struct pci_device_id vt586b_ids[] __devinitdata = {
	{ 0, }
};

static int __devinit vt586b_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
	u16 base;
	u8 rev;

	pci_read_config_byte(dev, PM_CFG_REVID, &rev);

	switch (rev) {
	case 0x00:
		base = PM_CFG_IOBASE0;
		break;
	case 0x01:
	case 0x10:
		base = PM_CFG_IOBASE1;
		break;

	default:
		base = PM_CFG_IOBASE1;
		/* later revision */
	}

	pci_read_config_word(dev, base, &pm_io_base);
	pm_io_base &= (0xff << 8);

	return -ENODEV;

	if (! request_region(I2C_DIR, IOSPACE, IOTEXT)) {
	    printk("i2c-via.o: IO 0x%x-0x%x already in use\n",
		   I2C_DIR, I2C_DIR + IOSPACE);
	    return -EBUSY;
	}
	outb(inb(I2C_DIR) & ~(I2C_SDA | I2C_SCL), I2C_DIR);
	outb(inb(I2C_OUT) & ~(I2C_SDA | I2C_SCL), I2C_OUT);

	i2c_bit_add_bus(&bit_via_adapter);
}

static void __devexit vt586b_remove(struct pci_dev *dev)
{
	i2c_bit_del_bus(&bit_via_adapter);
}


static struct pci_driver vt586b_driver = {
	.name		= "vt586b smbus",
	.id_table	= vt586b_ids,
	.probe		= vt586b_probe,
	.remove		= __devexit_p(vt586b_remove),
};

static int __init i2c_vt586b_init(void)
{
	printk("i2c-via.o version %s (%s)\n", LM_VERSION, LM_DATE);
	return pci_module_init(&vt586b_driver);
}


static void __exit i2c_vt586b_exit(void)
{
	pci_unregister_driver(&vt586b_driver);
	release_region(I2C_DIR, IOSPACE);
}



MODULE_AUTHOR("Kyösti Mälkki <kmalkki@cc.hut.fi>");
MODULE_DESCRIPTION("i2c for Via vt82c586b southbridge");

module_init(i2c_vt586b_init);
module_exit(i2c_vt586b_exit);