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/*

    i2c-savage4.c - Part of lm_sensors, Linux kernel modules for hardware

              monitoring

    Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>,

    Philip Edelbrock <phil@netroedge.com>,

    Ralph Metzler <rjkm@thp.uni-koeln.de>, and

    Mark D. Studebaker <mdsxyz123@yahoo.com>

    Based on code written by Ralph Metzler <rjkm@thp.uni-koeln.de> and

    Simon Vogl

    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.

*/

/* This interfaces to the I2C bus of the Savage4 to gain access to

   the BT869 and possibly other I2C devices. The DDC bus is not

   yet supported because its register is not memory-mapped.

   However we leave the DDC code here, commented out, to make

   it easier to add later.

*/

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/pci.h>

#include <linux/i2c.h>

#include <linux/i2c-algo-bit.h>

#include <asm/io.h>

/* 3DFX defines */

#define PCI_CHIP_SAVAGE3D       0x8A20

#define PCI_CHIP_SAVAGE3D_MV    0x8A21

#define PCI_CHIP_SAVAGE4        0x8A22

#define PCI_CHIP_SAVAGE2000     0x9102

#define PCI_CHIP_PROSAVAGE_PM   0x8A25

#define PCI_CHIP_PROSAVAGE_KM   0x8A26

#define PCI_CHIP_SAVAGE_MX_MV   0x8c10

#define PCI_CHIP_SAVAGE_MX      0x8c11

#define PCI_CHIP_SAVAGE_IX_MV   0x8c12

#define PCI_CHIP_SAVAGE_IX      0x8c13

#define REG                     0xff20  /* Serial Port 1 Register */

/* bit locations in the register */

#define DDC_ENAB                0x00040000

#define DDC_SCL_OUT             0x00080000

#define DDC_SDA_OUT             0x00100000

#define DDC_SCL_IN              0x00200000

#define DDC_SDA_IN              0x00400000

#define I2C_ENAB                0x00000020

#define I2C_SCL_OUT             0x00000001

#define I2C_SDA_OUT             0x00000002

#define I2C_SCL_IN              0x00000008

#define I2C_SDA_IN              0x00000010

/* initialization states */

#define INIT2                   0x20

#define INIT3                   0x04

/* delays */

#define CYCLE_DELAY             10

#define TIMEOUT                 (HZ / 2)

static void *ioaddr;

/* The sav GPIO registers don't have individual masks for each bit

   so we always have to read before writing. */

static void bit_savi2c_setscl(void *data, int val)

{

        unsigned int r;

        r = readl(ioaddr + REG);

        if(val)

                r |= I2C_SCL_OUT;

        else

                r &= ~I2C_SCL_OUT;

        writel(r, ioaddr + REG);

        readl(ioaddr + REG);    /* flush posted write */

}

static void bit_savi2c_setsda(void *data, int val)

{

        unsigned int r;

        r = readl(ioaddr + REG);

        if(val)

                r |= I2C_SDA_OUT;

        else

                r &= ~I2C_SDA_OUT;

        writel(r, ioaddr + REG);

        readl(ioaddr + REG);    /* flush posted write */

}

/* The GPIO pins are open drain, so the pins always remain outputs.

   We rely on the i2c-algo-bit routines to set the pins high before

   reading the input from other chips. */

static int bit_savi2c_getscl(void *data)

{

        return (0 != (readl(ioaddr + REG) & I2C_SCL_IN));

}

static int bit_savi2c_getsda(void *data)

{

        return (0 != (readl(ioaddr + REG) & I2C_SDA_IN));

}

/* Configures the chip */

static int config_s4(struct pci_dev *dev)

{

        unsigned int cadr;

        /* map memory */

        cadr = dev->resource[0].start;

        cadr &= PCI_BASE_ADDRESS_MEM_MASK;

        ioaddr = ioremap_nocache(cadr, 0x0080000);

        if (ioaddr) {

                /* writel(0x8160, ioaddr + REG2); */

                writel(0x00000020, ioaddr + REG);

                dev_info(&dev->dev, "Using Savage4 at %p\n", ioaddr);

                return 0;

        }

        return -ENODEV;

}

static struct i2c_algo_bit_data sav_i2c_bit_data = {

        .setsda         = bit_savi2c_setsda,

        .setscl         = bit_savi2c_setscl,

        .getsda         = bit_savi2c_getsda,

        .getscl         = bit_savi2c_getscl,

        .udelay         = CYCLE_DELAY,

        .mdelay         = CYCLE_DELAY,

        .timeout        = TIMEOUT

};

static struct i2c_adapter savage4_i2c_adapter = {

        .owner          = THIS_MODULE,

        .name           = "I2C Savage4 adapter",

        .algo_data      = &sav_i2c_bit_data,

};

static struct pci_device_id savage4_ids[] __devinitdata = {

        { PCI_DEVICE(PCI_VENDOR_ID_S3, PCI_CHIP_SAVAGE4) },

        { PCI_DEVICE(PCI_VENDOR_ID_S3, PCI_CHIP_SAVAGE2000) },

        { 0, }

};

static int __devinit savage4_probe(struct pci_dev *dev, const struct pci_device_id *id)

{

        int retval;

        retval = config_s4(dev);

        if (retval)

                return retval;

        /* set up the sysfs linkage to our parent device */

        savage4_i2c_adapter.dev.parent = &dev->dev;

        return i2c_bit_add_bus(&savage4_i2c_adapter);

}

static void __devexit savage4_remove(struct pci_dev *dev)

{

        i2c_bit_del_bus(&savage4_i2c_adapter);

        iounmap(ioaddr);

}

static struct pci_driver savage4_driver = {

        .name           = "savage4 smbus",

        .id_table       = savage4_ids,

        .probe          = savage4_probe,

        .remove         = __devexit_p(savage4_remove),

};

static int __init i2c_savage4_init(void)

{

        return pci_module_init(&savage4_driver);

}

static void __exit i2c_savage4_exit(void)

{

        pci_unregister_driver(&savage4_driver);

}

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>, "

                "Philip Edelbrock <phil@netroedge.com>, "

                "Ralph Metzler <rjkm@thp.uni-koeln.de>, "

                "and Mark D. Studebaker <mdsxyz123@yahoo.com>");

MODULE_DESCRIPTION("Savage4 I2C/SMBus driver");

MODULE_LICENSE("GPL");

module_init(i2c_savage4_init);

module_exit(i2c_savage4_exit);