i2c-pca-isa.c

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/*
 *  i2c-pca-isa.c driver for PCA9564 on ISA boards
 *    Copyright (C) 2004 Arcom Control Systems
 *    Copyright (C) 2008 Pengutronix
 *
 *  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/moduleparam.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/isa.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>
#include <linux/io.h>

#include <asm/irq.h>

#define DRIVER "i2c-pca-isa"
#define IO_SIZE 4

static unsigned long base;
static int irq = -1;

/* Data sheet recommends 59kHz for 100kHz operation due to variation
 * in the actual clock rate */
static int clock  = 59000;

static struct i2c_adapter pca_isa_ops;
static wait_queue_head_t pca_wait;

static void pca_isa_writebyte(void *pd, int reg, int val)
{
#ifdef DEBUG_IO
    static char *names[] = { "T/O", "DAT", "ADR", "CON" };
    printk(KERN_DEBUG "*** write %s at %#lx <= %#04x\n", names[reg],
           base+reg, val);
#endif
    outb(val, base+reg);
}

static int pca_isa_readbyte(void *pd, int reg)
{
    int res = inb(base+reg);
#ifdef DEBUG_IO
    {
        static char *names[] = { "STA", "DAT", "ADR", "CON" };
        printk(KERN_DEBUG "*** read  %s => %#04x\n", names[reg], res);
    }
#endif
    return res;
}

static int pca_isa_waitforcompletion(void *pd)
{
    unsigned long timeout;
    long ret;

    if (irq > -1) {
        ret = wait_event_timeout(pca_wait,
                pca_isa_readbyte(pd, I2C_PCA_CON)
                & I2C_PCA_CON_SI, pca_isa_ops.timeout);
    } else {
        /* Do polling */
        timeout = jiffies + pca_isa_ops.timeout;
        do {
            ret = time_before(jiffies, timeout);
            if (pca_isa_readbyte(pd, I2C_PCA_CON)
                    & I2C_PCA_CON_SI)
                break;
            udelay(100);
        } while (ret);
    }

    return ret > 0;
}

static void pca_isa_resetchip(void *pd)
{
    /* apparently only an external reset will do it. not a lot can be done */
    printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
}

static irqreturn_t pca_handler(int this_irq, void *dev_id) {
    wake_up(&pca_wait);
    return IRQ_HANDLED;
}

static struct i2c_algo_pca_data pca_isa_data = {
    /* .data intentionally left NULL, not needed with ISA */
    .write_byte     = pca_isa_writebyte,
    .read_byte      = pca_isa_readbyte,
    .wait_for_completion    = pca_isa_waitforcompletion,
    .reset_chip     = pca_isa_resetchip,
};

static struct i2c_adapter pca_isa_ops = {
    .owner          = THIS_MODULE,
    .algo_data  = &pca_isa_data,
    .name       = "PCA9564/PCA9665 ISA Adapter",
    .timeout    = HZ,
};

static int __devinit pca_isa_match(struct device *dev, unsigned int id)
{
    int match = base != 0;

    if (match) {
        if (irq <= -1)
            dev_warn(dev, "Using polling mode (specify irq)\n");
    } else
        dev_err(dev, "Please specify I/O base\n");

    return match;
}

static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
{
    init_waitqueue_head(&pca_wait);

    dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq);

#ifdef CONFIG_PPC
    if (check_legacy_ioport(base)) {
        dev_err(dev, "I/O address %#08lx is not available\n", base);
        goto out;
    }
#endif

    if (!request_region(base, IO_SIZE, "i2c-pca-isa")) {
        dev_err(dev, "I/O address %#08lx is in use\n", base);
        goto out;
    }

    if (irq > -1) {
        if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) {
            dev_err(dev, "Request irq%d failed\n", irq);
            goto out_region;
        }
    }

    pca_isa_data.i2c_clock = clock;
    if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
        dev_err(dev, "Failed to add i2c bus\n");
        goto out_irq;
    }

    return 0;

 out_irq:
    if (irq > -1)
        free_irq(irq, &pca_isa_ops);
 out_region:
    release_region(base, IO_SIZE);
 out:
    return -ENODEV;
}

static int __devexit pca_isa_remove(struct device *dev, unsigned int id)
{
    i2c_del_adapter(&pca_isa_ops);

    if (irq > -1) {
        disable_irq(irq);
        free_irq(irq, &pca_isa_ops);
    }
    release_region(base, IO_SIZE);

    return 0;
}

static struct isa_driver pca_isa_driver = {
    .match      = pca_isa_match,
    .probe      = pca_isa_probe,
    .remove     = __devexit_p(pca_isa_remove),
    .driver = {
        .owner  = THIS_MODULE,
        .name   = DRIVER,
    }
};

static int __init pca_isa_init(void)
{
    return isa_register_driver(&pca_isa_driver, 1);
}

static void __exit pca_isa_exit(void)
{
    isa_unregister_driver(&pca_isa_driver);
}

MODULE_AUTHOR("Ian Campbell <[email protected]>");
MODULE_DESCRIPTION("ISA base PCA9564/PCA9665 driver");
MODULE_LICENSE("GPL");

module_param(base, ulong, 0);
MODULE_PARM_DESC(base, "I/O base address");

module_param(irq, int, 0);
MODULE_PARM_DESC(irq, "IRQ");
module_param(clock, int, 0);
MODULE_PARM_DESC(clock, "Clock rate in hertz.\n\t\t"
        "For PCA9564: 330000,288000,217000,146000,"
        "88000,59000,44000,36000\n"
        "\t\tFor PCA9665:\tStandard: 60300 - 100099\n"
        "\t\t\t\tFast: 100100 - 400099\n"
        "\t\t\t\tFast+: 400100 - 10000099\n"
        "\t\t\t\tTurbo: Up to 1265800");

module_init(pca_isa_init);
module_exit(pca_isa_exit);