/*
 *  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 <asm/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)
{
        long ret = ~0;
        unsigned long timeout;

        if (irq > -1) {
                ret = wait_event_interruptible_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;
                while (((pca_isa_readbyte(pd, I2C_PCA_CON)
                                & I2C_PCA_CON_SI) == 0)
                                && (ret = time_before(jiffies, timeout)))
                        udelay(100);
        }
        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_interruptible(&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 <icampbell@arcom.com>");
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);