/*
 * Altera University Program PS2 controller driver
 *
 * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
 *
 * Based on sa1111ps2.c, which is:
 * Copyright (C) 2002 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>

#define DRV_NAME "altera_ps2"

struct ps2if {
        struct serio *io;
        struct resource *iomem_res;
        void __iomem *base;
        unsigned irq;
};

/*
 * Read all bytes waiting in the PS2 port.  There should be
 * at the most one, but we loop for safety.
 */
static irqreturn_t altera_ps2_rxint(int irq, void *dev_id)
{
        struct ps2if *ps2if = dev_id;
        unsigned int status;
        int handled = IRQ_NONE;

        while ((status = readl(ps2if->base)) & 0xffff0000) {
                serio_interrupt(ps2if->io, status & 0xff, 0);
                handled = IRQ_HANDLED;
        }

        return handled;
}

/*
 * Write a byte to the PS2 port.
 */
static int altera_ps2_write(struct serio *io, unsigned char val)
{
        struct ps2if *ps2if = io->port_data;

        writel(val, ps2if->base);
        return 0;
}

static int altera_ps2_open(struct serio *io)
{
        struct ps2if *ps2if = io->port_data;

        /* clear fifo */
        while (readl(ps2if->base) & 0xffff0000)
                /* empty */;

        writel(1, ps2if->base + 4); /* enable rx irq */
        return 0;
}

static void altera_ps2_close(struct serio *io)
{
        struct ps2if *ps2if = io->port_data;

        writel(0, ps2if->base); /* disable rx irq */
}

/*
 * Add one device to this driver.
 */
static int __devinit altera_ps2_probe(struct platform_device *pdev)
{
        struct ps2if *ps2if;
        struct serio *serio;
        int error, irq;

        ps2if = kzalloc(sizeof(struct ps2if), GFP_KERNEL);
        serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
        if (!ps2if || !serio) {
                error = -ENOMEM;
                goto err_free_mem;
        }

        serio->id.type          = SERIO_8042;
        serio->write            = altera_ps2_write;
        serio->open             = altera_ps2_open;
        serio->close            = altera_ps2_close;
        strlcpy(serio->name, dev_name(&pdev->dev), sizeof(serio->name));
        strlcpy(serio->phys, dev_name(&pdev->dev), sizeof(serio->phys));
        serio->port_data        = ps2if;
        serio->dev.parent       = &pdev->dev;
        ps2if->io               = serio;

        ps2if->iomem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (ps2if->iomem_res == NULL) {
                error = -ENOENT;
                goto err_free_mem;
        }


        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                error = -ENXIO;
                goto err_free_mem;
        }
        ps2if->irq = irq;

        if (!request_mem_region(ps2if->iomem_res->start,
                                resource_size(ps2if->iomem_res), pdev->name)) {
                error = -EBUSY;
                goto err_free_mem;
        }

        ps2if->base = ioremap(ps2if->iomem_res->start,
                              resource_size(ps2if->iomem_res));
        if (!ps2if->base) {
                error = -ENOMEM;
                goto err_free_res;
        }

        error = request_irq(ps2if->irq, altera_ps2_rxint, 0, pdev->name, ps2if);
        if (error) {
                dev_err(&pdev->dev, "could not allocate IRQ %d: %d\n",
                        ps2if->irq, error);
                goto err_unmap;
        }

        dev_info(&pdev->dev, "base %p, irq %d\n", ps2if->base, ps2if->irq);

        serio_register_port(ps2if->io);
        platform_set_drvdata(pdev, ps2if);

        return 0;

 err_unmap:
        iounmap(ps2if->base);
 err_free_res:
        release_mem_region(ps2if->iomem_res->start,
                           resource_size(ps2if->iomem_res));
 err_free_mem:
        kfree(ps2if);
        kfree(serio);
        return error;
}

/*
 * Remove one device from this driver.
 */
static int __devexit altera_ps2_remove(struct platform_device *pdev)
{
        struct ps2if *ps2if = platform_get_drvdata(pdev);

        platform_set_drvdata(pdev, NULL);
        serio_unregister_port(ps2if->io);
        free_irq(ps2if->irq, ps2if);
        iounmap(ps2if->base);
        release_mem_region(ps2if->iomem_res->start,
                           resource_size(ps2if->iomem_res));
        kfree(ps2if);

        return 0;
}

/*
 * Our device driver structure
 */
static struct platform_driver altera_ps2_driver = {
        .probe          = altera_ps2_probe,
        .remove         = __devexit_p(altera_ps2_remove),
        .driver = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
};

static int __init altera_ps2_init(void)
{
        return platform_driver_register(&altera_ps2_driver);
}

static void __exit altera_ps2_exit(void)
{
        platform_driver_unregister(&altera_ps2_driver);
}

module_init(altera_ps2_init);
module_exit(altera_ps2_exit);

MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);