altera_ps2.c

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/*
 * Altera University Program PS2 controller driver
 *
 * Copyright (C) 2008 Thomas Chou <[email protected]>
 *
 * 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>
#include <linux/of.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;
}

#ifdef CONFIG_OF
static const struct of_device_id altera_ps2_match[] = {
    { .compatible = "ALTR,ps2-1.0", },
    {},
};
MODULE_DEVICE_TABLE(of, altera_ps2_match);
#endif /* CONFIG_OF */

/*
 * 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,
        .of_match_table = of_match_ptr(altera_ps2_match),
    },
};
module_platform_driver(altera_ps2_driver);

MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
MODULE_AUTHOR("Thomas Chou <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);