sa1111ps2.c

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/*
 *  linux/drivers/input/serio/sa1111ps2.c
 *
 *  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 as published by
 * the Free Software Foundation; either version 2 of the License.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/io.h>

#include <asm/hardware/sa1111.h>

#define PS2CR       0x0000
#define PS2STAT     0x0004
#define PS2DATA     0x0008
#define PS2CLKDIV   0x000c
#define PS2PRECNT   0x0010

#define PS2CR_ENA   0x08
#define PS2CR_FKD   0x02
#define PS2CR_FKC   0x01

#define PS2STAT_STP 0x0100
#define PS2STAT_TXE 0x0080
#define PS2STAT_TXB 0x0040
#define PS2STAT_RXF 0x0020
#define PS2STAT_RXB 0x0010
#define PS2STAT_ENA 0x0008
#define PS2STAT_RXP 0x0004
#define PS2STAT_KBD 0x0002
#define PS2STAT_KBC 0x0001

struct ps2if {
    struct serio        *io;
    struct sa1111_dev   *dev;
    void __iomem        *base;
    unsigned int        open;
    spinlock_t      lock;
    unsigned int        head;
    unsigned int        tail;
    unsigned char       buf[4];
};

/*
 * Read all bytes waiting in the PS2 port.  There should be
 * at the most one, but we loop for safety.  If there was a
 * framing error, we have to manually clear the status.
 */
static irqreturn_t ps2_rxint(int irq, void *dev_id)
{
    struct ps2if *ps2if = dev_id;
    unsigned int scancode, flag, status;

    status = sa1111_readl(ps2if->base + PS2STAT);
    while (status & PS2STAT_RXF) {
        if (status & PS2STAT_STP)
            sa1111_writel(PS2STAT_STP, ps2if->base + PS2STAT);

        flag = (status & PS2STAT_STP ? SERIO_FRAME : 0) |
               (status & PS2STAT_RXP ? 0 : SERIO_PARITY);

        scancode = sa1111_readl(ps2if->base + PS2DATA) & 0xff;

        if (hweight8(scancode) & 1)
            flag ^= SERIO_PARITY;

        serio_interrupt(ps2if->io, scancode, flag);

        status = sa1111_readl(ps2if->base + PS2STAT);
        }

        return IRQ_HANDLED;
}

/*
 * Completion of ps2 write
 */
static irqreturn_t ps2_txint(int irq, void *dev_id)
{
    struct ps2if *ps2if = dev_id;
    unsigned int status;

    spin_lock(&ps2if->lock);
    status = sa1111_readl(ps2if->base + PS2STAT);
    if (ps2if->head == ps2if->tail) {
        disable_irq_nosync(irq);
        /* done */
    } else if (status & PS2STAT_TXE) {
        sa1111_writel(ps2if->buf[ps2if->tail], ps2if->base + PS2DATA);
        ps2if->tail = (ps2if->tail + 1) & (sizeof(ps2if->buf) - 1);
    }
    spin_unlock(&ps2if->lock);

    return IRQ_HANDLED;
}

/*
 * Write a byte to the PS2 port.  We have to wait for the
 * port to indicate that the transmitter is empty.
 */
static int ps2_write(struct serio *io, unsigned char val)
{
    struct ps2if *ps2if = io->port_data;
    unsigned long flags;
    unsigned int head;

    spin_lock_irqsave(&ps2if->lock, flags);

    /*
     * If the TX register is empty, we can go straight out.
     */
    if (sa1111_readl(ps2if->base + PS2STAT) & PS2STAT_TXE) {
        sa1111_writel(val, ps2if->base + PS2DATA);
    } else {
        if (ps2if->head == ps2if->tail)
            enable_irq(ps2if->dev->irq[1]);
        head = (ps2if->head + 1) & (sizeof(ps2if->buf) - 1);
        if (head != ps2if->tail) {
            ps2if->buf[ps2if->head] = val;
            ps2if->head = head;
        }
    }

    spin_unlock_irqrestore(&ps2if->lock, flags);
    return 0;
}

static int ps2_open(struct serio *io)
{
    struct ps2if *ps2if = io->port_data;
    int ret;

    ret = sa1111_enable_device(ps2if->dev);
    if (ret)
        return ret;

    ret = request_irq(ps2if->dev->irq[0], ps2_rxint, 0,
              SA1111_DRIVER_NAME(ps2if->dev), ps2if);
    if (ret) {
        printk(KERN_ERR "sa1111ps2: could not allocate IRQ%d: %d\n",
            ps2if->dev->irq[0], ret);
        sa1111_disable_device(ps2if->dev);
        return ret;
    }

    ret = request_irq(ps2if->dev->irq[1], ps2_txint, 0,
              SA1111_DRIVER_NAME(ps2if->dev), ps2if);
    if (ret) {
        printk(KERN_ERR "sa1111ps2: could not allocate IRQ%d: %d\n",
            ps2if->dev->irq[1], ret);
        free_irq(ps2if->dev->irq[0], ps2if);
        sa1111_disable_device(ps2if->dev);
        return ret;
    }

    ps2if->open = 1;

    enable_irq_wake(ps2if->dev->irq[0]);

    sa1111_writel(PS2CR_ENA, ps2if->base + PS2CR);
    return 0;
}

static void ps2_close(struct serio *io)
{
    struct ps2if *ps2if = io->port_data;

    sa1111_writel(0, ps2if->base + PS2CR);

    disable_irq_wake(ps2if->dev->irq[0]);

    ps2if->open = 0;

    free_irq(ps2if->dev->irq[1], ps2if);
    free_irq(ps2if->dev->irq[0], ps2if);

    sa1111_disable_device(ps2if->dev);
}

/*
 * Clear the input buffer.
 */
static void __devinit ps2_clear_input(struct ps2if *ps2if)
{
    int maxread = 100;

    while (maxread--) {
        if ((sa1111_readl(ps2if->base + PS2DATA) & 0xff) == 0xff)
            break;
    }
}

static unsigned int __devinit ps2_test_one(struct ps2if *ps2if,
                       unsigned int mask)
{
    unsigned int val;

    sa1111_writel(PS2CR_ENA | mask, ps2if->base + PS2CR);

    udelay(2);

    val = sa1111_readl(ps2if->base + PS2STAT);
    return val & (PS2STAT_KBC | PS2STAT_KBD);
}

/*
 * Test the keyboard interface.  We basically check to make sure that
 * we can drive each line to the keyboard independently of each other.
 */
static int __devinit ps2_test(struct ps2if *ps2if)
{
    unsigned int stat;
    int ret = 0;

    stat = ps2_test_one(ps2if, PS2CR_FKC);
    if (stat != PS2STAT_KBD) {
        printk("PS/2 interface test failed[1]: %02x\n", stat);
        ret = -ENODEV;
    }

    stat = ps2_test_one(ps2if, 0);
    if (stat != (PS2STAT_KBC | PS2STAT_KBD)) {
        printk("PS/2 interface test failed[2]: %02x\n", stat);
        ret = -ENODEV;
    }

    stat = ps2_test_one(ps2if, PS2CR_FKD);
    if (stat != PS2STAT_KBC) {
        printk("PS/2 interface test failed[3]: %02x\n", stat);
        ret = -ENODEV;
    }

    sa1111_writel(0, ps2if->base + PS2CR);

    return ret;
}

/*
 * Add one device to this driver.
 */
static int __devinit ps2_probe(struct sa1111_dev *dev)
{
    struct ps2if *ps2if;
    struct serio *serio;
    int ret;

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


    serio->id.type      = SERIO_8042;
    serio->write        = ps2_write;
    serio->open     = ps2_open;
    serio->close        = ps2_close;
    strlcpy(serio->name, dev_name(&dev->dev), sizeof(serio->name));
    strlcpy(serio->phys, dev_name(&dev->dev), sizeof(serio->phys));
    serio->port_data    = ps2if;
    serio->dev.parent   = &dev->dev;
    ps2if->io       = serio;
    ps2if->dev      = dev;
    sa1111_set_drvdata(dev, ps2if);

    spin_lock_init(&ps2if->lock);

    /*
     * Request the physical region for this PS2 port.
     */
    if (!request_mem_region(dev->res.start,
                dev->res.end - dev->res.start + 1,
                SA1111_DRIVER_NAME(dev))) {
        ret = -EBUSY;
        goto free;
    }

    /*
     * Our parent device has already mapped the region.
     */
    ps2if->base = dev->mapbase;

    sa1111_enable_device(ps2if->dev);

    /* Incoming clock is 8MHz */
    sa1111_writel(0, ps2if->base + PS2CLKDIV);
    sa1111_writel(127, ps2if->base + PS2PRECNT);

    /*
     * Flush any pending input.
     */
    ps2_clear_input(ps2if);

    /*
     * Test the keyboard interface.
     */
    ret = ps2_test(ps2if);
    if (ret)
        goto out;

    /*
     * Flush any pending input.
     */
    ps2_clear_input(ps2if);

    sa1111_disable_device(ps2if->dev);
    serio_register_port(ps2if->io);
    return 0;

 out:
    sa1111_disable_device(ps2if->dev);
    release_mem_region(dev->res.start, resource_size(&dev->res));
 free:
    sa1111_set_drvdata(dev, NULL);
    kfree(ps2if);
    kfree(serio);
    return ret;
}

/*
 * Remove one device from this driver.
 */
static int __devexit ps2_remove(struct sa1111_dev *dev)
{
    struct ps2if *ps2if = sa1111_get_drvdata(dev);

    serio_unregister_port(ps2if->io);
    release_mem_region(dev->res.start, resource_size(&dev->res));
    sa1111_set_drvdata(dev, NULL);

    kfree(ps2if);

    return 0;
}

/*
 * Our device driver structure
 */
static struct sa1111_driver ps2_driver = {
    .drv = {
        .name   = "sa1111-ps2",
        .owner  = THIS_MODULE,
    },
    .devid      = SA1111_DEVID_PS2,
    .probe      = ps2_probe,
    .remove     = __devexit_p(ps2_remove),
};

static int __init ps2_init(void)
{
    return sa1111_driver_register(&ps2_driver);
}

static void __exit ps2_exit(void)
{
    sa1111_driver_unregister(&ps2_driver);
}

module_init(ps2_init);
module_exit(ps2_exit);

MODULE_AUTHOR("Russell King <[email protected]>");
MODULE_DESCRIPTION("SA1111 PS2 controller driver");
MODULE_LICENSE("GPL");