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sa1111ps2.c

/*
 *  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/system.h>

#include <asm/hardware/sa1111.h>

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 + SA1111_PS2STAT);
      while (status & PS2STAT_RXF) {
            if (status & PS2STAT_STP)
                  sa1111_writel(PS2STAT_STP, ps2if->base + SA1111_PS2STAT);

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

            scancode = sa1111_readl(ps2if->base + SA1111_PS2DATA) & 0xff;

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

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

            status = sa1111_readl(ps2if->base + SA1111_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 + SA1111_PS2STAT);
      if (ps2if->head == ps2if->tail) {
            disable_irq(irq);
            /* done */
      } else if (status & PS2STAT_TXE) {
            sa1111_writel(ps2if->buf[ps2if->tail], ps2if->base + SA1111_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 + SA1111_PS2STAT) & PS2STAT_TXE) {
            sa1111_writel(val, ps2if->base + SA1111_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;

      sa1111_enable_device(ps2if->dev);

      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);
            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);
            return ret;
      }

      ps2if->open = 1;

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

      sa1111_writel(PS2CR_ENA, ps2if->base + SA1111_PS2CR);
      return 0;
}

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

      sa1111_writel(0, ps2if->base + SA1111_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 + SA1111_PS2DATA) & 0xff) == 0xff)
                  break;
      }
}

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

      sa1111_writel(PS2CR_ENA | mask, ps2if->base + SA1111_PS2CR);

      udelay(2);

      val = sa1111_readl(ps2if->base + SA1111_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 __init 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 + SA1111_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->dev.bus_id, sizeof(serio->name));
      strlcpy(serio->phys, dev->dev.bus_id, 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 + SA1111_PS2CLKDIV);
      sa1111_writel(127, ps2if->base + SA1111_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,
                     dev->res.end - dev->res.start + 1);
 free:
      sa1111_set_drvdata(dev, NULL);
      kfree(ps2if);
      kfree(serio);
      return ret;
}

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

      serio_unregister_port(ps2if->io);
      release_mem_region(dev->res.start,
                     dev->res.end - dev->res.start + 1);
      sa1111_set_drvdata(dev, NULL);

      kfree(ps2if);

      return 0;
}

/*
 * Our device driver structure
 */
static struct sa1111_driver ps2_driver = {
      .drv = {
            .name = "sa1111-ps2",
      },
      .devid            = SA1111_DEVID_PS2,
      .probe            = ps2_probe,
      .remove           = 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 <rmk@arm.linux.org.uk>");
MODULE_DESCRIPTION("SA1111 PS2 controller driver");
MODULE_LICENSE("GPL");

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