/*
   *  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
  ",
  			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
  ",
  			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 ps2_clear_input(struct ps2if *ps2if)
  {
  	int maxread = 100;
  
  	while (maxread--) {
  		if ((sa1111_readl(ps2if->base + PS2DATA) & 0xff) == 0xff)
  			break;
  	}
  }
  
  static unsigned int 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 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
  ", stat);
  		ret = -ENODEV;
  	}
  
  	stat = ps2_test_one(ps2if, 0);
  	if (stat != (PS2STAT_KBC | PS2STAT_KBD)) {
  		printk("PS/2 interface test failed[2]: %02x
  ", stat);
  		ret = -ENODEV;
  	}
  
  	stat = ps2_test_one(ps2if, PS2CR_FKD);
  	if (stat != PS2STAT_KBC) {
  		printk("PS/2 interface test failed[3]: %02x
  ", stat);
  		ret = -ENODEV;
  	}
  
  	sa1111_writel(0, ps2if->base + PS2CR);
  
  	return ret;
  }
  
  /*
   * Add one device to this driver.
   */
  static int 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 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		= 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");