text: /*
   * 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>
  #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);
  #else /* CONFIG_OF */
  #define altera_ps2_match NULL
  #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 = altera_ps2_match,
  	},
  };
  module_platform_driver(altera_ps2_driver);
  
  MODULE_DESCRIPTION("Altera University Program PS2 controller driver");
  MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:" DRV_NAME);
  