drivers/input/serio/xilinx_ps2.c - linux - Git at Google

 /*
  * Xilinx XPS PS/2 device driver
  *
  * (c) 2005 MontaVista Software, Inc.
  * (c) 2008 Xilinx, Inc.
  *
  * 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, or (at your
  * option) any later version.
  *
  * You should have received a copy of the GNU General Public License along
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 675 Mass Ave, Cambridge, MA 02139, USA.
  */


 #include <linux/module.h>
 #include <linux/serio.h>
 #include <linux/interrupt.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/io.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_platform.h>

 #define DRIVER_NAME		"xilinx_ps2"

 /* Register offsets for the xps2 device */
 #define XPS2_SRST_OFFSET	0x00000000 /* Software Reset register */
 #define XPS2_STATUS_OFFSET	0x00000004 /* Status register */
 #define XPS2_RX_DATA_OFFSET	0x00000008 /* Receive Data register */
 #define XPS2_TX_DATA_OFFSET	0x0000000C /* Transmit Data register */
 #define XPS2_GIER_OFFSET	0x0000002C /* Global Interrupt Enable reg */
 #define XPS2_IPISR_OFFSET	0x00000030 /* Interrupt Status register */
 #define XPS2_IPIER_OFFSET	0x00000038 /* Interrupt Enable register */

 /* Reset Register Bit Definitions */
 #define XPS2_SRST_RESET		0x0000000A /* Software Reset  */

 /* Status Register Bit Positions */
 #define XPS2_STATUS_RX_FULL	0x00000001 /* Receive Full  */
 #define XPS2_STATUS_TX_FULL	0x00000002 /* Transmit Full  */

 /* Bit definitions for ISR/IER registers. Both the registers have the same bit
  * definitions and are only defined once. */
 #define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
 #define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
 #define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
 #define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
 #define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
 #define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */

 /* Mask for all the Transmit Interrupts */
 #define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)

 /* Mask for all the Receive Interrupts */
 #define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
 				 XPS2_IPIXR_RX_FULL)

 /* Mask for all the Interrupts */
 #define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
 				 XPS2_IPIXR_WDT_TOUT)

 /* Global Interrupt Enable mask */
 #define XPS2_GIER_GIE_MASK	0x80000000

 struct xps2data {
 	int irq;
 	spinlock_t lock;
 	void __iomem *base_address;	/* virt. address of control registers */
 	unsigned int flags;
 	struct serio serio;		/* serio */
 };

 /************************************/
 /* XPS PS/2 data transmission calls */
 /************************************/

 /**
  * xps2_recv() - attempts to receive a byte from the PS/2 port.
  * @drvdata:	pointer to ps2 device private data structure
  * @byte:	address where the read data will be copied
  *
  * If there is any data available in the PS/2 receiver, this functions reads
  * the data, otherwise it returns error.
  */
 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
 {
 	u32 sr;
 	int status = -1;

 	/* If there is data available in the PS/2 receiver, read it */
 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 	if (sr & XPS2_STATUS_RX_FULL) {
 		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
 		status = 0;
 	}

 	return status;
 }

 /*********************/
 /* Interrupt handler */
 /*********************/
 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
 {
 	struct xps2data *drvdata = dev_id;
 	u32 intr_sr;
 	u8 c;
 	int status;

 	/* Get the PS/2 interrupts and clear them */
 	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
 	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);

 	/* Check which interrupt is active */
 	if (intr_sr & XPS2_IPIXR_RX_OVF)
 		dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");

 	if (intr_sr & XPS2_IPIXR_RX_ERR)
 		drvdata->flags |= SERIO_PARITY;

 	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
 		drvdata->flags |= SERIO_TIMEOUT;

 	if (intr_sr & XPS2_IPIXR_RX_FULL) {
 		status = xps2_recv(drvdata, &c);

 		/* Error, if a byte is not received */
 		if (status) {
 			dev_err(drvdata->serio.dev.parent,
 				"wrong rcvd byte count (%d)\n", status);
 		} else {
 			serio_interrupt(&drvdata->serio, c, drvdata->flags);
 			drvdata->flags = 0;
 		}
 	}

 	return IRQ_HANDLED;
 }

 /*******************/
 /* serio callbacks */
 /*******************/

 /**
  * sxps2_write() - sends a byte out through the PS/2 port.
  * @pserio:	pointer to the serio structure of the PS/2 port
  * @c:		data that needs to be written to the PS/2 port
  *
  * This function checks if the PS/2 transmitter is empty and sends a byte.
  * Otherwise it returns error. Transmission fails only when nothing is connected
  * to the PS/2 port. Thats why, we do not try to resend the data in case of a
  * failure.
  */
 static int sxps2_write(struct serio *pserio, unsigned char c)
 {
 	struct xps2data *drvdata = pserio->port_data;
 	unsigned long flags;
 	u32 sr;
 	int status = -1;

 	spin_lock_irqsave(&drvdata->lock, flags);

 	/* If the PS/2 transmitter is empty send a byte of data */
 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
 	if (!(sr & XPS2_STATUS_TX_FULL)) {
 		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
 		status = 0;
 	}

 	spin_unlock_irqrestore(&drvdata->lock, flags);

 	return status;
 }

 /**
  * sxps2_open() - called when a port is opened by the higher layer.
  * @pserio:	pointer to the serio structure of the PS/2 device
  *
  * This function requests irq and enables interrupts for the PS/2 device.
  */
 static int sxps2_open(struct serio *pserio)
 {
 	struct xps2data *drvdata = pserio->port_data;
 	int error;
 	u8 c;

 	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
 				DRIVER_NAME, drvdata);
 	if (error) {
 		dev_err(drvdata->serio.dev.parent,
 			"Couldn't allocate interrupt %d\n", drvdata->irq);
 		return error;
 	}

 	/* start reception by enabling the interrupts */
 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
 	(void)xps2_recv(drvdata, &c);

 	return 0;		/* success */
 }

 /**
  * sxps2_close() - frees the interrupt.
  * @pserio:	pointer to the serio structure of the PS/2 device
  *
  * This function frees the irq and disables interrupts for the PS/2 device.
  */
 static void sxps2_close(struct serio *pserio)
 {
 	struct xps2data *drvdata = pserio->port_data;

 	/* Disable the PS2 interrupts */
 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
 	free_irq(drvdata->irq, drvdata);
 }

 /**
  * xps2_of_probe - probe method for the PS/2 device.
  * @of_dev:	pointer to OF device structure
  * @match:	pointer to the structure used for matching a device
  *
  * This function probes the PS/2 device in the device tree.
  * It initializes the driver data structure and the hardware.
  * It returns 0, if the driver is bound to the PS/2 device, or a negative
  * value if there is an error.
  */
 static int __devinit xps2_of_probe(struct platform_device *ofdev)
 {
 	struct resource r_irq; /* Interrupt resources */
 	struct resource r_mem; /* IO mem resources */
 	struct xps2data *drvdata;
 	struct serio *serio;
 	struct device *dev = &ofdev->dev;
 	resource_size_t remap_size, phys_addr;
 	int error;

 	dev_info(dev, "Device Tree Probing \'%s\'\n",
 			ofdev->dev.of_node->name);

 	/* Get iospace for the device */
 	error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
 	if (error) {
 		dev_err(dev, "invalid address\n");
 		return error;
 	}

 	/* Get IRQ for the device */
 	if (of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq) == NO_IRQ) {
 		dev_err(dev, "no IRQ found\n");
 		return -ENODEV;
 	}

 	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
 	if (!drvdata) {
 		dev_err(dev, "Couldn't allocate device private record\n");
 		return -ENOMEM;
 	}

 	dev_set_drvdata(dev, drvdata);

 	spin_lock_init(&drvdata->lock);
 	drvdata->irq = r_irq.start;

 	phys_addr = r_mem.start;
 	remap_size = resource_size(&r_mem);
 	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
 		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
 			(unsigned long long)phys_addr);
 		error = -EBUSY;
 		goto failed1;
 	}

 	/* Fill in configuration data and add them to the list */
 	drvdata->base_address = ioremap(phys_addr, remap_size);
 	if (drvdata->base_address == NULL) {
 		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
 			(unsigned long long)phys_addr);
 		error = -EFAULT;
 		goto failed2;
 	}

 	/* Disable all the interrupts, just in case */
 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);

 	/* Reset the PS2 device and abort any current transaction, to make sure
 	 * we have the PS2 in a good state */
 	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);

 	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
 		 (unsigned long long)phys_addr, drvdata->base_address,
 		 drvdata->irq);

 	serio = &drvdata->serio;
 	serio->id.type = SERIO_8042;
 	serio->write = sxps2_write;
 	serio->open = sxps2_open;
 	serio->close = sxps2_close;
 	serio->port_data = drvdata;
 	serio->dev.parent = dev;
 	snprintf(serio->name, sizeof(serio->name),
 		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
 	snprintf(serio->phys, sizeof(serio->phys),
 		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);

 	serio_register_port(serio);

 	return 0;		/* success */

 failed2:
 	release_mem_region(phys_addr, remap_size);
 failed1:
 	kfree(drvdata);
 	dev_set_drvdata(dev, NULL);

 	return error;
 }

 /**
  * xps2_of_remove - unbinds the driver from the PS/2 device.
  * @of_dev:	pointer to OF device structure
  *
  * This function is called if a device is physically removed from the system or
  * if the driver module is being unloaded. It frees any resources allocated to
  * the device.
  */
 static int __devexit xps2_of_remove(struct platform_device *of_dev)
 {
 	struct device *dev = &of_dev->dev;
 	struct xps2data *drvdata = dev_get_drvdata(dev);
 	struct resource r_mem; /* IO mem resources */

 	serio_unregister_port(&drvdata->serio);
 	iounmap(drvdata->base_address);

 	/* Get iospace of the device */
 	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
 		dev_err(dev, "invalid address\n");
 	else
 		release_mem_region(r_mem.start, resource_size(&r_mem));

 	kfree(drvdata);

 	dev_set_drvdata(dev, NULL);

 	return 0;
 }

 /* Match table for of_platform binding */
 static const struct of_device_id xps2_of_match[] __devinitconst = {
 	{ .compatible = "xlnx,xps-ps2-1.00.a", },
 	{ /* end of list */ },
 };
 MODULE_DEVICE_TABLE(of, xps2_of_match);

 static struct platform_driver xps2_of_driver = {
 	.driver = {
 		.name = DRIVER_NAME,
 		.owner = THIS_MODULE,
 		.of_match_table = xps2_of_match,
 	},
 	.probe		= xps2_of_probe,
 	.remove		= __devexit_p(xps2_of_remove),
 };
 module_platform_driver(xps2_of_driver);

 MODULE_AUTHOR("Xilinx, Inc.");
 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
 MODULE_LICENSE("GPL");
	/*
	* Xilinx XPS PS/2 device driver
	*
	* (c) 2005 MontaVista Software, Inc.
	* (c) 2008 Xilinx, Inc.
	*
	* 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, or (at your
	* option) any later version.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 675 Mass Ave, Cambridge, MA 02139, USA.
	*/


	#include <linux/module.h>
	#include <linux/serio.h>
	#include <linux/interrupt.h>
	#include <linux/errno.h>
	#include <linux/slab.h>
	#include <linux/init.h>
	#include <linux/list.h>
	#include <linux/io.h>
	#include <linux/of_address.h>
	#include <linux/of_device.h>
	#include <linux/of_platform.h>

	#define DRIVER_NAME "xilinx_ps2"

	/* Register offsets for the xps2 device */
	#define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */
	#define XPS2_STATUS_OFFSET 0x00000004 /* Status register */
	#define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */
	#define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */
	#define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */
	#define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */
	#define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */

	/* Reset Register Bit Definitions */
	#define XPS2_SRST_RESET 0x0000000A /* Software Reset */

	/* Status Register Bit Positions */
	#define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */
	#define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */

	/* Bit definitions for ISR/IER registers. Both the registers have the same bit
	* definitions and are only defined once. */
	#define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
	#define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
	#define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */
	#define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */
	#define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */
	#define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */

	/* Mask for all the Transmit Interrupts */
	#define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK \| XPS2_IPIXR_TX_ACK)

	/* Mask for all the Receive Interrupts */
	#define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF \| XPS2_IPIXR_RX_ERR \| \
	XPS2_IPIXR_RX_FULL)

	/* Mask for all the Interrupts */
	#define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL \| XPS2_IPIXR_RX_ALL \| \
	XPS2_IPIXR_WDT_TOUT)

	/* Global Interrupt Enable mask */
	#define XPS2_GIER_GIE_MASK 0x80000000

	struct xps2data {
	int irq;
	spinlock_t lock;
	void __iomem base_address; / virt. address of control registers */
	unsigned int flags;
	struct serio serio; /* serio */
	};

	/************************************/
	/* XPS PS/2 data transmission calls */
	/************************************/

	/**
	* xps2_recv() - attempts to receive a byte from the PS/2 port.
	* @drvdata: pointer to ps2 device private data structure
	* @byte: address where the read data will be copied
	*
	* If there is any data available in the PS/2 receiver, this functions reads
	* the data, otherwise it returns error.
	*/
	static int xps2_recv(struct xps2data drvdata, u8 byte)
	{
	u32 sr;
	int status = -1;

	/* If there is data available in the PS/2 receiver, read it */
	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
	if (sr & XPS2_STATUS_RX_FULL) {
	*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
	status = 0;
	}

	return status;
	}

	/*********************/
	/* Interrupt handler */
	/*********************/
	static irqreturn_t xps2_interrupt(int irq, void *dev_id)
	{
	struct xps2data *drvdata = dev_id;
	u32 intr_sr;
	u8 c;
	int status;

	/* Get the PS/2 interrupts and clear them */
	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);

	/* Check which interrupt is active */
	if (intr_sr & XPS2_IPIXR_RX_OVF)
	dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");

	if (intr_sr & XPS2_IPIXR_RX_ERR)
	drvdata->flags \|= SERIO_PARITY;

	if (intr_sr & (XPS2_IPIXR_TX_NOACK \| XPS2_IPIXR_WDT_TOUT))
	drvdata->flags \|= SERIO_TIMEOUT;

	if (intr_sr & XPS2_IPIXR_RX_FULL) {
	status = xps2_recv(drvdata, &c);

	/* Error, if a byte is not received */
	if (status) {
	dev_err(drvdata->serio.dev.parent,
	"wrong rcvd byte count (%d)\n", status);
	} else {
	serio_interrupt(&drvdata->serio, c, drvdata->flags);
	drvdata->flags = 0;
	}
	}

	return IRQ_HANDLED;
	}

	/*******************/
	/* serio callbacks */
	/*******************/

	/**
	* sxps2_write() - sends a byte out through the PS/2 port.
	* @pserio: pointer to the serio structure of the PS/2 port
	* @c: data that needs to be written to the PS/2 port
	*
	* This function checks if the PS/2 transmitter is empty and sends a byte.
	* Otherwise it returns error. Transmission fails only when nothing is connected
	* to the PS/2 port. Thats why, we do not try to resend the data in case of a
	* failure.
	*/
	static int sxps2_write(struct serio *pserio, unsigned char c)
	{
	struct xps2data *drvdata = pserio->port_data;
	unsigned long flags;
	u32 sr;
	int status = -1;

	spin_lock_irqsave(&drvdata->lock, flags);

	/* If the PS/2 transmitter is empty send a byte of data */
	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
	if (!(sr & XPS2_STATUS_TX_FULL)) {
	out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
	status = 0;
	}

	spin_unlock_irqrestore(&drvdata->lock, flags);

	return status;
	}

	/**
	* sxps2_open() - called when a port is opened by the higher layer.
	* @pserio: pointer to the serio structure of the PS/2 device
	*
	* This function requests irq and enables interrupts for the PS/2 device.
	*/
	static int sxps2_open(struct serio *pserio)
	{
	struct xps2data *drvdata = pserio->port_data;
	int error;
	u8 c;

	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
	DRIVER_NAME, drvdata);
	if (error) {
	dev_err(drvdata->serio.dev.parent,
	"Couldn't allocate interrupt %d\n", drvdata->irq);
	return error;
	}

	/* start reception by enabling the interrupts */
	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
	(void)xps2_recv(drvdata, &c);

	return 0; /* success */
	}

	/**
	* sxps2_close() - frees the interrupt.
	* @pserio: pointer to the serio structure of the PS/2 device
	*
	* This function frees the irq and disables interrupts for the PS/2 device.
	*/
	static void sxps2_close(struct serio *pserio)
	{
	struct xps2data *drvdata = pserio->port_data;

	/* Disable the PS2 interrupts */
	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
	free_irq(drvdata->irq, drvdata);
	}

	/**
	* xps2_of_probe - probe method for the PS/2 device.
	* @of_dev: pointer to OF device structure
	* @match: pointer to the structure used for matching a device
	*
	* This function probes the PS/2 device in the device tree.
	* It initializes the driver data structure and the hardware.
	* It returns 0, if the driver is bound to the PS/2 device, or a negative
	* value if there is an error.
	*/
	static int __devinit xps2_of_probe(struct platform_device *ofdev)
	{
	struct resource r_irq; /* Interrupt resources */
	struct resource r_mem; /* IO mem resources */
	struct xps2data *drvdata;
	struct serio *serio;
	struct device *dev = &ofdev->dev;
	resource_size_t remap_size, phys_addr;
	int error;

	dev_info(dev, "Device Tree Probing \'%s\'\n",
	ofdev->dev.of_node->name);

	/* Get iospace for the device */
	error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
	if (error) {
	dev_err(dev, "invalid address\n");
	return error;
	}

	/* Get IRQ for the device */
	if (of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq) == NO_IRQ) {
	dev_err(dev, "no IRQ found\n");
	return -ENODEV;
	}

	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
	if (!drvdata) {
	dev_err(dev, "Couldn't allocate device private record\n");
	return -ENOMEM;
	}

	dev_set_drvdata(dev, drvdata);

	spin_lock_init(&drvdata->lock);
	drvdata->irq = r_irq.start;

	phys_addr = r_mem.start;
	remap_size = resource_size(&r_mem);
	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
	dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
	(unsigned long long)phys_addr);
	error = -EBUSY;
	goto failed1;
	}

	/* Fill in configuration data and add them to the list */
	drvdata->base_address = ioremap(phys_addr, remap_size);
	if (drvdata->base_address == NULL) {
	dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
	(unsigned long long)phys_addr);
	error = -EFAULT;
	goto failed2;
	}

	/* Disable all the interrupts, just in case */
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);

	/* Reset the PS2 device and abort any current transaction, to make sure
	* we have the PS2 in a good state */
	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);

	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
	(unsigned long long)phys_addr, drvdata->base_address,
	drvdata->irq);

	serio = &drvdata->serio;
	serio->id.type = SERIO_8042;
	serio->write = sxps2_write;
	serio->open = sxps2_open;
	serio->close = sxps2_close;
	serio->port_data = drvdata;
	serio->dev.parent = dev;
	snprintf(serio->name, sizeof(serio->name),
	"Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
	snprintf(serio->phys, sizeof(serio->phys),
	"xilinxps2/serio at %08llX", (unsigned long long)phys_addr);

	serio_register_port(serio);

	return 0; /* success */

	failed2:
	release_mem_region(phys_addr, remap_size);
	failed1:
	kfree(drvdata);
	dev_set_drvdata(dev, NULL);

	return error;
	}

	/**
	* xps2_of_remove - unbinds the driver from the PS/2 device.
	* @of_dev: pointer to OF device structure
	*
	* This function is called if a device is physically removed from the system or
	* if the driver module is being unloaded. It frees any resources allocated to
	* the device.
	*/
	static int __devexit xps2_of_remove(struct platform_device *of_dev)
	{
	struct device *dev = &of_dev->dev;
	struct xps2data *drvdata = dev_get_drvdata(dev);
	struct resource r_mem; /* IO mem resources */

	serio_unregister_port(&drvdata->serio);
	iounmap(drvdata->base_address);

	/* Get iospace of the device */
	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
	dev_err(dev, "invalid address\n");
	else
	release_mem_region(r_mem.start, resource_size(&r_mem));

	kfree(drvdata);

	dev_set_drvdata(dev, NULL);

	return 0;
	}

	/* Match table for of_platform binding */
	static const struct of_device_id xps2_of_match[] __devinitconst = {
	{ .compatible = "xlnx,xps-ps2-1.00.a", },
	{ /* end of list */ },
	};
	MODULE_DEVICE_TABLE(of, xps2_of_match);

	static struct platform_driver xps2_of_driver = {
	.driver = {
	.name = DRIVER_NAME,
	.owner = THIS_MODULE,
	.of_match_table = xps2_of_match,
	},
	.probe = xps2_of_probe,
	.remove = __devexit_p(xps2_of_remove),
	};
	module_platform_driver(xps2_of_driver);

	MODULE_AUTHOR("Xilinx, Inc.");
	MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
	MODULE_LICENSE("GPL");