drivers/char/pc8736x_gpio.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* linux/drivers/char/pc8736x_gpio.c

    National Semiconductor PC8736x GPIO driver.  Allows a user space
    process to play with the GPIO pins.

    Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com>

    adapted from linux/drivers/char/scx200_gpio.c
    Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>,
 */

 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/cdev.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/mutex.h>
 #include <linux/nsc_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>

 #define DEVNAME "pc8736x_gpio"

 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
 MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
 MODULE_LICENSE("GPL");

 static int major;		/* default to dynamic major */
 module_param(major, int, 0);
 MODULE_PARM_DESC(major, "Major device number");

 static DEFINE_MUTEX(pc8736x_gpio_config_lock);
 static unsigned pc8736x_gpio_base;
 static u8 pc8736x_gpio_shadow[4];

 #define SIO_BASE1       0x2E	/* 1st command-reg to check */
 #define SIO_BASE2       0x4E	/* alt command-reg to check */

 #define SIO_SID		0x20	/* SuperI/O ID Register */
 #define SIO_SID_PC87365	0xe5	/* Expected value in ID Register for PC87365 */
 #define SIO_SID_PC87366	0xe9	/* Expected value in ID Register for PC87366 */

 #define SIO_CF1		0x21	/* chip config, bit0 is chip enable */

 #define PC8736X_GPIO_RANGE	16 /* ioaddr range */
 #define PC8736X_GPIO_CT		32 /* minors matching 4 8 bit ports */

 #define SIO_UNIT_SEL	0x7	/* unit select reg */
 #define SIO_UNIT_ACT	0x30	/* unit enable */
 #define SIO_GPIO_UNIT	0x7	/* unit number of GPIO */
 #define SIO_VLM_UNIT	0x0D
 #define SIO_TMS_UNIT	0x0E

 /* config-space addrs to read/write each unit's runtime addr */
 #define SIO_BASE_HADDR		0x60
 #define SIO_BASE_LADDR		0x61

 /* GPIO config-space pin-control addresses */
 #define SIO_GPIO_PIN_SELECT	0xF0
 #define SIO_GPIO_PIN_CONFIG     0xF1
 #define SIO_GPIO_PIN_EVENT      0xF2

 static unsigned char superio_cmd = 0;
 static unsigned char selected_device = 0xFF;	/* bogus start val */

 /* GPIO port runtime access, functionality */
 static int port_offset[] = { 0, 4, 8, 10 };	/* non-uniform offsets ! */
 /* static int event_capable[] = { 1, 1, 0, 0 };   ports 2,3 are hobbled */

 #define PORT_OUT	0
 #define PORT_IN		1
 #define PORT_EVT_EN	2
 #define PORT_EVT_STST	3

 static struct platform_device *pdev;  /* use in dev_*() */

 static inline void superio_outb(int addr, int val)
 {
 	outb_p(addr, superio_cmd);
 	outb_p(val, superio_cmd + 1);
 }

 static inline int superio_inb(int addr)
 {
 	outb_p(addr, superio_cmd);
 	return inb_p(superio_cmd + 1);
 }

 static int pc8736x_superio_present(void)
 {
 	int id;

 	/* try the 2 possible values, read a hardware reg to verify */
 	superio_cmd = SIO_BASE1;
 	id = superio_inb(SIO_SID);
 	if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
 		return superio_cmd;

 	superio_cmd = SIO_BASE2;
 	id = superio_inb(SIO_SID);
 	if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
 		return superio_cmd;

 	return 0;
 }

 static void device_select(unsigned devldn)
 {
 	superio_outb(SIO_UNIT_SEL, devldn);
 	selected_device = devldn;
 }

 static void select_pin(unsigned iminor)
 {
 	/* select GPIO port/pin from device minor number */
 	device_select(SIO_GPIO_UNIT);
 	superio_outb(SIO_GPIO_PIN_SELECT,
 		     ((iminor << 1) & 0xF0) | (iminor & 0x7));
 }

 static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits,
 					    u32 func_slct)
 {
 	u32 config, new_config;

 	mutex_lock(&pc8736x_gpio_config_lock);

 	device_select(SIO_GPIO_UNIT);
 	select_pin(index);

 	/* read current config value */
 	config = superio_inb(func_slct);

 	/* set new config */
 	new_config = (config & mask) | bits;
 	superio_outb(func_slct, new_config);

 	mutex_unlock(&pc8736x_gpio_config_lock);

 	return config;
 }

 static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits)
 {
 	return pc8736x_gpio_configure_fn(index, mask, bits,
 					 SIO_GPIO_PIN_CONFIG);
 }

 static int pc8736x_gpio_get(unsigned minor)
 {
 	int port, bit, val;

 	port = minor >> 3;
 	bit = minor & 7;
 	val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
 	val >>= bit;
 	val &= 1;

 	dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n",
 		minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit,
 		val);

 	return val;
 }

 static void pc8736x_gpio_set(unsigned minor, int val)
 {
 	int port, bit, curval;

 	minor &= 0x1f;
 	port = minor >> 3;
 	bit = minor & 7;
 	curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);

 	dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n",
 		pc8736x_gpio_base + port_offset[port] + PORT_OUT,
 		curval, bit, (curval & ~(1 << bit)), val, (val << bit));

 	val = (curval & ~(1 << bit)) | (val << bit);

 	dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)"
 		" %2x -> %2x\n", minor, port, bit, curval, val);

 	outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT);

 	curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
 	val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);

 	dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
 	pc8736x_gpio_shadow[port] = val;
 }

 static int pc8736x_gpio_current(unsigned minor)
 {
 	int port, bit;
 	minor &= 0x1f;
 	port = minor >> 3;
 	bit = minor & 7;
 	return ((pc8736x_gpio_shadow[port] >> bit) & 0x01);
 }

 static void pc8736x_gpio_change(unsigned index)
 {
 	pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
 }

 static struct nsc_gpio_ops pc8736x_gpio_ops = {
 	.owner		= THIS_MODULE,
 	.gpio_config	= pc8736x_gpio_configure,
 	.gpio_dump	= nsc_gpio_dump,
 	.gpio_get	= pc8736x_gpio_get,
 	.gpio_set	= pc8736x_gpio_set,
 	.gpio_change	= pc8736x_gpio_change,
 	.gpio_current	= pc8736x_gpio_current
 };

 static int pc8736x_gpio_open(struct inode *inode, struct file *file)
 {
 	unsigned m = iminor(inode);
 	file->private_data = &pc8736x_gpio_ops;

 	dev_dbg(&pdev->dev, "open %d\n", m);

 	if (m >= PC8736X_GPIO_CT)
 		return -EINVAL;
 	return nonseekable_open(inode, file);
 }

 static const struct file_operations pc8736x_gpio_fileops = {
 	.owner	= THIS_MODULE,
 	.open	= pc8736x_gpio_open,
 	.write	= nsc_gpio_write,
 	.read	= nsc_gpio_read,
 	.llseek = no_llseek,
 };

 static void __init pc8736x_init_shadow(void)
 {
 	int port;

 	/* read the current values driven on the GPIO signals */
 	for (port = 0; port < 4; ++port)
 		pc8736x_gpio_shadow[port]
 		    = inb_p(pc8736x_gpio_base + port_offset[port]
 			    + PORT_OUT);

 }

 static struct cdev pc8736x_gpio_cdev;

 static int __init pc8736x_gpio_init(void)
 {
 	int rc;
 	dev_t devid;

 	pdev = platform_device_alloc(DEVNAME, 0);
 	if (!pdev)
 		return -ENOMEM;

 	rc = platform_device_add(pdev);
 	if (rc) {
 		rc = -ENODEV;
 		goto undo_platform_dev_alloc;
 	}
 	dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");

 	if (!pc8736x_superio_present()) {
 		rc = -ENODEV;
 		dev_err(&pdev->dev, "no device found\n");
 		goto undo_platform_dev_add;
 	}
 	pc8736x_gpio_ops.dev = &pdev->dev;

 	/* Verify that chip and it's GPIO unit are both enabled.
 	   My BIOS does this, so I take minimum action here
 	 */
 	rc = superio_inb(SIO_CF1);
 	if (!(rc & 0x01)) {
 		rc = -ENODEV;
 		dev_err(&pdev->dev, "device not enabled\n");
 		goto undo_platform_dev_add;
 	}
 	device_select(SIO_GPIO_UNIT);
 	if (!superio_inb(SIO_UNIT_ACT)) {
 		rc = -ENODEV;
 		dev_err(&pdev->dev, "GPIO unit not enabled\n");
 		goto undo_platform_dev_add;
 	}

 	/* read the GPIO unit base addr that chip responds to */
 	pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
 			     | superio_inb(SIO_BASE_LADDR));

 	if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
 		rc = -ENODEV;
 		dev_err(&pdev->dev, "GPIO ioport %x busy\n",
 			pc8736x_gpio_base);
 		goto undo_platform_dev_add;
 	}
 	dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);

 	if (major) {
 		devid = MKDEV(major, 0);
 		rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
 	} else {
 		rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
 		major = MAJOR(devid);
 	}

 	if (rc < 0) {
 		dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
 		goto undo_request_region;
 	}
 	if (!major) {
 		major = rc;
 		dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
 	}

 	pc8736x_init_shadow();

 	/* ignore minor errs, and succeed */
 	cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
 	cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);

 	return 0;

 undo_request_region:
 	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
 undo_platform_dev_add:
 	platform_device_del(pdev);
 undo_platform_dev_alloc:
 	platform_device_put(pdev);

 	return rc;
 }

 static void __exit pc8736x_gpio_cleanup(void)
 {
 	dev_dbg(&pdev->dev, "cleanup\n");

 	cdev_del(&pc8736x_gpio_cdev);
 	unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
 	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);

 	platform_device_unregister(pdev);
 }

 module_init(pc8736x_gpio_init);
 module_exit(pc8736x_gpio_cleanup);
	// SPDX-License-Identifier: GPL-2.0-only
	/* linux/drivers/char/pc8736x_gpio.c

	National Semiconductor PC8736x GPIO driver. Allows a user space
	process to play with the GPIO pins.

	Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com>

	adapted from linux/drivers/char/scx200_gpio.c
	Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>,
	*/

	#include <linux/fs.h>
	#include <linux/module.h>
	#include <linux/errno.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/cdev.h>
	#include <linux/io.h>
	#include <linux/ioport.h>
	#include <linux/mutex.h>
	#include <linux/nsc_gpio.h>
	#include <linux/platform_device.h>
	#include <linux/uaccess.h>

	#define DEVNAME "pc8736x_gpio"

	MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
	MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
	MODULE_LICENSE("GPL");

	static int major; /* default to dynamic major */
	module_param(major, int, 0);
	MODULE_PARM_DESC(major, "Major device number");

	static DEFINE_MUTEX(pc8736x_gpio_config_lock);
	static unsigned pc8736x_gpio_base;
	static u8 pc8736x_gpio_shadow[4];

	#define SIO_BASE1 0x2E /* 1st command-reg to check */
	#define SIO_BASE2 0x4E /* alt command-reg to check */

	#define SIO_SID 0x20 /* SuperI/O ID Register */
	#define SIO_SID_PC87365 0xe5 /* Expected value in ID Register for PC87365 */
	#define SIO_SID_PC87366 0xe9 /* Expected value in ID Register for PC87366 */

	#define SIO_CF1 0x21 /* chip config, bit0 is chip enable */

	#define PC8736X_GPIO_RANGE 16 /* ioaddr range */
	#define PC8736X_GPIO_CT 32 /* minors matching 4 8 bit ports */

	#define SIO_UNIT_SEL 0x7 /* unit select reg */
	#define SIO_UNIT_ACT 0x30 /* unit enable */
	#define SIO_GPIO_UNIT 0x7 /* unit number of GPIO */
	#define SIO_VLM_UNIT 0x0D
	#define SIO_TMS_UNIT 0x0E

	/* config-space addrs to read/write each unit's runtime addr */
	#define SIO_BASE_HADDR 0x60
	#define SIO_BASE_LADDR 0x61

	/* GPIO config-space pin-control addresses */
	#define SIO_GPIO_PIN_SELECT 0xF0
	#define SIO_GPIO_PIN_CONFIG 0xF1
	#define SIO_GPIO_PIN_EVENT 0xF2

	static unsigned char superio_cmd = 0;
	static unsigned char selected_device = 0xFF; /* bogus start val */

	/* GPIO port runtime access, functionality */
	static int port_offset[] = { 0, 4, 8, 10 }; /* non-uniform offsets ! */
	/* static int event_capable[] = { 1, 1, 0, 0 }; ports 2,3 are hobbled */

	#define PORT_OUT 0
	#define PORT_IN 1
	#define PORT_EVT_EN 2
	#define PORT_EVT_STST 3

	static struct platform_device pdev; / use in dev_() /

	static inline void superio_outb(int addr, int val)
	{
	outb_p(addr, superio_cmd);
	outb_p(val, superio_cmd + 1);
	}

	static inline int superio_inb(int addr)
	{
	outb_p(addr, superio_cmd);
	return inb_p(superio_cmd + 1);
	}

	static int pc8736x_superio_present(void)
	{
	int id;

	/* try the 2 possible values, read a hardware reg to verify */
	superio_cmd = SIO_BASE1;
	id = superio_inb(SIO_SID);
	if (id == SIO_SID_PC87365 \|\| id == SIO_SID_PC87366)
	return superio_cmd;

	superio_cmd = SIO_BASE2;
	id = superio_inb(SIO_SID);
	if (id == SIO_SID_PC87365 \|\| id == SIO_SID_PC87366)
	return superio_cmd;

	return 0;
	}

	static void device_select(unsigned devldn)
	{
	superio_outb(SIO_UNIT_SEL, devldn);
	selected_device = devldn;
	}

	static void select_pin(unsigned iminor)
	{
	/* select GPIO port/pin from device minor number */
	device_select(SIO_GPIO_UNIT);
	superio_outb(SIO_GPIO_PIN_SELECT,
	((iminor << 1) & 0xF0) \| (iminor & 0x7));
	}

	static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits,
	u32 func_slct)
	{
	u32 config, new_config;

	mutex_lock(&pc8736x_gpio_config_lock);

	device_select(SIO_GPIO_UNIT);
	select_pin(index);

	/* read current config value */
	config = superio_inb(func_slct);

	/* set new config */
	new_config = (config & mask) \| bits;
	superio_outb(func_slct, new_config);

	mutex_unlock(&pc8736x_gpio_config_lock);

	return config;
	}

	static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits)
	{
	return pc8736x_gpio_configure_fn(index, mask, bits,
	SIO_GPIO_PIN_CONFIG);
	}

	static int pc8736x_gpio_get(unsigned minor)
	{
	int port, bit, val;

	port = minor >> 3;
	bit = minor & 7;
	val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
	val >>= bit;
	val &= 1;

	dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n",
	minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit,
	val);

	return val;
	}

	static void pc8736x_gpio_set(unsigned minor, int val)
	{
	int port, bit, curval;

	minor &= 0x1f;
	port = minor >> 3;
	bit = minor & 7;
	curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);

	dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n",
	pc8736x_gpio_base + port_offset[port] + PORT_OUT,
	curval, bit, (curval & ~(1 << bit)), val, (val << bit));

	val = (curval & ~(1 << bit)) \| (val << bit);

	dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)"
	" %2x -> %2x\n", minor, port, bit, curval, val);

	outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT);

	curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
	val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);

	dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
	pc8736x_gpio_shadow[port] = val;
	}

	static int pc8736x_gpio_current(unsigned minor)
	{
	int port, bit;
	minor &= 0x1f;
	port = minor >> 3;
	bit = minor & 7;
	return ((pc8736x_gpio_shadow[port] >> bit) & 0x01);
	}

	static void pc8736x_gpio_change(unsigned index)
	{
	pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
	}

	static struct nsc_gpio_ops pc8736x_gpio_ops = {
	.owner = THIS_MODULE,
	.gpio_config = pc8736x_gpio_configure,
	.gpio_dump = nsc_gpio_dump,
	.gpio_get = pc8736x_gpio_get,
	.gpio_set = pc8736x_gpio_set,
	.gpio_change = pc8736x_gpio_change,
	.gpio_current = pc8736x_gpio_current
	};

	static int pc8736x_gpio_open(struct inode inode, struct file file)
	{
	unsigned m = iminor(inode);
	file->private_data = &pc8736x_gpio_ops;

	dev_dbg(&pdev->dev, "open %d\n", m);

	if (m >= PC8736X_GPIO_CT)
	return -EINVAL;
	return nonseekable_open(inode, file);
	}

	static const struct file_operations pc8736x_gpio_fileops = {
	.owner = THIS_MODULE,
	.open = pc8736x_gpio_open,
	.write = nsc_gpio_write,
	.read = nsc_gpio_read,
	.llseek = no_llseek,
	};

	static void __init pc8736x_init_shadow(void)
	{
	int port;

	/* read the current values driven on the GPIO signals */
	for (port = 0; port < 4; ++port)
	pc8736x_gpio_shadow[port]
	= inb_p(pc8736x_gpio_base + port_offset[port]
	+ PORT_OUT);

	}

	static struct cdev pc8736x_gpio_cdev;

	static int __init pc8736x_gpio_init(void)
	{
	int rc;
	dev_t devid;

	pdev = platform_device_alloc(DEVNAME, 0);
	if (!pdev)
	return -ENOMEM;

	rc = platform_device_add(pdev);
	if (rc) {
	rc = -ENODEV;
	goto undo_platform_dev_alloc;
	}
	dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");

	if (!pc8736x_superio_present()) {
	rc = -ENODEV;
	dev_err(&pdev->dev, "no device found\n");
	goto undo_platform_dev_add;
	}
	pc8736x_gpio_ops.dev = &pdev->dev;

	/* Verify that chip and it's GPIO unit are both enabled.
	My BIOS does this, so I take minimum action here
	*/
	rc = superio_inb(SIO_CF1);
	if (!(rc & 0x01)) {
	rc = -ENODEV;
	dev_err(&pdev->dev, "device not enabled\n");
	goto undo_platform_dev_add;
	}
	device_select(SIO_GPIO_UNIT);
	if (!superio_inb(SIO_UNIT_ACT)) {
	rc = -ENODEV;
	dev_err(&pdev->dev, "GPIO unit not enabled\n");
	goto undo_platform_dev_add;
	}

	/* read the GPIO unit base addr that chip responds to */
	pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
	\| superio_inb(SIO_BASE_LADDR));

	if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
	rc = -ENODEV;
	dev_err(&pdev->dev, "GPIO ioport %x busy\n",
	pc8736x_gpio_base);
	goto undo_platform_dev_add;
	}
	dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);

	if (major) {
	devid = MKDEV(major, 0);
	rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
	} else {
	rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
	major = MAJOR(devid);
	}

	if (rc < 0) {
	dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
	goto undo_request_region;
	}
	if (!major) {
	major = rc;
	dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
	}

	pc8736x_init_shadow();

	/* ignore minor errs, and succeed */
	cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
	cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);

	return 0;

	undo_request_region:
	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
	undo_platform_dev_add:
	platform_device_del(pdev);
	undo_platform_dev_alloc:
	platform_device_put(pdev);

	return rc;
	}

	static void __exit pc8736x_gpio_cleanup(void)
	{
	dev_dbg(&pdev->dev, "cleanup\n");

	cdev_del(&pc8736x_gpio_cdev);
	unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);

	platform_device_unregister(pdev);
	}

	module_init(pc8736x_gpio_init);
	module_exit(pc8736x_gpio_cleanup);