/* 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 %dn",

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:%dn",

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 -> %2xn", 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: %xn", 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 %dn", 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 Initializingn");

if (!pc8736x_superio_present()) {

rc = -ENODEV;

dev_err(&pdev->dev, "no device foundn");

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 enabledn");

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 enabledn");

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 busyn",

pc8736x_gpio_base);

goto undo_platform_dev_add;

}

dev_info(&pdev->dev, "GPIO ioport %x reservedn", 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: %dn", rc);

goto undo_request_region;

}

if (!major) {

major = rc;

dev_dbg(&pdev->dev, "got dynamic major %dn", 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, "cleanupn");

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);