/* 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 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/config.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/nsc_gpio.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define NAME "pc8736x_gpio"
MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
MODULE_DESCRIPTION("NatSemi SCx200 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_SPINLOCK(pc8736x_gpio_config_lock);
static unsigned pc8736x_gpio_base;
#define SIO_BASE1 0x2E /* 1st command-reg to check */
#define SIO_BASE2 0x4E /* alt command-reg to check */
#define SIO_BASE_OFFSET 0x20
#define SIO_SID 0x20 /* SuperI/O ID Register */
#define SIO_SID_VALUE 0xe9 /* Expected value in SuperI/O ID Register */
#define SIO_CF1 0x21 /* chip config, bit0 is chip enable */
#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 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)
{
/* try the 2 possible values, read a hardware reg to verify */
superio_cmd = SIO_BASE1;
if (superio_inb(SIO_SID) == SIO_SID_VALUE)
return superio_cmd;
superio_cmd = SIO_BASE2;
if (superio_inb(SIO_SID) == SIO_SID_VALUE)
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;
unsigned long flags;
spin_lock_irqsave(&pc8736x_gpio_config_lock, flags);
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);
spin_unlock_irqrestore(&pc8736x_gpio_config_lock, flags);
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;
printk(KERN_INFO NAME ": _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);
printk(KERN_INFO NAME
": 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);
printk(KERN_INFO NAME ": 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);
printk(KERN_INFO NAME ": wrote %x, read: %x\n", curval, val);
}
static void pc8736x_gpio_set_high(unsigned index)
{
pc8736x_gpio_set(index, 1);
}
static void pc8736x_gpio_set_low(unsigned index)
{
pc8736x_gpio_set(index, 0);
}
static int pc8736x_gpio_current(unsigned index)
{
printk(KERN_WARNING NAME ": pc8736x_gpio_current unimplemented\n");
return 0;
}
static void pc8736x_gpio_change(unsigned index)
{
pc8736x_gpio_set(index, !pc8736x_gpio_get(index));
}
extern void nsc_gpio_dump(unsigned iminor);
static struct nsc_gpio_ops pc8736x_access = {
.owner = THIS_MODULE,
.gpio_config = pc8736x_gpio_configure,
.gpio_dump = nsc_gpio_dump,
.gpio_get = pc8736x_gpio_get,
.gpio_set = pc8736x_gpio_set,
.gpio_set_high = pc8736x_gpio_set_high,
.gpio_set_low = pc8736x_gpio_set_low,
.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_access;
printk(KERN_NOTICE NAME " open %d\n", m);
if (m > 63)
return -EINVAL;
return nonseekable_open(inode, file);
}
static struct file_operations pc8736x_gpio_fops = {
.owner = THIS_MODULE,
.open = pc8736x_gpio_open,
.write = nsc_gpio_write,
.read = nsc_gpio_read,
};
static int __init pc8736x_gpio_init(void)
{
int r, rc;
printk(KERN_DEBUG NAME " initializing\n");
if (!pc8736x_superio_present()) {
printk(KERN_ERR NAME ": no device found\n");
return -ENODEV;
}
/* 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)) {
printk(KERN_ERR NAME ": device not enabled\n");
return -ENODEV;
}
device_select(SIO_GPIO_UNIT);
if (!superio_inb(SIO_UNIT_ACT)) {
printk(KERN_ERR NAME ": GPIO unit not enabled\n");
return -ENODEV;
}
/* read GPIO unit base address */
pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
| superio_inb(SIO_BASE_LADDR));
if (request_region(pc8736x_gpio_base, 16, NAME))
printk(KERN_INFO NAME ": GPIO ioport %x reserved\n",
pc8736x_gpio_base);
r = register_chrdev(major, NAME, &pc8736x_gpio_fops);
if (r < 0) {
printk(KERN_ERR NAME ": unable to register character device\n");
return r;
}
if (!major) {
major = r;
printk(KERN_DEBUG NAME ": got dynamic major %d\n", major);
}
pc8736x_init_shadow();
return 0;
}
static void __exit pc8736x_gpio_cleanup(void)
{
printk(KERN_DEBUG NAME " cleanup\n");
release_region(pc8736x_gpio_base, 16);
unregister_chrdev(major, NAME);
}
module_init(pc8736x_gpio_init);
module_exit(pc8736x_gpio_cleanup);
