/* $Id: gpio.c,v 1.17 2005/06/19 17:06:46 starvik Exp $
 *
 * Etrax general port I/O device
 *
 * Copyright (c) 1999, 2000, 2001, 2002 Axis Communications AB
 *
 * Authors:    Bjorn Wesen      (initial version)
 *             Ola Knutsson     (LED handling)
 *             Johan Adolfsson  (read/set directions, write, port G)
 *
 * $Log: gpio.c,v $
 * Revision 1.17  2005/06/19 17:06:46  starvik
 * Merge of Linux 2.6.12.
 *
 * Revision 1.16  2005/03/07 13:02:29  starvik
 * Protect driver global states with spinlock
 *
 * Revision 1.15  2005/01/05 06:08:55  starvik
 * No need to do local_irq_disable after local_irq_save.
 *
 * Revision 1.14  2004/12/13 12:21:52  starvik
 * Added I/O and DMA allocators from Linux 2.4
 *
 * Revision 1.12  2004/08/24 07:19:59  starvik
 * Whitespace cleanup
 *
 * Revision 1.11  2004/05/14 07:58:03  starvik
 * Merge of changes from 2.4
 *
 * Revision 1.9  2003/09/11 07:29:48  starvik
 * Merge of Linux 2.6.0-test5
 *
 * Revision 1.8  2003/07/04 08:27:37  starvik
 * Merge of Linux 2.5.74
 *
 * Revision 1.7  2003/01/10 07:44:07  starvik
 * init_ioremap is now called by kernel before drivers are initialized
 *
 * Revision 1.6  2002/12/11 13:13:57  starvik
 * Added arch/ to v10 specific includes
 * Added fix from Linux 2.4 in serial.c (flush_to_flip_buffer)
 *
 * Revision 1.5  2002/11/20 11:56:11  starvik
 * Merge of Linux 2.5.48
 *
 * Revision 1.4  2002/11/18 10:10:05  starvik
 * Linux 2.5 port of latest gpio.c from Linux 2.4
 *
 * Revision 1.20  2002/10/16 21:16:24  johana
 * Added support for PA high level interrupt.
 * That gives 2ms response time with iodtest for high levels and 2-12 ms
 * response time on low levels if the check is not made in
 * process.c:cpu_idle() as well.
 *
 * Revision 1.19  2002/10/14 18:27:33  johana
 * Implemented alarm handling so select() now works.
 * Latency is around 6-9 ms with a etrax_gpio_wake_up_check() in
 * cpu_idle().
 * Otherwise I get 15-18 ms (same as doing the poll in userspace -
 * but less overhead).
 * TODO? Perhaps we should add the check in IMMEDIATE_BH (or whatever it
 * is in 2.4) as well?
 * TODO? Perhaps call request_irq()/free_irq() only when needed?
 * Increased version to 2.5
 *
 * Revision 1.18  2002/10/11 15:02:00  johana
 * Mask inverted 8 bit value in setget_input().
 *
 * Revision 1.17  2002/06/17 15:53:01  johana
 * Added IO_READ_INBITS, IO_READ_OUTBITS, IO_SETGET_INPUT and IO_SETGET_OUTPUT
 * that take a pointer as argument and thus can handle 32 bit ports (G)
 * correctly.
 * These should be used instead of IO_READBITS, IO_SETINPUT and IO_SETOUTPUT.
 * (especially if Port G bit 31 is used)
 *
 * Revision 1.16  2002/06/17 09:59:51  johana
 * Returning 32 bit values in the ioctl return value doesn't work if bit
 * 31 is set (could happen for port G), so mask it of with 0x7FFFFFFF.
 * A new set of ioctl's will be added.
 *
 * Revision 1.15  2002/05/06 13:19:13  johana
 * IO_SETINPUT returns mask with bit set = inputs for PA and PB as well.
 *
 * Revision 1.14  2002/04/12 12:01:53  johana
 * Use global r_port_g_data_shadow.
 * Moved gpio_init_port_g() closer to gpio_init() and marked it __init.
 *
 * Revision 1.13  2002/04/10 12:03:55  johana
 * Added support for port G /dev/gpiog (minor 3).
 * Changed indentation on switch cases.
 * Fixed other spaces to tabs.
 *
 * Revision 1.12  2001/11/12 19:42:15  pkj
 * * Corrected return values from gpio_leds_ioctl().
 * * Fixed compiler warnings.
 *
 * Revision 1.11  2001/10/30 14:39:12  johana
 * Added D() around gpio_write printk.
 *
 * Revision 1.10  2001/10/25 10:24:42  johana
 * Added IO_CFG_WRITE_MODE ioctl and write method that can do fast
 * bittoggling in the kernel. (This speeds up programming an FPGA with 450kB
 * from ~60 seconds to 4 seconds).
 * Added save_flags/cli/restore_flags in ioctl.
 *
 * Revision 1.9  2001/05/04 14:16:07  matsfg
 * Corrected spelling error
 *
 * Revision 1.8  2001/04/27 13:55:26  matsfg
 * Moved initioremap.
 * Turns off all LEDS on init.
 * Added support for shutdown and powerbutton.
 *
 * Revision 1.7  2001/04/04 13:30:08  matsfg
 * Added bitset and bitclear for leds. Calls init_ioremap to set up memmapping
 *
 * Revision 1.6  2001/03/26 16:03:06  bjornw
 * Needs linux/config.h
 *
 * Revision 1.5  2001/03/26 14:22:03  bjornw
 * Namechange of some config options
 *
 * Revision 1.4  2001/02/27 13:52:48  bjornw
 * malloc.h -> slab.h
 *
 * Revision 1.3  2001/01/24 15:06:48  bjornw
 * gpio_wq correct type
 *
 * Revision 1.2  2001/01/18 16:07:30  bjornw
 * 2.4 port
 *
 * Revision 1.1  2001/01/18 15:55:16  bjornw
 * Verbatim copy of etraxgpio.c from elinux 2.0 added
 *
 *
 */


#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/interrupt.h>

#include <asm/etraxgpio.h>
#include <asm/arch/svinto.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/arch/io_interface_mux.h>

#define GPIO_MAJOR 120  /* experimental MAJOR number */

#define D(x)

#if 0
static int dp_cnt;
#define DP(x) do { dp_cnt++; if (dp_cnt % 1000 == 0) x; }while(0)
#else
#define DP(x)
#endif
        
static char gpio_name[] = "etrax gpio";

#if 0
static wait_queue_head_t *gpio_wq;
#endif

static int gpio_ioctl(struct inode *inode, struct file *file,
                      unsigned int cmd, unsigned long arg);
static ssize_t gpio_write(struct file * file, const char * buf, size_t count,
                          loff_t *off);
static int gpio_open(struct inode *inode, struct file *filp);
static int gpio_release(struct inode *inode, struct file *filp);
static unsigned int gpio_poll(struct file *filp, struct poll_table_struct *wait);

/* private data per open() of this driver */

struct gpio_private {
        struct gpio_private *next;
        /* These fields are for PA and PB only */
        volatile unsigned char *port, *shadow;
        volatile unsigned char *dir, *dir_shadow;
        unsigned char changeable_dir;
        unsigned char changeable_bits;
        unsigned char clk_mask;
        unsigned char data_mask;
        unsigned char write_msb;
        unsigned char pad1, pad2, pad3;
        /* These fields are generic */
        unsigned long highalarm, lowalarm;
        wait_queue_head_t alarm_wq;
        int minor;
};

/* linked list of alarms to check for */

static struct gpio_private *alarmlist = 0;

static int gpio_some_alarms = 0; /* Set if someone uses alarm */
static unsigned long gpio_pa_irq_enabled_mask = 0;

static DEFINE_SPINLOCK(gpio_lock); /* Protect directions etc */

/* Port A and B use 8 bit access, but Port G is 32 bit */
#define NUM_PORTS (GPIO_MINOR_B+1)

static volatile unsigned char *ports[NUM_PORTS] = { 
        R_PORT_PA_DATA, 
        R_PORT_PB_DATA,
};
static volatile unsigned char *shads[NUM_PORTS] = {
        &port_pa_data_shadow, 
        &port_pb_data_shadow
};

/* What direction bits that are user changeable 1=changeable*/
#ifndef CONFIG_ETRAX_PA_CHANGEABLE_DIR
#define CONFIG_ETRAX_PA_CHANGEABLE_DIR 0x00
#endif
#ifndef CONFIG_ETRAX_PB_CHANGEABLE_DIR
#define CONFIG_ETRAX_PB_CHANGEABLE_DIR 0x00
#endif

#ifndef CONFIG_ETRAX_PA_CHANGEABLE_BITS
#define CONFIG_ETRAX_PA_CHANGEABLE_BITS 0xFF
#endif
#ifndef CONFIG_ETRAX_PB_CHANGEABLE_BITS
#define CONFIG_ETRAX_PB_CHANGEABLE_BITS 0xFF
#endif


static unsigned char changeable_dir[NUM_PORTS] = { 
        CONFIG_ETRAX_PA_CHANGEABLE_DIR,
        CONFIG_ETRAX_PB_CHANGEABLE_DIR 
};
static unsigned char changeable_bits[NUM_PORTS] = { 
        CONFIG_ETRAX_PA_CHANGEABLE_BITS,
        CONFIG_ETRAX_PB_CHANGEABLE_BITS 
};

static volatile unsigned char *dir[NUM_PORTS] = { 
        R_PORT_PA_DIR, 
        R_PORT_PB_DIR 
};

static volatile unsigned char *dir_shadow[NUM_PORTS] = {
        &port_pa_dir_shadow, 
        &port_pb_dir_shadow 
};

/* All bits in port g that can change dir. */
static const unsigned long int changeable_dir_g_mask = 0x01FFFF01;

/* Port G is 32 bit, handle it special, some bits are both inputs 
   and outputs at the same time, only some of the bits can change direction
   and some of them in groups of 8 bit. */
static unsigned long changeable_dir_g;
static unsigned long dir_g_in_bits;
static unsigned long dir_g_out_bits;
static unsigned long dir_g_shadow; /* 1=output */

#define USE_PORTS(priv) ((priv)->minor <= GPIO_MINOR_B)



static unsigned int 
gpio_poll(struct file *file,
          poll_table *wait)
{
        unsigned int mask = 0;
        struct gpio_private *priv = (struct gpio_private *)file->private_data;
        unsigned long data;
        spin_lock(&gpio_lock);
        poll_wait(file, &priv->alarm_wq, wait);
        if (priv->minor == GPIO_MINOR_A) {
                unsigned long flags;
                unsigned long tmp;
                data = *R_PORT_PA_DATA;
                /* PA has support for high level interrupt -
                 * lets activate for those low and with highalarm set
                 */
                tmp = ~data & priv->highalarm & 0xFF;
                tmp = (tmp << R_IRQ_MASK1_SET__pa0__BITNR);
                local_irq_save(flags);
                gpio_pa_irq_enabled_mask |= tmp;
                *R_IRQ_MASK1_SET = tmp;
                local_irq_restore(flags);

        } else if (priv->minor == GPIO_MINOR_B)
                data = *R_PORT_PB_DATA;
        else if (priv->minor == GPIO_MINOR_G)
                data = *R_PORT_G_DATA;
        else {
                spin_unlock(&gpio_lock);
                return 0;
        }
        
        if ((data & priv->highalarm) ||
            (~data & priv->lowalarm)) {
                mask = POLLIN|POLLRDNORM;
        }

        spin_unlock(&gpio_lock);
        
        DP(printk("gpio_poll ready: mask 0x%08X\n", mask));

        return mask;
}

int etrax_gpio_wake_up_check(void)
{
        struct gpio_private *priv = alarmlist;
        unsigned long data = 0;
        int ret = 0;
        spin_lock(&gpio_lock);
        while (priv) {
                if (USE_PORTS(priv)) {
                        data = *priv->port;
                } else if (priv->minor == GPIO_MINOR_G) {
                        data = *R_PORT_G_DATA;
                }
                if ((data & priv->highalarm) ||
                    (~data & priv->lowalarm)) {
                        DP(printk("etrax_gpio_wake_up_check %i\n",priv->minor));
                        wake_up_interruptible(&priv->alarm_wq);
                        ret = 1;
                }
                priv = priv->next;
        }
        spin_unlock(&gpio_lock);
        return ret;
}

static irqreturn_t
gpio_poll_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        if (gpio_some_alarms) {
                etrax_gpio_wake_up_check();
                return IRQ_HANDLED;
        }
        return IRQ_NONE;
}

static irqreturn_t
gpio_pa_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        unsigned long tmp;
        spin_lock(&gpio_lock);
        /* Find what PA interrupts are active */
        tmp = (*R_IRQ_READ1);

        /* Find those that we have enabled */
        tmp &= gpio_pa_irq_enabled_mask;

        /* Clear them.. */
        *R_IRQ_MASK1_CLR = tmp;
        gpio_pa_irq_enabled_mask &= ~tmp;

        spin_unlock(&gpio_lock);

        if (gpio_some_alarms) {
                return IRQ_RETVAL(etrax_gpio_wake_up_check());
        }
        return IRQ_NONE;
}


static ssize_t gpio_write(struct file * file, const char * buf, size_t count,
                          loff_t *off)
{
        struct gpio_private *priv = (struct gpio_private *)file->private_data;
        unsigned char data, clk_mask, data_mask, write_msb;
        unsigned long flags;

        spin_lock(&gpio_lock);

        ssize_t retval = count;
        if (priv->minor !=GPIO_MINOR_A && priv->minor != GPIO_MINOR_B) {
                retval = -EFAULT;
                goto out;
        }
    
        if (!access_ok(VERIFY_READ, buf, count)) {
                retval = -EFAULT;
                goto out;
        }
        clk_mask = priv->clk_mask;
        data_mask = priv->data_mask;
        /* It must have been configured using the IO_CFG_WRITE_MODE */
        /* Perhaps a better error code? */
        if (clk_mask == 0 || data_mask == 0) {
                retval = -EPERM;
                goto out;
        }
        write_msb = priv->write_msb;
        D(printk("gpio_write: %lu to data 0x%02X clk 0x%02X msb: %i\n",count, data_mask, clk_mask, write_msb));
        while (count--) {
                int i;
                data = *buf++;
                if (priv->write_msb) {
                        for (i = 7; i >= 0;i--) {
                                local_irq_save(flags);
                                *priv->port = *priv->shadow &= ~clk_mask;
                                if (data & 1<<i)
                                        *priv->port = *priv->shadow |= data_mask;
                                else
                                        *priv->port = *priv->shadow &= ~data_mask;
                        /* For FPGA: min 5.0ns (DCC) before CCLK high */
                                *priv->port = *priv->shadow |= clk_mask;
                                local_irq_restore(flags);
                        }
                } else {
                        for (i = 0; i <= 7;i++) {
                                local_irq_save(flags);
                                *priv->port = *priv->shadow &= ~clk_mask;
                                if (data & 1<<i)
                                        *priv->port = *priv->shadow |= data_mask;
                                else
                                        *priv->port = *priv->shadow &= ~data_mask;
                        /* For FPGA: min 5.0ns (DCC) before CCLK high */
                                *priv->port = *priv->shadow |= clk_mask;
                                local_irq_restore(flags);
                        }
                }
        }
out:
        spin_unlock(&gpio_lock);
        return retval;
}



static int
gpio_open(struct inode *inode, struct file *filp)
{
        struct gpio_private *priv;
        int p = iminor(inode);

        if (p > GPIO_MINOR_LAST)
                return -EINVAL;

        priv = kmalloc(sizeof(struct gpio_private),
                                              GFP_KERNEL);

        if (!priv)
                return -ENOMEM;

        priv->minor = p;

        /* initialize the io/alarm struct and link it into our alarmlist */

        priv->next = alarmlist;
        alarmlist = priv;
        if (USE_PORTS(priv)) { /* A and B */
                priv->port = ports[p];
                priv->shadow = shads[p];
                priv->dir = dir[p];
                priv->dir_shadow = dir_shadow[p];
                priv->changeable_dir = changeable_dir[p];
                priv->changeable_bits = changeable_bits[p];
        } else {
                priv->port = NULL;
                priv->shadow = NULL;
                priv->dir = NULL;
                priv->dir_shadow = NULL;
                priv->changeable_dir = 0;
                priv->changeable_bits = 0;
        }

        priv->highalarm = 0;
        priv->lowalarm = 0;
        priv->clk_mask = 0;
        priv->data_mask = 0;
        init_waitqueue_head(&priv->alarm_wq);

        filp->private_data = (void *)priv;

        return 0;
}

static int
gpio_release(struct inode *inode, struct file *filp)
{
        struct gpio_private *p;
        struct gpio_private *todel;

        spin_lock(&gpio_lock);

        p = alarmlist;
        todel = (struct gpio_private *)filp->private_data;

        /* unlink from alarmlist and free the private structure */

        if (p == todel) {
                alarmlist = todel->next;
        } else {
                while (p->next != todel)
                        p = p->next;
                p->next = todel->next;
        }

        kfree(todel);
        /* Check if there are still any alarms set */
        p = alarmlist;
        while (p) {
                if (p->highalarm | p->lowalarm) {
                        gpio_some_alarms = 1;
                        spin_unlock(&gpio_lock);
                        return 0;
                }
                p = p->next;
        }
        gpio_some_alarms = 0;
        spin_unlock(&gpio_lock);
        return 0;
}

/* Main device API. ioctl's to read/set/clear bits, as well as to 
 * set alarms to wait for using a subsequent select().
 */

unsigned long inline setget_input(struct gpio_private *priv, unsigned long arg)
{
        /* Set direction 0=unchanged 1=input, 
         * return mask with 1=input 
         */
        unsigned long flags;
        if (USE_PORTS(priv)) {
                local_irq_save(flags);
                *priv->dir = *priv->dir_shadow &= 
                ~((unsigned char)arg & priv->changeable_dir);
                local_irq_restore(flags);
                return ~(*priv->dir_shadow) & 0xFF; /* Only 8 bits */
        } else if (priv->minor == GPIO_MINOR_G) {
                /* We must fiddle with R_GEN_CONFIG to change dir */
                local_irq_save(flags);
                if (((arg & dir_g_in_bits) != arg) && 
                    (arg & changeable_dir_g)) {
                        arg &= changeable_dir_g;
                        /* Clear bits in genconfig to set to input */
                        if (arg & (1<<0)) {
                                genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g0dir);
                                dir_g_in_bits |= (1<<0);
                                dir_g_out_bits &= ~(1<<0);
                        }
                        if ((arg & 0x0000FF00) == 0x0000FF00) {
                                genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g8_15dir);
                                dir_g_in_bits |= 0x0000FF00;
                                dir_g_out_bits &= ~0x0000FF00;
                        }
                        if ((arg & 0x00FF0000) == 0x00FF0000) {
                                genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g16_23dir);
                                dir_g_in_bits |= 0x00FF0000;
                                dir_g_out_bits &= ~0x00FF0000;
                        }
                        if (arg & (1<<24)) {
                                genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g24dir);
                                dir_g_in_bits |= (1<<24);
                                dir_g_out_bits &= ~(1<<24);
                        }
                        D(printk(KERN_INFO "gpio: SETINPUT on port G set "
                                 "genconfig to 0x%08lX "
                                 "in_bits: 0x%08lX "
                                 "out_bits: 0x%08lX\n",
                                 (unsigned long)genconfig_shadow,
                                 dir_g_in_bits, dir_g_out_bits));
                        *R_GEN_CONFIG = genconfig_shadow;
                        /* Must be a >120 ns delay before writing this again */
                                
                }
                local_irq_restore(flags);
                return dir_g_in_bits;
        }
        return 0;
} /* setget_input */

unsigned long inline setget_output(struct gpio_private *priv, unsigned long arg)
{
        unsigned long flags;
        if (USE_PORTS(priv)) {
                local_irq_save(flags);
                *priv->dir = *priv->dir_shadow |= 
                  ((unsigned char)arg & priv->changeable_dir);
                local_irq_restore(flags);
                return *priv->dir_shadow;
        } else if (priv->minor == GPIO_MINOR_G) {
                /* We must fiddle with R_GEN_CONFIG to change dir */                    
                local_irq_save(flags);
                if (((arg & dir_g_out_bits) != arg) &&
                    (arg & changeable_dir_g)) {
                        /* Set bits in genconfig to set to output */
                        if (arg & (1<<0)) {
                                genconfig_shadow |= IO_MASK(R_GEN_CONFIG,g0dir);
                                dir_g_out_bits |= (1<<0);
                                dir_g_in_bits &= ~(1<<0);
                        }
                        if ((arg & 0x0000FF00) == 0x0000FF00) {
                                genconfig_shadow |= IO_MASK(R_GEN_CONFIG,g8_15dir);
                                dir_g_out_bits |= 0x0000FF00;
                                dir_g_in_bits &= ~0x0000FF00;
                        }
                        if ((arg & 0x00FF0000) == 0x00FF0000) {
                                genconfig_shadow |= IO_MASK(R_GEN_CONFIG,g16_23dir);
                                dir_g_out_bits |= 0x00FF0000;
                                dir_g_in_bits &= ~0x00FF0000;
                        }
                        if (arg & (1<<24)) {
                                genconfig_shadow |= IO_MASK(R_GEN_CONFIG,g24dir);
                                dir_g_out_bits |= (1<<24);
                                dir_g_in_bits &= ~(1<<24);
                        }
                        D(printk(KERN_INFO "gpio: SETOUTPUT on port G set "
                                 "genconfig to 0x%08lX "
                                 "in_bits: 0x%08lX "
                                 "out_bits: 0x%08lX\n",
                                 (unsigned long)genconfig_shadow,
                                 dir_g_in_bits, dir_g_out_bits));
                        *R_GEN_CONFIG = genconfig_shadow;
                        /* Must be a >120 ns delay before writing this again */
                }
                local_irq_restore(flags);
                return dir_g_out_bits & 0x7FFFFFFF;
        }
        return 0;
} /* setget_output */

static int
gpio_leds_ioctl(unsigned int cmd, unsigned long arg);

static int
gpio_ioctl(struct inode *inode, struct file *file,
           unsigned int cmd, unsigned long arg)
{
        unsigned long flags;
        unsigned long val;
        int ret = 0;

        struct gpio_private *priv = (struct gpio_private *)file->private_data;
        if (_IOC_TYPE(cmd) != ETRAXGPIO_IOCTYPE) {
                return -EINVAL;
        }

        spin_lock(&gpio_lock);

        switch (_IOC_NR(cmd)) {
        case IO_READBITS: /* Use IO_READ_INBITS and IO_READ_OUTBITS instead */
                // read the port
                if (USE_PORTS(priv)) {
                        ret =  *priv->port;
                } else if (priv->minor == GPIO_MINOR_G) {
                        ret =  (*R_PORT_G_DATA) & 0x7FFFFFFF;
                }
                break;
        case IO_SETBITS:
                local_irq_save(flags);
                // set changeable bits with a 1 in arg
                if (USE_PORTS(priv)) {
                        *priv->port = *priv->shadow |= 
                          ((unsigned char)arg & priv->changeable_bits);
                } else if (priv->minor == GPIO_MINOR_G) {
                        *R_PORT_G_DATA = port_g_data_shadow |= (arg & dir_g_out_bits);
                }
                local_irq_restore(flags);
                break;
        case IO_CLRBITS:
                local_irq_save(flags);
                // clear changeable bits with a 1 in arg
                if (USE_PORTS(priv)) {
                        *priv->port = *priv->shadow &= 
                         ~((unsigned char)arg & priv->changeable_bits);
                } else if (priv->minor == GPIO_MINOR_G) {
                        *R_PORT_G_DATA = port_g_data_shadow &= ~((unsigned long)arg & dir_g_out_bits);
                }
                local_irq_restore(flags);
                break;
        case IO_HIGHALARM:
                // set alarm when bits with 1 in arg go high
                priv->highalarm |= arg;
                gpio_some_alarms = 1;
                break;
        case IO_LOWALARM:
                // set alarm when bits with 1 in arg go low
                priv->lowalarm |= arg;
                gpio_some_alarms = 1;
                break;
        case IO_CLRALARM:
                // clear alarm for bits with 1 in arg
                priv->highalarm &= ~arg;
                priv->lowalarm  &= ~arg;
                {
                        /* Must update gpio_some_alarms */
                        struct gpio_private *p = alarmlist;
                        int some_alarms;
                        some_alarms = 0;
                        while (p) {
                                if (p->highalarm | p->lowalarm) {
                                        some_alarms = 1;
                                        break;
                                }
                                p = p->next;
                        }
                        gpio_some_alarms = some_alarms;
                }
                break;
        case IO_READDIR: /* Use IO_SETGET_INPUT/OUTPUT instead! */
                /* Read direction 0=input 1=output */
                if (USE_PORTS(priv)) {
                        ret = *priv->dir_shadow;
                } else if (priv->minor == GPIO_MINOR_G) {
                        /* Note: Some bits are both in and out,
                         * Those that are dual is set here as well.
                         */
                        ret = (dir_g_shadow | dir_g_out_bits) & 0x7FFFFFFF;
                }
                break;
        case IO_SETINPUT: /* Use IO_SETGET_INPUT instead! */
                /* Set direction 0=unchanged 1=input, 
                 * return mask with 1=input 
                 */
                ret = setget_input(priv, arg) & 0x7FFFFFFF;
                break;
        case IO_SETOUTPUT: /* Use IO_SETGET_OUTPUT instead! */
                /* Set direction 0=unchanged 1=output, 
                 * return mask with 1=output 
                 */
                ret =  setget_output(priv, arg) & 0x7FFFFFFF;
                break;
        case IO_SHUTDOWN:
                SOFT_SHUTDOWN();
                break;
        case IO_GET_PWR_BT:
#if defined (CONFIG_ETRAX_SOFT_SHUTDOWN)
                ret = (*R_PORT_G_DATA & ( 1 << CONFIG_ETRAX_POWERBUTTON_BIT));
#else
                ret = 0;
#endif
                break;
        case IO_CFG_WRITE_MODE:
                priv->clk_mask = arg & 0xFF;
                priv->data_mask = (arg >> 8) & 0xFF;
                priv->write_msb = (arg >> 16) & 0x01;
                /* Check if we're allowed to change the bits and
                 * the direction is correct
                 */
                if (!((priv->clk_mask & priv->changeable_bits) &&
                      (priv->data_mask & priv->changeable_bits) &&
                      (priv->clk_mask & *priv->dir_shadow) &&
                      (priv->data_mask & *priv->dir_shadow)))
                {
                        priv->clk_mask = 0;
                        priv->data_mask = 0;
                        ret = -EPERM;
                }
                break;
        case IO_READ_INBITS: 
                /* *arg is result of reading the input pins */
                if (USE_PORTS(priv)) {
                        val = *priv->port;
                } else if (priv->minor == GPIO_MINOR_G) {
                        val = *R_PORT_G_DATA;
                }
                if (copy_to_user((unsigned long*)arg, &val, sizeof(val)))
                        ret = -EFAULT;
                break;
        case IO_READ_OUTBITS:
                 /* *arg is result of reading the output shadow */
                if (USE_PORTS(priv)) {
                        val = *priv->shadow;
                } else if (priv->minor == GPIO_MINOR_G) {
                        val = port_g_data_shadow;
                }
                if (copy_to_user((unsigned long*)arg, &val, sizeof(val)))
                        ret = -EFAULT;
                break;
        case IO_SETGET_INPUT: 
                /* bits set in *arg is set to input,
                 * *arg updated with current input pins.
                 */
                if (copy_from_user(&val, (unsigned long*)arg, sizeof(val)))
                {
                        ret = -EFAULT;
                        break;
                }
                val = setget_input(priv, val);
                if (copy_to_user((unsigned long*)arg, &val, sizeof(val)))
                        ret = -EFAULT;
                break;
        case IO_SETGET_OUTPUT:
                /* bits set in *arg is set to output,
                 * *arg updated with current output pins.
                 */
                if (copy_from_user(&val, (unsigned long*)arg, sizeof(val)))
                {
                        ret = -EFAULT;
                        break;
                }
                val = setget_output(priv, val);
                if (copy_to_user((unsigned long*)arg, &val, sizeof(val)))
                        ret = -EFAULT;
                break;
        default:
                if (priv->minor == GPIO_MINOR_LEDS)
                        ret = gpio_leds_ioctl(cmd, arg);
                else
                        ret = -EINVAL;
        } /* switch */

        spin_unlock(&gpio_lock);
        return ret;
}

static int
gpio_leds_ioctl(unsigned int cmd, unsigned long arg)
{
        unsigned char green;
        unsigned char red;

        switch (_IOC_NR(cmd)) {
        case IO_LEDACTIVE_SET:
                green = ((unsigned char) arg) & 1;
                red   = (((unsigned char) arg) >> 1) & 1;
                LED_ACTIVE_SET_G(green);
                LED_ACTIVE_SET_R(red);
                break;

        case IO_LED_SETBIT:
                LED_BIT_SET(arg);
                break;

        case IO_LED_CLRBIT:
                LED_BIT_CLR(arg);
                break;

        default:
                return -EINVAL;
        } /* switch */

        return 0;
}

const struct file_operations gpio_fops = {
        .owner       = THIS_MODULE,
        .poll        = gpio_poll,
        .ioctl       = gpio_ioctl,
        .write       = gpio_write,
        .open        = gpio_open,
        .release     = gpio_release,
};


void ioif_watcher(const unsigned int gpio_in_available,
                  const unsigned int gpio_out_available,
                  const unsigned char pa_available,
                  const unsigned char pb_available)
{
        unsigned long int flags;
        D(printk("gpio.c: ioif_watcher called\n"));
        D(printk("gpio.c: G in: 0x%08x G out: 0x%08x PA: 0x%02x PB: 0x%02x\n",
                 gpio_in_available, gpio_out_available, pa_available, pb_available));

        spin_lock_irqsave(&gpio_lock, flags);

        dir_g_in_bits = gpio_in_available;
        dir_g_out_bits = gpio_out_available;

        /* Initialise the dir_g_shadow etc. depending on genconfig */
        /* 0=input 1=output */
        if (genconfig_shadow & IO_STATE(R_GEN_CONFIG, g0dir, out)) 
                dir_g_shadow |= (1 << 0);
        if (genconfig_shadow & IO_STATE(R_GEN_CONFIG, g8_15dir, out))
                dir_g_shadow |= 0x0000FF00;
        if (genconfig_shadow & IO_STATE(R_GEN_CONFIG, g16_23dir, out))
                dir_g_shadow |= 0x00FF0000;
        if (genconfig_shadow & IO_STATE(R_GEN_CONFIG, g24dir, out))
                dir_g_shadow |= (1 << 24);

        changeable_dir_g = changeable_dir_g_mask;
        changeable_dir_g &= dir_g_out_bits;
        changeable_dir_g &= dir_g_in_bits;
        /* Correct the bits that can change direction */ 
        dir_g_out_bits &= ~changeable_dir_g;
        dir_g_out_bits |= dir_g_shadow;
        dir_g_in_bits &= ~changeable_dir_g;
        dir_g_in_bits |= (~dir_g_shadow & changeable_dir_g);

        spin_unlock_irqrestore(&gpio_lock, flags);

        printk(KERN_INFO "GPIO port G: in_bits: 0x%08lX out_bits: 0x%08lX val: %08lX\n",
               dir_g_in_bits, dir_g_out_bits, (unsigned long)*R_PORT_G_DATA);
        printk(KERN_INFO "GPIO port G: dir: %08lX changeable: %08lX\n",
               dir_g_shadow, changeable_dir_g);
}

/* main driver initialization routine, called from mem.c */

static __init int
gpio_init(void)
{
        int res;
#if defined (CONFIG_ETRAX_CSP0_LEDS)
        int i;
#endif
        printk("gpio init\n");

        /* do the formalities */

        res = register_chrdev(GPIO_MAJOR, gpio_name, &gpio_fops);
        if (res < 0) {
                printk(KERN_ERR "gpio: couldn't get a major number.\n");
                return res;
        }

        /* Clear all leds */
#if defined (CONFIG_ETRAX_CSP0_LEDS) ||  defined (CONFIG_ETRAX_PA_LEDS) || defined (CONFIG_ETRAX_PB_LEDS)
        LED_NETWORK_SET(0);
        LED_ACTIVE_SET(0);
        LED_DISK_READ(0);
        LED_DISK_WRITE(0);

#if defined (CONFIG_ETRAX_CSP0_LEDS)
        for (i = 0; i < 32; i++) {
                LED_BIT_SET(i);
        }
#endif

#endif
        /* The I/O interface allocation watcher will be called when
         * registering it. */
        if (cris_io_interface_register_watcher(ioif_watcher)){
                printk(KERN_WARNING "gpio_init: Failed to install IO if allocator watcher\n");
        }

        printk(KERN_INFO "ETRAX 100LX GPIO driver v2.5, (c) 2001, 2002, 2003, 2004 Axis Communications AB\n");
        /* We call etrax_gpio_wake_up_check() from timer interrupt and
         * from cpu_idle() in kernel/process.c
         * The check in cpu_idle() reduces latency from ~15 ms to ~6 ms
         * in some tests.
         */  
        if (request_irq(TIMER0_IRQ_NBR, gpio_poll_timer_interrupt,
                        IRQF_SHARED | IRQF_DISABLED,"gpio poll", NULL)) {
                printk(KERN_CRIT "err: timer0 irq for gpio\n");
        }
        if (request_irq(PA_IRQ_NBR, gpio_pa_interrupt,
                        IRQF_SHARED | IRQF_DISABLED,"gpio PA", NULL)) {
                printk(KERN_CRIT "err: PA irq for gpio\n");
        }
        

        return res;
}

/* this makes sure that gpio_init is called during kernel boot */

module_init(gpio_init);