//驱动代码如下.主设备号设为232 ,适用GEC2410 十六键矩阵键盘

#include
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#define S3C2410_GPG11 S3C2410_GPIONO(S3C2410_GPIO_BANKG, 11) // S3C2410_GPG11 undefined in regs-gpio.h

#define DEVICE_NAME "matrix_button" 
#define BUTTON_MAJOR 232

unsigned int s3c2410_gpio_getpin(unsigned int pin)
{
     unsigned long base = S3C2410_GPIO_BASE(pin);
     unsigned long offs = S3C2410_GPIO_OFFSET(pin); 
         return __raw_readl(base + 0x04) & (1<< offs);
}

void s3c2410_gpio_cfgpin(unsigned int pin, unsigned int function)
{
    unsigned long base = S3C2410_GPIO_BASE(pin);
    unsigned long mask;
    unsigned long con;
    unsigned long flags;
    if(pin        mask=1<    else
        mask =3<< (S3C2410_GPIO_OFFSET(pin)*2);
    local_irq_save(flags);

    con = __raw_readl(base + 0x00);

    con &= ~mask;
    con |= function;

    __raw_writel(con, base + 0x00);

    local_irq_restore(flags);
}

void s3c2410_gpio_setpin(unsigned int pin, unsigned int to)
{
    unsigned long base = S3C2410_GPIO_BASE(pin);
    unsigned long offs = S3C2410_GPIO_OFFSET(pin);
    unsigned long flags;
    unsigned long dat;

    local_irq_save(flags);

    dat = __raw_readl(base + 0x04);
    dat &= ~(1 << offs);
    dat |= to << offs;
    __raw_writel(dat, base + 0x04);

    local_irq_restore(flags);
}

#define EXTINT_OFF (IRQ_EINT4 - 4)

// clear SRCPND&INTPND
void s3c_irq_ack(unsigned int irqno) 
{
    unsigned long bitval = 1UL << (irqno - IRQ_EINT0);
    __raw_writel(bitval, S3C2410_SRCPND);
    __raw_writel(bitval, S3C2410_INTPND);
    return;
}
void s3c_irqext_ack(unsigned int irqno)
{
    unsigned long req;
    unsigned long bit;
    bit = 1UL << (irqno - EXTINT_OFF);
    __raw_writel(bit, S3C2410_EINTPEND);
    req = __raw_readl(S3C2410_EINTPEND);
    if (irqno <= IRQ_EINT7 )
    {
        if ((req & 0xf0) == 0)
        s3c_irq_ack(IRQ_EINT4t7);
    }
    else
    {
        if ((req >> 8) == 0)
        s3c_irq_ack(IRQ_EINT8t23);
    }
    return;
}

// set external interrupt mode, trigger type and gpio registers
int realarm_interrupt_init(unsigned int irq, unsigned int type)
{
    unsigned long gpcon_reg;
    unsigned long gpcon_offset;
    unsigned long extint_reg;
    unsigned long extint_offset;
    unsigned long newvalue = 0;
    unsigned long value;
    if ((irq >= IRQ_EINT0) && (irq <= IRQ_EINT3))
    {
        gpcon_reg = S3C2410_GPFCON;
        extint_reg = S3C2410_EXTINT0;
        gpcon_offset = (irq - IRQ_EINT0) * 2;
        extint_offset = (irq - IRQ_EINT0) * 4;
    }
    else if ((irq >= IRQ_EINT4) && (irq <= IRQ_EINT7))
    {
        gpcon_reg = S3C2410_GPFCON;
        extint_reg = S3C2410_EXTINT0;
        gpcon_offset = (irq - EXTINT_OFF) * 2;
        extint_offset = (irq - EXTINT_OFF) * 4;
    }
    else if ((irq >= IRQ_EINT8) && (irq <= IRQ_EINT15))
    {
        gpcon_reg = S3C2410_GPGCON;
        extint_reg = S3C2410_EXTINT1;
        gpcon_offset = (irq - IRQ_EINT8) * 2;
        extint_offset = (irq - IRQ_EINT8) * 4;
    }
    else if ((irq >= IRQ_EINT16) && (irq <= IRQ_EINT23))
    {
        gpcon_reg = S3C2410_GPGCON;
        extint_reg = S3C2410_EXTINT2;
        gpcon_offset = (irq - IRQ_EINT8) * 2;
        extint_offset = (irq - IRQ_EINT16) * 4;
    } else
    {
        return -1;
    }
    /* Set the GPIO to external interrupt mode */
    value = __raw_readl(gpcon_reg);
    value = (value & ~(3 << gpcon_offset)) | (0x02 << gpcon_offset);
    __raw_writel(value, gpcon_reg);
    /* Set the external interrupt to pointed trigger type */
    switch (type)
    {
    case IRQT_NOEDGE:
        printk(KERN_WARNING "No edge setting!\n");
        break;
    case IRQT_RISING:
        newvalue = S3C2410_EXTINT_RISEEDGE;
        break;
    case IRQT_FALLING:
        newvalue = S3C2410_EXTINT_FALLEDGE;
        break;
    case IRQT_BOTHEDGE:
        newvalue = S3C2410_EXTINT_BOTHEDGE;
        break;
    case IRQT_LOW:
        newvalue = S3C2410_EXTINT_LOWLEV;
        break;
    case IRQT_HIGH:
        newvalue = S3C2410_EXTINT_HILEV;
        break;
    default:
        printk(KERN_ERR "No such irq type %d", type);
        return -1;
    }
    value = __raw_readl(extint_reg);
    value = (value & ~(7 << extint_offset)) | (newvalue << extint_offset);
    __raw_writel(value, extint_reg);
    return 0;
}

static struct key_info { 
int irq_no; 
unsigned int gpio_port; 
int function_inp;
int function_eintn; 
}key_info_tab[4]={
        { IRQ_EINT0, S3C2410_GPF0,S3C2410_GPF0_INP,S3C2410_GPF0_EINT0}, 
        { IRQ_EINT2, S3C2410_GPF2,S3C2410_GPF2_INP,S3C2410_GPF2_EINT2}, 
        { IRQ_EINT11,S3C2410_GPG3,S3C2410_GPG3_INP,S3C2410_GPG3_EINT11 }, 
        { IRQ_EINT19,S3C2410_GPG11,S3C2410_GPG11_INP,S3C2410_GPG11_EINT19}};

struct matrix_button
{
    int key_value;
    int ready;
    int open_count;
    wait_queue_head_t buttons_wait;
    struct cdev cdev;
    struct semaphore sem;
};

static struct matrix_button* matrix_button_dev;

static struct output_pin
{
    unsigned int gpio_pin;
    int function_outp;
}output_pin_tab[4]={
    {S3C2410_GPE11,S3C2410_GPE11_OUTP},
    {S3C2410_GPG6,S3C2410_GPG6_OUTP},
    {S3C2410_GPE13,S3C2410_GPE13_OUTP},
    {S3C2410_GPG2,S3C2410_GPG2_OUTP}
};

static int  key_scan(void)
{

    int i,j,k,ret=0;
    for(i=0;i<4;i++)
    {
                
            for(j=0;j<4;j++)
            {
                if(i==j)s3c2410_gpio_setpin(output_pin_tab[j].gpio_pin,0);
                 else s3c2410_gpio_setpin(output_pin_tab[j].gpio_pin,1);
            }
            for(k=0;k<4;k++)
            {
                if(s3c2410_gpio_getpin(key_info_tab[k].gpio_port)==0)
                {
                    ret=i*10+k+1;
                    return ret;
                }
            }
    }    
    return ret;
}

static void port_init(void)
{
    int i;
    for(i=0;i<4;i++)
    {
        s3c2410_gpio_cfgpin(output_pin_tab[i].gpio_pin,output_pin_tab[i].function_outp);
        s3c2410_gpio_setpin(output_pin_tab[i].gpio_pin,0);
        s3c2410_gpio_cfgpin(key_info_tab[i].gpio_port,key_info_tab[i].function_eintn);
        realarm_interrupt_init(key_info_tab[i].irq_no,IRQT_FALLING);
    }
}

static irqreturn_t matrix_button_irq(int irq, void *dev_id, struct pt_regs *reg) 
{ 
    struct matrix_button *dev=dev_id;
    struct key_info *k; 
    int i; 
    int found = 0;
    int flags;
    down(&dev->sem); 
    for (i = 0; i < sizeof(key_info_tab)/ sizeof(key_info_tab[0]); i++)
    { 
            k = key_info_tab + i; 
            if (k->irq_no == irq)
            { 
                    found = 1; 
                    break; 
            } 
    } 
    if (!found) 
    { 
        printk(KERN_NOTICE "bad irq %d in button\n", irq); 
        return IRQ_HANDLED; 
    } 
    save_flags(flags); // save CPSR
    cli();     // Close interrupt 
    if(k->irq_no        s3c_irq_ack(k->irq_no);
    else
        s3c_irqext_ack(k->irq_no);
    for(i=0;i    {
        k=key_info_tab+i;
        s3c2410_gpio_cfgpin(k->gpio_port,k->function_inp);
    }
    mdelay(100);
    dev->key_value=key_scan();
    if(dev->key_value==0)
    {
        up(&dev->sem);
        port_init();
        restore_flags(flags);
        return IRQ_HANDLED; 
    }
    dev->ready=1;
    up(&dev->sem);
    wake_up(&dev->buttons_wait);
    port_init();
    restore_flags(flags); 
    return IRQ_HANDLED; 
}

static int request_irqs(struct matrix_button *dev) 
{ 
    struct key_info *k; 
    int i; 
    for (i = 0; i < sizeof(key_info_tab) / sizeof(key_info_tab[0]); i++)
    { 
        k = key_info_tab + i;
        if (request_irq(k->irq_no, &matrix_button_irq, SA_INTERRUPT, DEVICE_NAME, dev)) return -1;  
    } 
    return 0; 
}

static void free_irqs(struct matrix_button *dev) 
{ 
    struct key_info *k; 
    int i; 
    for (i = 0; i < sizeof(key_info_tab) / sizeof(key_info_tab[0]); i++)
    { 
        k = key_info_tab + i; 
        free_irq(k->irq_no,dev); 
    } 
}

static int matrix_button_read(struct file * filp, char __user * buffer, size_t count, loff_t *f_pos) 
{ 
    struct matrix_button *dev=filp->private_data; 
    down(&dev->sem); 
    if(!dev->ready)
       return -EAGAIN;
    copy_to_user(buffer, &dev->key_value, sizeof(int)); 
    dev->ready = 0; 
    up(&dev->sem);
    return count; 
}

static unsigned int matrix_button_poll( struct file *filp, struct poll_table_struct *wait) 
{ 
    struct matrix_button *dev=filp->private_data; 
    poll_wait(filp, &dev->buttons_wait, wait); 
    if (dev->ready) 
        return POLLIN;
    else 
        return 0;
}

static int matrix_button_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) 
{ 
    switch(cmd) { 
    default: 
    return -EINVAL; 
    } 
}

static int matrix_button_open(struct inode *inode,struct file *filp)
{
    int ret;
    struct matrix_button *dev;
    dev=container_of(inode->i_cdev,struct matrix_button,cdev);
    down(&dev->sem);
    filp->private_data=dev;
    if(dev->open_count==0)
    {
        ret = request_irqs(dev); 
        if (ret) 
        {
        cdev_del(&matrix_button_dev->cdev);
        unregister_chrdev_region(MKDEV(BUTTON_MAJOR,0),1);
        kfree(matrix_button_dev);
        printk(DEVICE_NAME " can't request irqs\n"); 
        return ret; 
        }
    }
    dev->open_count++;
    up(&dev->sem);
    return 0;
}

static int matrix_button_release(struct inode *inode,struct file *filp)
{
    struct matrix_button *dev=filp->private_data;
    down(&dev->sem);
    if((dev->open_count--)==1)
        free_irqs(dev);
    up(&dev->sem);
    return 0;
}

static struct file_operations matrix_button_fops = { 
owner: THIS_MODULE, 
ioctl: matrix_button_ioctl, 
poll: matrix_button_poll, 
read: matrix_button_read, 
open: matrix_button_open,
release:matrix_button_release
};

static int __init matrix_button_init(void) 
{ 
    int ret; 
    dev_t dev=MKDEV(BUTTON_MAJOR,0);
    ret=register_chrdev_region(dev,1,"matrix_button");
    if(ret<0)
        return ret;
    matrix_button_dev=kmalloc(sizeof(struct matrix_button),GFP_KERNEL);
    memset(matrix_button_dev,0,sizeof(struct matrix_button));
    matrix_button_dev->ready=0;
    matrix_button_dev->key_value=0;
    matrix_button_dev->open_count=0;
    init_waitqueue_head(&matrix_button_dev->buttons_wait);
    init_MUTEX(&matrix_button_dev->sem);    
    cdev_init(&matrix_button_dev->cdev,&matrix_button_fops);
    matrix_button_dev->cdev.owner=THIS_MODULE;
    matrix_button_dev->cdev.ops=&matrix_button_fops;
    port_init();
    ret=cdev_add(&matrix_button_dev->cdev,dev,1);
    if(ret)
        printk(KERN_NOTICE "Error %d",ret); 
    
    return 0; 
}

static void __exit matrix_button_exit(void) 
{ 
    cdev_del(&matrix_button_dev->cdev);
    unregister_chrdev_region(MKDEV(BUTTON_MAJOR,0),1);
    kfree(matrix_button_dev);
    free_irqs(matrix_button_dev);  
}

module_init(matrix_button_init); 
module_exit(matrix_button_exit); 
MODULE_LICENSE("GPL");

//以下为测试代码

#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include  
#include

int main(void) 
{ 
    int buttons_fd,i; 
    int key_value; 
    buttons_fd = open("/dev/matrix_button", 0); 
    if (buttons_fd < 0) { 
    perror("open device buttons"); 
    exit(1); 
    } 
    for (;;) 
    { 
        fd_set rds; 
        int ret; 
        FD_ZERO(&rds); 
        FD_SET(buttons_fd, &rds); 
        ret = select(buttons_fd + 1, &rds, NULL, NULL, NULL); 
        if (ret < 0) 
        { 
            perror("select"); 
            exit(1); 
        } 
        if (ret == 0) 
        { 
            printf("Timeout.\n"); 
        } 
        else if (FD_ISSET(buttons_fd, &rds)) 
        { 
            int ret = read(buttons_fd, &key_value, sizeof key_value); 
            if (ret != sizeof key_value) 
            { 
                if (errno != EAGAIN) 
                    perror("read buttons\n"); 
                continue; 
            } 
            else 
            { 
                printf("buttons_value: %d\n", key_value); 
            } 
        } 
    } 
    close(buttons_fd); 
    return 0; 
}