LINUX 产生PPM 驱动例子

APP：

//author:DriverMonkey
//phone:13410905075
//mail:bookworepeng@Hotmail.com
//qq:196568501


#include<stdio.h>
#include<string.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<unistd.h>

#define US (1000)

#define PPM_CHANEL 8
#define FIX_LOW_TIME 100*US
#define FIX_SYNC_TIME 5000

static long long ppm_values[(PPM_CHANEL + 1)*2] =
       {FIX_LOW_TIME,1000*US,   // 1
       FIX_LOW_TIME,1000*US,    // 2
       FIX_LOW_TIME,1000*US,    // 3
       FIX_LOW_TIME,1000*US,    // 4
       FIX_LOW_TIME,1000*US,    // 5
       FIX_LOW_TIME,1000*US,    // 6
       FIX_LOW_TIME,1000*US,    // 7
       FIX_LOW_TIME,1000*US,    // 8
       FIX_LOW_TIME,FIX_SYNC_TIME*US, };    // 9


int main(int argc,char *args[])
{
    int fd;
    int channel = 0;
    long long value = 0;

    fd=open("/dev/ppm",O_WRONLY|O_CREAT,0640);
    if(fd < 0)
        return 0;

    if(argc > 3)
        return;
    channel = atol(args[1]);
    printf("input channle is: %d
", channel);

    value  = atol(args[2]);
    printf("input value is: %d
", (int)value );

    printf("old value is:%d
",(int)ppm_values[channel*2 + 1]);
    ppm_values[channel*2 + 1] = value*US;
    printf("new value is:%d
",(int)ppm_values[channel*2 + 1]);

    write(fd,ppm_values,sizeof(ppm_values));

    sleep(20);
    close(fd);
}

Driver:

//author:DriverMonkey
//phone:13410905075
//mail:bookworepeng@Hotmail.com
//qq:196568501


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/syscalls.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/of_platform.h>
#include <linux/uaccess.h>
#include <linux/string.h>

#include <mach/gpio.h>
#include <mach/irqs.h>

#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))

#define US (1000)

#define PPM_CHANEL 8
#define FIX_LOW_TIME 100*US


struct ppm_dev
{
    struct cdev cdev;
    dev_t devno;
    struct class *ppm_class;
    int message_cdev_open;
};

struct ppm_dev ppm_dev;


static long long ppm_values[(PPM_CHANEL + 1)*2] =
       {FIX_LOW_TIME,1000*US,   // 1
       FIX_LOW_TIME,1000*US,    // 2
       FIX_LOW_TIME,1000*US,    // 3
       FIX_LOW_TIME,1000*US,    // 4
       FIX_LOW_TIME,1000*US,    // 5
       FIX_LOW_TIME,1000*US,    // 6
       FIX_LOW_TIME,1000*US,    // 7
       FIX_LOW_TIME,1000*US,    // 8
       FIX_LOW_TIME,5000*US, }; // 9

ktime_t ktime;
static struct hrtimer hr_timer;

static enum hrtimer_restart hrtimer_callback(struct hrtimer *timer)
{
    static int index = 0;
    static ktime_t ktime;
    if(index == ((PPM_CHANEL + 1)*2))
        index = 0;
    ktime.tv64 = ppm_values[index];
    hrtimer_forward(timer, timer->base->get_time(), ktime);
    index++;
    if(ktime.tv64 == FIX_LOW_TIME)
        gpio_direction_output(GPIO_TO_PIN(0,27), 0);
    else
        gpio_direction_output(GPIO_TO_PIN(0,27), 1);

    //printk("%d
",(int)ktime.tv64);

    return HRTIMER_RESTART;
}


static int ppm_open(struct inode *node, struct file *fd)
{
    int ret = 0;

    printk("ppm_open()++
");

    ktime = ktime_set( 0, 200*1000);                   // 200us
    hrtimer_init( &hr_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL );
    hr_timer.function = &hrtimer_callback;
    hrtimer_start( &hr_timer, ktime, HRTIMER_MODE_REL );


    printk("ppm_open()--
");

    return ret;
}

 ssize_t ppm_write(struct file *pfile,
                    const char __user *buffer,
                    size_t size,
                    loff_t *pnull)

{

    printk("ppm_write()++
");

    if(size != sizeof(ppm_values))
        return 0;

    copy_from_user(ppm_values, buffer, size);

    printk("ppm_write()--
");

    return size;
}
static int ppm_fasync(int fd, struct file *filp, int mode)
{

    printk("ppm_fasync()++
");


    printk("ppm_fasync()--
");

    return 0;
}

static int ppm_release(struct inode *node, struct file *fd)
{
    printk("ppm_release()++
");

    hrtimer_cancel(&hr_timer);
    printk("ppm_release()--
");
    return 0;
}


struct file_operations meassage_operatons =
{
    .owner = THIS_MODULE,
    .open = ppm_open,

    .write = ppm_write,
    .fasync = ppm_fasync,
    .release = ppm_release,
};

static int __init ppm_init(void)
{
    struct ppm_dev * dev;
    int ret = 0;


    dev = &ppm_dev;

    alloc_chrdev_region(&dev->devno, 0, 1, "out_ppm");

    dev->ppm_class = class_create(THIS_MODULE, "ppm_class");
    if(IS_ERR(dev->ppm_class)) {
         printk(KERN_ERR"Err: failed in creating class./n");
         goto fail1;
     }
    device_create(dev->ppm_class, NULL, dev->devno, NULL, "ppm");


    //init irq
    ret = gpio_request(GPIO_TO_PIN(0,27), "ppm_inter");
    if(ret){
        printk(KERN_ERR"gpio_request() failed !
");
        goto fail1;
    }
    ret = gpio_direction_output(GPIO_TO_PIN(0,27), 1);
    if(ret){
        printk(KERN_ERR"gpio_direction_input() failed !
");
        goto fail2;
    }

    cdev_init(&dev->cdev, &meassage_operatons);
    cdev_add(&dev->cdev, dev->devno, 1);


    if(ret){
        printk(KERN_ERR"request_irq() failed ! %d
", ret);
        goto fail2;
    }

   printk("ppm_to_app_init(void)--
");
    return 0;

fail2:
    gpio_free(GPIO_TO_PIN(0,27));
fail1:
    device_destroy(dev->ppm_class, dev->devno);
    class_destroy(dev->ppm_class);
    cdev_del(&dev->cdev);
    unregister_chrdev_region(dev->devno, 1);

    return ret;
}
static void __exit ppm_exit(void)
{
    struct ppm_dev *dev = &ppm_dev;

   // printk("ppm_to_app_exit(void)++
");
    gpio_free(GPIO_TO_PIN(0,27));

    device_destroy(dev->ppm_class, dev->devno);
    class_destroy(dev->ppm_class);
    cdev_del(&dev->cdev);
    unregister_chrdev_region(dev->devno, 1);

   // printk("ppm_to_app_exit(void)--
");
}
module_init(ppm_init);
module_exit(ppm_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Driver Monkey");
MODULE_DESCRIPTION("Test ppm");