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\n", channel);
- value = atol(args[2]);
- printf("input value is: %d\n", (int)value );
- printf("old value is:%d\n",(int)ppm_values[channel*2 + 1]);
- ppm_values[channel*2 + 1] = value*US;
- printf("new value is:%d\n",(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\n",(int)ktime.tv64);
- return HRTIMER_RESTART;
- }
- static int ppm_open(struct inode *node, struct file *fd)
- {
- int ret = 0;
- printk("ppm_open()++\n");
- 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()--\n");
- return ret;
- }
- ssize_t ppm_write(struct file *pfile,
- const char __user *buffer,
- size_t size,
- loff_t *pnull)
- {
- printk("ppm_write()++\n");
- if(size != sizeof(ppm_values))
- return 0;
- copy_from_user(ppm_values, buffer, size);
- printk("ppm_write()--\n");
- return size;
- }
- static int ppm_fasync(int fd, struct file *filp, int mode)
- {
- printk("ppm_fasync()++\n");
- printk("ppm_fasync()--\n");
- return 0;
- }
- static int ppm_release(struct inode *node, struct file *fd)
- {
- printk("ppm_release()++\n");
- hrtimer_cancel(&hr_timer);
- printk("ppm_release()--\n");
- 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 !\n");
- goto fail1;
- }
- ret = gpio_direction_output(GPIO_TO_PIN(0,27), 1);
- if(ret){
- printk(KERN_ERR"gpio_direction_input() failed !\n");
- goto fail2;
- }
- cdev_init(&dev->cdev, &meassage_operatons);
- cdev_add(&dev->cdev, dev->devno, 1);
- if(ret){
- printk(KERN_ERR"request_irq() failed ! %d\n", ret);
- goto fail2;
- }
- printk("ppm_to_app_init(void)--\n");
- 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)++\n");
- 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)--\n");
- }
- module_init(ppm_init);
- module_exit(ppm_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Driver Monkey");
- MODULE_DESCRIPTION("Test ppm");
作者:柒月
Q群 :2122210(嵌入式/机器学习)