Question

我正在使用i.mx6quad和debian jessie（3.14.60-fslc-imx6-sr）。

我希望使用PARALLEL 8BIT接口连接ov5642相机模块（使用8gpios作为数据，3作为控制信号）。我编写了一个linux内核模块来处理来自控制信号的中断。来自VSYNC和HREF信号的中断服务正常但是当我连接一个比HREF或VSYNC快得多的PCLK（大约8MHz）信号时，我的linux挂机，直到我断开与PCLK的连线（一切卡住）。要连接PCLK我使用GPIO90（DISP1_DATA22），但我也尝试过使用其他gpios。

现在我的问题是我应该使用哪个GPIO来正确地为PCLK这样的快速信号提供服务，或者我该怎么做才能避免linux挂起？

我包含了我使用的Linux内核模块代码。

#include<linux/init.h>
#include<linux/module.h>
#include<linux/kernel.h>
#include<linux/gpio.h>
#include<linux/interrupt.h>

static unsigned int VSYNC_gpio_number=79;
static unsigned int HREF_gpio_number=76;
static unsigned int PCLK_gpio_number=90;
static unsigned int VSYNC_irqNumber;
static unsigned int HREF_irqNumber;
static unsigned int PCLK_irqNumber;

static irq_handler_t VSYNC_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs);
static irq_handler_t HREF_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs);
static irq_handler_t PCLK_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs);


int __init camera_module_test_init(void){//init_module() 
    int result=0;

    printk(KERN_INFO "GPIO_TEST: Initializing the GPIO_TEST LKM\n");
//VSYNC init
    if(!gpio_is_valid(VSYNC_gpio_number)){
        printk(KERN_INFO "GPIO TEST: invalid VSYNC GPIO\n");
        return -ENODEV;
    }
//HREF init
    if(!gpio_is_valid(HREF_gpio_number)){
    printk(KERN_INFO "GPIO TEST: INVALID HREF GPIO\n");
    return -ENODEV; 
    }
//PCLK init
    if(!gpio_is_valid(PCLK_gpio_number)){
    printk(KERN_INFO "GPIO TEST: INVALID PCLK GPIO\n");
    return -ENODEV;
    }

    //ledOn=true;
//VSYNC
    gpio_request(VSYNC_gpio_number,"sysfs");
    gpio_direction_input(VSYNC_gpio_number);    
    gpio_export(VSYNC_gpio_number,false);  // causes gpioX to appear in sysfs /sys/class/gpio/
//HREF
    gpio_request(HREF_gpio_number,"sysfs");
    gpio_direction_input(HREF_gpio_number);
    gpio_export(HREF_gpio_number,false);
//PCLK
    gpio_request(PCLK_gpio_number,"sysfs");
    gpio_direction_input(PCLK_gpio_number);
    gpio_export(PCLK_gpio_number,false);


    // GPIO numbers and IRQ numbers are not the same
//MAPPING   GPIO NUMBERS TO IRQ NUMBERS
//---------
    VSYNC_irqNumber = gpio_to_irq(VSYNC_gpio_number);
    printk(KERN_INFO "GPIO_TEST: VSYNC signal is mapped to IRQ: %d\n",VSYNC_irqNumber);
    //
    HREF_irqNumber=gpio_to_irq(HREF_gpio_number);
    printk(KERN_INFO "GPIO TEST: HREF signal is mapped to IRQ: %d\n",HREF_irqNumber);
    //
    PCLK_irqNumber=gpio_to_irq(PCLK_gpio_number);
    printk(KERN_INFO "GPIO TEST: PCLK signal is mapped to IRQ: %d\n",PCLK_irqNumber);

    //requests an interrupt line
//VSYNC 
    result=request_irq(VSYNC_irqNumber,(irq_handler_t)VSYNC_gpio_irq_handler,IRQF_TRIGGER_RISING,"VSYNC_gpio_handler",NULL);
    if(result==0){  //if success
        printk(KERN_INFO "GPIO_TEST: The VSYNC interrupt request result is: %d\n",result);
        }   
        else{
    printk(KERN_INFO "GPIO_TEST: The VSYNC interrupt request FAIL !!! (%d)\n",result);  
    return result;  
    }
//HREF  
    result=request_irq(HREF_irqNumber,(irq_handler_t)HREF_gpio_irq_handler,IRQF_TRIGGER_RISING,"HREF_gpio_handler",NULL);
    if(result==0){ //if success
    printk(KERN_INFO "GPIO_TEST: The HREF interrupt request result is: %d\n",result);
    }
    else{
    printk(KERN_INFO "GPIO_TEST: The HREF interrupt request FAIL !!! (%d)\n",result);
    return result;  
    }
//PCLK
    result=request_irq(PCLK_irqNumber,(irq_handler_t)PCLK_gpio_irq_handler,IRQF_TRIGGER_RISING,"PCLK_gpio_handler",NULL);   
    if(result==0){// if success
    printk(KERN_INFO "GPIO_TEST: The PCLK interrupt request result is: %d\n",result);
    }
    else{
    printk(KERN_INFO "GPIO_TEST: The PCLK interrupt request FAIL !!! (%d)\n",result);   
    return result;
    }

    printk(KERN_INFO "MODULE LOADED.... WAITING FOR INTERRUPTION\n");   

    return result;
}

static void __exit camera_module_test_exit(void){ //cleanup_module(void){
    printk(KERN_INFO "EXITING CAMERA_LKM_MODULE_TEST\n");

//unexporting GPIOs
    gpio_unexport(VSYNC_gpio_number);
    gpio_unexport(HREF_gpio_number);
    gpio_unexport(PCLK_gpio_number);
//freeing IRQs
    free_irq(VSYNC_irqNumber,NULL);
    free_irq(HREF_irqNumber,NULL);
    free_irq(PCLK_irqNumber,NULL);
//freeing memory
    gpio_free(VSYNC_gpio_number);
    gpio_free(HREF_gpio_number);
    gpio_free(PCLK_gpio_number);

    printk(KERN_INFO "GOODBYE world - MODULE CLOSED\n");
}


static irq_handler_t VSYNC_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs){
    printk(KERN_INFO "* VSYNC Interrupt on rising! *\n");

    return (irq_handler_t)IRQ_HANDLED;
}

static irq_handler_t HREF_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs){
    printk(KERN_INFO "-- HREF interrupt! on rising --\n");

    return (irq_handler_t)IRQ_HANDLED;  
}

static irq_handler_t PCLK_gpio_irq_handler(unsigned int irq,void *dev_id,struct pt_regs *regs){
    printk(KERN_INFO "// PCLK interrupt! on rising //\n");

    return (irq_handler_t)IRQ_HANDLED;
}

module_init(camera_module_test_init);
module_exit(camera_module_test_exit);

MODULE_LICENSE("GPL");

我可以补充说，我正在使用附加图像中显示的可用gpios的蜂鸣板门。

hummingboard gate available gpios

如何将ov5642相机模块像素时钟（8MHz）连接到imx6四核

0 个答案: