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linux 2.6.30内核，9g45开发板，gpio驱动

2012-04-19 01:58:56 312 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

gaoqiaoming 墨衍会员 · AI 创作全网分发关注 + 加入社区

AT91SAM9G45 PWM应用最近在玩AT91SAM9G45的板子, 发现Linux系统下的PWM输出频率仅有100Hz. 通常情况下PWM频率可调是个必要功能, 现在和大家分享一下实现方法. 环境: AT91SAM9G45 +linux-3.5 步骤1: make menuconfig配置内核, 开启PWM输出功能. Device Drivers ---> Misc devices ---> 阅读详情

求一个atmel sam9g45开发板的gpio驱动程序，应用程序通过写入1/0控制led灯的亮暗，管脚用AT91_PIN_PB20,用insmod加载，小弟对驱动一无所知，也不知道问题讲清楚没，刚开始了解一天，求大牛帮忙

...全文

Linux驱动开发——LED驱动开发本文是学习rk3568开发板驱动开发的记录，代码依托于rk3568开发板。Linux下外设驱动，最终都是配置相应的硬件寄存器，本文中的LED灯驱动也是对rk3568的io口进行配置。阅读详情

gaoqiaoming

驱动开发/核心开发 21,620 成员 21,709 内容

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切换为时间正序

gaoqiaoming 2012-04-27

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驱动已经好了，成功加载实现控制led的亮跟灭了，结贴给分了

nadleeh 2012-04-26

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内核里面写的话要用到ioremap，具体百度下

nadleeh 2012-04-26

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说下步骤吧，首先你得有电路图，知道LED和芯片怎么连的，连到那跟脚上去了（一般是GPXX），然后去查芯片文档关于GPXX的描述，然后建立指针，赋值。。。。

pengchy 2012-04-19

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给你提供一个代码,你在自己的内核交叉编译环境上编译,有可能头文件引用的不怎么正确,编译的时候修改一下就OK了.
头文件: geo_ds_gpio.h



#ifndef __GEO_DS_GPIO_H__

#define __GEO_DS_GPIO_H__



#include <linux/sched.h>

#include <linux/init.h>



/* PIN definitions */



#define GEO_DS_GPIO_MAGIC       's'



#define SWITCH_LED_ON           _IOW( GEO_DS_GPIO_MAGIC, 0, int ))



#define GEO_DS_GPIO_MAXNR       1



/* PIN definitions */

#define PIN_LED_STAT            AT91_PIN_PB30



#endif  // __GEO_DS_GPIO_H__

代码: geo_ds_gpio.c



#include <linux/init.h>

#include <linux/module.h>           /* get MOD_DEC_USE_COUNT, not the version string */

#include <linux/moduleparam.h>

#include <linux/version.h>          /* need it for conditionals in geoad.h */

#include <linux/kernel.h>

#include <linux/proc_fs.h>

#include <linux/errno.h>            /* error codes */

#include <linux/types.h>            /* size_t */

#include <linux/fcntl.h>

#include <linux/interrupt.h>

#include <linux/string.h>

#include <asm/arch/gpio.h>

#include <linux/cdev.h>

#include <linux/delay.h>



#include <asm/system.h>             /* rmb(), wmb() */

#include <asm/io.h>                 /* inb(), outb() */

#include <asm/uaccess.h>



#include <mach/board.h>

#include <mach/gpio.h>

#include <mach/at91sam9_smc.h>

#include <mach/at91_ssc.h>



#include "geo_ds_gpio.h"            /* local definitions */



#define GPIO_NR_DEVS        1       /* device number */



int gpio_major = 105;               /* major device number */

int gpio_nr_devs = GPIO_NR_DEVS;    /* number of gpio control devices */

char gpio_name[16];                 /* device name */



MODULE_AUTHOR( "Pengchy" );

MODULE_LICENSE( "GPL" );



int gpio_ioctl( struct inode *inode, struct file *filp, unsigned int cmd,

                unsigned long arg )

{

    if( _IOC_TYPE(cmd) != GEO_DS_GPIO_MAGIC )

        return -EINVAL;

    if( _IOC_NR(cmd) >= GEO_DS_GPIO_MAXNR )

        return -EINVAL;

    

    switch( cmd )

    {

    case SWITCH_LED_ON:

        at91_set_gpio_value( PIN_LED_STAT, arg ); break;

    default:

        return -ENOTTY;

    }



    return 0;

}



/*

 * Open and close.

 */

int gpio_open( struct inode *inode, struct file *filp )

{    

    return 0;

}



int gpio_release( struct inode *inode, struct file *filp )

{

    return 0;

}



/* for device gpio control */

static struct file_operations gpio_fops = 

{

    .owner   =  THIS_MODULE,

    .open    =  gpio_open,

    .release =  gpio_release,

    .ioctl   =  gpio_ioctl,

};



struct GPIO_DEVS

{

    struct cdev cdev;                   /* Char device structure */

};



static struct GPIO_DEVS gpio_device;



static struct gpio_dev_info

{

    char *name;

    struct GPIO_DEVS *dev;

    struct file_operations *fops;

} gpio_devs[] = {

    { "gpio_ctl", &gpio_device, &gpio_fops }

};



/*

 * Set up the char_dev structure for this device.

 */

void gpio_setup_cdev( struct gpio_dev_info *devinfo, int index )

{

    int err, devno = MKDEV( gpio_major, index );

    struct GPIO_DEVS *dev = devinfo->dev;

    

    /* Do the cdev stuff. */

    cdev_init( &dev->cdev, devinfo->fops );

    kobject_set_name( &dev->cdev.kobj, devinfo->name );

    dev->cdev.owner = THIS_MODULE;

    dev->cdev.ops = devinfo->fops;

    err = cdev_add( &dev->cdev, devno, 1 );

    

    /* Fail gracefully if need be */

    if( err )

    {

        printk( KERN_NOTICE "Error %d adding %s\n", err, devinfo->name );

        kobject_put( &dev->cdev.kobj );

    }

    else

        printk( KERN_NOTICE "%s registered at %x\n", devinfo->name, devno );

}



static void init_hardware_pin()

{

    at91_set_gpio_output( PIN_LED_STAT, 1 );

}



static int __init gpio_init( void )

{

    int err = -1, i = 0;

    dev_t devno = MKDEV( gpio_major, 0 );

    

    memset( gpio_name, '\0', sizeof(gpio_name) );

    sprintf( gpio_name, "%s", "gpio_ctl" );

    

    /*

     * Get a range of minor numbers to work with, asking for a dynamic

     * major unless directed otherwise at load time.

     */

    if( gpio_major )

        err = register_chrdev_region( devno, gpio_nr_devs, gpio_name );

    else

    {

        err = alloc_chrdev_region( &devno, 0, gpio_nr_devs, gpio_name );

        gpio_major = MAJOR( devno );

    }

    

    if( err < 0 )

    {

        printk( KERN_WARNING "gpio: can't get major %d\n", gpio_major );

        goto err001;

    }

    

    // Setup the geo devices.

    for( i = 0; i < gpio_nr_devs; i++ )

        gpio_setup_cdev( &gpio_devs[i], i );

    

    init_hardware_pin();

    

    printk( KERN_INFO "***************** gpio control driver started **************\n" );

    

    return 0;



err001:

    return err;

}



static void __exit gpio_exit( void )

{

    int i = 0;

    dev_t devno = MKDEV( gpio_major, 0 );

        

    init_hardware_pin();



    /* Clean up the static devs */

    for( i = 0; i < gpio_nr_devs; i++ )

    {

        struct GPIO_DEVS *dev = gpio_devs[i].dev;

        cdev_del( &dev->cdev );

    }

    

    unregister_chrdev_region( devno, gpio_nr_devs );

}



module_init( gpio_init );

module_exit( gpio_exit );

awsqsh 2012-04-19

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去找本书抄抄得了要别人帮你写个驱动，估计大家都不愿意。

✦双11狂欢大促✦

linux 2.6.30内核，9g45开发板，gpio驱动

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