本文介绍了一种基于S3C24XX芯片的LED驱动程序设计，包括驱动结构、设备注册流程及应用程序控制LED的方法。
主机： centos 6.7
开发板： FL2440
系统内核版本：Linux 3.0
编译器： arm-Linux-gcc-4.5.4
芯片： Samsung S3C2400
驱动程序：
[hongfuhao@centos6 platform_led]$ ls
plat_led.
[hongfuhao@centos6 platform_led]$ vim plat_led.c
- /*********************************************************************************
- * Copyright: (C) 2011 Guo Wenxue<guowenxue@gmail.com>
- * All rights reserved.
- *
- * Filename: s3c_led.c
- * Description: This is the common LED driver runs on S3C24XX.
- *
- * Version: 1.0.0(10/27/2011~)
- * Author: Guo Wenxue <guowenxue@gmail.com>
- * ChangeLog: 1, Release initial version on "10/27/2011 11:39:10 AM"
- *
- ********************************************************************************/
- #include "s3c_driver.h"
- #define DRV_AUTHOR "Guo Wenxue <guowenxue@gmail.com>"
- #define DRV_DESC "S3C24XX LED driver"
- /* Driver version*/
- #define DRV_MAJOR_VER 1
- #define DRV_MINOR_VER 0
- #define DRV_REVER_VER 0
- #define DEV_NAME DEV_LED_NAME
- //#define DEV_MAJOR DEV_LED_MAJOR
- #ifndef DEV_MAJOR
- #define DEV_MAJOR 0 /* dynamic major by default */
- #endif
- #define TIMER_TIMEOUT 40
- static int debug = DISABLE;
- static int dev_major = DEV_MAJOR;
- static int dev_minor = 0;
- /* ============================ Platform Device part ===============================*/
- /* LED hardware informtation structure*/
- struct s3c_led_info //LED结构体的定义
- {
- unsigned char num; /* The LED number */
- unsigned int gpio; /* Which GPIO the LED used */
- unsigned char active_level; /* The GPIO pin level(HIGHLEVEL or LOWLEVEL) to turn on or off */
- unsigned char status; /* Current LED status: OFF/ON */
- unsigned char blink; /* Blink or not */
- };
- /* The LED platform device private data structure */
- struct s3c_led_platform_data //总线的定义
- {
- struct s3c_led_info *leds;
- int nleds;
- };
- /* LED hardware informtation data*/
- static struct s3c_led_info s3c_leds[] = { //LED灯的信息
- [0] = {
- .num = 1,
- .gpio = S3C2410_GPB(5),
- .active_level = LOWLEVEL,
- .status = OFF,
- .blink = ENABLE,
- },
- [1] = {
- .num = 2,
- .gpio = S3C2410_GPB(6),
- .active_level = LOWLEVEL,
- .status = OFF,
- .blink = DISABLE,
- },
- [2] = {
- .num = 3,
- .gpio = S3C2410_GPB(8),
- .active_level = LOWLEVEL,
- .status = OFF,
- .blink = DISABLE,
- },
- [3] = {
- .num = 4,
- .gpio = S3C2410_GPB(10),
- .active_level = LOWLEVEL,
- .status = OFF,
- .blink = DISABLE,
- },
- };
- /* The LED platform device private data */
- static struct s3c_led_platform_data s3c_led_data = {//定义LED灯的结构体信息
- .leds = s3c_leds,//LED灯的每条信息
- .nleds = ARRAY_SIZE(s3c_leds),//灯数
- };
- struct led_device//定义led_device的结构体
- {
- struct s3c_led_platform_data *data;
- struct cdev cdev;
- struct class *dev_class;
- struct timer_list blink_timer;
- } led_device;
- static void platform_led_release(struct device * dev)//撤销LED灯的函数
- {
- int i;
- struct s3c_led_platform_data *pdata = dev->platform_data;
- dbg_print("%s():%d\n", __FUNCTION__,__LINE__);
- /* Turn all LED off */
- for(i=0; i<pdata->nleds; i++)
- {
- s3c2410_gpio_setpin(pdata->leds[i].gpio, ~pdata->leds[i].active_level);
- }
- }
- static struct platform_device s3c_led_device = {//定义设备结构体
- .name = "s3c_led",
- .id = 1,
- .dev =
- {
- .platform_data = &s3c_led_data,
- .release = platform_led_release,
- },
- };
- /* ===================== led device driver part ===========================*/
- void led_timer_handler(unsigned long data)//实现LED灯的状态
- {
- int i;
- struct s3c_led_platform_data *pdata = (struct s3c_led_platform_data *)data;
- for(i=0; i<pdata->nleds; i++)
- {
- if(ON == pdata->leds[i].status)//判断LED灯的亮灭
- {
- s3c2410_gpio_setpin(pdata->leds[i].gpio, pdata->leds[i].active_level);
- }
- else
- {
- s3c2410_gpio_setpin(pdata->leds[i].gpio, ~pdata->leds[i].active_level);
- }
- if(ENABLE == pdata->leds[i].blink ) /* LED should blink */ //LED灯闪
- {
- /* Switch status between 0 and 1 to turn LED ON or off */
- pdata->leds[i].status = pdata->leds[i].status ^ 0x01;
- }
- mod_timer(&(led_device.blink_timer), jiffies + TIMER_TIMEOUT);//计时器更新，jiffies是全局变量，在头文件
- }
- }
- static int led_open(struct inode *inode, struct file *file)//LED开启函数
- {
- struct led_device *pdev ;
- struct s3c_led_platform_data *pdata;
- /*container_of 在Linux内核中是一个常用的宏，用于从包含在某个结构中的指针获得结构本身的指针，
- 就是通过结构体变量中某个成员的首地址进而获得整个结构体变量的首地址*/
- pdev = container_of(inode->i_cdev,struct led_device, cdev);
- pdata = pdev->data;
- file->private_data = pdata;
- return 0;
- }
- static int led_release(struct inode *inode, struct file *file)//LED关闭函数{
- return 0;
- }
- static void print_led_help(void)//帮助信息
- {
- printk("Follow is the ioctl() command for LED driver:\n");
- printk("Enable Driver debug command: %u\n", SET_DRV_DEBUG);
- printk("Get Driver verion command : %u\n", GET_DRV_VER);
- printk("Turn LED on command : %u\n", LED_ON);
- printk("Turn LED off command : %u\n", LED_OFF);
- printk("Turn LED blink command : %u\n", LED_BLINK);
- }
- /* compatible with kernel version >=2.6.38*/
- static long led_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
- {
- struct s3c_led_platform_data *pdata = file->private_data;
- switch (cmd)
- {
- case SET_DRV_DEBUG:
- dbg_print("%s driver debug now.\n", DISABLE == arg ? "Disable" : "Enable");
- debug = (0==arg) ? DISABLE : ENABLE;
- break;
- case GET_DRV_VER:
- print_version(DRV_VERSION);
- return DRV_VERSION;
- case LED_OFF:
- if(pdata->nleds <= arg)
- {
- printk("LED%ld doesn't exist\n", arg);
- return -ENOTTY;
- }
- pdata->leds[arg].status = OFF;
- pdata->leds[arg].blink = DISABLE;
- break;
- case LED_ON:
- if(pdata->nleds <= arg)
- {
- printk("LED%ld doesn't exist\n", arg);
- return -ENOTTY;
- }
- pdata->leds[arg].status = ON;
- pdata->leds[arg].blink = DISABLE;
- break;
- case LED_BLINK:
- if(pdata->nleds <= arg)
- {
- printk("LED%ld doesn't exist\n", arg);
- return -ENOTTY;
- }
- pdata->leds[arg].blink = ENABLE;
- pdata->leds[arg].status = ON;
- break;
- default:
- dbg_print("%s driver don't support ioctl command=%d\n", DEV_NAME, cmd);
- print_led_help();
- return -EINVAL;
- }
- return 0;
- }
- static struct file_operations led_fops = {
- .owner = THIS_MODULE,
- .open = led_open,
- .release = led_release,
- .unlocked_ioctl = led_ioctl, /* compatible with kernel version >=2.6.38*/
- };
- static int s3c_led_probe(struct platform_device *dev)//设备和驱动相互识别是调用从由内核把platform_device传到probe函数
- {
- struct s3c_led_platform_data *pdata = dev->dev.platform_data;
- int result = 0;
- int i;
- dev_t devno;
- /* Initialize the LED status */
- for(i=0; i<pdata->nleds; i++)
- {
- s3c2410_gpio_cfgpin(pdata->leds[i].gpio, S3C2410_GPIO_OUTPUT);
- if(ON == pdata->leds[i].status)//LED管脚亮
- {
- s3c2410_gpio_setpin(pdata->leds[i].gpio, pdata->leds[i].active_level);
- }
- Else//LED管脚灭
- {
- s3c2410_gpio_setpin(pdata->leds[i].gpio, ~pdata->leds[i].active_level);
- }
- }
- /* Alloc the device for driver */
- if (0 != dev_major)
- {
- devno = MKDEV(dev_major, dev_minor);
- result = register_chrdev_region(devno, 1, DEV_NAME);
- }
- else
- {//动态分配主次设备号
- result = alloc_chrdev_region(&devno, dev_minor, 1, DEV_NAME);
- dev_major = MAJOR(devno);
- }
- /* Alloc for device major failure */
- if (result < 0)
- {//分配失败打印信息
- printk("%s driver can't get major %d\n", DEV_NAME, dev_major);
- return result;
- }
- /* Initialize button structure and register cdev*/
- memset(&led_device, 0, sizeof(led_device));
- led_device.data = dev->dev.platform_data;
- cdev_init (&(led_device.cdev), &led_fops);
- led_device.cdev.owner = THIS_MODULE;
- result = cdev_add (&(led_device.cdev), devno , 1);
- if (result)
- {
- printk (KERN_NOTICE "error %d add %s device", result, DEV_NAME);
- goto ERROR;
- }
- led_device.dev_class = class_create(THIS_MODULE, DEV_NAME);
- if(IS_ERR(led_device.dev_class))
- {
- printk("%s driver create class failture\n",DEV_NAME);
- result = -ENOMEM;
- goto ERROR;
- }
- #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)
- device_create(led_device.dev_class, NULL, devno, NULL, DEV_NAME);
- #else
- device_create (led_device.dev_class, NULL, devno, DEV_NAME);
- #endif
- /* Initial the LED blink timer */
- init_timer(&(led_device.blink_timer));//初始化闪烁定时器
- led_device.blink_timer.function = led_timer_handler;//时间到了执行函数
- led_device.blink_timer.data = (unsigned long)pdata;//函数传参
- led_device.blink_timer.expires = jiffies + TIMER_TIMEOUT;//时间间隔
- add_timer(&(led_device.blink_timer));
- printk("S3C %s driver version %d.%d.%d initiliazed.\n", DEV_NAME, DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER);
- return 0;
- ERROR:
- printk("S3C %s driver version %d.%d.%d install failure.\n", DEV_NAME, DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER);
- cdev_del(&(led_device.cdev));
- unregister_chrdev_region(devno, 1);
- return result;
- }
- static int s3c_led_remove(struct platform_device *dev)//释放主次设备号给Linux内核
- {
- dev_t devno = MKDEV(dev_major, dev_minor);
- del_timer(&(led_device.blink_timer));
- cdev_del(&(led_device.cdev));
- device_destroy(led_device.dev_class, devno);
- class_destroy(led_device.dev_class);
- unregister_chrdev_region(devno, 1);
- printk("S3C %s driver removed\n", DEV_NAME);
- return 0;
- }
- static struct platform_driver s3c_led_driver = {//定义总线驱动结构体
- .probe = s3c_led_probe,//注册设备主次设备号
- .remove = s3c_led_remove,
- .driver = {
- .name = "s3c_led",
- .owner = THIS_MODULE,
- },
- };
- static int __init s3c_led_init(void)//LED初始化
- {
- int ret = 0;
- ret = platform_device_register(&s3c_led_device);
- if(ret)
- {
- printk(KERN_ERR "%s:%d: Can't register platform device %d\n", __FUNCTION__,__LINE__, ret);
- goto fail_reg_plat_dev;
- }
- dbg_print("Regist S3C LED Platform Device successfully.\n");
- ret = platform_driver_register(&s3c_led_driver);
- if(ret)
- {
- printk(KERN_ERR "%s:%d: Can't register platform driver %d\n", __FUNCTION__,__LINE__, ret);
- goto fail_reg_plat_drv;
- }
- dbg_print("Regist S3C LED Platform Driver successfully.\n");
- return 0;
- fail_reg_plat_drv:
- platform_driver_unregister(&s3c_led_driver);
- fail_reg_plat_dev:
- return ret;
- }
- static void s3c_led_exit(void)//LED撤销
- {
- dbg_print("%s():%d remove LED platform drvier\n", __FUNCTION__,__LINE__);
- platform_driver_unregister(&s3c_led_driver);
- dbg_print("%s():%d remove LED platform device\n", __FUNCTION__,__LINE__);
- platform_device_unregister(&s3c_led_device);
- }
- module_init(s3c_led_init);
- module_exit(s3c_led_exit);
- module_param(debug, int, S_IRUGO);
- module_param(dev_major, int, S_IRUGO);
- module_param(dev_minor, int, S_IRUGO);
- MODULE_AUTHOR(DRV_AUTHOR);
- MODULE_DESCRIPTION(DRV_DESC);
- MODULE_LICENSE("GPL");
- MODULE_ALIAS("platform:S3C24XX_led");
- </pre><p><strong>[leiyuxing@centos6 platform_led]$ vim Makefile</strong></p><p></p><pre code_snippet_id="1822395" snippet_file_name="blog_20160811_2_2241077" name="code" class="html">
- obj-m:=plat_led.c
- C=/opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-gcc
- KDIR?=/home/leiyuxing/fl2440/kernel/linux-3.0
- obj-m:=plat_led.o
- default:
- $(MAKE) -C $(KDIR) M=`pwd` modules
- make clean
- clean:
- rm -f *.o *mod.c *.order *.symvers
应用程序：
[hongfuhao@centos6 platform_led]$ vim plat_ioctl.c
- *********************************************************************************
- * Copyright: (C) 2016 hongfuhao <70786774@qq.com>
- * All rights reserved.
- *
- * Filename: plat_icotl.c
- * Description: This file
- *
- * Version: 1.0.0(07/27/2016)
- * Author: hongfuhao <70786774@qq.com>
- * ChangeLog: 1, Release initial version on "07/27/2016 10:24:30 AM"
- *
- ********************************************************************************/
- #include <stdio.h>
- #include <stdarg.h>
- #include <fcntl.h>
- #include <sys/types.h>
- #include <errno.h>
- #include <sys/ioctl.h>
- #include <sys/stat.h>
- #include <unistd.h>
- #include <stdlib.h>
- #define PLATDRV_MAGIC 0x60
- #define LED_OFF _IO (PLATDRV_MAGIC, 0x18)
- #define LED_ON _IO (PLATDRV_MAGIC, 0x19)
- #define LED_BLINK _IO (PLATDRV_MAGIC, 0x1A)
- #define DEVNAMELEN 10
- int main (int argc,char **argv)
- {
- int fd;
- fd=open("dev/led",O_RDWR);
- ioctl(fd,LED_ON,0);
- ioctl(fd,LED_ON,1);
- ioctl(fd,LED_ON,2);
- ioctl(fd,LED_BLINK,3);
- close(fd);
- return 0;
- }
[hongfuhao@centos6platform_led_test]$ /opt/buildroot-2012.08/arm920t/usr/bin/arm-linux-gcc plat_ioctl.c
[hongfuhao@centos6 platform_led_test]$ ls
a.out plat_ioctl.c
[hongfuhao@centos6 platform_led_test]$ ls
a.out plat_ioctl.c
在开发板上的操作：
>: tftp -gr plat_led.ko 192.168.1.2
plat_led.ko 100% |*******************************| 8827 0:00:00 ETA
>: tftp -gr a.out 192.168.1.2
>:insmod plat_led.ko
>: chmod 777 a.out
>: ./a.out
此时你就会看到led0,led1,led2是稳定红灯，lled3是一闪一闪的红灯
扫一扫
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