plat_button驱动实例

前面对plat_button驱动代码重要部分做了简要分析，现在基于plat_button驱动代码写一个测试程序，用以测试驱动代码的功能是否正确。

驱动代码源码

/********************************************************************************* * Copyright: (C) 2017 Li Wanneng<liwjng@gmail.com> * All rights reserved. * * Filename: plat_button.c * Description: This is the common button driver runs on S3C2440 * * Version: 1.0.0(4/10/2017~) * Author: Li Wanneng<liwjng@gmail.com> * ChangeLog: 1, Release initial version on "4/10/2017 11:39:10 AM" * ********************************************************************************/ #include "s3c_driver.h" #define DRV_AUTHOR "Li Wanneng<liwjng@gmail.com>" #define DRV_DESC "S3C24XX button driver" /* Driver version*/ #define DRV_MAJOR_VER 1 #define DRV_MINOR_VER 0 #define DRV_REVER_VER 0 #define DEV_NAME DEV_BUTTON_NAME //#define DEV_MAJOR DEV_BUTTON_MAJOR #ifndef DEV_MAJOR #define DEV_MAJOR 0 /* dynamic major by default */ #endif #define BUTTON_UP 0 /* Button status is up */ #define BUTTON_DOWN 1 /* Button status is pushed down */ #define BUTTON_UNCERTAIN 2 /* Button status uncerntain */ #define TIMER_DELAY_DOWN (HZ/50) /*Remove button push down dithering timer delay 20ms */ #define TIMER_DELAY_UP (HZ/10) /*Remove button up dithering timer delay 100ms */ static int debug = DISABLE; static int dev_major = DEV_MAJOR; static int dev_minor = 0; /*============================ Platform Device part ===============================*/ /* Button hardware informtation structure*/ struct s3c_button_info { unsigned char num; /*Button nubmer */ char * name; /*Button name */ int nIRQ; /*Button IRQ number*/ unsigned int setting; /*Button IRQ Pin Setting*/ unsigned int gpio; /*Button GPIO port */ }; /* The button plaotform device private data structure */ struct s3c_button_platform_data { struct s3c_button_info *buttons; int nbuttons; }; /* Button hardware informtation data*/ static struct s3c_button_info s3c_buttons[] = { [0] = { .num = 1, .name = "KEY1", .nIRQ = IRQ_EINT0, .gpio = S3C2410_GPF(0), .setting = S3C2410_GPF0_EINT0, }, [1] = { .num = 2, .name = "KEY2", .nIRQ = IRQ_EINT2, .gpio = S3C2410_GPF(2), .setting = S3C2410_GPF2_EINT2, }, [2] = { .num = 3, .name = "KEY3", .nIRQ = IRQ_EINT3, .gpio = S3C2410_GPF(3), .setting = S3C2410_GPF3_EINT3, }, [3] = { .num = 4, .name = "KEY4", .nIRQ = IRQ_EINT4, .gpio = S3C2410_GPF(4), .setting = S3C2410_GPF4_EINT4, }, }; /* The button platform device private data */ static struct s3c_button_platform_data s3c_button_data = { .buttons = s3c_buttons, .nbuttons = ARRAY_SIZE(s3c_buttons), }; struct button_device { unsigned char *status; /* The buttons Push down or up status */ struct s3c_button_platform_data *data; /* The buttons hardware information data */ struct timer_list *timers; /* The buttons remove dithering timers */ wait_queue_head_t waitq; /* Wait queue for poll() */ volatile int ev_press; /* Button pressed event */ struct cdev cdev; struct class *dev_class; } button_device; static void platform_button_release(struct device * dev) { return; } static struct platform_device s3c_button_device = { .name = "s3c_button", .id = 1, .dev = { .platform_data = &s3c_button_data, .release = platform_button_release, }, }; /*中断服务程序，确定中断号即哪一个按键按下*/ static irqreturn_t s3c_button_intterupt(int irq,void *de_id)//下降沿中断，中断服务函数 { int i; int found = 0; struct s3c_button_platform_data *pdata = button_device.data; for(i=0; i<pdata->nbuttons; i++) { if(irq == pdata->buttons[i].nIRQ) { found = 1; break; } } if(!found) /* An ERROR interrupt */ return IRQ_NONE; /* Only when button is up then we will handle this event */ if(BUTTON_UP == button_device.status[i]) { button_device.status[i] = BUTTON_UNCERTAIN; mod_timer(&(button_device.timers[i]), jiffies+TIMER_DELAY_DOWN);//激活定时器 } return IRQ_HANDLED; } /*如果定时器中断相应，事件处理*/ static void button_timer_handler(unsigned long data)//定时器中断服务函数 { struct s3c_button_platform_data *pdata = button_device.data; int num =(int)data; int status = s3c2410_gpio_getpin( pdata->buttons[num].gpio ); if(LOWLEVEL == status) { if(BUTTON_UNCERTAIN == button_device.status[num]) /* Come from interrupt */ { //dbg_print("Key pressed!\n"); button_device.status[num] = BUTTON_DOWN; printk("%s pressed.\n", pdata->buttons[num].name); /* Wake up the wait queue for read()/poll() */ button_device.ev_press = 1; wake_up_interruptible(&(button_device.waitq));//唤醒等待队列 } /* Cancel the dithering */ mod_timer(&(button_device.timers[num]), jiffies+TIMER_DELAY_UP); } else { //dbg_print("Key Released!\n"); button_device.status[num] = BUTTON_UP; // enable_irq(pdata->buttons[num].nIRQ); } return ; } /*===================== Button device driver part ===========================*/ static int button_open(struct inode *inode, struct file *file) { struct button_device *pdev ; struct s3c_button_platform_data *pdata; int i, result; pdev = container_of(inode->i_cdev,struct button_device, cdev);//从inode结构体获取idev信息 pdata = pdev->data; file->private_data = pdev; /* Malloc for all the buttons remove dithering timer */ pdev->timers = (struct timer_list *) kmalloc(pdata->nbuttons*sizeof(struct timer_list), GFP_KERNEL); if(NULL == pdev->timers) { printk("Alloc %s driver for timers failure.\n", DEV_NAME); return -ENOMEM; } memset(pdev->timers, 0, pdata->nbuttons*sizeof(struct timer_list)); /* Malloc for all the buttons status buffer */ pdev->status = (unsigned char *)kmalloc(pdata->nbuttons*sizeof(unsigned char), GFP_KERNEL); if(NULL == pdev->status) { printk("Alloc %s driver for status failure.\n", DEV_NAME); result = -ENOMEM; goto ERROR; } memset(pdev->status, 0, pdata->nbuttons*sizeof(unsigned char)); init_waitqueue_head(&(pdev->waitq)); for(i=0; i<pdata->nbuttons; i++) { /* Initialize all the buttons status to UP */ pdev->status[i] = BUTTON_UP; /* Initialize all the buttons' remove dithering timer */ setup_timer(&(pdev->timers[i]), button_timer_handler, i); /* Set all the buttons GPIO to EDGE_FALLING interrupt mode */ s3c2410_gpio_cfgpin(pdata->buttons[i].gpio, pdata->buttons[i].setting);//配置gpio引脚为中断模式 irq_set_irq_type(pdata->buttons[i].nIRQ, IRQ_TYPE_EDGE_FALLING);//中断模式为下降沿触发 /* Request for button GPIO pin interrupt */ /*一旦发生中断请求，调用s3c_button_intterupt函数*/ result = request_irq(pdata->buttons[i].nIRQ, s3c_button_intterupt, IRQF_DISABLED, DEV_NAME, (void *)i); if( result )//如果中断申请失败 { result = -EBUSY; goto ERROR1; } } return 0; ERROR1: kfree((unsigned char *)pdev->status); while(--i) { disable_irq(pdata->buttons[i].nIRQ); free_irq(pdata->buttons[i].nIRQ, (void *)i); } ERROR: kfree(pdev->timers); return result; } /*__user表示该变量是从用户空间传过来的地址，不可直接使用*/ static int button_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct button_device *pdev = file->private_data; struct s3c_button_platform_data *pdata; int i, ret; unsigned int status = 0; pdata = pdev->data; dbg_print("ev_press: %d\n", pdev->ev_press); if(!pdev->ev_press)//如果按键没有按下，ev_press=0 { if(file->f_flags & O_NONBLOCK) { dbg_print("read() without block mode.\n"); return -EAGAIN; } else { /* Read() will be blocked here */ dbg_print("read() blocked here now.\n"); /*该函数修改task的状态为TASK_INTERRUPTIBLE，意味着该进程将不会继续运行直到被唤醒，然后被添加到等待队列wq中。*/ wait_event_interruptible(pdev->waitq, pdev->ev_press); } } pdev->ev_press = 0;//清除标志位 for(i=0; i<pdata->nbuttons; i++) { dbg_print("button[%d] status=%d\n", i, pdev->status[i]); /*假如key3按下 status[0] = 0 status[1] = 0 status[2] = 1 status[3] = 0 status[2]<<2 | status = 0001<<2 | status = 0100 | 0000 = 0100 status = 0100 = 4 所以status = 4的时候表示按键3按下*/ status |= (pdev->status[i]<<i); //通过位操作判断哪一个按键按下，并将其状态保存到status } /*copy_to_user(void __user *to, const void *from, unsigned long n)*/ ret = copy_to_user(buf, (void *)&status, min(sizeof(status), count));//多了一个count参数算怎么回事儿 return ret ? -EFAULT : min(sizeof(status), count); } static unsigned int button_poll(struct file *file, poll_table * wait) { struct button_device *pdev = file->private_data; unsigned int mask = 0; /*void poll_wait(struct file *filp, wait_queue_head_t *queue, poll_table *wait);*/ /*typedef struct poll_table_struct { poll_queue_proc qproc; unsigned long key; } poll_table*/ poll_wait(file, &(pdev->waitq), wait); if(pdev->ev_press) { mask |= POLLIN | POLLRDNORM; /* The data aviable */ } return mask; } static int button_release(struct inode *inode, struct file *file) { int i; struct button_device *pdev = file->private_data; struct s3c_button_platform_data *pdata; pdata = pdev->data; for(i=0; i<pdata->nbuttons; i++) { disable_irq(pdata->buttons[i].nIRQ); free_irq(pdata->buttons[i].nIRQ, (void *)i); del_timer(&(pdev->timers[i])); } kfree(pdev->timers); kfree((unsigned char *)pdev->status); return 0; } static struct file_operations button_fops = { .owner = THIS_MODULE, .open = button_open, .read = button_read, .poll = button_poll, .release = button_release, }; static int s3c_button_probe(struct platform_device *dev) { int result = 0; dev_t devno; /* Alloc the device for driver */ if (0 != dev_major) //分配主次设备号 { devno = MKDEV(dev_major, dev_minor); result = register_chrdev_region(devno, 1, DEV_NAME); } else { result = alloc_chrdev_region(&devno, dev_minor, 1, DEV_NAME); dev_major = MAJOR(devno); } /* Alloc for device major failure */ if (result < 0) { printk("%s driver can't get major %d\n", DEV_NAME, dev_major); return result; } /* Initialize button_device structure and register cdev*/ memset(&button_device, 0, sizeof(button_device)); button_device.data = dev->dev.platform_data; cdev_init (&(button_device.cdev), &button_fops);//初始化cdev button_device.cdev.owner = THIS_MODULE; result = cdev_add (&(button_device.cdev), devno , 1); //添加cdev到内核 if (result) { printk (KERN_NOTICE "error %d add %s device", result, DEV_NAME); goto ERROR; } button_device.dev_class = class_create(THIS_MODULE, DEV_NAME); if(IS_ERR(button_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(button_device.dev_class, NULL, devno, NULL, DEV_NAME); #else device_create (button_device.dev_class, NULL, devno, DEV_NAME); #endif 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(&(button_device.cdev)); unregister_chrdev_region(devno, 1); return result; } static int s3c_button_remove(struct platform_device *dev) { dev_t devno = MKDEV(dev_major, dev_minor); cdev_del(&(button_device.cdev)); device_destroy(button_device.dev_class, devno); class_destroy(button_device.dev_class); unregister_chrdev_region(devno, 1); printk("S3C %s driver removed\n", DEV_NAME); return 0; } /*===================== Platform Device and driver regist part ===========================*/ static struct platform_driver s3c_button_driver = { .probe = s3c_button_probe, .remove = s3c_button_remove, .driver = { .name = "s3c_kbd", .owner = THIS_MODULE, }, }; static int __init s3c_button_init(void) { int ret = 0; ret = platform_device_register(&s3c_button_device);//注册设备 if(ret) { printk(KERN_ERR "%s: Can't register platform device %d\n", __FUNCTION__, ret); goto fail_reg_plat_dev; } dbg_print("Regist S3C %s Device successfully.\n", DEV_NAME); ret = platform_driver_register(&s3c_button_driver);//注册驱动 if(ret) { printk(KERN_ERR "%s: Can't register platform driver %d\n", __FUNCTION__, ret); goto fail_reg_plat_drv; } dbg_print("Regist S3C %s Driver successfully.\n", DEV_NAME); return 0; fail_reg_plat_drv: platform_driver_unregister(&s3c_button_driver); fail_reg_plat_dev: return ret; } static void s3c_button_exit(void) { platform_driver_unregister(&s3c_button_driver); dbg_print("S3C %s platform device removed.\n", DEV_NAME); platform_device_unregister(&s3c_button_device); dbg_print("S3C %s platform driver removed.\n", DEV_NAME); } module_init(s3c_button_init); module_exit(s3c_button_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_button");

s3c_driver.h

在s3c_driver中定义了驱动程序中用到的相关宏

/******************************************************************************** * Copyright: (C) 2017 Li Wanneng<liwjng@gmail.com> * All rights reserved. * * Filename: app_turnled.c * Description: This file * * Version: 1.0.0(04/10/2017) * Author: Li Wanneng <liwjng@gmail.com> * ChangeLog: 1, Release initial version on "04/10/2017 01:26:36 AM" * ********************************************************************************/ #ifndef __S3C_DRIVER_H #define __S3C_DRIVER_H #include <linux/version.h> #include <linux/kernel.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/module.h> #include <linux/kref.h> #include <linux/spinlock.h> #include <asm/uaccess.h> #include <linux/mutex.h> #include <linux/delay.h> #include <linux/fs.h> #include <linux/device.h> #include <linux/i2c.h> #include <linux/string.h> #include <linux/bcd.h> #include <linux/miscdevice.h> #include <linux/poll.h> #include <linux/irq.h> #include <linux/interrupt.h> #include <linux/sysfs.h> #include <linux/proc_fs.h> #include <linux/rtc.h> #include <linux/spinlock.h> #include <linux/usb.h> #include <asm/uaccess.h> #include <asm/delay.h> #include <linux/syscalls.h> /* For sys_access*/ #include <linux/platform_device.h> #include <linux/unistd.h> #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/serial.h> #include <linux/serial_core.h> #include <linux/irq.h> #include <mach/regs-gpio.h> #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32) #include <mach/hardware.h> #include <mach/gpio.h> #include <asm/irq.h> #else #include <asm-arm/irq.h> #include <asm/arch/gpio.h> #include <asm/arch/hardware.h> #endif #include "plat_ioctl.h" /* =========================================================================== * S3C24XX device driver common macro definition *===========================================================================*/ #define ENPULLUP 1 #define DISPULLUP 0 #define HIGHLEVEL 1 #define LOWLEVEL 0 #define INPUT 1 #define OUTPUT 0 #define OFF 0 #define ON 1 #define ENABLE 1 #define DISABLE 0 #define TRUE 1 #define FALSE 0 /* =========================================================================== * S3C24XX device driver name and Major number define *===========================================================================*/ #define DEV_LED_NAME "led" #define DEV_LED_MAJOR 203 #define DEV_BUTTON_NAME "button" #define DEV_BUTTON_MAJOR "211" #define DEV_ADC_NAME "adc" #define DEV_ADC_MAJOR "212" /* ***** Bit Operate Define *****/ #define SET_BIT(data, i) ((data) |= (1 << (i))) /* Set the bit "i" in "data" to 1 */ #define CLR_BIT(data, i) ((data) &= ~(1 << (i))) /* Clear the bit "i" in "data" to 0 */ #define NOT_BIT(data, i) ((data) ^= (1 << (i))) /* Inverse the bit "i" in "data" */ #define GET_BIT(data, i) ((data) >> (i) & 1) /* Get the value of bit "i" in "data" */ #define L_SHIFT(data, i) ((data) << (i)) /* Shift "data" left for "i" bit */ #define R_SHIFT(data, i) ((data) >> (i)) /* Shift "data" Right for "i" bit */ /* =========================================================================== * S3C24XX device driver common function definition *===========================================================================*/ #define SLEEP(x) {DECLARE_WAIT_QUEUE_HEAD (stSleep); if (10 > x) mdelay ((x * 1000)); \ else wait_event_interruptible_timeout (stSleep, 0, (x / 10));} #define VERSION_CODE(a,b,c) ( ((a)<<16) + ((b)<<8) + (c)) #define DRV_VERSION VERSION_CODE(DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER) #define MAJOR_VER(a) ((a)>>16&0xFF) #define MINOR_VER(a) ((a)>>8&0xFF) #define REVER_VER(a) ((a)&0xFF) #define dbg_print(format,args...) if(DISABLE!=debug) \ {printk("[kernel] ");printk(format, ##args);} static inline void print_version(int version) { #ifdef __KERNEL__ printk("%d.%d.%d\n", MAJOR_VER(version), MINOR_VER(version), REVER_VER(version)); #else printf("%d.%d.%d\n", MAJOR_VER(version), MINOR_VER(version), REVER_VER(version)); #endif } #endif /* __S3C_DRIVER_H */

makefile

1 LINUX_SRC?=../../kernel/linux-lwn-3.0.1 CROSS_COMPILE=/opt/dl/buildroot-2012.08/ARM920t/usr/bin/arm-linux- obj-m := plat_button.o modules: @make -C $(LINUX_SRC) M=`pwd` modules @make clean clean: rm -f *.ko.* *.o *mod.c *.order *.symvers

测试程序源码

/********************************************************************************* * Copyright: (C) 2017 Li Wanneng<liwjng@gmail.com> * All rights reserved. * * Filename: app_turnled.c * Description: This file * * Version: 1.0.0(04/10/2017) * Author: Li Wanneng <liwjng@gmail.com> * ChangeLog: 1, Release initial version on "04/10/2017 01:26:36 AM" * ********************************************************************************/ #include <stdio.h> #include <stdlib.h> #include <sys/ioctl.h> #include <fcntl.h> #include <unistd.h> #define KEY1 0x01 #define KEY2 0x02 #define KEY3 0x04 #define KEY4 0x08 #define PLATDRV_MAGIC 0x60 #define OFF _IO (PLATDRV_MAGIC,0x18) #define ON _IO (PLATDRV_MAGIC,0X19) /******************************************************************************** * Description: * Input Args: * Output Args: * Return Value: ********************************************************************************/ int main (int argc, char **argv) { int button_fd; int led_fd; int ret_button; int current_button; button_fd = open("/dev/button",0); if(button_fd<0) { printf("open button failed.\n"); exit(1); } while(1) { ret_button = read(button_fd,¤t_button,sizeof(4)); if(ret_button!=sizeof(current_button)) { printf("Read() button failed.\n"); } else { switch(current_button) { case KEY1: printf("Turn led0 ON.\n"); if(led_fd>=0) { ioctl(led_fd,OFF); close(led_fd); } led_fd = open("/dev/led0",O_RDWR,755); break; case KEY2: printf("Turn led1 ON\n"); if(led_fd>=0) { ioctl(led_fd,OFF); close(led_fd); } led_fd = open("/dev/led1",O_RDWR,755); break; case KEY3: printf("Turn led2 ON.\n"); if(led_fd>=0) { ioctl(led_fd,OFF); close(led_fd); } led_fd = open("/dev/led2",O_RDWR,755); break; case KEY4: printf("Turn led3 ON.\n"); if(led_fd>=0) { ioctl(led_fd,OFF); close(led_fd); } led_fd = open("/dev/led3",O_RDWR,755); break; default:printf("errno.\n"); } if(led_fd<0) { printf("open led failed.\n"); exit(1); } } ioctl(led_fd,ON); } ioctl(led_fd,OFF); close(led_fd); close(button_fd); return 0; } /* ----- End of main() ----- */

从源码可以看出，测试程序实现的功能为4个按键分别对应4个LED灯，每按下一个按键，对应的LED灯点亮，其他LED灯熄灭。

编译烧录到开发板

使用make命令编译生成.ko驱动文件

使用交叉编译将测试程序编译生成可在开发板执行的二进制文件turn

在开发板上测试