IO端口映射和IO內(nèi)存映射(詳解S3C24XX_GPIO驅(qū)動(dòng))

1 #include 2 #include 3 #include 4 #include 5 #include 6 #include 7 #include 8 #include 9 #include 10 #include 11 12 #define DEVICE_NAME     "leds"  13 /* 加載模式后，執(zhí)行”cat /proc/devices”命令看到的設(shè)備名稱 */14 #define LED_MAJOR       231     /* 主設(shè)備號 */15 16 static struct class *leds_class;17 static struct class_device    *leds_class_devs[4];18 19 /* bit0<=>D10, 0:亮, 1:滅 20  *  bit1<=>D11, 0:亮, 1:滅 21  *  bit2<=>D12, 0:亮, 1:滅 22  */ 23 static char leds_status = 0x0;  24 static DECLARE_MUTEX(leds_lock); // 定義賦值25 26 //static int minor;27 static unsigned long gpio_va;  //gpio基址28 #define GPIO_OFT(x) ((x) - 0x56)29 //GPIO 配置寄存器30 #define GPFCON  (*(volatile unsigned long *)(gpio_va + GPIO_OFT(0x56050)))31 //GPIO 數(shù)據(jù)寄存器32 #define GPFDAT  (*(volatile unsigned long *)(gpio_va + GPIO_OFT(0x56054)))33 /* 應(yīng)用程序?qū)υO(shè)備文件/dev/leds執(zhí)行open(...)時(shí)，34  * 就會調(diào)用s3c24xx_leds_open函數(shù)35  */36 static int s3c24xx_leds_open(struct inode *inode, struct file *file)37 {38     int minor = MINOR(inode->i_rdev); //MINOR(inode->i_cdev);39     switch(minor)40     {41         case 0: /* /dev/leds */42         {43             // 配置3引腳為輸出44             //s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);45             GPFCON &= ~(0x3<<(4*2));46             GPFCON = (1<<(4*2));47             48             //s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);49             GPFCON &= ~(0x3<<(5*2));50             GPFCON = (1<<(5*2));51 52             //s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);53             GPFCON &= ~(0x3<<(6*2));54             GPFCON = (1<<(6*2));55 56             // 都輸出057             //s3c2410_gpio_setpin(S3C2410_GPF4, 0);58             GPFDAT &= ~(1<<4);59             60             //s3c2410_gpio_setpin(S3C2410_GPF5, 0);61             GPFDAT &= ~(1<<5);62             //s3c2410_gpio_setpin(S3C2410_GPF6, 0);63             GPFDAT &= ~(1<<6);64 65             down(&leds_lock);66             leds_status = 0x0;67             up(&leds_lock);68                 69             break;70         }71 72         case 1: /* /dev/led1 */73         {74             s3c2410_gpio_cfgpin(S3C2410_GPF4, S3C2410_GPF4_OUTP);75             s3c2410_gpio_setpin(S3C2410_GPF4, 0);76             77             down(&leds_lock);78             leds_status &= ~(1<<0);79             up(&leds_lock);80             81             break;82         }83 84         case 2: /* /dev/led2 */85         {86             s3c2410_gpio_cfgpin(S3C2410_GPF5, S3C2410_GPF5_OUTP);87             s3c2410_gpio_setpin(S3C2410_GPF5, 0);88             leds_status &= ~(1<<1);89             break;90         }91 92         case 3: /* /dev/led3 */93         {94             s3c2410_gpio_cfgpin(S3C2410_GPF6, S3C2410_GPF6_OUTP);95             s3c2410_gpio_setpin(S3C2410_GPF6, 0);96 97             down(&leds_lock);98             leds_status &= ~(1<<2);99             up(&leds_lock);100             101             break;102         }103     }    104     return 0;105 }106 static int s3c24xx_leds_read(struct file *filp, char __user *buff, 107                                          size_t count, loff_t *offp)108 {109     int minor = MINOR(filp->f_dentry->d_inode->i_rdev);110     char val;112     switch (minor)113     {114         case 0: /* /dev/leds */115         {116             copy_to_user(buff, (const void *)&leds_status, 1);117             break;118         }119         case 1: /* /dev/led1 */120         {121             down(&leds_lock);122             val = leds_status & 0x1;123             up(&leds_lock);124             copy_to_user(buff, (const void *)&val, 1);125             break;126         }127         case 2: /* /dev/led2 */128         {129             down(&leds_lock);130             val = (leds_status>>1) & 0x1;131             up(&leds_lock);132             copy_to_user(buff, (const void *)&val, 1);133             break;134         }135         case 3: /* /dev/led3 */136         {137             down(&leds_lock);138             val = (leds_status>>2) & 0x1;139             up(&leds_lock);140             copy_to_user(buff, (const void *)&val, 1);141             break;142         }143     }144     return 1;145 }146 static ssize_t s3c24xx_leds_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)147 {148     //int minor = MINOR(inode->i_rdev); //MINOR(inode->i_cdev);149     int minor = MINOR(file->f_dentry->d_inode->i_rdev);150     char val;151     copy_from_user(&val, buf, 1);152     switch (minor)153     {154         case 0: /* /dev/leds */155         {            156             s3c2410_gpio_setpin(S3C2410_GPF4, (val & 0x1));157             s3c2410_gpio_setpin(S3C2410_GPF5, (val & 0x1));158             s3c2410_gpio_setpin(S3C2410_GPF6, (val & 0x1));159             down(&leds_lock);160             leds_status = val;161             up(&leds_lock);162             break;163         }164         case 1: /* /dev/led1 */165         {166             s3c2410_gpio_setpin(S3C2410_GPF4, val);167             if (val == 0)168             {169                 down(&leds_lock);170                 leds_status &= ~(1<<0);171                 up(&leds_lock);172             }173             else174             {175                 down(&leds_lock);176                 leds_status = (1<<0);                177                 up(&leds_lock);178             }179             break;180         }181         case 2: /* /dev/led2 */182         {183             s3c2410_gpio_setpin(S3C2410_GPF5, val);184             if (val == 0)185             {186                 down(&leds_lock);187                 leds_status &= ~(1<<1);188                 up(&leds_lock);189             }190             else191             {192                 down(&leds_lock);193                 leds_status = (1<<1);                194                 up(&leds_lock);195             }196             break;197         }198         case 3: /* /dev/led3 */199         {200             s3c2410_gpio_setpin(S3C2410_GPF6, val);201             if (val == 0)202             {203                 down(&leds_lock);204                 leds_status &= ~(1<<2);205                 up(&leds_lock);206             }207             else208             {209                 down(&leds_lock);210                 leds_status = (1<<2);                211                 up(&leds_lock);212             }213             break;214         }215     }216     return 1;217 }218 /* 這個(gè)結(jié)構(gòu)是字符設(shè)備驅(qū)動(dòng)程序的核心219  * 當(dāng)應(yīng)用程序操作設(shè)備文件時(shí)所調(diào)用的open、read、write等函數(shù)，220  * 最終會調(diào)用這個(gè)結(jié)構(gòu)中指定的對應(yīng)函數(shù)221  */static struct file_operations s3c24xx_leds_fops = {223     .owner  =   THIS_MODULE,    /* 這是一個(gè)宏，推向編譯模塊時(shí)自動(dòng)創(chuàng)建的__this_module變量 */224     .open   =   s3c24xx_leds_open,     225     .read    =    s3c24xx_leds_read,       226     .write    =    s3c24xx_leds_write,       227 };228 229 /*230  * 執(zhí)行insmod命令時(shí)就會調(diào)用這個(gè)函數(shù) 231  */232 static int __init s3c24xx_leds_init(void)233 {234     int ret;235     int minor = 0;236 237     gpio_va = ioremap(0x56, 0x100);238     if (!gpio_va) {239         return -EIO;240     }241     /* 注冊字符設(shè)備242      * 參數(shù)為主設(shè)備號、設(shè)備名字、file_operations結(jié)構(gòu)；243      * 這樣，主設(shè)備號就和具體的file_operations結(jié)構(gòu)聯(lián)系起來了，244      * 操作主設(shè)備為LED_MAJOR的設(shè)備文件時(shí)，就會調(diào)用s3c24xx_leds_fops中的相關(guān)成員函數(shù)245      * LED_MAJOR可以設(shè)為0，表示由內(nèi)核自動(dòng)分配主設(shè)備號246      */247     ret = register_chrdev(LED_MAJOR, DEVICE_NAME, &s3c24xx_leds_fops);248     if (ret < 0) {249       printk(DEVICE_NAME " cant register major numbern");250       return ret;251     }252     leds_class = class_create(THIS_MODULE, "leds");253     if (IS_ERR(leds_class))254         return PTR_ERR(leds_class);255     256     leds_class_devs[0] = class_device_create(leds_class, NULL, MKDEV(LED_MAJOR, 0), NULL, "leds");257     258     for (minor = 1; minor < 4; minor++)259     {260         leds_class_devs[minor] = class_device_create(leds_class, NULL, MKDEV(LED_MAJOR, minor), NULL, "led%d", minor);261         if (unlikely(IS_ERR(leds_class_devs[minor])))262             return PTR_ERR(leds_class_devs[minor]);263     }264         265     printk(DEVICE_NAME " initializedn");266     return 0;267 }268 269 /*270  * 執(zhí)行rmmod命令時(shí)就會調(diào)用這個(gè)函數(shù) 271  */272 static void __exit s3c24xx_leds_exit(void)273 {274     int minor;275     /* 卸載驅(qū)動(dòng)程序 */276     unregister_chrdev(LED_MAJOR, DEVICE_NAME);277 278     for (minor = 0; minor < 4; minor++)279     {280         class_device_unregister(leds_class_devs[minor]);281     }282     class_destroy(leds_class);283     //釋放IO端口284     iounmap(gpio_va);285 }286 287 /* 這兩行指定驅(qū)動(dòng)程序的初始化函數(shù)和卸載函數(shù) */288 module_init(s3c24xx_leds_init);289 module_exit(s3c24xx_leds_exit);290 291 /* 描述驅(qū)動(dòng)程序的一些信息，不是必須的 */292 MODULE_LICENSE("GPL");