标签：image NPU temp 寄存器 while fcntl 轮询 gcc 高电平
主要电路连接如下：
从电路图中可以发现开发板上6个按键连接到了GPN0~5，当按键弹起时IO状态应为高电平，当按键按下时IO口状态为低电平。
下图为寄存器的名称和地址：
下图为配置寄存器的描述：
下图为数据寄存器和上/下拉寄存器：
需要注意的是，GPN默认是下拉使能，从电路图中判断按键应该配置为上拉使能，其他没什么好说的。
key.c
1 #include <linux/init.h> 2 #include <linux/module.h> 3 #include <linux/io.h> 4 #include <linux/fs.h> 5 #include <linux/miscdevice.h> 6 #include <asm/uaccess.h> 7 8 #define GPNCON 0x7F008830 9 #define GPNDAT 0x7F008834 10 #define GPNPUD 0x7F008838 11 12 static int *__gp_gpndat = NULL; 13 14 static int key_open (struct inode *p_node, struct file *p_file) 15 { 16 int *p_gpncon = NULL; 17 int *p_gpnpud = NULL; 18 int temp; 19 20 p_gpncon = ioremap(GPNCON, 4); 21 __gp_gpndat = ioremap(GPNDAT, 4); 22 p_gpnpud = ioremap(GPNPUD, 4); 23 24 temp = readl(p_gpncon); 25 temp &= ~(0xFFF); 26 writel(temp, p_gpncon); 27 28 temp = readl(p_gpnpud); 29 temp &= ~(0xFFF); 30 temp |= 0xAAA; 31 writel(temp, p_gpnpud); 32 33 return 0; 34 } 35 36 static ssize_t key_read (struct file *p_file, char *p_dat, size_t size, loff_t *p_loff) 37 { 38 int key; 39 char i; 40 41 key = readl(__gp_gpndat); 42 if ((key & 0x3F) != 0x3F) { 43 for (i = 1; i <= 6; i++) { 44 if ((key & 1) == 0) { 45 if (copy_to_user(p_dat, &i, 1)) { 46 return -1; 47 } 48 return 1; 49 } 50 key >>= 1; 51 } 52 } 53 54 return 0; 55 } 56 57 static struct file_operations fops = { 58 .owner = THIS_MODULE, 59 .open = key_open, 60 .read = key_read, 61 }; 62 63 static struct miscdevice key_dev = { 64 .minor = MISC_DYNAMIC_MINOR, 65 .name = "mykey", 66 .fops = &fops, 67 }; 68 69 static int __init key_init (void) 70 { 71 misc_register(&key_dev); 72 73 return 0; 74 } 75 76 static void __exit key_exit (void) 77 { 78 misc_deregister(&key_dev); 79 } 80 81 module_init(key_init); 82 module_exit(key_exit); 83 84 MODULE_LICENSE("GPL");
key_app.c
1 #include <stdio.h> 2 #include <sys/types.h> 3 #include <sys/stat.h> 4 #include <fcntl.h> 5 6 int main(int argc, const char *argv[]) 7 { 8 int fd; 9 char key_val; 10 int key_push_flag = 0; 11 int key_val_temp; 12 int cnt; 13 14 fd = open("/dev/mykey", O_RDWR); 15 16 while (1) { 17 cnt = read(fd, &key_val, 1); 18 if ((key_push_flag == 0) && (1 == cnt)) { 19 key_push_flag = 1; 20 21 key_val_temp = key_val; 22 printf("key %d down\n", key_val_temp); 23 } else if (cnt == 0) { 24 key_push_flag = 0; 25 } 26 } 27 28 return 0; 29 }
Makefile
1 obj-m := key.o 2 KDIR = /home/linux/zkf/6410/urbetter-linux2.6.28-v1.0 3 4 all: 5 make -C $(KDIR) M=$(PWD) modules CROSS_COMPILE=arm-none-linux-gnueabi- ARCH=arm 6 arm-none-linux-gnueabi-gcc key_app.c -o key_app 7 sudo cp key_app ~/zkf/6410/rootfs/home/test 8 sudo cp key.ko ~/zkf/6410/rootfs/home/test 9 clean: 10 rm *.o *.mod.c *.symvers *.order
加载模块：insmod key.ko
运行key_app，现象如下图：
标签：image NPU temp 寄存器 while fcntl 轮询 gcc 高电平
原文地址：https://www.cnblogs.com/Suzkfly/p/10317763.html
