linux 驅動中建立乙個裝置的例子很多，以下例子是建立多個字元裝置的例子，包括驅動部分和測試部分
驅動部分包括 globalmem.c makefile兩個檔案：
globalmem.c file:
#include #include #include #include #include #include #include #include #include #include #include #include #include #define globalmem_size 0x1000 //global memory size 4kb
#define mem_clear 0x1 //clear all the mem
#define globalmem_major 350 //globalmem major number
static struct class* globalmem_class0;
static struct class* globalmem_class1;
static int globalmem_major = globalmem_major;
struct globalmem_dev;
struct globalmem_dev* globalmem_devp;
void globalmem_setup_cdev(struct globalmem_dev * dev, int index);
int globalmem_init(void)else
if(result < 0)
globalmem_devp = kmalloc(2 * sizeof(struct globalmem_dev), gfp_kernel);
if(!globalmem_devp)
memset(globalmem_devp, 0, 2 * sizeof(struct globalmem_dev));
globalmem_setup_cdev(&globalmem_devp[0], 0);
globalmem_setup_cdev(&globalmem_devp[1], 1);
globalmem_class0 = class_create(this_module, "globalmem0"); //create file under /sys/class
device_create(globalmem_class0, null, mkdev(globalmem_major, 0), null, "globalmem_0"); //globalmem_0 is the name under /dev/
globalmem_class1 = class_create(this_module, "globalmem1"); //create file under /sys/class
device_create(globalmem_class1, null, mkdev(globalmem_major, 1), null, "globalmem_1"); //globalmem_1 is the name under /dev/
return 0;
fail_malloc:
unregister_chrdev_region(devno, 1);
return result;
}void globalmem_exit(void)
static int globalmem_open_0(struct inode* inode, struct file* filp)
static int globalmem_open_1(struct inode* inode, struct file* filp)
static ssize_t globalmem_read_0(struct file* filp, char __user * buf, size_t count, loff_t * ppos)
static ssize_t globalmem_read_1(struct file* filp, char __user * buf, size_t count, loff_t * ppos)
static ssize_t globalmem_write_0(struct file* filp, const char __user * buf, size_t count, loff_t * ppos)
static ssize_t globalmem_write_1(struct file* filp, const char __user * buf, size_t count, loff_t * ppos)
static loff_t globalmem_llseek_0(struct file* filp, loff_t offset, int orig)
static loff_t globalmem_llseek_1(struct file* filp, loff_t offset, int orig)
static long globalmem_ioctl_0(struct file * filp, unsigned int cmd, unsigned long arg)
static long globalmem_ioctl_1(struct file * filp, unsigned int cmd, unsigned long arg)
static const struct file_operations globalmem_fops = ,
[1] =
};void globalmem_setup_cdev(struct globalmem_dev* dev, int index)
module_init(globalmem_init);
module_exit(globalmem_exit);
module_license("dual bsd/gpl");
module_author("***");
module_description("global mem test");
1,1 top
makefile file:
mymodule-objs := globalmem.o
obj-m := globalmem.o
pwd:=$(shell pwd)
kernel_dir=/sziauto/android_src/m6_lch_1280x800/svn_m6_jb42_0403/branches/branches-lch/out/target/product/t37lchaudi/obj/kernel_obj/
cross_compile=/sziauto/android_src/m6_lch_1280x800/svn_m6_jb42_0403/branches/branches-lch/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin
pwd:=$(shell pwd)
all:
make arch=arm $(cross_compile) -c $(kernel_dir) m=$(pwd) modules
clean:
rm -rf *.o modules.order *.ko module.symvers *.mod.c
測試部分包括 android.mk driver_test.c
driver_test.c ：
#include #include #include #include #include #define buffer_len 100
int main(int argc, char* argv);
char content[buffer_len] = ;
const char* path0 = "/dev/globalmem_0";
const char* path1 = "/dev/globalmem_1";
while(1)
fd = open(path0, o_rdwr);
}else if(param[0] == '1')
fd = open(path1, o_rdwr);
}}else if(param[0] == 'r' || param[0] == 'r')else if(param[0] == 'w' || param[0] == 'w')else if(param[0] == 'i' || param[0] == 'i')else if(param[0] == 'q' || param[0] == 'q')
}return 0;
}
android.mk
include $(clear_vars)
local_src_files := \
driver_test.c
local_module_tags := optional
local_module := driver_test
include $(build_executable)
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