Linux驅動編程實踐之LED驅動

開發板：TQ2440

內核：2.6.30.4-EmbedSky

實現目標：控制led開關，並當前讀取狀態

-------驅動實現 mini2440_leds.c-------

1. #include <linux/miscdevice.h>
2. #include <linux/delay.h>
3. #include <asm/irq.h>
4. #include <mach/regs-gpio.h>
5. #include <mach/hardware.h>
6. #include <linux/kernel.h>
7. #include <linux/module.h>
8. #include <linux/init.h>
9. #include <linux/mm.h>
10. #include <linux/fs.h>
11. #include <linux/types.h>
12. #include <linux/delay.h>
13. #include <linux/moduleparam.h>
14. #include <linux/slab.h>
15. #include <linux/errno.h>
16. #include <linux/ioctl.h>
17. #include <linux/cdev.h>
18. #include <linux/string.h>
19. #include <linux/list.h>
20. #include <linux/pci.h>
21. #include <asm/uaccess.h>
22. #include <asm/atomic.h>
23. #include <asm/unistd.h>
26. #define DEVICE_NAME "leds" //要操作的設備名稱，加載成功後在/dev/下出現
27. //操作的4個led
28. static unsigned long led_table [] = {
29. S3C2410_GPB5,
30. S3C2410_GPB6,
31. S3C2410_GPB7,
32. S3C2410_GPB8,
33. };
34. //輸出
35. static unsigned int led_cfg_table [] = {
36. S3C2410_GPB5_OUTP,
37. S3C2410_GPB6_OUTP,
38. S3C2410_GPB7_OUTP,
39. S3C2410_GPB8_OUTP,
40. };
42. /*static unsigned int led_cfg_table1 [] = {
43. S3C2410_GPB5_INP,
44. S3C2410_GPB6_INP,
45. S3C2410_GPB7_INP,
46. S3C2410_GPB8_INP,
47. };*/
49. static int sbc2440_leds_ioctl(
50. struct inode *inode,
51. struct file *file,
52. unsigned int cmd,
53. unsigned long arg)
54. {
55. unsigned char i,tmp;
57. switch(cmd) {
58. case 0:
59. case 1:
60. if (arg > 4) {
61. return -EINVAL;
62. }
63. s3c2410_gpio_cfgpin(led_table[arg], led_cfg_table[arg]);
64. s3c2410_gpio_setpin(led_table[arg], !cmd); //關或開
65. return 0;
66. case 2:
67. tmp = s3c2410_gpio_getpin(led_table[arg]); //讀取狀態
68. tmp = tmp >>(arg+5);
70. return (unsigned int)tmp;
71. default:
72. return -EINVAL;
73. }
74. }
76. static struct file_operations dev_fops = {
77. .owner = THIS_MODULE,
78. .ioctl = sbc2440_leds_ioctl,
79. };
80. //混雜結構
81. static struct miscdevice misc = {
82. .minor = MISC_DYNAMIC_MINOR,
83. .name = DEVICE_NAME,
84. .fops = &dev_fops,
85. };
87. static int __init dev_init(void)
88. {
89. int ret;
91. int i;
92. //初始化四個led,並打開
93. for (i = 0; i < 4; i++) {
94. s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
95. s3c2410_gpio_setpin(led_table[i], 0);
96. }
98. ret = misc_register(&misc);
100. printk (DEVICE_NAME"\tinitialized\n");
102. return ret;
103. }
105. static void __exit dev_exit(void)
106. {
107. misc_deregister(&misc);
108. }
110. module_init(dev_init);
111. module_exit(dev_exit);
112. MODULE_LICENSE("GPL");
113. MODULE_AUTHOR("FriendlyARM Inc.");

======應用程序app-led.c======

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <unistd.h>
4. #include <sys/ioctl.h>
6. int main(int argc, char **argv)
7. {
8. int on;
9. int led_no;
10. int fd;
11. if (argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2],"%d", &on) != 1 ||
12. on < 0 || on > 2 || led_no < 0 || led_no > 3) {
13. fprintf(stderr, "Usage: leds led_no 0|1|2\n");
14. exit(1);
15. }
16. fd = open("/dev/leds", 0);
17. if (fd < 0) {
18. perror("open device leds");
19. exit(1);
20. }
21. if(on==2) //讀取led狀態
22. {
23. printf("state:=%d\n",ioctl(fd, on, led_no));
24. }
25. else //控制led開或關，即0，1
26. {
27. ioctl(fd, on, led_no);
28. }
29. close(fd);
30. return 0;
31. }

=========Makefile==========

1. ifneq ($(KERNELRELEASE),)
3. obj-m := mini2440_leds.oelse
4. KDIR := /opt/guoqian/opt/EmbedSky/linux-2.6.30.4
6. all:
7. make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-
8. clean:
9. rm -f *.ko *.o *.mod.o *.mod.c *.symvers modul*
10. endif

=======操作結果======
[root@EmbedSky /tmp]# insmod mini2440_leds.ko
[root@EmbedSky /tmp]# ./app-led 1 2
state:=0
[root@EmbedSky /tmp]# ./app-led 1 0
[root@EmbedSky /tmp]# ./app-led 1 2
state:=1
[root@EmbedSky /tmp]#