LCD of the core bus, frambuffer (sb)

Step 1: Cut out the LCD driver that comes with the board

Cut out an LCD. Different from the previous drivers like LED and buzzer, you can directly comment it in make menuconfig and compile to generate zImage image. This will limit many functions of the board. You can only comment the driver in /driver/video/s3c-fb0.c in the source code package to kill the LCD driver that comes with the board!

After the comment, make generates a new zImage image. Before downloading the newly generated zImage to the board, start the board and you can see the fb0 device in the /dev directory.

Observe that there is also a fb file under the /sys/class/graphics/ directory.

Then download the new image file to the board and find that the files in the two directories are gone. Before writing the LCD driver yourself, you need to understand how the driver works. The process of creating the device file /dev/fb0 is as follows:

The module code written is as follows:

1 #include

2 #include

3 #include

4 #include

5 #include

6 #include

7 #include

8 #include

9 #include

10 #include

11 #include

12 #include

13 #include

14 #include

15 #include

16 #include

17 #include

18 #include

19 #include

20 #include

21 #include

22 #include

23 #include

24 #include

25

26 #include

27 #include

28 #include

29 #include

30 #include

31 #include

32 #include

33

34 MODULE_LICENSE("GPL");

35 MODULE_AUTHOR("bunfly");

36

37 int s3c_probe(struct platform_device *dev);

38

39 struct platform_driver s3c_fb = {

40     .probe = s3c_probe,

41     .driver = {

42         .name = "exynos4-fb",

43     },

44 };

45

46 struct fb_info info;

47

48 int test_init(void)

49 {

50     platform_driver_register(&s3c_fb);

51 }

52

53 void test_exit(void)

54 {

55 }

56

57 module_init(test_init);

58 module_exit(test_exit);

59

60 int s3c_probe(struct platform_device *dev)

61 {

62     printk("proben");

63     register_framebuffer(&info);

64     return 0;

65 }

66

Through this module, you can see the fb0 device under the /dev directory: