write gpio reg

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FILENAME:setreg.c

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1 /*

2 * Configure GPIO

3 */

5 #include <stdio.h>

6 #include <sys/ioctl.h>

7 #include <sys/types.h>

8 #include <sys/stat.h>

9 #include <sys/wait.h>

10 #include <termios.h>

11 #include <fcntl.h>

12 #include <unistd.h>

13 #include <string.h>

14 #include <sys/mman.h>

16 #define IO_REG_BASE 0xE0000000

17 #define IO_REG_SIZE 0x100000 /* 1M bytes */

18 #define GPDIR_OFFSET 0xC00

19 #define GPODR_OFFSET 0xC04

20 #define GPDAT_OFFSET 0xC08

22 #define RETURN_FAILED (-1)

23 #define IO_REG32_READ(_reg) (*((volatile unsigned int*) (_reg)))

24 #define IO_REG32_WRITE(_reg, _val) ((*((volatile unsigned int*) (_reg))) = (_val))

26 static void *gpio_base_addr;

27 static int mem_fd;

29 /*

30 * Map GPIO base address

31 */

32 int mmap_io(void)

33 {

34 // mmap CPU register's IO spaces

35 mem_fd = open("/dev/mem", O_RDWR | O_SYNC);

36 if (mem_fd < 0) {

37 printf("open /dev/mem error !\n\r");

38 return RETURN_FAILED;

39 }

41 gpio_base_addr = mmap(0, IO_REG_SIZE, (PROT_READ | PROT_WRITE),

42 MAP_SHARED, mem_fd, IO_REG_BASE);

44 if (gpio_base_addr == NULL) {

45 printf("mmap error ! \n\r");

46 close(mem_fd);

47 return RETURN_FAILED;

48 }

50 return (int) gpio_base_addr;

51 }

53 int munmap_io(void)

54 {

55 if(mem_fd < 0)

56 return RETURN_FAILED;

58 // unmap

59 if(munmap(gpio_base_addr, IO_REG_SIZE) < 0) {

60 return RETURN_FAILED;

61 }

63 if(close(mem_fd) < 0) {

64 return RETURN_FAILED;

65 }

66 }

68 void show_gpio_data(void)

69 {

70 printf("--- Readout value of GPIO registers ---\n");

71 printf("GPDIR: %08x\n", IO_REG32_READ(gpio_base_addr + GPDIR_OFFSET));

72 printf("GPODR: %08x\n", IO_REG32_READ(gpio_base_addr + GPODR_OFFSET));

73 printf("GPDAT: %08x\n", IO_REG32_READ(gpio_base_addr + GPDAT_OFFSET));

74 return;

75 }

77 int main(int argc,char **argv)

78 {

79 unsigned int roffset= 0;

80 unsigned int val = 0;

82 if (argc < 3) {

83 printf("Usage:\n");

84 printf(" %s register_offset value, like %s 0xC00 0x00C00000 to set GPIO DIR register value to 0x00C00000\n", argv[0], argv[0]);

85 return -1;

86 }

88 /* Map IMMR register base */

89 if(mmap_io() < 0 ) {

90 return RETURN_FAILED;

91 }

93 roffset = strtoul(argv[1], NULL, 16);

94 val = strtoul(argv[2], NULL, 16);

96 /* Set register value */

97 IO_REG32_WRITE( (gpio_base_addr+roffset), val);

99 printf("After register set, register 0x%08X, value: 0x%08X\n", roffset, IO_REG32_READ(gpio_base_addr + roffset) );

100

101 /* unmap */

102 munmap_io();

103 return(0);

104 }

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