在用户态控制GPIO的程序，省去了写驱动的麻烦，减少了系统调用，
直接将GPIO块的寄存器映射到用户空间，直接控制寄存器，提高了效率
本程序可直接用对应的cross compiler进行编译：
arm-linux-gcc -o gpio_ctrl gpio_ctrl.c
/*
* gpio_ctrl.c: user mode software to control the GPIO of S3C2440
* Author Youri Zhang 2010-12-28 (yahui9635@gmail.com)
* Reach the Author first before release this program.
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#undef PAGE_SIZE
#undef PAGE_MASK
#define APP_NAME "gpio_ctrl"
#define VERSION "1.0"
#define BUILD_DATE __DATE__
#define PAGE_SHIFT 12
#define PAGE_SIZE (1<<PAGE_SHIFT) /* 4096byte Per Mapped Memory page */
#define PAGE_MASK (~(PAGE_SIZE-1) )
#define GPIO_EndAddr 0x560000DC
#define GPIO_StartAddr 0x56000000
#define CLKREG_StartAddr 0x4C000000
#define CLKREG_EndAddr 0x4C000018
#define CLKCON 0x0C
#define REG(Addr) (*(volatile unsigned int*) (Addr))
static char* GPIOConStatus[4] = {"INPUT", "OUTPUT", "SpecialUse", "Reserved"};
static char* GPIODataStatus[2] = {"LOW", "HIGH"};
static char* GPIOPullupStatus[2] = {"Enabled", "Disabled"};
static void print_usage(void)
{
fprintf(stdout,"************Help information for %s*************\n",APP_NAME);
fprintf(stdout,"[Usage] %s -[b:n:c:w:p:rsdh] <value>\n", APP_NAME);
fprintf(stdout,"Version: %s, Date: %s, Author: Youri Zhang\n\n", VERSION, BUILD_DATE);
fprintf(stdout,"\t-b : (Must use 1st)specify the GPIO Bank index\n\t\t==>GPA's index is 0, GPB's index is 1 ... GPH's index is 7, GPJ's index is 8\n");
fprintf(stdout,"\t-n : (Must use 2nd)specify the GPIO num in GPIO Bank\n");
fprintf(stdout,"\t-c : Config the GPIO type(GPA use)\n\t\t==>OUTPUT:'-c 0x00', Special use:'-c 0x01'\n");
fprintf(stdout,"\t-c : Config the GPIO type(GPB--J use)\n\t\t==>INPUT:'-c 0x00', OUTPUT:'-c 0x01', Special use:'-c 0x02', Reserved:'-c 0x03'\n");
fprintf(stdout,"\t-w : Write value to GPIO pin's Data_reg\n");
fprintf(stdout,"\t-p : Config value to GPIO pin's Pullup_reg\n\t\t==>Enable:'-p 0x00', Disable:'-p 0x01'\n");
fprintf(stdout,"\t-r : Read the GPIO pin Data_reg's value\n");
fprintf(stdout,"\t-s : Show the GPIO pin Config_reg's value\n");
fprintf(stdout,"\t-d : Display the GPIO pin Pullup_reg's value\n");
fprintf(stdout,"\t-h : This help information\n\n");
fprintf(stdout,"Ex:\tConfig GPG4 output & write 0 to GPG4 Data_reg&enable pullup&read Data_reg&show configure&show pullup\n\t\t==> (%s -b 6 -n 4 -c 1 -w 0 -p 0 -s -r -d)\n", APP_NAME);
fprintf(stdout,"\t\t==> (%s -b 0x06 -n 0x04 -c 0x01 -w 0x00 -p 0x00 -s -r -d)\n\t\t--> both decimal and hexadecimal input are ok!\n", APP_NAME);
fprintf(stdout,"Ex:\tConfig the GPA4 output and write 0 to GPG4 Data_reg\n\t\t==> (%s -b 0 -n 4 -c 0x00 -w 0)\n", APP_NAME);
fprintf(stdout,"Ex:\tConfig the GPG4 output and read GPG4 Data_reg's value\n\t\t==> (%s -b 6 -n 4 -c 0x01 -r)\n", APP_NAME);
fprintf(stdout,"Ex:\tConfig the GPG4 output and show GPG4 Config_reg's value\n\t\t==> (%s -b 6 -n 4 -c 0x01 -s)\n", APP_NAME);
}
/* enable PCLK(50Mhz) to GPIO Block */
static void s3c2440_clkcon_init(void* REG_CLK)
{
REG((unsigned int)REG_CLK+CLKCON) |=0x2000;
}
static void s3c2440_gpio_cfgpin(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit, unsigned int Function)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
if(Addr_offset>0)
{
Function &= 3;
tmp &= ~(3<<MaskBit); /*used for GPIO Bank B-J, which use the 2 bits Mask*/
}
else
{
Function &= 1;
tmp &= ~(1<<MaskBit); /*used for GPIO Bank A, which use the 1 bit Mask*/
}
tmp|= (Function<<MaskBit);
REG((unsigned int)Regaddr +Addr_offset)=tmp;
}
static unsigned int s3c2440_gpio_getcfg(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
tmp >>= MaskBit;
if(Addr_offset>0x0c)
tmp &= 3; /*used for GPIO Bank B-J, which use the 2 bits Mask*/
else
tmp &= 1; /*used for GPIO Bank A, which use the 1 bit Mask*/
return tmp;
}
static void s3c2440_gpio_setpin(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit, unsigned int to)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
tmp &= ~(1<<MaskBit);
tmp |= (!!to<<MaskBit);
REG((unsigned int)Regaddr +Addr_offset)=tmp;
}
static unsigned int s3c2440_gpio_getpin(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
tmp &= (1<<MaskBit);
return tmp?1:0;
}
static void s3c2440_gpio_pullup(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit, unsigned int to)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
tmp &= ~(1<<MaskBit);
tmp |= !!to << MaskBit;
REG((unsigned int)Regaddr +Addr_offset)=tmp;
}
static unsigned int s3c2440_gpio_getpull(void *Regaddr, unsigned int Addr_offset, unsigned int MaskBit)
{
unsigned int tmp=0;
tmp=REG((unsigned int)Regaddr +Addr_offset);
tmp &= (1<<MaskBit);
return tmp?1:0;
}
int main(int argc, char* argv[])
{
int fd=-1, opt = -1, Bank_num=-1, Addr_offset=-1, MaskBit=-1, Function=-1, to=-1,pullup=-1;
void* GpioBase = NULL;
void* CLKBASE = NULL;
if(argc==2 && !strcmp(argv[1],"-h"))
{
print_usage();
exit(1);
}
else if(argc > 5 && argc < 15)
{
if(strcmp(argv[1],"-b") || strcmp(argv[3],"-n"))
{
fprintf(stdout, "[Error]: '-b' must be used as the first option && '-n' must be used as second the option\n");
fprintf(stdout, "For Example: %s -b 6 -n 4 -c 1 -w 0 -p 0 -s -r -d\n",APP_NAME);
print_usage();
exit(1);
}
fd = open("/dev/mem", O_RDWR | O_SYNC);
if(fd<0)
{
fprintf(stderr, "open /dev/mem error\n");
exit(1);
}
CLKBASE = mmap(NULL, (CLKREG_EndAddr-CLKREG_StartAddr), PROT_READ|PROT_WRITE, MAP_SHARED,fd, CLKREG_StartAddr & PAGE_MASK);
if(CLKBASE == NULL || CLKBASE == MAP_FAILED)
{
fprintf(stderr, "[Error]: S3C2440 CLKCON base mmap error\n");
goto failed;
}
//fprintf(stdout, "Re-Maped 0x%X to Space Addr:0x%X, Maped Size 0x%X bytes\n",CLKREG_StartAddr,CLKBASE ,(CLKREG_EndAddr-CLKREG_StartAddr));
GpioBase = mmap(NULL, (GPIO_EndAddr-GPIO_StartAddr), PROT_READ|PROT_WRITE, MAP_SHARED,fd, GPIO_StartAddr & PAGE_MASK);
if(GpioBase == NULL || GpioBase == MAP_FAILED)
{
fprintf(stderr, "S3C2440 gpio base mmap error\n");
goto failed;
}
//fprintf(stdout, "Re-Maped 0x%X to Space Addr:0x%X, Maped Size 0x%X\n",GPIO_StartAddr,GpioBase,(GPIO_EndAddr-GPIO_StartAddr));
s3c2440_clkcon_init(CLKBASE);
while ((opt = getopt(argc, argv, "b: n: c: w: p: rsdh")) != -1)
{
switch (opt)
{
case 'b': /* Bank num to program */
Bank_num = strtoul(optarg, NULL, 0);
if( Bank_num < 0 || Bank_num > 8){
fprintf(stderr, "[Error]: Please input correct Bank index num, the Bank index num should be 0--8 !\n");
goto failed;
}
Addr_offset = Bank_num * 0x10;
if(Addr_offset==0x80)
Addr_offset += 0x50;
//fprintf(stdout,"The Addr_offset is 0x%X\n",Addr_offset);
break;
case 'n': /*GPIO num in Bank to program, GPIO num is the Mask bit*/
MaskBit = strtoul(optarg, NULL, 0);
if( MaskBit < 0 || MaskBit > 25){
fprintf(stderr, "[Error]: Please input correct GPIO index num, the GPIO index num should be 0--25(max) !\n");
goto failed;
}
//fprintf(stdout,"The MaskBit is 0x%u\n",MaskBit);
break;
case 'c': /* The value to config the gpio_config_reg */
Function = strtoul(optarg, NULL, 0);
if( Function < 0 || Function > 3){
fprintf(stderr, "[Error]: Please input correct 'Config_reg' value, the value should be 0x00--0x03 !\n");
goto failed;
}
if(Bank_num>0)
{
s3c2440_gpio_cfgpin(GpioBase,Addr_offset,MaskBit*2,Function);
fprintf(stdout,"...Writing the 'Config_reg' to %s...\n",GPIOConStatus[Function]);
}
else
{
s3c2440_gpio_cfgpin(GpioBase,Addr_offset,MaskBit,Function);
fprintf(stdout,"...Writing the 'Config_reg' to %s...\n",GPIOConStatus[Function+1]);
}
break;
case 'w': /* The value to write to the gpio_data_reg*/
to = strtoul(optarg, NULL, 0);
if( to < 0 || to > 1){
fprintf(stderr, "[Error]: Please input correct 'Data_reg' value, the value should be 0x00--0x01 !\n");
goto failed;
}
s3c2440_gpio_setpin(GpioBase, Addr_offset+4, MaskBit, to);
fprintf(stdout,"...Writing the 'Data_reg' to %s...\n",GPIODataStatus[to]);
break;
case 'p': /* The value to write to the gpio_data_reg*/
pullup = strtoul(optarg, NULL, 0);
if( pullup < 0 || pullup > 1){
fprintf(stderr, "[Error]: Please input correct 'Pullup_reg' value, the value should be 0x00--0x01 !\n");
goto failed;
}
if(Bank_num>0)
{
s3c2440_gpio_pullup(GpioBase, Addr_offset+8, MaskBit, pullup);
fprintf(stdout,"...Writing the 'Pullup_reg' to %s...\n",GPIOPullupStatus[pullup]);
}
else fprintf(stderr,"[Error]: Can't set Pullup for GPIO Bank A%s\n");
break;
case 'r': /* Read the value of the gpio_data_reg*/
fprintf(stdout,"The 'Data_reg' value is--> %s\n",GPIODataStatus[s3c2440_gpio_getpin(GpioBase, Addr_offset+4, MaskBit)]);
break;
case 's': /* Show the value of the gpio_configure_reg*/
if(Bank_num>0)
fprintf(stdout,"The 'Config_reg' value is--> %s\n",GPIOConStatus[s3c2440_gpio_getcfg(GpioBase, Addr_offset, MaskBit*2)]);
else
fprintf(stdout,"The 'Config_reg' value is-->%s\n",GPIOConStatus[s3c2440_gpio_getcfg(GpioBase, Addr_offset, MaskBit)+1]);
break;
case 'd': /* Display the value of the pullup_reg*/
if(Bank_num>0)
fprintf(stdout,"The 'Pullup_reg' value is--> %s\n",GPIOPullupStatus[s3c2440_gpio_getpull(GpioBase, Addr_offset+8, MaskBit)]);
else
fprintf(stderr,"[Error]: Can't get pullup status for GPIO Bank A\n");
break;
case 'h': /* help information */
print_usage();
goto failed;
default :
fprintf(stderr, "[Error]: Uncompleted/Unknown option: %c\n", optopt);
print_usage();
goto failed;
}
}
}
else
{
fprintf(stderr, "[Error]: The format of the input options is not correct!\n");
fprintf(stderr, "[Error]: The quantity of the input options is not correct!\n");
fprintf(stderr, "[Error]: Please use '%s -h' to get the help information!\n", APP_NAME);
print_usage();
exit(1);
}
munmap(GpioBase,(GPIO_EndAddr-GPIO_StartAddr));
munmap(CLKBASE,(CLKREG_EndAddr-CLKREG_StartAddr));
close(fd);
exit(0);
failed:
opt =-1;
Bank_num = -1;
Addr_offset = -1;
MaskBit = -1;
Function = -1,
to = -1;
pullup = -1;
munmap(GpioBase,(GPIO_EndAddr-GPIO_StartAddr));
munmap(CLKBASE,(CLKREG_EndAddr-CLKREG_StartAddr));
close(fd);
GpioBase = NULL;
CLKBASE = NULL;
exit(1);
}