[linux] 通用的 uart & gpio & led & key 示例代码
这是给 wiki.sipeed.com/m3axpi 准备的示例代码。
gpio & pwm
- linux_gpio.h
#ifndef __LINUX_GPIO_H
#define __LINUX_GPIO_H
#ifdef __cplusplus
extern "C"
{
#endif
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
void _pwm_init(char *pin, uint64_t fre, float duty);
void _pwm_set_duty(char * pin, float duty);
void _pwm_deinit(char *pin);
/*
_pwm_init("PH8", 50000, 0.1);
sleep(1);
_pwm_set_duty("PH8", 0.6);
sleep(1);
_pwm_set_duty("PH8", 0.3);
sleep(1);
_pwm_deinit("PH8");
*/
void* _gpio_init(char* pin, int mode, int state);
void _gpio_deinit(char* pin);
void _gpio_read(char* pin, int* state);
/*
// _gpio_init("PH7", 0, 0);
// for (int i = 0; i < 30; i++)
// {
// int val = 0;
// _gpio_read("PH7", &val);
// printf("%d\r\n", val);
// sleep(1);
// }
// _gpio_deinit("PH7");
// return;
*/
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LINUX_GPIO_H */
- linux_gpio.c
#include "linux_gpio.h"
int _write_file_only(char* path, char* buf, size_t count)
{
int fd, res;
fd = open(path, O_WRONLY | O_NONBLOCK);
if (fd < 0)
return -1;
res = write(fd, buf, count);
if (res < 0)
{
close(fd);
return -2;
}
res = close(fd);
if (res < 0)
return -3;
return res;
}
int _read_file_only(char* path, char* buf, size_t count)
{
int fd, res;
fd = open(path, O_RDONLY | O_NONBLOCK);
if (fd < 0)
return -1;
res = read(fd, buf, count);
if (res < 0)
{
close(fd);
return -2;
}
res = close(fd);
if (res < 0)
return -3;
return res;
}
int _get_pwm_num(char *pin)
{
int pwm_num = 0;
if (strlen(pin) < 3) return -1;
if (!strcmp(pin, "PD1") || !strcmp(pin, "PH0"))
{
pwm_num = 0;
}
else if (!strcmp(pin, "PD2") || !strcmp(pin, "PH1"))
{
pwm_num = 1;
}
else if (!strcmp(pin, "PD3") || !strcmp(pin, "PH2"))
{
pwm_num = 2;
}
else if (!strcmp(pin, "PD4") || !strcmp(pin, "PH3"))
{
pwm_num = 3;
}
else if (!strcmp(pin, "PD5") || !strcmp(pin, "PH4"))
{
pwm_num = 4;
}
else if (!strcmp(pin, "PD6") || !strcmp(pin, "PH5"))
{
pwm_num = 5;
}
else if (!strcmp(pin, "PD7") || !strcmp(pin, "PH6"))
{
pwm_num = 6;
}
else if (!strcmp(pin, "PD8") || !strcmp(pin, "PH7"))
{
pwm_num = 7;
}
else if (!strcmp(pin, "PD9") || !strcmp(pin, "PH8"))
{
pwm_num = 8;
}
else if (!strcmp(pin, "PD19") || !strcmp(pin, "PD22") || !strcmp(pin, "PH9"))
{
pwm_num = 9;
}
else
{
pwm_num = -1;
}
return pwm_num;
}
/**
* @brief 初始化pwm
* @details
* @param [in] pwm_id 按键id(0 按键0,1 按键1)
* @param [in] fre 频率
* @param [in] duty 占空比
* @retval
*/
void _pwm_init(char *pin, uint64_t fre, float duty)
{
int res = 0;
char path[100];
char arg[20];
int pwm_id;
uint64_t period = 0, duty_cycle = 0;
pwm_id = _get_pwm_num(pin);
if (-1 == pwm_id) return;
snprintf(arg, sizeof(arg), "%d", pwm_id);
res = _write_file_only("/sys/class/pwm/pwmchip0/export", arg, strlen(arg));
if (res < 0) {return;}
period = 1000000000 / fre;
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/period", pwm_id);
snprintf(arg, sizeof(arg), "%lld", period);
res = _write_file_only(path, arg, strlen(arg));
if (res < 0) {return;}
duty = duty > 1.0 ? 1.0 : duty;
duty = 1.0 - duty;
duty_cycle = period * duty;
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/duty_cycle", pwm_id);
snprintf(arg, sizeof(arg), "%lld", duty_cycle);
res = _write_file_only(path, arg, strlen(arg));
if (res < 0) {return;}
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/enable", pwm_id);
res = _write_file_only(path, "1", 1);
if (res < 0) {return;}
}
void _pwm_deinit(char *pin)
{
int res = 0;
char path[100];
char arg[20];
int pwm_id;
pwm_id = _get_pwm_num(pin);
if (-1 == pwm_id) return;
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/enable", pwm_id);
res = _write_file_only(path, "0", 1);
if (res < 0) {return;}
snprintf(arg, sizeof(arg), "%d", pwm_id);
res = _write_file_only("/sys/class/pwm/pwmchip0/unexport", arg, strlen(arg));
if (res < 0) {return;}
}
void _pwm_set_duty(char * pin, float duty)
{
int res = 0;
char path[100];
char arg[20];
int pwm_id;
uint64_t period = 0, duty_cycle = 0;
pwm_id = _get_pwm_num(pin);
if (-1 == pwm_id) return;
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/period", pwm_id);
res = _read_file_only(path, arg, sizeof(arg));
if (res < 0) {return;}
period = atoi(arg);
duty = 1.0 - duty;
duty_cycle = period * duty;
snprintf(arg, sizeof(arg), "%lld", duty_cycle);
snprintf(path, sizeof(path), "/sys/class/pwm/pwmchip0/pwm%d/duty_cycle", pwm_id);
res = _write_file_only(path, arg, strlen(arg));
if (res < 0) {return;}
}
/**
* @brief 将字符引脚编号转换为数字引脚编号
* @param [in] pin 字符引脚编号,格式必须为PAxx~PHxx，且xx的范围为0~31
* @retval 返回数字引脚编号，如果为-1，则执行失败
*/
int _get_gpio_num(char* pin)
{
if (strlen(pin) < 3)
return -1;
char c;
int group_id, group_offset, gpio_num;
c = pin[0];
if (c != 'p' && c != 'P')
{
return -1;
}
c = pin[1];
if ('a' <= c && c <= 'z') // 限制a~z
{
group_id = c - 'a';
}
else if ('A' <= c && c <= 'Z') // 限制A~Z
{
group_id = c - 'A';
}
else
{
return -1;
}
group_offset = atoi(pin + 2);
if (group_offset > 31)
{
return -1;
}
gpio_num = (group_id << 5) + group_offset;
return gpio_num;
}
/**
* @brief 向export文件注册gpio
* @param [in] gpio 引脚编号
* @retval 返回0，成功，小于0，失败
*/
int gpio_export(uint32_t gpio)
{
int len, res;
char buf[10];
len = snprintf(buf, sizeof(buf), "%d", gpio);
if (len > sizeof(buf))
return -1;
res = _write_file_only("/sys/class/gpio" "/export", buf, len);
if (res < 0)
{
perror("gpio_export");
}
return res;
}
/**
* @brief 向unexport文件取消注册gpio
* @param [in] gpio 引脚编号
* @retval 返回0，成功，小于0，失败
*/
int gpio_unexport(uint32_t gpio)
{
int len, res;
char buf[10];
len = snprintf(buf, sizeof(buf), "%d", gpio);
if (len > sizeof(buf))
return -1;
res = _write_file_only("/sys/class/gpio" "/unexport", buf, len);
if (res < 0)
{
perror("gpio unexport");
}
return res;
}
/**
* @brief 设置gpio输入/输出模式
* @param [in] gpio 引脚编号
* @param [in] mode 引脚模式,取值如下:
* 0,输入模式
* 1,输出模式，默认低电平
* 2,输出模式，默认低电平
* 3,输出模式，默认高电平
* @retval 返回0，成功，小于0，失败
*/
int gpio_set_dir(uint32_t gpio, uint32_t mode)
{
int len, res;
char path[40];
len = snprintf(path, sizeof(path), "/sys/class/gpio" "/gpio%d/direction", gpio);
if (len > sizeof(path))
return -1;
mode = mode > 3 ? 3 : mode;
switch(mode)
{
case 0:res = _write_file_only(path, "in", sizeof("in"));break;
case 1:res = _write_file_only(path, "out", sizeof("out"));break;
case 2:res = _write_file_only(path, "low", sizeof("low"));break;
case 3:res = _write_file_only(path, "high", sizeof("high"));break;
default:break;
}
return res;
}
/**
* @brief 设置gpio电平
* @param [in] gpio 引脚编号
* @param [in] value 引脚电平(1,高电平;0,低电平)
* @retval 返回0，成功，小于0，失败
*/
int gpio_set_value(uint32_t gpio, uint32_t value)
{
int len, res;
char path[40];
len = snprintf(path, sizeof(path), "/sys/class/gpio" "/gpio%d/value", gpio);
if (len > sizeof(path))
return -1;
if (value)
res = _write_file_only(path, "1", 2);
else
res = _write_file_only(path, "0", 2);
return res;
}
/**
* @brief 读取gpio电平
* @param [in] gpio 引脚编号
* @param [out] value 引脚电平(1,高电平;0,低电平)
* @retval 返回0，成功，小于0，失败
*/
int gpio_get_value(uint32_t gpio, uint32_t *value)
{
int len, res;
char path[40], state;
len = snprintf(path, sizeof(path), "/sys/class/gpio" "/gpio%d/value", gpio);
if (len > sizeof(path))
return -1;
res = _read_file_only(path, &state, 1);
if (res < 0)
return res;
*value = state == '0' ? 0 : 1;
return res;
}
/**
* @brief 初始化gpio
* @note 还没有限制io_num的范围，需要注意
* @param [in] dev 设备名
* @param [in] mode 模式
* @param [in] state 初始状态值
* @retval 0 成功 <0 失败
*/
void* _gpio_init(char* pin, int mode, int state)
{
int res = -1;
int io_num = _get_gpio_num(pin);
if (io_num < 0)
{
return (void *)res;
}
/* 向export文件注册一个gpio */
res = gpio_export(io_num);
if (res < 0) return (void *)res;
/* 设置gpio方向 */
res = gpio_set_dir(io_num, mode);
if (res < 0) return (void *)res;
if (mode > 0)
{
/* 设置gpio电平 */
res = gpio_set_value(io_num, state);
if (res < 0) return (void *)res;
}
return (void*)res;
}
/**
* @brief 初始化gpio
* @note 还没有限制io_num的范围，需要注意
* @param [in] handle 设备名
* @retval
*/
void _gpio_deinit(char* pin)
{
int res;
int io_num = _get_gpio_num(pin);
if (io_num < 0) return;
res = gpio_unexport(io_num);
if (res < 0) return;
}
/**
* @brief 读gpio电平，只能在输入模式下调用
* @note
* @param [in] handle 句柄，用来传入文件描述符
* @param [out] state 状态值
* @retval
*/
void _gpio_read(char* pin, int* state)
{
int io_num = _get_gpio_num(pin);
if (io_num < 0) return;
gpio_get_value(io_num, (uint32_t *)state);
}
/**
* @brief 写gpio电平，只能在输出模式下调用
* @note
* @param [in] handle 句柄，用来传入文件描述符
* @param [in] state 状态值
* @retval
*/
void _gpio_write(char* pin, int state)
{
int io_num = _get_gpio_num(pin);
if (io_num < 0) return;
gpio_set_value(io_num, state);
}
linux uart ttySX
- linux_uart.h
#ifndef __LINUX_UART_H
#define __LINUX_UART_H
#ifdef __cplusplus
extern "C"
{
#endif
#include "stdint.h"
#define PRINF_HEX_ARR(str,buf,len)\
do{\
char *buff = (char *)buf;\
printf("\e[32m[%s](%d):\e[0m", str, len);\
for (int i = 0;i < len; ++i)\
{\
printf("0x%.2X ", buff[i] & 0xff);\
}\
printf("\r\n");\
} while (0);
typedef struct{
int baud;
int data_bits;
int stop_bits;
char parity;
}uart_t;
int linux_uart_init(char* dev, void* param);
void linux_uart_deinit(int fd);
int linux_uart_read(int fd, int cnt, uint8_t* buf);
int linux_uart_write(int fd, int cnt, uint8_t* buf);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /* __LINUX_UART_H */
- linux_uart.c
#include "linux_uart.h"
#include <stdio.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>
#include <linux/serial.h>
static int _get_baud(int baud)
{
switch (baud)
{
case 9600:return B9600;
case 19200:return B19200;
case 38400:return B38400;
case 57600:return B57600;
case 115200:return B115200;
case 230400:return B230400;
case 460800:return B460800;
case 500000:return B500000;
case 576000:return B576000;
case 921600:return B921600;
#ifdef B1000000
case 1000000:return B1000000;
#endif
#ifdef B1152000
case 1152000:return B1152000;
#endif
#ifdef B1500000
case 1500000:return B1500000;
#endif
#ifdef B2000000
case 2000000:return B2000000;
#endif
#ifdef B2500000
case 2500000:return B2500000;
#endif
#ifdef B3000000
case 3000000:return B3000000;
#endif
#ifdef B3500000
case 3500000:return B3500000;
#endif
#ifdef B4000000
case 4000000:return B4000000;
#endif
default:return -1;
}
}
static void clear_custom_speed_flag(int _fd)
{
struct serial_struct ss;
if (ioctl(_fd, TIOCGSERIAL, &ss) < 0) {
// return silently as some devices do not support TIOCGSERIAL
return;
}
if ((ss.flags & ASYNC_SPD_MASK) != ASYNC_SPD_CUST)
return;
ss.flags &= ~ASYNC_SPD_MASK;
if (ioctl(_fd, TIOCSSERIAL, &ss) < 0) {
perror("TIOCSSERIAL failed");
exit(1);
}
}
/**
* @brief 初始化uart
* @note
* @param [in] dev 设备名
* @param [in] param 参数
* @retval
*/
int linux_uart_init(char* dev, void* param)
{
int fd;
uart_t* cfg = (uart_t *)param;
int baud = _get_baud(cfg->baud);
int data_bits = cfg->data_bits, stop_bits = cfg->stop_bits;
char parity = cfg->parity;
fd = open(dev, O_RDWR | O_NONBLOCK | O_NOCTTY);
// fd = open(dev, O_RDWR | O_NOCTTY);
if (fd < 0)
{
return fd;
}
struct termios opt;
memset(&opt, 0, sizeof(opt));
/* 忽略modem，使能读模式 */
opt.c_cflag |= CLOCAL | CREAD;
/* 设置波特率 */
opt.c_cflag |= baud;
/* 设置数据位 */
switch (data_bits)
{
case 7:
opt.c_cflag |= CS7;
break;
case 8:
opt.c_cflag |= CS8;
break;
default:break;
}
/* 设置奇偶校验位 */
switch (parity)
{
case 'N':
case 'n':
opt.c_iflag &= ~INPCK;
opt.c_cflag &= ~PARENB;
break;
case 'O':
case 'o':
opt.c_iflag |= (INPCK | ISTRIP);
opt.c_cflag |= (PARODD | PARENB);
break;
case 'E':
case 'e':
opt.c_iflag |= (INPCK | ISTRIP);
opt.c_cflag |= PARENB;
opt.c_cflag &= ~PARODD;
break;
default:break;
}
/* 设置停止位 */
switch (stop_bits)
{
case 1:
opt.c_cflag &= ~CSTOPB;
break;
case 2:
opt.c_cflag |= CSTOPB;
break;
default:break;
}
/* 设置流控制 */
opt.c_cflag &= ~CRTSCTS;
/* 最小字节数与等待时间 */
opt.c_cc[VMIN] = 1;
opt.c_cc[VTIME] = 0;
/* 刷新串口，更新配置 */
tcflush(fd, TCIOFLUSH);
tcsetattr(fd, TCSANOW, &opt);
clear_custom_speed_flag(fd);
return fd;
}
void linux_uart_deinit(int fd)
{
int res;
res = close(fd);
if (res < 0)
fprintf(stderr, "uart close fd(%d) err:%s\n", fd, strerror(errno));
else
fd = -1;
}
linux key & led
- key_led.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/prctl.h>
#include <fcntl.h>
#include <sys/poll.h>
#include <time.h>
char set_key_led_irq_in(unsigned int gpio_num, unsigned int led_num) // user key num 85 led0 68 led1 69
{
FILE *fp;
char file_name[50];
unsigned int led = led_num + 68;
//key
sprintf(file_name, "/sys/class/gpio/export");
fp = fopen(file_name, "w");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "%d", gpio_num);
fclose(fp);
//led
sprintf(file_name, "/sys/class/gpio/export");
fp = fopen(file_name, "w");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "%d", led);
fclose(fp);
//set key in
sprintf(file_name, "/sys/class/gpio/gpio%d/direction", gpio_num);
fp = fopen(file_name, "rb+");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "in");
fclose(fp);
//set key edge
sprintf(file_name, "/sys/class/gpio/gpio%d/edge", gpio_num);
fp = fopen(file_name, "rb+");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "falling");
fclose(fp);
//set led out
sprintf(file_name, "/sys/class/gpio/gpio%d/direction", led);
fp = fopen(file_name, "rb+");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "out");
fclose(fp);
//set led 0
sprintf(file_name, "/sys/class/gpio/gpio%d/value", led);
fp = fopen(file_name, "rb+");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "0");
fclose(fp);
}
char set_led_status(unsigned int led_num, bool led_status) // user key num 85 led0 68 led1 69
{
FILE *fp;
char file_name[50];
unsigned int led = led_num + 68;
sprintf(file_name, "/sys/class/gpio/gpio%d/value", led);
fp = fopen(file_name, "rb+");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
if (led_status)
fprintf(fp, "1");
else
fprintf(fp, "0");
fclose(fp);
}
char unset_key_led_irq(unsigned int gpio_num, unsigned int led_num)
{
FILE *fp;
char file_name[50];
unsigned char buf[10];
unsigned int led = led_num + 68;
sprintf(file_name, "/sys/class/gpio/unexport");
fp = fopen(file_name, "w");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "%d", gpio_num);
fclose(fp);
sprintf(file_name, "/sys/class/gpio/unexport");
fp = fopen(file_name, "w");
if (fp == NULL)
{
printf("Cannot open %s.\n", file_name);
return -1;
}
fprintf(fp, "%d", led);
fclose(fp);
}
int main(int argc, char *argv[])
{
AX_S32 s32Ret = -1;
int val;
char buff[10];
int gpio_fd = -1;
bool rectrl = false;
bool blink = false;
struct pollfd fds;
set_key_led_irq_in(85, 0);
gpio_fd = open("/sys/class/gpio/gpio85/value", O_RDONLY);
if (gpio_fd == -1)
printf("gpio open err! \n");
fds.fd = gpio_fd;
fds.events = POLLPRI;
s32Ret = read(gpio_fd, buff, 10);
if (s32Ret == -1)
printf("read gpio err! \n");
printf("hello start!\r\n");
while (1)
{
//读取按键中断
s32Ret = poll(&fds, 1, 0);
if (fds.revents & POLLPRI)
{
s32Ret = lseek(gpio_fd, 0, SEEK_SET);
if (s32Ret == -1)
printf("lseek err! \n");
s32Ret = read(gpio_fd, buff, 10);
if (s32Ret == -1)
printf("read gpio err! \n");
if (!rectrl)
{
rectrl = true;
}
else
{
rectrl = false;
set_led_status(0, 0);
}
printf("get interrupt\n");
}
if(rectrl)
{
if (!blink)
{
blink = true;
set_led_status(0, blink);
}
else
{
blink = false;
set_led_status(0, blink);
}
}
usleep(500000);
}
unset_key_led_irq(85, 0);
printf("end!\r\n");
exit(0);
}
linux i2c
https://wiki.sipeed.com/soft/maixpy3/zh/usage/hardware/I2C.html
https://zhuanlan.zhihu.com/p/575318033
linux spi
https://wiki.sipeed.com/soft/maixpy3/zh/usage/hardware/SPI.html
