Linux Spidev spi 9bits 模式参考代码

/*
 * SPI testing utility (using spidev driver)
 *
 * Copyright (c) 2007  MontaVista Software, Inc.
 * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 *
 * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
 */

#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))

static void pabort(const char *s)
{
perror(s);
abort();
}

static const char *device = "/dev/spidev1.1";
static uint8_t mode;
static uint8_t bits = 9;
static uint32_t speed = 500000;
static uint16_t delay;

static void transfer(int fd)
{
int ret;
uint8_t tx[] = {
//0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
//0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
//0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD,
//0xF0, 0x0D,
0xA5,0xF0,0x85
};
uint8_t rx[ARRAY_SIZE(tx)] = {0, };
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long)tx,
.rx_buf = (unsigned long)rx,
.len = ARRAY_SIZE(tx),
.delay_usecs = delay,
.speed_hz = speed,
.bits_per_word = bits,
};

ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
pabort("can't send spi message");

for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
if (!(ret % 6))
puts("");
printf("%.2X ", rx[ret]);
}
puts("");
}

static void send_cmd(int fd, uint8_t cmd,uint8_t size)  
{  
    int ret;  
    uint16_t tx[64] = {0};  
    uint16_t rx[ARRAY_SIZE(tx)] = {0};  
  
    tx[0] = cmd;  
  
    struct spi_ioc_transfer tr = {  
        .tx_buf = (unsigned long)tx,  
        .rx_buf = (unsigned long)rx,  
        .len = size*2,//sizeof(tx),  
        .delay_usecs = delay,  
        .speed_hz = speed,  
        .bits_per_word = bits,  
    };  
  
    ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);  
    if (ret < 1)  
        pabort("can't send spi message");  
    printf("read:\r\n ");
    for (ret = 0; ret < size; ret++) {
printf("%.2X ", rx[ret]);
}
printf("\r\n ");
}  
  
static void send_data(int fd, uint8_t data)  
{  
    int ret;  
    uint16_t tx[1];  
    uint16_t rx[ARRAY_SIZE(tx)] = {0};  
  
    tx[0] = 0x100 | (uint16_t)data;  
  
    struct spi_ioc_transfer tr = {  
        .tx_buf = (unsigned long)tx,  
        .rx_buf = (unsigned long)rx,  
        .len = sizeof(tx),  
        .delay_usecs = delay,  
        .speed_hz = speed,  
        .bits_per_word = bits,  
    };  
  
    ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);  
    if (ret < 1)  
        pabort("can't send spi message");  
  printf("read:\r\n ");
    for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
printf("%.2X ", rx[ret]);
}
printf("\r\n ");
}  

static void print_usage(const char *prog)
{
printf("Usage: %s [-DsbdlHOLC3]\n", prog);
puts("  -D --device   device to use (default /dev/spidev1.1)\n"
    "  -s --speed    max speed (Hz)\n"
    "  -d --delay    delay (usec)\n"
    "  -b --bpw      bits per word \n"
    "  -l --loop     loopback\n"
    "  -H --cpha     clock phase\n"
    "  -O --cpol     clock polarity\n"
    "  -L --lsb      least significant bit first\n"
    "  -C --cs-high  chip select active high\n"
    "  -3 --3wire    SI/SO signals shared\n");
exit(1);
}

static void parse_opts(int argc, char *argv[])
{
while (1) {
static const struct option lopts[] = {
{ "device",  1, 0, 'D' },
{ "speed",   1, 0, 's' },
{ "delay",   1, 0, 'd' },
{ "bpw",     1, 0, 'b' },
{ "loop",    0, 0, 'l' },
{ "cpha",    0, 0, 'H' },
{ "cpol",    0, 0, 'O' },
{ "lsb",     0, 0, 'L' },
{ "cs-high", 0, 0, 'C' },
{ "3wire",   0, 0, '3' },
{ "no-cs",   0, 0, 'N' },
{ "ready",   0, 0, 'R' },
{ NULL, 0, 0, 0 },
};
int c;

c = getopt_long(argc, argv, "D:s:d:b:lHOLC3NR", lopts, NULL);

if (c == -1)
break;

switch (c) {
case 'D':
device = optarg;
break;
case 's':
speed = atoi(optarg);
break;
case 'd':
delay = atoi(optarg);
break;
case 'b':
bits = atoi(optarg);
break;
case 'l':
mode |= SPI_LOOP;
break;
case 'H':
mode |= SPI_CPHA;
break;
case 'O':
mode |= SPI_CPOL;
break;
case 'L':
mode |= SPI_LSB_FIRST;
break;
case 'C':
mode |= SPI_CS_HIGH;
break;
case '3':
mode |= SPI_3WIRE;
break;
case 'N':
mode |= SPI_NO_CS;
break;
case 'R':
mode |= SPI_READY;
break;
default:
print_usage(argv[0]);
break;
}
}
}

int main(int argc, char *argv[])
{
int ret = 0;
int fd;

parse_opts(argc, argv);

fd = open(device, O_RDWR);
if (fd < 0)
pabort("can't open device");

/*
* spi mode
*/
ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
if (ret == -1)
pabort("can't set spi mode");

ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
if (ret == -1)
pabort("can't get spi mode");

/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't set bits per word");

ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't get bits per word");

/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't set max speed hz");

ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't get max speed hz");

printf("spi mode: %d\n", mode);
printf("bits per word: %d\n", bits);
printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);

//transfer(fd);
send_cmd(fd,0x01,1);
usleep(10000);
send_cmd(fd,0x04,5);//Read display identification information (04h)
send_cmd(fd,0x09,6);//Read Display Status (09h)
send_cmd(fd,0xdc,3);//Read ID3 (DCh)
close(fd);

return ret;
}