Linux 2.6.23下SPI设备模型--------基于AT91RM9200分析

1、内核版本：LINUX2.6.23

 

在内核艮目录下：make menuconfig后，进入driver->spi supprot目录下，配置如下

 

 

在character devices-->下，取消

   既可以

 

2、修改文件arch/arm/mach-at91/board-dk.c 中：

 

static struct spi_board_info dk_spi_devices[] = {
 { /* DataFlash chip */
 // .modalias = "mtd_dataflash",
  .modalias = "spidev",
  .chip_select = 0,
  .max_speed_hz = 15 * 1000 * 1000,
 },

 { /* UR6HCPS2-SP40 PS2-to-SPI adapter */
  .modalias = "ur6hcps2",   //修改成.modalias = "spidev",即可添加一个设备节点
  .chip_select = 1,
  .max_speed_hz = 250 *  1000,
 },
 { /* TLV1504 ADC, 4 channels, 10 bits; one is a temp sensor */
  .modalias = "tlv1504",//修改成.modalias = "spidev",即可添加一个设备节点
  .chip_select = 2,
  .max_speed_hz = 20 * 1000 * 1000,
 },
#ifdef CONFIG_MTD_AT91_DATAFLASH_CARD
 { /* DataFlash card */
  .modalias = "mtd_dataflash",//修改成.modalias = "spidev",即可添加一个设备节点
  .chip_select = 3,
  .max_speed_hz = 15 * 1000 * 1000,
 }
#endif
};

 

3、修改好后，即可编译：make zImage;make uImage

生成的内核down到flash后，即可发现在/dev下生产了设备节点spidev

 

4、测试代码

 

/*
 * 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>
#include <math.h>

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

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

//static char *device = "/dev/spidev1.1";
//static char *device = "/dev/spidev0.1"; //chip_select = 1 46 pio
static char *device = "/dev/spidev0.2";  //chip_select = 2  47 pio
//static char *device = "/dev/spidev0.3"; //chip_select = 3  48 pio
static uint8_t mode;
static uint8_t bits = 8;
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,
 };*/
 uint8_t tx[] = {
  0xaa, 0xaa, 0xaa, 0xaa
  //0x55,0x55,0x55,0x55
  };
 uint8_t rx[ARRAY_SIZE(tx)] = {0, };
 //struct spi_ioc_transfer tr[2]; 
 //tr[0].tx_buf = (unsigned long)tx;
 //tr[0].rx_buf = (unsigned long)rx;
 
 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("");
}

void print_usage(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);
}

void parse_opts(int argc, char *argv[])
{
 while (1) {
  static 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' },
   { NULL, 0, 0, 0 },
  };
  int c;

  c = getopt_long(argc, argv, "D:s:d:b:lHOLC3", 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;
  default:
   print_usage(argv[0]);
   break;
  }
 }
}

int main(int argc, char *argv[])
{
 int ret = 0;
 int fd;
 unsigned char test_write[4] = {0};
 unsigned char test_read[4] = {0};
 //unsigned char buf1, buf2, buf3, buf4;
 uint8_t buf1[2], buf2[2], buf3[2], buf4[2];
 int a1, a2, a3, a4, i, j;
 
 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);

 printf("Please Input(xx xx xx xx): ");
 //scanf("%s %s %s %s", &buf1, &buf2, &buf3, &buf4 );
 scanf("%s %s %s %s", buf1, buf2, buf3, buf4 );
 a1 = StrToHex(buf1);
 a2 = StrToHex(buf2);
 a3 = StrToHex(buf3);
 a4 = StrToHex(buf4);
 //printf("------------a1 = %x a2 = %x a2 = %x a2 = %x/n", a1, a2, a3, a4);
 test_write[0] = a1;
 test_write[1] = a2;
 test_write[2] = a3;
 test_write[3] = a4;
 //printf("buf1 = %x buf2 = %x buf3 = %x buf4 = %x/n", buf1, buf2, buf3, buf4);
 
 while(1)
 {
  write(fd, test_write, sizeof(test_write));
  read(fd, test_read, sizeof(test_read));
  
  for(j = 0; j < sizeof(test_read); j++)
  {
   printf("test_write[%d] = %x    ", j, test_write[j]);
   
   printf("test_read[%d] = %x", j, test_read[j]);
   printf("/n");
  }
  //transfer(fd);
 }
 close(fd);
 return ret;
}

 

int StrToHex( char *p )
{
 int i, sum;
 int temp, length;
 char c;
 sum = 0;
 length = strlen( p );
 for( i = 0; i < length ; i++ )
 {
  // Modify in 2010-09-19 by Lijun Hua, 讲字母转化成16进制数
  c = *p;
  if( c >= 'a' && c <= 'z')
  {
   temp = c - 87;
   sum += (temp)* ( pow(16, (length - i - 1)) );
  }
  else if( c >= 'A' && c <= 'Z')
  {
   temp = c - 55;
   sum += (temp)* ( pow(16, (length - i - 1)) );
  }
  else
  {
   temp = c - 48;
   sum = sum + ( temp ) * pow(16, ( length - i - 1 ) ); //double pow(double x, double y);x 的 y 次方 xy
  }

  p = p + 1;
 }
 return sum;
}