Linux下SPI驱动的移植和应用程序的测试

Linux2.6.32下SPI驱动的移植如下图所示：

下面需要修改部分内核代码，具体操作如下：

1.  修改arch/arm/mach-s3c2440/mach-mini2440.c文件

在include头文件代码行之后增加如下代码

//spi  add by shiguang 
#include  
#include  
 
static struct spi_board_info s3c2410_spi0_board[] = { 
        [0] = { 
                 .modalias = "spidev", 
                .bus_num        = 0,  
                .chip_select        = 0, 
                .irq = IRQ_EINT9, 
                .max_speed_hz         = 500*1000, 
        }, 
}; 
 
static struct s3c2410_spi_info s3c2410_spi0_platdata = { 
        .pin_cs = S3C2410_GPG(2), 
        .num_cs = 1, 
        .bus_num = 0, 
}; 
//end add spi 

 

然后在函数__initmini2440_machine_init的开头增加下列代码

//spi add by shiguang

s3c_device_spi0.dev.platform_data=&s3c2410_spi0_platdata;

spi_register_board_info(s3c2410_spi0_board,ARRAY_SIZE(s3c2410_spi0_board));

//end spi

 

在mini2440_devices数组的最后中添加

&s3c_device_spi0,// add by shiguang

 

2.修改drivers/spi/spi_s3c24xx.c文件

在文件开头增加下列代码

//add by shiguang

#include

 

在s3c24xx_spi_initialsetup函数结尾增加下列代码

// add by shiguang

s3c2410_gpio_cfgpin(hw->pdata->pin_cs,S3C2410_GPIO_OUTPUT);

s3c2410_gpio_cfgpin(0x8B, S3C2410_GPIO_SFN2);

s3c2410_gpio_cfgpin(0x8C, S3C2410_GPIO_SFN2);

s3c2410_gpio_cfgpin(0x8D, S3C2410_GPIO_SFN2);

// end add

3. 最后重新编译内核

重启mini2440，查看/dev下的设备文件

[root@ShiGuang /]# ls /dev/spidev0.0 -l
crw-rw----    1 root     root     153,   0 Jan  1 08:00 /dev/spidev0.0
[root@ShiGuang /]# 

4. 应用程序测试

测设程序取至Linux源码包下的/home/youshan/linux-2.6.32.2/Documentation/spi/spidev_test.c ，这里我再把它贴一遍。

 /*
  * SPI testing utility (using spidev driver)
  *
  * Copyright (c) 2007  MontaVista Software, Inc.
  * Copyright (c) 2007  Anton Vorontsov
  *
  * 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
 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include

 #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 = 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 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 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);

         close(fd);

         return ret;
 }

只需将mini2440的SPI rx和tx短接就可以收到数据。结果如下图所示：

测试完毕！OVER！