在freescale mx6q平台上添加spi资源

1：配置管脚为SPI功能

在board-mx6q_sabresd.h的最后添加，复制被重定义

（以添加SPI2为例）

1. <span style="font-size:18px;">        MX6Q_PAD_EIM_CS0__ECSPI2_SCLK,
2. MX6Q_PAD_EIM_CS1__ECSPI2_MOSI,
3. MX6Q_PAD_EIM_OE__ECSPI2_MISO,
4. MX6Q_PAD_CSI0_DAT11__ECSPI2_SS0 ,
5. </span>

之后再板级文件board-mx6q_sabresd.c中将有相关函数对管脚进行统一初始化。

完成寄存器配置的工作。

1. <span style="font-size:18px;">  mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_pads,
2. ARRAY_SIZE(mx6q_sabresd_pads));
3. mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_cstm_tq_pads,\
4. ARRAY_SIZE(mx6q_sabresd_cstm_tq_pads));</span>

2：在板级文件board-mx6q_sabresd.c中添加以下代码

将匹配到driver/spi/spidev.c文件中的驱动源码

2.1完成SPI master的注册

SPI2片选管脚宏定义：

1. <span style="font-size:14px;">#define SABRESD_ECSPI2_CS0 IMX_GPIO_NR(5, 29)</span>

添加相关结构体

1. <span style="font-size:14px;">static int mx6q_marsboard_spi1_cs[] = {
2. SABRESD_ECSPI2_CS0,
3. };
4. </span>

1. <span style="font-size:14px;">static const struct spi_imx_master mx6q_sabresd_spi2_data __initconst = {
2. .chipselect = mx6q_marsboard_spi2_cs,
3. .num_chipselect = ARRAY_SIZE(mx6q_marsboard_spi1_cs),
4. };
5. </span>

2.2在spi 总线上匹配spi2的驱动文件

mx6q平台有2路spi资源，0/1,其中的bus_num则为挂载驱动的总线选择。

1. <span style="font-size:18px;"><span style="font-size:14px;">static struct mtd_partition imx6_sabrelite_spi_nor_partitions[] = {
2. {
3. .name = "bootloader",
4. .offset = 0,
5. .size = 0x00100000,
6. },
7. {
8. .name = "kernel",
9. .offset = MTDPART_OFS_APPEND,
10. .size = MTDPART_SIZ_FULL,
11. },
12. };
13. static struct flash_platform_data imx6_sabrelite__spi_flash_data = {
14. .name = "spidev",  / /匹配原则。
15. .parts = imx6_sabrelite_spi_nor_partitions,
16. .nr_parts = ARRAY_SIZE(imx6_sabrelite_spi_nor_partitions),
17. .type = "sst25vf016b",
18. };
19. static struct spi_board_info imx6_sabrelite_spi_nor_device[] __initdata = {
20. {
21. .modalias = "spidev",
22. .max_speed_hz = 20000000, /* max spi clock (SCK) speed in HZ */
23. .bus_num = 1,    //设备挂载第几号spi总线上
24. .chip_select = 0,
25. .platform_data = &imx6_sabrelite__spi_flash_data,
26. },
27. };
28. spi_register_board_info(imx6_sabrelite_spi_nor_device,
29. ARRAY_SIZE(imx6_sabrelite_spi_nor_device));
30. imx6q_add_ecspi(0, &mx6q_sabrelite_spi2_data);
31. </span>
32. </span>

3：内核配置

查看spidev.c文件目录下的Kconfig以及Makefile得知内核驱动的添加方法

选择蓝色部分选项，将spidev.c文件添加到内核中。

4：查看开发板/sys/bus/spi/drivers/spidev目录

在/dev下生成设备文件/dev/spidev1.0

5:使用freescale官方的bsp包中的spi测试程序对接口进行测试

1. <span style="font-size:12px;">/*
2. * SPI testing utility (using spidev driver)
3. *
4. * Copyright (c) 2007  MontaVista Software, Inc.
5. * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
6. *
7. * This program is free software; you can redistribute it and/or modify
8. * it under the terms of the GNU General Public License as published by
9. * the Free Software Foundation; either version 2 of the License.
10. *
11. * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
12. */
13. #include <stdint.h>
14. #include <unistd.h>
15. #include <stdio.h>
16. #include <stdlib.h>
17. #include <getopt.h>
18. #include <fcntl.h>
19. #include <sys/ioctl.h>
20. #include <linux/types.h>
21. #include <linux/spi/spidev.h>
22. #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
23. static void pabort(const char *s)
24. {
25. perror(s);
26. abort();
27. }
28. static const char *device = "/dev/spidev1.0";
29. static uint8_t mode;
30. static uint8_t bits = 8;
31. static uint32_t speed = 500000;
32. static uint16_t delay;
33. static void transfer(int fd)
34. {
35. int ret;
36. uint8_t tx[] = {
37. 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
38. 0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
39. 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
40. 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
41. 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
42. 0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD,
43. 0xF0, 0x0D,
44. };
45. uint8_t rx[ARRAY_SIZE(tx)] = {0, };
46. struct spi_ioc_transfer tr = {
47. .tx_buf = (unsigned long)tx,
48. .rx_buf = (unsigned long)rx,
49. .len = ARRAY_SIZE(tx),
50. .delay_usecs = delay,
51. .speed_hz = speed,
52. .bits_per_word = bits,
53. };
54. ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
55. if (ret < 1)
56. pabort("can't send spi message");
57. for (ret = 0; ret < ARRAY_SIZE(tx); ret++) {
58. if (!(ret % 6))
59. puts("");
60. printf("%.2X ", rx[ret]);
61. }
62. puts("");
63. }
64. int main(int argc, char *argv[])
65. {
66. int ret = 0;
67. int fd;
68. //parse_opts(argc, argv); /* for what ,unknow*/
69. fd = open(device, O_RDWR);
70. if (fd < 0)
71. pabort("can't open device");
72. /*
73. * spi mode
74. */
75. ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
76. if (ret == -1)
77. pabort("can't set spi mode");
78. ret = ioctl(fd, SPI_IOC_RD_MODE, &mode);
79. if (ret == -1)
80. pabort("can't get spi mode");
81. /*
82. * bits per word
83. */
84. ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
85. if (ret == -1)
86. pabort("can't set bits per word");
87. ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
88. if (ret == -1)
89. pabort("can't get bits per word");
90. /*
91. * max speed hz
92. */
93. ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
94. if (ret == -1)
95. pabort("can't set max speed hz");
96. ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
97. if (ret == -1)
98. pabort("can't get max speed hz");
99. printf("spi mode: %d\n", mode);
100. printf("bits per word: %d\n", bits);
101. printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
102. transfer(fd);
103. close(fd);
104. return ret;
105. }
106. </span>

执行应用程序，可以看到时序模式（spi 4种时序模式第0种），时钟频率等参数。

    /*
8     * SPI testing utility (using spidev driver)
9     *
10     * Copyright (c) 2007  MontaVista Software, Inc.
11     * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
12     *
13     * This program is free software; you can redistribute it and/or modify
14     * it under the terms of the GNU General Public License as published by
15     * the Free Software Foundation; either version 2 of the License.
16     *
17     * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
18     */

    #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/spidev1.0";
    static uint8_t mode;
    static uint8_t bits = ;
    static uint32_t speed = ;
    static uint16_t delay=;

    static void transfer(int fd)
    {
        int ret;
        uint8_t tx[] = {
            0x11, 0x12, 0x18, 0x78, 0x24, 0xa2,
            0x40, 0x00, 0x13, 0x00, 0x00, 0x95,
            0x23, 0x56, 0x54, 0x34, 0x45, 0x65,
            0x69, 0x78, 0x98, 0xFF, 0xFF, 0x36,
        };
        uint8_t rx[ARRAY_SIZE(tx)] = {, };
        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,
            .cs_change=
        };

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

        for (ret = ; ret < ARRAY_SIZE(tx); ret++) {
            if (!(ret % ))
                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/spidev1.0)\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();
    }

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

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

            if (c == -)
                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 '':
                mode |= SPI_3WIRE;
                break;
            case 'N':
                mode |= SPI_NO_CS;
                break;
            case 'R':
                mode |= SPI_READY;
                break;
            default:
                print_usage(argv[]);
                break;
            }
        }
    }

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

        parse_opts(argc, argv);

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

        /*
173         * spi mode
174         */
        ret = ioctl(fd, SPI_IOC_WR_MODE, &mode);
        if (ret == -)
            pabort("can't set spi mode");

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

        /*
184         * bits per word
185         */
        ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
        if (ret == -)
            pabort("can't set bits per word");

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

        /*
195         * max speed hz
196         */
        ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
        if (ret == -)
            pabort("can't set max speed hz");

        ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
        if (ret == -)
            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/);

        transfer(fd);

        close(fd);

        return ret;
    }