freescale spi driver

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）

       

 <span style="font-size:18px;">        MX6Q_PAD_EIM_CS0__ECSPI2_SCLK,
         MX6Q_PAD_EIM_CS1__ECSPI2_MOSI,
         MX6Q_PAD_EIM_OE__ECSPI2_MISO,
         MX6Q_PAD_CSI0_DAT11__ECSPI2_SS0 ,
 </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。

 <span style="font-size:18px;">  mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_pads,
         ARRAY_SIZE(mx6q_sabresd_pads));

     mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_cstm_tq_pads,\
         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：

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

添加相关结构体

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

 

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

 <span style="font-size:18px;"><span style="font-size:14px;">static struct mtd_partition imx6_sabrelite_spi_nor_partitions[] = {
  {
   .name = "bootloader",
   .offset = 0,
   .size = 0x00100000,
  },
  {
   .name = "kernel",
   .offset = MTDPART_OFS_APPEND,
   .size = MTDPART_SIZ_FULL,
  },
 };


 static struct flash_platform_data imx6_sabrelite__spi_flash_data = {
  .name = "spidev",  / /匹配原则。
  .parts = imx6_sabrelite_spi_nor_partitions,
  .nr_parts = ARRAY_SIZE(imx6_sabrelite_spi_nor_partitions),
  .type = "sst25vf016b",
 };




 static struct spi_board_info imx6_sabrelite_spi_nor_device[] __initdata = {
  {
   .modalias = "spidev",
   .max_speed_hz = 20000000, /* max spi clock (SCK) speed in HZ */
   .bus_num = 1,    //设备挂载第几号spi总线上
   .chip_select = 0,
   .platform_data = &imx6_sabrelite__spi_flash_data,
  },
 };


 spi_register_board_info(imx6_sabrelite_spi_nor_device,
 ARRAY_SIZE(imx6_sabrelite_spi_nor_device));

 imx6q_add_ecspi(0, &mx6q_sabrelite_spi2_data);






 </span>
 </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

 <span style="font-size:12px;">/*
  * SPI testing utility (using spidev driver)
  *
  * Copyright (c) 2007  MontaVista Software, Inc.
  * Copyright (c) 2007  Anton Vorontsov <[email protected]>
  *
  * 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/spidev1.0";
 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("");
 }


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

     //parse_opts(argc, argv); /* for what ,unknow*/

     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;
 }
 </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。

 短路则与输入一致