正文
在freescale mx6q平台上添加spi资源
小程序：扫一扫查出行【扫一扫了解最新限行尾号】
复制小程序
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 <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/spidev1.0";
- 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。
/*
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;
}
