This is an old revision of the document!
SPI
This page introduces how you can use SPI interface using Expansion Board.
Reading the SPI Flash device ID on Expansion-Board
To use spidev on your ODROID-XU3 you should fix device tree source.
To use the SPI, you first need to update the kernel version to “3.10.82” or higher.
sudo apt-get update && sudo apt-get dist-upgrade
SPI MODE 3 doesn't work by unknown reason. Please try to use the SPI MODE 0.
How to fix device tree blob with command line
Install device tree compiler package.
sudo apt-get install device-tree-compiler
Edit dtb file.
sudo -s fdtput -t x /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000 samsung,spi-src-clk 0 fdtput -t x /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000 num-cs 0 fdtput -c /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev fdtput -t s /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev compatible "spidev" fdtput -t x /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev reg 0 fdtput -t i /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev spi-max-frequency 20000000 fdtput -c /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev/controller-data fdtput -t x /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev/controller-data cs-gpio 0x46, 0x5, 0x0 fdtput -t x /media/boot/exynos5422-odroidxu3.dtb /spi@12d30000/spidev/controller-data samsung,spi-feedback-delay 0
Reboot.
reboot
Check your SPI node.
ls /dev/spidev*
Compile & run SPI test example source code
gcc -o spidev_test spidev_test.c
odroid@odroid:~$ ./spidev_test spi mode: 0 bits per word: 8 max speed: 500000 Hz (500 KHz) 34 34 34 34
- spidev_test.c
/* * 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 <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <sys/ioctl.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 void transfer(int fd) { int ret; uint8_t tx[] = { 0xAB, 0x00, 0x00, 0x00 }; 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; tr[0].len = ARRAY_SIZE(tx); tr[0].speed_hz = speed; tr[0].bits_per_word = bits; tr[0].delay_usecs = 0; tr[0].cs_change = 0; tr[1].tx_buf = (unsigned long)tx; tr[1].rx_buf = (unsigned long)rx; tr[1].len = ARRAY_SIZE(tx); tr[1].speed_hz = speed; tr[1].bits_per_word = bits; tr[1].delay_usecs = 0; tr[1].cs_change = 0; ret = ioctl(fd, SPI_IOC_MESSAGE(2), 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(void) { int ret = 0; int fd; 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; }
If you want to use 16bit/32bit length protocol with different SPI speed on XU4, refer this c1_hardware_spidev.
