/*
 * SPI testing utility (using spidev driver)
 *
 * Copyright (c) 2011  Critical Link LLC
 * 
 * This code is based on the software from the following:
 *
 * 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 <sys/types.h>
#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>
#include <unistd.h>


#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))

static void pabort(const char *s)
{
	perror(s);
	abort();
}

static const char *device = "/dev/spidev1.1";
static uint8_t mode;
static uint8_t bits = 8;
static uint32_t numbytes = 38;
static uint32_t speed = 500000;
static uint16_t delay;
static uint8_t loopback = 0;
static uint32_t loops = 1;
static uint8_t quiet = 0;

static int transfer(int fd)
{
	int ret, i, rv = 0;
	uint8_t tx[512];
	uint8_t rx[ARRAY_SIZE(tx)];
	struct spi_ioc_transfer tr = {
		.tx_buf = (unsigned long)tx,
		.rx_buf = (unsigned long)rx,
		.len = numbytes,
		.delay_usecs = delay,
		.speed_hz = speed,
		.bits_per_word = bits,
	};

	for (i = 0; i < ARRAY_SIZE(tx); i++)
	{
		tx[i] = i&0x0FF;
		rx[i] = ~tx[i];
	}

	ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
	if (ret == 1)
		pabort("can't send spi message");

	for (ret = 0; ret < numbytes; ret++) {
		if (loopback && (tx[ret] != rx[ret]))
		{
			rv = -1;
			break;
		}
	}

	if (!quiet || rv) 
	{
		for (ret = 0; ret < numbytes; ret++) {
			if (!(ret % 8))
				puts("");
			printf("%.2X ", rx[ret]);
		}
		puts("");
	}

	if (rv)
		printf("ERROR DETECTED IN RECEIVE STREAM\n");

	return rv;
}

static void print_usage(const char *prog)
{
	printf("Usage: %s [-DsqrbndlHOLC3]\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"
	     "  -r --repeat   number of cycles to repeat\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"
	     "  -n --numbytes number of bytes to send\n"
	     "  -q --quiet    don't display results\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' },
			{ "numbytes",1, 0, 'n' },
			{ "repeat",  1, 0, 'r' },
			{ "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' },
			{ "quiet",   0, 0, 'q' },
			{ NULL, 0, 0, 0 },
		};
		int c;

		c = getopt_long(argc, argv, "D:s:d:b:n:r:lqHOLC3NR", 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 'r':
			loops = atoi(optarg);
			if (loops <= 0) loops = 1;
			printf("running %d loops\n", loops);
			break;
		case 'n':
			numbytes = atoi(optarg);
			if (numbytes <= 0) numbytes = 38;
			if (numbytes > 512) numbytes = 512;
			break;
		case 'l':
			mode |= SPI_LOOP;
			loopback = 1;
			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;
		case 'q':
			quiet = 1;
			break;
		default:
			print_usage(argv[0]);
			break;
		}
	}
}

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

	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);

	for (i = 1; i <= loops; i++)
	{
		ret = transfer(fd);
		if (ret) {
			printf("Failed after %d cycles\n",i);
			break;
		}
		if (!(i % 10))
			printf(".");	
		if (!(i % 400))
			printf("\n");
	}

	if (!ret)
		printf("%d cycles run\n", i-1);

	close(fd);

	return ret;
}