/* RTDM header */
#include <rtdm/rtdm.h>

/* BCM283x SPI RTDM driver header */
#include "spi-bcm283x-rtdm.h"

/** Transmit buffer */
static uint8_t tx_buffer[BCM283X_SPI_BUFFER_SIZE_MAX];

/** Receive buffer */
static uint8_t rx_buffer[BCM283X_SPI_BUFFER_SIZE_MAX];

/** Handle to the bcm283x rtdm spi driver instance. */
static int device_handle = -1;

/**
 * Open and configure device
 * @return 0 in case of success, a negative value otherwise.
 */
int open_device() {

	int res;
	int value;

	/* Open device */
	res = open("/dev/rtdm/spidev0.0", O_RDWR);
	if (res < 0) {
		printf("%s: Could not open spi device, open has failed with %d (%s).", __FUNCTION__, errno, strerror(errno));
		return;
	} else {
		printf("%s: Device opened.", __FUNCTION__);
		device_handle = res;
	}

	/* Configure device */
	value = BCM283X_SPI_BIT_ORDER_MSBFIRST;
	res = ioctl(device_handle, BCM283X_SPI_SET_BIT_ORDER, &value);
	if (res < 0) {
		printf("%s: Could not configure bit order, ioctl has failed with %d (%s).", __FUNCTION__, errno, strerror(errno));
		device_handle = NULL;
		return -1;
	}
	value = BCM283X_SPI_DATA_MODE_0;
	res = ioctl(device_handle, BCM283X_SPI_SET_DATA_MODE, &value);
	if (res < 0) {
		printf("%s: Could not configure data mode, ioctl has failed with %d (%s).", __FUNCTION__, errno, strerror(errno));
		device_handle = NULL;
		return -1;
	}
	value = BCM283X_SPI_SPEED_8MHz;
	res = ioctl(device_handle, BCM283X_SPI_SET_SPEED, &value);
	if (res < 0) {
		printf("%s: Could not configure bus speed, ioctl has failed with %d (%s).", __FUNCTION__, errno, strerror(errno));
		device_handle = NULL;
		return -1;
	}
	value = BCM283X_SPI_CS_POL_LOW;
	res = ioctl(device_handle, BCM283X_SPI_SET_CS_POLARITY, &value);
	if (res < 0) {
		printf("%s: Could not configure chip select polarity, ioctl has failed with %d (%s).", __FUNCTION__, errno, strerror(errno));
		device_handle = NULL;
		return -1;
	}

	printf("%s: Device sucessfully configured.", __FUNCTION__);
	return 0;

}

int main() {

	int res;

	/* Open device */
	res = open_device();
	if (res < 0) {
		printf("%s: Could not open device, exiting.", __FUNCTION__);
		return -1;
	}

	/* Do stuff */
	while (...) {
		ssize_t size;

		/* Write from tx buffer */
		size = write(device_handle, (const void *) tx_buffer, spi_frame_size);

		/* Receive to rx buffer */
		memset(rx_buffer, 0, 1024);
		size = read(device_handle, (void *) rx_buffer, spi_frame_size);

		/* ... */
	}

}