Sample Apps: App to talk to spidev devices

This patch adds a sample application "spi_xfer" to talk to
 spidev devices like FPGA, IMU and CAN in the Aero platform.

This sample app is based off of the similar application "spitr"
which can be found at https://github.com/icpda/sample_apps/tree/master/spi_tools

Signed-off-by: Jayaraman, Venkat <[email protected]>

spidev-app/spi_xfer.c

@@ -0,0 +1,158 @@
+/* SPI Transfer basic application
+ *
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Author: Israel Cepeda <[email protected]>
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <linux/spi/spidev.h>
+
+#define SPIDEV "/dev/spidev%d.%d"
+
+struct spidev {
+ char node[20];
+ uint8_t mode;
+ uint8_t bits;
+ uint32_t speed;
+ int fd;
+};
+
+struct transfer {
+ int words;
+ long data;
+ int len;
+};
+
+/*
+ * Transfer function
+ */
+void transfer(struct spidev *dev, struct transfer *tr)
+{
+ struct spi_ioc_transfer iotr;
+ uint8_t *tx, *rx;
+ int ret, len = dev->bits/8 * tr->words;
+ int i;
+
+ if (len < tr->len)
+ len = tr->len;
+
+ tx = malloc(len);
+ rx = malloc(len);
+
+ if (!tx || !rx) {
+ printf("ERROR: No memory\n");
+ return;
+ }
+
+ memcpy(tx, &tr->data, tr->len);
+ memset(&tx[tr->len], 0x00, len - tr->len);
+ memset(rx, 0xff, len);
+
+ printf("TX: ");
+ for (i = 0; i < len; i++)
+ printf("0x%x ", tx[i]);
+ printf("\n");
+
+ /* prepare transfer */
+ iotr.tx_buf = (unsigned long)tx;
+ iotr.rx_buf = (unsigned long)rx;
+ iotr.len = len;
+
+ ret = ioctl(dev->fd, SPI_IOC_MESSAGE(1), &iotr);
+ if (ret < 1)
+ printf("ERROR: failed to transfer %s\n", dev->node);
+ else {
+ printf("RX: ");
+ for (i = 0; i < len; i++)
+ printf("0x%x ", rx[i]);
+ printf("\n");
+ }
+
+ free(tx);
+ free(rx);
+}
+
+/*
+ * Main function
+ */
+int main(int argc, char **argv)
+{
+ struct spidev dev;
+ struct transfer tr;
+ int bus = 0, cs = 0, words = 0, ret = 0;
+ char c, *data = 0;
+
+ while ((c = getopt(argc, argv, "b:c:w:d:")) != -1) {
+ switch (c) {
+ case 'b':
+ bus = atoi(optarg);
+ break;
+ case 'c':
+ cs = atoi(optarg);
+ break;
+ case 'd':
+ data = optarg;
+ break;
+ case 'w':
+ words = atoi(optarg);
+ break;
+ default:
+ return -1;
+ }
+ }
+
+ sprintf(dev.node, SPIDEV, bus, cs);
+
+ /* open spi device */
+ dev.fd = open(dev.node, O_RDWR);
+ if (dev.fd < 0) {
+ printf("ERROR: failed to open %s\n", dev.node);
+ ret = -errno;
+ return ret;
+ }
+
+ /* spi mode */
+ ret = ioctl(dev.fd, SPI_IOC_RD_MODE, &dev.mode);
+ if (ret == -1)
+ printf("ERROR: faild to get mode %s\n", dev.node);
+
+ /* bits per word */
+ ret = ioctl(dev.fd, SPI_IOC_RD_BITS_PER_WORD, &dev.bits);
+ if (ret == -1)
+ printf("ERROR: faild to get bits per word %s\n", dev.node);
+
+ /* max speed hz */
+ ret = ioctl(dev.fd, SPI_IOC_RD_MAX_SPEED_HZ, &dev.speed);
+ if (ret == -1)
+ printf("ERROR: faild to get max speed hz %s\n", dev.node);
+
+ /* spi device info */
+ printf("spi mode: %d\n", dev.mode);
+ printf("bits per word: %d\n", dev.bits);
+ printf("max speed: %d Hz\n", dev.speed);
+
+ if (data) {
+ tr.words = words > 0 ? words : 1;
+ tr.data = strtol(data, NULL, 16);
+ tr.len = strlen(data) / (2 * dev.bits / 8);
+ transfer(&dev, &tr);
+ } else
+ printf("ERROR: No data specified\n");
+
+ /* close spi device */
+ close(dev.fd);
+
+ return ret;
+}