spi: implemented write functions

Still basic, more work needed

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>

src/spi/spi.c

@@ -23,13 +23,39 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <linux/spi/spidev.h>
+#include <stdio.h>
+#include <fcntl.h>
 
 #include "spi.h"
 
+#define MAX_SIZE 64
+#define SPI_MAX_LENGTH 4096
+
 maa_spi_context*
 maa_spi_init()
 {
-    return NULL;
+    double bus = maa_check_spi();
+    if(bus < 0) {
+        fprintf(stderr, "Failed. SPI platform Error\n");
+        return NULL;
+    }
+    maa_spi_context* dev = (maa_spi_context*) malloc(sizeof(maa_spi_context));
+    memset(dev, 0, sizeof(maa_spi_context));
+
+    char path[MAX_SIZE];
+    sprintf(path, "/dev/spidev%.1f", bus);
+
+    dev->spifd = open(path, O_RDWR);
+    if (dev->spifd < 0) {
+        fprintf(stderr, "Failed opening SPI Device. bus:%s\n", path);
+        free(dev);
+        return NULL;
+    }
+
+    return dev;
 }
 
 maa_result_t
@@ -44,10 +70,47 @@ maa_spi_frequency(maa_spi_context* spi, int hz)
     return MAA_ERROR_FEATURE_NOT_IMPLEMENTED;
 }
 
-unsigned int
+uint8_t
-maa_spi_write(maa_spi_context* spi, unsigned int data)
+maa_spi_write(maa_spi_context* spi, uint8_t data)
 {
-    return 0;
+    struct spi_ioc_transfer msg;
+    memset(&msg, 0, sizeof(msg));
+
+    uint16_t length = 1;
+
+    uint8_t recv = 0;
+    msg.tx_buf = (unsigned long) &data;
+    msg.rx_buf = (unsigned long) &recv;
+    msg.speed_hz = 100000;
+    msg.bits_per_word = 8;
+    msg.delay_usecs = 0;
+    msg.len = length;
+    if(ioctl(spi->spifd, SPI_IOC_MESSAGE(1), &msg) < 0) {
+        fprintf(stderr, "Failed to perform spi transfer\n");
+        return -1;
+    }
+    return recv;
+}
+
+uint8_t*
+maa_spi_write_buf(maa_spi_context* spi, uint8_t* data, int length)
+{
+    struct spi_ioc_transfer msg;
+    memset(&msg, 0, sizeof(msg));
+
+    uint8_t* recv = malloc(sizeof(uint8_t) * length);
+
+    msg.tx_buf = (unsigned long) data;
+    msg.rx_buf = (unsigned long) recv;
+    msg.speed_hz = 100000;
+    msg.bits_per_word = 8;
+    msg.delay_usecs = 0;
+    msg.len = length;
+    if(ioctl(spi->spifd, SPI_IOC_MESSAGE(1), &msg) < 0) {
+        fprintf(stderr, "Failed to perform spi transfer\n");
+        return NULL;
+    }
+    return recv;
 }
 
 maa_result_t