Added I2C read/write support, on cape bus for now

1 files changed, 53 insertions, 0 deletions

diff --git a/i2c.c b/i2c.c
new file mode 100644
index 0000000..02e5812
--- /dev/null
+++ b/i2c.c
@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+
+
+#define I2C_BUS "/dev/i2c-3"
+
+
+int I2C_Write(int address, int value) {
+
+	struct i2c_smbus_ioctl_data argswrite;
+
+        argswrite.read_write = I2C_SMBUS_WRITE;
+        argswrite.size = I2C_SMBUS_BYTE;
+        argswrite.data = NULL;		
+	argswrite.command = value;
+
+	int device = open(I2C_BUS, O_RDWR);
+
+	if (device == -1) return device;
+
+	ioctl(device, I2C_SLAVE, address);
+	ioctl(device, I2C_SMBUS, &argswrite);	
+
+	close(device);
+}
+
+
+int I2C_Read(int address) {
+
+	union i2c_smbus_data data;
+        struct i2c_smbus_ioctl_data argsread;
+        
+        argsread.read_write = I2C_SMBUS_READ;
+        argsread.size = I2C_SMBUS_BYTE;
+        argsread.data = &data;
+        argsread.command = 0;
+
+        int device = open(I2C_BUS, O_RDWR);
+
+        if (device == -1) return device;
+
+        ioctl(device, I2C_SLAVE, address);
+        ioctl(device, I2C_SMBUS, &argsread);              
+
+        close(device);
+
+	return data.byte;
+}
+