Staging: iio: Added define guards where needed

The following files were added define guards to prevent multiple
inclusion.
Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/Documentation/iio_utils.h

@@ -6,6 +6,8 @@
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */
+#ifndef _IIO_UTILS_H
+#define _IIO_UTILS_H
 
 #include <string.h>
 #include <stdlib.h>
@@ -681,3 +683,5 @@ int read_sysfs_string(const char *filename, const char *basedir, char *str)
 	free(temp);
 	return ret;
 }
+
+#endif /* _IIO_UTILS_H */

drivers/staging/iio/accel/sca3000.h

@@ -38,6 +38,9 @@
  * Can probably alleviate this by reading the interrupt register on start, but
  * that is really just brushing the problem under the carpet.
  */
+#ifndef _SCA3000
+#define _SCA3000
+
 #define SCA3000_WRITE_REG(a) (((a) << 2) | 0x02)
 #define SCA3000_READ_REG(a) ((a) << 2)
 
@@ -272,4 +275,4 @@ static inline void sca3000_ring_int_process(u8 val, void *ring)
 }
 
 #endif
-
+#endif /* _SCA3000 */

drivers/staging/iio/frequency/dds.h

@@ -5,6 +5,8 @@
  *
  * Licensed under the GPL-2 or later.
  */
+#ifndef IIO_DDS_H_
+#define IIO_DDS_H_
 
 /**
  * /sys/bus/iio/devices/.../out_altvoltageX_frequencyY
@@ -108,3 +110,5 @@
 #define IIO_CONST_ATTR_OUT_WAVETYPES_AVAILABLE(_channel, _output, _modes)\
 	IIO_CONST_ATTR(							\
 	out_altvoltage##_channel##_out##_output##_wavetype_available, _modes)
+
+#endif /* IIO_DDS_H_ */

drivers/staging/iio/meter/meter.h

+#ifndef _METER_H
+#define _METER_H
+
 #include <linux/iio/sysfs.h>
 
 /* metering ic types of attribute */
@@ -394,3 +397,4 @@
 #define IIO_EVENT_ATTR_VPKLVL_EXC(_evlist, _show, _store, _mask) \
 	IIO_EVENT_ATTR_SH(vpklvl_exc, _evlist, _show, _store, _mask)
 
+#endif /* _METER_H */

drivers/staging/iio/resolver/ad2s1210.h

@@ -8,6 +8,8 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#ifndef _AD2S1210_H
+#define _AD2S1210_H
 
 struct ad2s1210_platform_data {
 	unsigned sample;
@@ -15,3 +17,4 @@ struct ad2s1210_platform_data {
 	unsigned res[2];
 	bool gpioin;
 };
+#endif /* _AD2S1210_H */