tools:iio:iio_utils: pass strings as const

Mark strings, which are not supposed to be changed (basedir, filename,
value), as const in function parameters.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index dfee1a3..ec9ab7f 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -634,7 +634,8 @@
 	return ret;
 }
 
-static int _write_sysfs_int(char *filename, char *basedir, int val, int verify)
+static int _write_sysfs_int(const char *filename, const char *basedir, int val,
+			    int verify)
 {
 	int ret = 0;
 	FILE *sysfsfp;
@@ -707,7 +708,7 @@
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int write_sysfs_int(char *filename, char *basedir, int val)
+int write_sysfs_int(const char *filename, const char *basedir, int val)
 {
 	return _write_sysfs_int(filename, basedir, val, 0);
 }
@@ -721,13 +722,14 @@
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int write_sysfs_int_and_verify(char *filename, char *basedir, int val)
+int write_sysfs_int_and_verify(const char *filename, const char *basedir,
+			       int val)
 {
 	return _write_sysfs_int(filename, basedir, val, 1);
 }
 
-static int _write_sysfs_string(char *filename, char *basedir, char *val,
-			       int verify)
+static int _write_sysfs_string(const char *filename, const char *basedir,
+			       const char *val, int verify)
 {
 	int ret = 0;
 	FILE  *sysfsfp;
@@ -805,7 +807,8 @@
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int write_sysfs_string_and_verify(char *filename, char *basedir, char *val)
+int write_sysfs_string_and_verify(const char *filename, const char *basedir,
+				  const char *val)
 {
 	return _write_sysfs_string(filename, basedir, val, 1);
 }
@@ -818,7 +821,8 @@
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int write_sysfs_string(char *filename, char *basedir, char *val)
+int write_sysfs_string(const char *filename, const char *basedir,
+		       const char *val)
 {
 	return _write_sysfs_string(filename, basedir, val, 0);
 }
@@ -831,7 +835,7 @@
  * Returns the read integer value >= 0 on success, otherwise a negative error
  * code.
  **/
-int read_sysfs_posint(char *filename, char *basedir)
+int read_sysfs_posint(const char *filename, const char *basedir)
 {
 	int ret;
 	FILE  *sysfsfp;
@@ -875,7 +879,7 @@
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-int read_sysfs_float(char *filename, char *basedir, float *val)
+int read_sysfs_float(const char *filename, const char *basedir, float *val)
 {
 	int ret = 0;
 	FILE  *sysfsfp;
diff --git a/tools/iio/iio_utils.h b/tools/iio/iio_utils.h
index e5eb46a..379eed9 100644
--- a/tools/iio/iio_utils.h
+++ b/tools/iio/iio_utils.h
@@ -63,12 +63,15 @@
 int build_channel_array(const char *device_dir,
 						struct iio_channel_info **ci_array, int *counter);
 int find_type_by_name(const char *name, const char *type);
-int write_sysfs_int(char *filename, char *basedir, int val);
-int write_sysfs_int_and_verify(char *filename, char *basedir, int val);
-int write_sysfs_string_and_verify(char *filename, char *basedir, char *val);
-int write_sysfs_string(char *filename, char *basedir, char *val);
-int read_sysfs_posint(char *filename, char *basedir);
-int read_sysfs_float(char *filename, char *basedir, float *val);
+int write_sysfs_int(const char *filename, const char *basedir, int val);
+int write_sysfs_int_and_verify(const char *filename, const char *basedir,
+			       int val);
+int write_sysfs_string_and_verify(const char *filename, const char *basedir,
+				  const char *val);
+int write_sysfs_string(const char *filename, const char *basedir,
+		       const char *val);
+int read_sysfs_posint(const char *filename, const char *basedir);
+int read_sysfs_float(const char *filename, const char *basedir, float *val);
 int read_sysfs_string(const char *filename, const char *basedir, char *str);
 
 #endif /* _IIO_UTILS_H_ */