[PATCH v9 3/6] iio: tools: Add support for floating-point types in buffer scan elements

[Francesco Lavra <flavra@baylibre.com>]

A subsequent commit will add floating-point support to the ABI; enhance
the iio_generic_buffer tool to be able to parse this new data format.

Signed-off-by: Francesco Lavra <flavra@baylibre.com>
---
 tools/iio/iio_generic_buffer.c | 70 ++++++++++++++++++++++++++++++----
 tools/iio/iio_utils.c          | 12 +++---
 tools/iio/iio_utils.h          |  4 +-
 3 files changed, 70 insertions(+), 16 deletions(-)

diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c
index bc82bb6a7a2a..000193612aad 100644
--- a/tools/iio/iio_generic_buffer.c
+++ b/tools/iio/iio_generic_buffer.c
@@ -26,6 +26,7 @@
 #include <string.h>
 #include <poll.h>
 #include <endian.h>
+#include <float.h>
 #include <getopt.h>
 #include <inttypes.h>
 #include <stdbool.h>
@@ -89,12 +90,19 @@ static void print1byte(uint8_t input, struct iio_channel_info *info)
 	 */
 	input >>= info->shift;
 	input &= info->mask;
-	if (info->is_signed) {
+	switch (info->format) {
+	case 's': {
 		int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
 			     (8 - info->bits_used);
 		printf("%05f ", ((float)val + info->offset) * info->scale);
-	} else {
+		break;
+	}
+	case 'u':
 		printf("%05f ", ((float)input + info->offset) * info->scale);
+		break;
+	case 'f':
+		printf("<invalid 1-byte float> ");
+		break;
 	}
 }
 
@@ -112,12 +120,30 @@ static void print2byte(uint16_t input, struct iio_channel_info *info)
 	 */
 	input >>= info->shift;
 	input &= info->mask;
-	if (info->is_signed) {
+	switch (info->format) {
+	case 's': {
 		int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
 			      (16 - info->bits_used);
 		printf("%05f ", ((float)val + info->offset) * info->scale);
-	} else {
+		break;
+	}
+	case 'u':
 		printf("%05f ", ((float)input + info->offset) * info->scale);
+		break;
+	case 'f': {
+#if defined(__FLT16_MAX__)
+		union {
+			uint16_t u;
+			_Float16 f;
+		} converter;
+
+		converter.u = input;
+		printf("%05f ", ((float)converter.f + info->offset) * info->scale);
+#else
+		printf("<unsupported 2-byte float> ");
+#endif
+		break;
+	}
 	}
 }
 
@@ -135,12 +161,26 @@ static void print4byte(uint32_t input, struct iio_channel_info *info)
 	 */
 	input >>= info->shift;
 	input &= info->mask;
-	if (info->is_signed) {
+	switch (info->format) {
+	case 's': {
 		int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
 			      (32 - info->bits_used);
 		printf("%05f ", ((float)val + info->offset) * info->scale);
-	} else {
+		break;
+	}
+	case 'u':
 		printf("%05f ", ((float)input + info->offset) * info->scale);
+		break;
+	case 'f': {
+		union {
+			uint32_t u;
+			float f;
+		} converter;
+
+		converter.u = input;
+		printf("%05f ", (converter.f + info->offset) * info->scale);
+		break;
+	}
 	}
 }
 
@@ -158,7 +198,8 @@ static void print8byte(uint64_t input, struct iio_channel_info *info)
 	 */
 	input >>= info->shift;
 	input &= info->mask;
-	if (info->is_signed) {
+	switch (info->format) {
+	case 's': {
 		int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
 			      (64 - info->bits_used);
 		/* special case for timestamp */
@@ -167,8 +208,21 @@ static void print8byte(uint64_t input, struct iio_channel_info *info)
 		else
 			printf("%05f ",
 			       ((float)val + info->offset) * info->scale);
-	} else {
+		break;
+	}
+	case 'u':
 		printf("%05f ", ((float)input + info->offset) * info->scale);
+		break;
+	case 'f': {
+		union {
+			uint64_t u;
+			double f;
+		} converter;
+
+		converter.u = input;
+		printf("%05f ", (converter.f + info->offset) * info->scale);
+		break;
+	}
 	}
 }
 
diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
index c5c5082cb24e..e274a0d8376b 100644
--- a/tools/iio/iio_utils.c
+++ b/tools/iio/iio_utils.c
@@ -70,7 +70,7 @@ int iioutils_break_up_name(const char *full_name, char **generic_name)
 
 /**
  * iioutils_get_type() - find and process _type attribute data
- * @is_signed: output whether channel is signed
+ * @format: output channel format
  * @bytes: output how many bytes the channel storage occupies
  * @bits_used: output number of valid bits of data
  * @shift: output amount of bits to shift right data before applying bit mask
@@ -83,7 +83,7 @@ int iioutils_break_up_name(const char *full_name, char **generic_name)
  *
  * Returns a value >= 0 on success, otherwise a negative error code.
  **/
-static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
+static int iioutils_get_type(char *format, unsigned int *bytes,
 			     unsigned int *bits_used, unsigned int *shift,
 			     uint64_t *mask, unsigned int *be,
 			     const char *device_dir, int buffer_idx,
@@ -93,7 +93,7 @@ static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
 	int ret;
 	DIR *dp;
 	char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
-	char signchar, endianchar;
+	char formatchar, endianchar;
 	unsigned padint;
 	const struct dirent *ent;
 
@@ -140,7 +140,7 @@ static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
 			ret = fscanf(sysfsfp,
 				     "%ce:%c%u/%u>>%u",
 				     &endianchar,
-				     &signchar,
+				     &formatchar,
 				     bits_used,
 				     &padint, shift);
 			if (ret < 0) {
@@ -162,7 +162,7 @@ static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
 			else
 				*mask = (1ULL << *bits_used) - 1ULL;
 
-			*is_signed = (signchar == 's');
+			*format = formatchar;
 			if (fclose(sysfsfp)) {
 				ret = -errno;
 				fprintf(stderr, "Failed to close %s\n",
@@ -487,7 +487,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
 			if ((ret < 0) && (ret != -ENOENT))
 				goto error_cleanup_array;
 
-			ret = iioutils_get_type(&current->is_signed,
+			ret = iioutils_get_type(&current->format,
 						&current->bytes,
 						&current->bits_used,
 						&current->shift,
diff --git a/tools/iio/iio_utils.h b/tools/iio/iio_utils.h
index 663c94a6c705..8c72f002d050 100644
--- a/tools/iio/iio_utils.h
+++ b/tools/iio/iio_utils.h
@@ -32,7 +32,7 @@ extern const char *iio_dir;
  * @shift: amount of bits to shift right data before applying bit mask
  * @mask: a bit mask for the raw output
  * @be: flag if data is big endian
- * @is_signed: is the raw value stored signed
+ * @format: format of the raw value
  * @location: data offset for this channel inside the buffer (in bytes)
  **/
 struct iio_channel_info {
@@ -46,7 +46,7 @@ struct iio_channel_info {
 	unsigned shift;
 	uint64_t mask;
 	unsigned be;
-	unsigned is_signed;
+	char format;
 	unsigned location;
 };
 
-- 
2.39.5