tools:iio:generic_buffer: sign-extend and shift data

Refactor process_scan() to handle signed and unsigned data, respect shifts
and the data mask for 2, 4 and 8 byte sized scan elements.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 62 insertions, 35 deletions

diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
index 419e22736c3a..4cd246426b57 100644
--- a/tools/iio/generic_buffer.c
+++ b/tools/iio/generic_buffer.c
@@ -59,33 +59,80 @@ int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
         return bytes;
 }
 
-void print2byte(int input, struct iio_channel_info *info)
+void print2byte(uint16_t input, struct iio_channel_info *info)
 {
         /* First swap if incorrect endian */
         if (info->be)
-                input = be16toh((uint16_t)input);
+                input = be16toh(input);
         else
-                input = le16toh((uint16_t)input);
+                input = le16toh(input);
 
         /*
          * Shift before conversion to avoid sign extension
          * of left aligned data
          */
         input >>= info->shift;
+        input &= info->mask;
         if (info->is_signed) {
-                int16_t val = input;
+                int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
+                              (16 - info->bits_used);
+                printf("%05f ", ((float)val + info->offset) * info->scale);
+        } else {
+                printf("%05f ", ((float)input + info->offset) * info->scale);
+        }
+}
 
-                val &= (1 << info->bits_used) - 1;
-                val = (int16_t)(val << (16 - info->bits_used)) >>
-                        (16 - info->bits_used);
-                printf("%05f ", ((float)val + info->offset)*info->scale);
+void print4byte(uint32_t input, struct iio_channel_info *info)
+{
+        /* First swap if incorrect endian */
+        if (info->be)
+                input = be32toh(input);
+        else
+                input = le32toh(input);
+
+        /*
+         * Shift before conversion to avoid sign extension
+         * of left aligned data
+         */
+        input >>= info->shift;
+        input &= info->mask;
+        if (info->is_signed) {
+                int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
+                              (32 - info->bits_used);
+                printf("%05f ", ((float)val + info->offset) * info->scale);
         } else {
-                uint16_t val = input;
+                printf("%05f ", ((float)input + info->offset) * info->scale);
+        }
+}
 
-                val &= (1 << info->bits_used) - 1;
-                printf("%05f ", ((float)val + info->offset)*info->scale);
+void print8byte(uint64_t input, struct iio_channel_info *info)
+{
+        /* First swap if incorrect endian */
+        if (info->be)
+                input = be64toh(input);
+        else
+                input = le64toh(input);
+
+        /*
+         * Shift before conversion to avoid sign extension
+         * of left aligned data
+         */
+        input >>= info->shift;
+        input &= info->mask;
+        if (info->is_signed) {
+                int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
+                              (64 - info->bits_used);
+                /* special case for timestamp */
+                if (info->scale == 1.0f && info->offset == 0.0f)
+                        printf("%" PRId64 " ", val);
+                else
+                        printf("%05f ",
+                               ((float)val + info->offset) * info->scale);
+        } else {
+                printf("%05f ", ((float)input + info->offset) * info->scale);
         }
 }
+
 /**
  * process_scan() - print out the values in SI units
  * @data:               pointer to the start of the scan
@@ -108,32 +155,12 @@ void process_scan(char *data,
                                    &channels[k]);
                         break;
                 case 4:
-                        if (!channels[k].is_signed) {
-                                uint32_t val = *(uint32_t *)
-                                        (data + channels[k].location);
-                                printf("%05f ", ((float)val +
-                                                 channels[k].offset)*
-                                       channels[k].scale);
-
-                        }
+                        print4byte(*(uint32_t *)(data + channels[k].location),
+                                   &channels[k]);
                         break;
                 case 8:
-                        if (channels[k].is_signed) {
-                                int64_t val = *(int64_t *)
-                                        (data +
-                                         channels[k].location);
-                                if ((val >> channels[k].bits_used) & 1)
-                                        val = (val & channels[k].mask) |
-                                                ~channels[k].mask;
-                                /* special case for timestamp */
-                                if (channels[k].scale == 1.0f &&
-                                    channels[k].offset == 0.0f)
-                                        printf("%" PRId64 " ", val);
-                                else
-                                        printf("%05f ", ((float)val +
-                                                         channels[k].offset)*
-                                               channels[k].scale);
-                        }
+                        print8byte(*(uint64_t *)(data + channels[k].location),
+                                   &channels[k]);
                         break;
                 default:
                         break;