Re: [Patch v5 3/6] IIO: core: Modify scan element type

[Jonathan Cameron]

On April 14, 2014 11:33:12 PM GMT+01:00, Peter Meerwald  
wrote:
>> The current scan element type uses the following format:
>>   [be|le]:[s|u]bits/storagebits[>>shift].
>> To specify multiple elements in this type, added a repeat value.
>> So new format is:
>>   [be|le]:[s|u]bits/storagebits{X[repeat]}[>>shift].
>> Here X is specifying how may times, real/storage bits are repeating.
>> 
>> When X is value is 0 or 1, then repeat value is not used in the
>format,
>> and it will be same as existing format.
>
>minor comments inline
>
>> ---
>>  drivers/iio/industrialio-buffer.c | 41
>+--
>>  include/linux/iio/iio.h   |  9 +
>>  2 files changed, 44 insertions(+), 6 deletions(-)
>> 
>> diff --git a/drivers/iio/industrialio-buffer.c
>b/drivers/iio/industrialio-buffer.c
>> index e108f2a..aa90c68 100644
>> --- a/drivers/iio/industrialio-buffer.c
>> +++ b/drivers/iio/industrialio-buffer.c
>> @@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device
>*dev,
>>  type = IIO_BE;
>>  #endif
>>  }
>> -return sprintf(buf, "%s:%c%d/%d>>%u\n",
>> +if (this_attr->c->scan_type.repeat > 1)
>> +return sprintf(buf, "%s:%c%d/%d{%d[repeat]}>>%u\n",
>> +   iio_endian_prefix[type],
>> +   this_attr->c->scan_type.sign,
>> +   this_attr->c->scan_type.realbits,
>> +   this_attr->c->scan_type.storagebits,
>> +   this_attr->c->scan_type.repeat,
>> +   this_attr->c->scan_type.shift);
>> +else
>> +return sprintf(buf, "%s:%c%d/%d>>%u\n",
>> iio_endian_prefix[type],
>> this_attr->c->scan_type.sign,
>> this_attr->c->scan_type.realbits,
>> @@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct
>iio_dev *indio_dev,
>>  for_each_set_bit(i, mask,
>>   indio_dev->masklength) {
>>  ch = iio_find_channel_from_si(indio_dev, i);
>> -length = ch->scan_type.storagebits / 8;
>> +if (ch->scan_type.repeat > 1)
>> +length = ch->scan_type.storagebits / 8 *
>> +ch->scan_type.repeat;
>
>so storagebits should be a multiple of 8 and != 0;
>we cannot have repeated groups of say 4 bits

Indeed not. Having unaligned data would probably prove more painful than using 
more
 memory... Real requirements will be stricter as power of 2 multiples of bytes 
only.
This is in theory the plan for all buffer elements..
>
>> +else
>> +length = ch->scan_type.storagebits / 8;
>>  bytes = ALIGN(bytes, length);
>>  bytes += length;
>>  }
>>  if (timestamp) {
>>  ch = iio_find_channel_from_si(indio_dev,
>>indio_dev->scan_index_timestamp);
>> -length = ch->scan_type.storagebits / 8;
>> +if (ch->scan_type.repeat > 1)
>> +length = ch->scan_type.storagebits / 8 *
>> +ch->scan_type.repeat;
>> +else
>> +length = ch->scan_type.storagebits / 8;
>>  bytes = ALIGN(bytes, length);
>>  bytes += length;
>>  }
>> @@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct
>iio_dev *indio_dev,
>> indio_dev->masklength,
>> in_ind + 1);
>>  ch = iio_find_channel_from_si(indio_dev, in_ind);
>> -length = ch->scan_type.storagebits/8;
>> +if (ch->scan_type.repeat > 1)
>> +length = ch->scan_type.storagebits / 8 *
>> +ch->scan_type.repeat;
>> +else
>> +length = ch->scan_type.storagebits / 8;
>>  /* Make sure we are aligned */
>>  in_loc += length;
>>  if (in_loc % length)
>> @@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct
>iio_dev *indio_dev,
>>  goto error_clear_mux_table;
>>  }
>>  ch = iio_find_channel_from_si(indio_dev, in_ind);
>> -length = ch->scan_type.storagebits/8;
>> +if (ch->scan_type.repeat > 1)
>> +length = ch->scan_type.storagebits / 8 *
>> +ch->scan_type.repeat;
>> +else
>> +length = ch->scan_type.storagebits / 8;
>>  if (out_loc % length)
>>  out_loc += length - out_loc % length;
>>  if (in_loc % length)
>> @@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct
>iio_dev *indio_dev,
>>  }
>>  ch = iio_find_channel_from_si(indio_dev,
>>  indio_dev->scan_index_timestamp);
>> 

Re: [Patch v5 3/6] IIO: core: Modify scan element type

[Peter Meerwald]

> The current scan element type uses the following format:
>   [be|le]:[s|u]bits/storagebits[>>shift].
> To specify multiple elements in this type, added a repeat value.
> So new format is:
>   [be|le]:[s|u]bits/storagebits{X[repeat]}[>>shift].
> Here X is specifying how may times, real/storage bits are repeating.
> 
> When X is value is 0 or 1, then repeat value is not used in the format,
> and it will be same as existing format.

minor comments inline

> ---
>  drivers/iio/industrialio-buffer.c | 41 
> +--
>  include/linux/iio/iio.h   |  9 +
>  2 files changed, 44 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/industrialio-buffer.c 
> b/drivers/iio/industrialio-buffer.c
> index e108f2a..aa90c68 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device *dev,
>   type = IIO_BE;
>  #endif
>   }
> - return sprintf(buf, "%s:%c%d/%d>>%u\n",
> + if (this_attr->c->scan_type.repeat > 1)
> + return sprintf(buf, "%s:%c%d/%d{%d[repeat]}>>%u\n",
> +iio_endian_prefix[type],
> +this_attr->c->scan_type.sign,
> +this_attr->c->scan_type.realbits,
> +this_attr->c->scan_type.storagebits,
> +this_attr->c->scan_type.repeat,
> +this_attr->c->scan_type.shift);
> + else
> + return sprintf(buf, "%s:%c%d/%d>>%u\n",
>  iio_endian_prefix[type],
>  this_attr->c->scan_type.sign,
>  this_attr->c->scan_type.realbits,
> @@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct iio_dev 
> *indio_dev,
>   for_each_set_bit(i, mask,
>indio_dev->masklength) {
>   ch = iio_find_channel_from_si(indio_dev, i);
> - length = ch->scan_type.storagebits / 8;
> + if (ch->scan_type.repeat > 1)
> + length = ch->scan_type.storagebits / 8 *
> + ch->scan_type.repeat;

so storagebits should be a multiple of 8 and != 0;
we cannot have repeated groups of say 4 bits

> + else
> + length = ch->scan_type.storagebits / 8;
>   bytes = ALIGN(bytes, length);
>   bytes += length;
>   }
>   if (timestamp) {
>   ch = iio_find_channel_from_si(indio_dev,
> indio_dev->scan_index_timestamp);
> - length = ch->scan_type.storagebits / 8;
> + if (ch->scan_type.repeat > 1)
> + length = ch->scan_type.storagebits / 8 *
> + ch->scan_type.repeat;
> + else
> + length = ch->scan_type.storagebits / 8;
>   bytes = ALIGN(bytes, length);
>   bytes += length;
>   }
> @@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct iio_dev 
> *indio_dev,
>  indio_dev->masklength,
>  in_ind + 1);
>   ch = iio_find_channel_from_si(indio_dev, in_ind);
> - length = ch->scan_type.storagebits/8;
> + if (ch->scan_type.repeat > 1)
> + length = ch->scan_type.storagebits / 8 *
> + ch->scan_type.repeat;
> + else
> + length = ch->scan_type.storagebits / 8;
>   /* Make sure we are aligned */
>   in_loc += length;
>   if (in_loc % length)
> @@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct iio_dev 
> *indio_dev,
>   goto error_clear_mux_table;
>   }
>   ch = iio_find_channel_from_si(indio_dev, in_ind);
> - length = ch->scan_type.storagebits/8;
> + if (ch->scan_type.repeat > 1)
> + length = ch->scan_type.storagebits / 8 *
> + ch->scan_type.repeat;
> + else
> + length = ch->scan_type.storagebits / 8;
>   if (out_loc % length)
>   out_loc += length - out_loc % length;
>   if (in_loc % length)
> @@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct iio_dev 
> *indio_dev,
>   }
>   ch = iio_find_channel_from_si(indio_dev,
>   indio_dev->scan_index_timestamp);
> - length = ch->scan_type.storagebits/8;
> + if (ch->scan_type.repeat > 1)
> + length = ch->scan_type.storagebits / 8 *
> + ch->scan_type.repeat;
> + else
> + length = ch->scan_type.storagebits / 8;
>

[Patch v5 3/6] IIO: core: Modify scan element type

[Srinivas Pandruvada]

The current scan element type uses the following format:
  [be|le]:[s|u]bits/storagebits[>>shift].
To specify multiple elements in this type, added a repeat value.
So new format is:
  [be|le]:[s|u]bits/storagebits{X[repeat]}[>>shift].
Here X is specifying how may times, real/storage bits are repeating.

When X is value is 0 or 1, then repeat value is not used in the format,
and it will be same as existing format.

Signed-off-by: Srinivas Pandruvada 
---
 drivers/iio/industrialio-buffer.c | 41 +--
 include/linux/iio/iio.h   |  9 +
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c 
b/drivers/iio/industrialio-buffer.c
index e108f2a..aa90c68 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device *dev,
type = IIO_BE;
 #endif
}
-   return sprintf(buf, "%s:%c%d/%d>>%u\n",
+   if (this_attr->c->scan_type.repeat > 1)
+   return sprintf(buf, "%s:%c%d/%d{%d[repeat]}>>%u\n",
+  iio_endian_prefix[type],
+  this_attr->c->scan_type.sign,
+  this_attr->c->scan_type.realbits,
+  this_attr->c->scan_type.storagebits,
+  this_attr->c->scan_type.repeat,
+  this_attr->c->scan_type.shift);
+   else
+   return sprintf(buf, "%s:%c%d/%d>>%u\n",
   iio_endian_prefix[type],
   this_attr->c->scan_type.sign,
   this_attr->c->scan_type.realbits,
@@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct iio_dev 
*indio_dev,
for_each_set_bit(i, mask,
 indio_dev->masklength) {
ch = iio_find_channel_from_si(indio_dev, i);
-   length = ch->scan_type.storagebits / 8;
+   if (ch->scan_type.repeat > 1)
+   length = ch->scan_type.storagebits / 8 *
+   ch->scan_type.repeat;
+   else
+   length = ch->scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
if (timestamp) {
ch = iio_find_channel_from_si(indio_dev,
  indio_dev->scan_index_timestamp);
-   length = ch->scan_type.storagebits / 8;
+   if (ch->scan_type.repeat > 1)
+   length = ch->scan_type.storagebits / 8 *
+   ch->scan_type.repeat;
+   else
+   length = ch->scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
@@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
   indio_dev->masklength,
   in_ind + 1);
ch = iio_find_channel_from_si(indio_dev, in_ind);
-   length = ch->scan_type.storagebits/8;
+   if (ch->scan_type.repeat > 1)
+   length = ch->scan_type.storagebits / 8 *
+   ch->scan_type.repeat;
+   else
+   length = ch->scan_type.storagebits / 8;
/* Make sure we are aligned */
in_loc += length;
if (in_loc % length)
@@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
goto error_clear_mux_table;
}
ch = iio_find_channel_from_si(indio_dev, in_ind);
-   length = ch->scan_type.storagebits/8;
+   if (ch->scan_type.repeat > 1)
+   length = ch->scan_type.storagebits / 8 *
+   ch->scan_type.repeat;
+   else
+   length = ch->scan_type.storagebits / 8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
@@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
}
ch = iio_find_channel_from_si(indio_dev,
indio_dev->scan_index_timestamp);
-   length = ch->scan_type.storagebits/8;
+   if (ch->scan_type.repeat > 1)
+   length = ch->scan_type.storagebits / 8 *
+   ch->scan_type.repeat;
+   else
+   length = ch->scan_type.storagebits / 8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
diff --git 

[Patch v5 3/6] IIO: core: Modify scan element type

[Srinivas Pandruvada]

The current scan element type uses the following format:
  [be|le]:[s|u]bits/storagebits[shift].
To specify multiple elements in this type, added a repeat value.
So new format is:
  [be|le]:[s|u]bits/storagebits{X[repeat]}[shift].
Here X is specifying how may times, real/storage bits are repeating.

When X is value is 0 or 1, then repeat value is not used in the format,
and it will be same as existing format.

Signed-off-by: Srinivas Pandruvada srinivas.pandruv...@linux.intel.com
---
 drivers/iio/industrialio-buffer.c | 41 +--
 include/linux/iio/iio.h   |  9 +
 2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c 
b/drivers/iio/industrialio-buffer.c
index e108f2a..aa90c68 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device *dev,
type = IIO_BE;
 #endif
}
-   return sprintf(buf, %s:%c%d/%d%u\n,
+   if (this_attr-c-scan_type.repeat  1)
+   return sprintf(buf, %s:%c%d/%d{%d[repeat]}%u\n,
+  iio_endian_prefix[type],
+  this_attr-c-scan_type.sign,
+  this_attr-c-scan_type.realbits,
+  this_attr-c-scan_type.storagebits,
+  this_attr-c-scan_type.repeat,
+  this_attr-c-scan_type.shift);
+   else
+   return sprintf(buf, %s:%c%d/%d%u\n,
   iio_endian_prefix[type],
   this_attr-c-scan_type.sign,
   this_attr-c-scan_type.realbits,
@@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct iio_dev 
*indio_dev,
for_each_set_bit(i, mask,
 indio_dev-masklength) {
ch = iio_find_channel_from_si(indio_dev, i);
-   length = ch-scan_type.storagebits / 8;
+   if (ch-scan_type.repeat  1)
+   length = ch-scan_type.storagebits / 8 *
+   ch-scan_type.repeat;
+   else
+   length = ch-scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
if (timestamp) {
ch = iio_find_channel_from_si(indio_dev,
  indio_dev-scan_index_timestamp);
-   length = ch-scan_type.storagebits / 8;
+   if (ch-scan_type.repeat  1)
+   length = ch-scan_type.storagebits / 8 *
+   ch-scan_type.repeat;
+   else
+   length = ch-scan_type.storagebits / 8;
bytes = ALIGN(bytes, length);
bytes += length;
}
@@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
   indio_dev-masklength,
   in_ind + 1);
ch = iio_find_channel_from_si(indio_dev, in_ind);
-   length = ch-scan_type.storagebits/8;
+   if (ch-scan_type.repeat  1)
+   length = ch-scan_type.storagebits / 8 *
+   ch-scan_type.repeat;
+   else
+   length = ch-scan_type.storagebits / 8;
/* Make sure we are aligned */
in_loc += length;
if (in_loc % length)
@@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
goto error_clear_mux_table;
}
ch = iio_find_channel_from_si(indio_dev, in_ind);
-   length = ch-scan_type.storagebits/8;
+   if (ch-scan_type.repeat  1)
+   length = ch-scan_type.storagebits / 8 *
+   ch-scan_type.repeat;
+   else
+   length = ch-scan_type.storagebits / 8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
@@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct iio_dev 
*indio_dev,
}
ch = iio_find_channel_from_si(indio_dev,
indio_dev-scan_index_timestamp);
-   length = ch-scan_type.storagebits/8;
+   if (ch-scan_type.repeat  1)
+   length = ch-scan_type.storagebits / 8 *
+   ch-scan_type.repeat;
+   else
+   length = ch-scan_type.storagebits / 8;
if (out_loc % length)
out_loc += length - out_loc % length;
if (in_loc % length)
diff --git a/include/linux/iio/iio.h 

Re: [Patch v5 3/6] IIO: core: Modify scan element type

[Peter Meerwald]

 The current scan element type uses the following format:
   [be|le]:[s|u]bits/storagebits[shift].
 To specify multiple elements in this type, added a repeat value.
 So new format is:
   [be|le]:[s|u]bits/storagebits{X[repeat]}[shift].
 Here X is specifying how may times, real/storage bits are repeating.
 
 When X is value is 0 or 1, then repeat value is not used in the format,
 and it will be same as existing format.

minor comments inline

 ---
  drivers/iio/industrialio-buffer.c | 41 
 +--
  include/linux/iio/iio.h   |  9 +
  2 files changed, 44 insertions(+), 6 deletions(-)
 
 diff --git a/drivers/iio/industrialio-buffer.c 
 b/drivers/iio/industrialio-buffer.c
 index e108f2a..aa90c68 100644
 --- a/drivers/iio/industrialio-buffer.c
 +++ b/drivers/iio/industrialio-buffer.c
 @@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device *dev,
   type = IIO_BE;
  #endif
   }
 - return sprintf(buf, %s:%c%d/%d%u\n,
 + if (this_attr-c-scan_type.repeat  1)
 + return sprintf(buf, %s:%c%d/%d{%d[repeat]}%u\n,
 +iio_endian_prefix[type],
 +this_attr-c-scan_type.sign,
 +this_attr-c-scan_type.realbits,
 +this_attr-c-scan_type.storagebits,
 +this_attr-c-scan_type.repeat,
 +this_attr-c-scan_type.shift);
 + else
 + return sprintf(buf, %s:%c%d/%d%u\n,
  iio_endian_prefix[type],
  this_attr-c-scan_type.sign,
  this_attr-c-scan_type.realbits,
 @@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct iio_dev 
 *indio_dev,
   for_each_set_bit(i, mask,
indio_dev-masklength) {
   ch = iio_find_channel_from_si(indio_dev, i);
 - length = ch-scan_type.storagebits / 8;
 + if (ch-scan_type.repeat  1)
 + length = ch-scan_type.storagebits / 8 *
 + ch-scan_type.repeat;

so storagebits should be a multiple of 8 and != 0;
we cannot have repeated groups of say 4 bits

 + else
 + length = ch-scan_type.storagebits / 8;
   bytes = ALIGN(bytes, length);
   bytes += length;
   }
   if (timestamp) {
   ch = iio_find_channel_from_si(indio_dev,
 indio_dev-scan_index_timestamp);
 - length = ch-scan_type.storagebits / 8;
 + if (ch-scan_type.repeat  1)
 + length = ch-scan_type.storagebits / 8 *
 + ch-scan_type.repeat;
 + else
 + length = ch-scan_type.storagebits / 8;
   bytes = ALIGN(bytes, length);
   bytes += length;
   }
 @@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct iio_dev 
 *indio_dev,
  indio_dev-masklength,
  in_ind + 1);
   ch = iio_find_channel_from_si(indio_dev, in_ind);
 - length = ch-scan_type.storagebits/8;
 + if (ch-scan_type.repeat  1)
 + length = ch-scan_type.storagebits / 8 *
 + ch-scan_type.repeat;
 + else
 + length = ch-scan_type.storagebits / 8;
   /* Make sure we are aligned */
   in_loc += length;
   if (in_loc % length)
 @@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct iio_dev 
 *indio_dev,
   goto error_clear_mux_table;
   }
   ch = iio_find_channel_from_si(indio_dev, in_ind);
 - length = ch-scan_type.storagebits/8;
 + if (ch-scan_type.repeat  1)
 + length = ch-scan_type.storagebits / 8 *
 + ch-scan_type.repeat;
 + else
 + length = ch-scan_type.storagebits / 8;
   if (out_loc % length)
   out_loc += length - out_loc % length;
   if (in_loc % length)
 @@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct iio_dev 
 *indio_dev,
   }
   ch = iio_find_channel_from_si(indio_dev,
   indio_dev-scan_index_timestamp);
 - length = ch-scan_type.storagebits/8;
 + if (ch-scan_type.repeat  1)
 + length = ch-scan_type.storagebits / 8 *
 + ch-scan_type.repeat;
 + else
 + length = ch-scan_type.storagebits / 8;
   if (out_loc % length)
   out_loc += length - out_loc % length;
   if (in_loc % length)
 diff --git a/include/linux/iio/iio.h 

Re: [Patch v5 3/6] IIO: core: Modify scan element type

[Jonathan Cameron]

On April 14, 2014 11:33:12 PM GMT+01:00, Peter Meerwald pme...@pmeerw.net 
wrote:
 The current scan element type uses the following format:
   [be|le]:[s|u]bits/storagebits[shift].
 To specify multiple elements in this type, added a repeat value.
 So new format is:
   [be|le]:[s|u]bits/storagebits{X[repeat]}[shift].
 Here X is specifying how may times, real/storage bits are repeating.
 
 When X is value is 0 or 1, then repeat value is not used in the
format,
 and it will be same as existing format.

minor comments inline

 ---
  drivers/iio/industrialio-buffer.c | 41
+--
  include/linux/iio/iio.h   |  9 +
  2 files changed, 44 insertions(+), 6 deletions(-)
 
 diff --git a/drivers/iio/industrialio-buffer.c
b/drivers/iio/industrialio-buffer.c
 index e108f2a..aa90c68 100644
 --- a/drivers/iio/industrialio-buffer.c
 +++ b/drivers/iio/industrialio-buffer.c
 @@ -150,7 +150,16 @@ static ssize_t iio_show_fixed_type(struct device
*dev,
  type = IIO_BE;
  #endif
  }
 -return sprintf(buf, %s:%c%d/%d%u\n,
 +if (this_attr-c-scan_type.repeat  1)
 +return sprintf(buf, %s:%c%d/%d{%d[repeat]}%u\n,
 +   iio_endian_prefix[type],
 +   this_attr-c-scan_type.sign,
 +   this_attr-c-scan_type.realbits,
 +   this_attr-c-scan_type.storagebits,
 +   this_attr-c-scan_type.repeat,
 +   this_attr-c-scan_type.shift);
 +else
 +return sprintf(buf, %s:%c%d/%d%u\n,
 iio_endian_prefix[type],
 this_attr-c-scan_type.sign,
 this_attr-c-scan_type.realbits,
 @@ -474,14 +483,22 @@ static int iio_compute_scan_bytes(struct
iio_dev *indio_dev,
  for_each_set_bit(i, mask,
   indio_dev-masklength) {
  ch = iio_find_channel_from_si(indio_dev, i);
 -length = ch-scan_type.storagebits / 8;
 +if (ch-scan_type.repeat  1)
 +length = ch-scan_type.storagebits / 8 *
 +ch-scan_type.repeat;

so storagebits should be a multiple of 8 and != 0;
we cannot have repeated groups of say 4 bits

Indeed not. Having unaligned data would probably prove more painful than using 
more
 memory... Real requirements will be stricter as power of 2 multiples of bytes 
only.
This is in theory the plan for all buffer elements..

 +else
 +length = ch-scan_type.storagebits / 8;
  bytes = ALIGN(bytes, length);
  bytes += length;
  }
  if (timestamp) {
  ch = iio_find_channel_from_si(indio_dev,
indio_dev-scan_index_timestamp);
 -length = ch-scan_type.storagebits / 8;
 +if (ch-scan_type.repeat  1)
 +length = ch-scan_type.storagebits / 8 *
 +ch-scan_type.repeat;
 +else
 +length = ch-scan_type.storagebits / 8;
  bytes = ALIGN(bytes, length);
  bytes += length;
  }
 @@ -957,7 +974,11 @@ static int iio_buffer_update_demux(struct
iio_dev *indio_dev,
 indio_dev-masklength,
 in_ind + 1);
  ch = iio_find_channel_from_si(indio_dev, in_ind);
 -length = ch-scan_type.storagebits/8;
 +if (ch-scan_type.repeat  1)
 +length = ch-scan_type.storagebits / 8 *
 +ch-scan_type.repeat;
 +else
 +length = ch-scan_type.storagebits / 8;
  /* Make sure we are aligned */
  in_loc += length;
  if (in_loc % length)
 @@ -969,7 +990,11 @@ static int iio_buffer_update_demux(struct
iio_dev *indio_dev,
  goto error_clear_mux_table;
  }
  ch = iio_find_channel_from_si(indio_dev, in_ind);
 -length = ch-scan_type.storagebits/8;
 +if (ch-scan_type.repeat  1)
 +length = ch-scan_type.storagebits / 8 *
 +ch-scan_type.repeat;
 +else
 +length = ch-scan_type.storagebits / 8;
  if (out_loc % length)
  out_loc += length - out_loc % length;
  if (in_loc % length)
 @@ -990,7 +1015,11 @@ static int iio_buffer_update_demux(struct
iio_dev *indio_dev,
  }
  ch = iio_find_channel_from_si(indio_dev,
  indio_dev-scan_index_timestamp);
 -length = ch-scan_type.storagebits/8;
 +if (ch-scan_type.repeat  1)
 +length = ch-scan_type.storagebits / 8 *
 +ch-scan_type.repeat;
 +else
 +