linux.git/include/linux/iio/buffer.h, branch v7.2-rc1

iio: buffer: Move from int64_t to s64 for timestamp

2026-05-31T09:59:32+00:00

iio_push_to_buffers_with_ts_unaligned() uses int64_t for timestamp.
Move it from int64_t to s64 to make consistent with:
- iio_push_to_buffers_with_ts()
- all current users that supply s64 anyway

This will reduce potential of wrong type being chosen when using
this API.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Jonathan Cameron

iio: buffer: fix timestamp alignment when quaternion in scan

2026-04-27T08:58:15+00:00

Fix timestamp alignment when a scan buffer contains an element larger
than sizeof(int64_t). Currently s32 quaternions are the only such
element, and the one driver that has this (hid-sensor-rotation) has a
workaround in place already so this change does not affect it.

Previously, we assumed that the timestamp would always be 8-byte aligned
relative to the end of the scan buffer, but in the case of a scan buffer
a 16-byte quaternion vector, scan_bytes == 32, but the timestamp needs
to be placed at offset 16, not 24.

ts_offset is now a value in bytes so we have to change how the array
access is done.

Signed-off-by: David Lechner 
Reviewed-by: Nuno Sá 
Signed-off-by: Jonathan Cameron

iio: buffer: deprecated iio_push_to_buffers_with_timestamp()

2025-10-13T07:37:23+00:00

Replace the documentation of iio_push_to_buffers_with_timestamp() with
a deprecation notice pointing to the preferred alternative.

Signed-off-by: David Lechner 
Signed-off-by: Jonathan Cameron

iio: buffer: document iio_push_to_buffers_with_ts()

2025-10-13T07:37:23+00:00

Document the iio_push_to_buffers_with_ts() function.

This is copied and slightly cleaned up from
iio_push_to_buffers_with_timestamp().

Signed-off-by: David Lechner 
Signed-off-by: Jonathan Cameron

iio: introduced iio_push_to_buffers_with_ts() that takes a data_total_len argument.

2025-05-21T13:20:25+00:00

Check that data_total_len argument against iio_dev->scan_bytes.

The size needs to be at least as big as the scan. It can be larger,
which is typical if only part of fixed sized storage is used due to
a subset of channels being enabled.

Reviewed-by: Nuno Sá 
Reviewed-by: David Lechner 
Link: https://patch.msgid.link/20250413103443.2420727-6-jic23@kernel.org
Signed-off-by: Jonathan Cameron

iio: core: mark scan_timestamp as __private

2024-12-28T14:28:14+00:00

Since there are no more direct accesses to the indio_dev->scan_timestamp
value, it can be marked as __private and use the macro ACCESS_PRIVATE()
in order to access it. Like this, static checkers will be able to inform
in case someone tries to either write to the value, or read its value
directly.

Signed-off-by: Vasileios Amoiridis 
Link: https://patch.msgid.link/20241214191421.94172-5-vassilisamir@gmail.com
Signed-off-by: Jonathan Cameron

iio: Add output buffer support

2021-10-19T07:30:44+00:00

Currently IIO only supports buffer mode for capture devices like ADCs. Add
support for buffered mode for output devices like DACs.

The output buffer implementation is analogous to the input buffer
implementation. Instead of using read() to get data from the buffer write()
is used to copy data into the buffer.

poll() with POLLOUT will wakeup if there is space available.

Drivers can remove data from a buffer using iio_pop_from_buffer(), the
function can e.g. called from a trigger handler to write the data to
hardware.

A buffer can only be either a output buffer or an input, but not both. So,
for a device that has an ADC and DAC path, this will mean 2 IIO buffers
(one for each direction).

The direction of the buffer is decided by the new direction field of the
iio_buffer struct and should be set after allocating and before registering
it.

Co-developed-by: Lars-Peter Clausen 
Signed-off-by: Lars-Peter Clausen 
Co-developed-by: Alexandru Ardelean 
Signed-off-by: Alexandru Ardelean 
Signed-off-by: Mihail Chindris 
Link: https://lore.kernel.org/r/20211007080035.2531-2-mihail.chindris@analog.com
Signed-off-by: Jonathan Cameron

iio: core: Introduce iio_push_to_buffers_with_ts_unaligned()

2021-10-19T07:29:22+00:00

Whilst it is almost always possible to arrange for scan data to be
read directly into a buffer that is suitable for passing to
iio_push_to_buffers_with_timestamp(), there are a few places where
leading data needs to be skipped over.

For these cases introduce a function that will allocate an appropriate
sized and aligned bounce buffer (if not already allocated) and copy
the unaligned data into that before calling
iio_push_to_buffers_with_timestamp() on the bounce buffer.
We tie the lifespace of this buffer to that of the iio_dev.dev
which should ensure no memory leaks occur.

Signed-off-by: Jonathan Cameron 
Reviewed-by: Nuno Sá 
Link: https://lore.kernel.org/r/20210613151039.569883-2-jic23@kernel.org

iio: buffer: introduce support for attaching more IIO buffers

2021-03-11T20:47:05+00:00

With this change, calling iio_device_attach_buffer() will actually attach
more buffers.
Right now this doesn't do any validation of whether a buffer is attached
twice; maybe that can be added later (if needed). Attaching a buffer more
than once should yield noticeably bad results.

The first buffer is the legacy buffer, so a reference is kept to it.

At this point, accessing the data for the extra buffers (that are added
after the first one) isn't possible yet.

The iio_device_attach_buffer() is also changed to return an error code,
which for now is -ENOMEM if the array could not be realloc-ed for more
buffers.
To adapt to this new change iio_device_attach_buffer() is called last in
all place where it's called. The realloc failure is a bit difficult to
handle during un-managed calls when unwinding, so it's better to have this
as the last error in the setup_buffer calls.

At this point, no driver should call iio_device_attach_buffer() directly,
it should call one of the {devm_}iio_triggered_buffer_setup() or
devm_iio_kfifo_buffer_setup() or devm_iio_dmaengine_buffer_setup()
functions. This makes iio_device_attach_buffer() a bit easier to handle.

Signed-off-by: Alexandru Ardelean 
Link: https://lore.kernel.org/r/20210215104043.91251-20-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron

iio: buffer: remove iio_buffer_set_attrs() helper

2020-11-21T14:53:37+00:00

The iio_buffer_set_attrs() is no longer used in the drivers, so it can be
removed now.

Signed-off-by: Alexandru Ardelean 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20200929125949.69934-10-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron