xref: /openbmc/linux/Documentation/ABI/testing/sysfs-bus-iio-dma-buffer (revision 8dd06ef34b6e2f41b29fbf5fc1663780f2524285)
1*4538c185SLars-Peter ClausenWhat:		/sys/bus/iio/devices/iio:deviceX/buffer/length_align_bytes
2*4538c185SLars-Peter ClausenKernelVersion:	5.4
3*4538c185SLars-Peter ClausenContact:	linux-iio@vger.kernel.org
4*4538c185SLars-Peter ClausenDescription:
5*4538c185SLars-Peter Clausen		DMA buffers tend to have a alignment requirement for the
6*4538c185SLars-Peter Clausen		buffers. If this alignment requirement is not met samples might
7*4538c185SLars-Peter Clausen		be dropped from the buffer.
8*4538c185SLars-Peter Clausen
9*4538c185SLars-Peter Clausen		This property reports the alignment requirements in bytes.
10*4538c185SLars-Peter Clausen		This means that the buffer size in bytes needs to be a integer
11*4538c185SLars-Peter Clausen		multiple of the number reported by this file.
12*4538c185SLars-Peter Clausen
13*4538c185SLars-Peter Clausen		The alignment requirements in number of sample sets will depend
14*4538c185SLars-Peter Clausen		on the enabled channels and the bytes per channel. This means
15*4538c185SLars-Peter Clausen		that the alignment requirement in samples sets might change
16*4538c185SLars-Peter Clausen		depending on which and how many channels are enabled. Whereas
17*4538c185SLars-Peter Clausen		the alignment requirement reported in bytes by this property
18*4538c185SLars-Peter Clausen		will remain static and does not depend on which channels are
19*4538c185SLars-Peter Clausen		enabled.
20