linux_spi: Reduce maximum read chunksize

It turned out that older kernels use a single buffer of `bufsiz` bytes
for combined input and output data. So we have to account for the read
command + max 4 address bytes.

Change-Id: Ide50db38af1004fde09a70b15938e77f5e1285ac
Signed-off-by: Nico Huber <>
Tested-by: Julian von Mendel <>
Tested-by: build bot (Jenkins) <>
Reviewed-by: Julian von Mendel <>
Reviewed-by: David Hendricks <>
1 file changed