treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

Based on 3 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

spi: loopback-test: add elapsed time check

This adds checks whether the elapsed time is longer than the minimam
estimated time. The estimated time is calculated with the total
transfer length per clock rate and optional spi_transfer.delay_usecs.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: loopback-test: test zero-length transfer

In order to test various spi_messages including zero-length transfer,
this adds zero length into the iterate_len list.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: loopback-test: add ability to test zero-length transfer

The spi-loopback-test module currently cannot test the spi_message
including a zero-length transfer. Because the zero-length transfer is
treated as a special value in several meanings.

1. The number of spi_transfer to execute in one test case is described
by spi_test.transfer_count. It is normally computed by counting number
of transfers with len > 0 in spi_test.transfers array.

This change stops the detection for the number of spi_transfer. Each
spi_test.transfer_count needs to be filled by hand now.

2. The spi_test.iterate_len is a list of transfer length to iterate on.
This list is terminated by zero, so zero-length transfer cannot be
included.

This changes the terminal value from 0 to -1.

3. The length for the spi_transfer masked by spi_test.iterate_transfer_mask
is iterated. Before starting the iteration, the default value which
is statically initialized is applied. In order to specify the default
value, zero-length is reserved.

Currently, the default values are always '1'. So this removes this
trick and add '1' to iterate_len list.

By applying all these changes, the spi-loopback-test can execute spi
messages with zero-length transfer.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: loopback: added additional non-power of 2 transfer lengthes

Added additional transfer length to test that are not a power of 2.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: add loopback test driver to allow for spi_master regression tests

This driver is submitting lots of distinct spi-messages messages
with all kinds of alignments and length pattern.
Also distinct kinds of transfer pattern tests are implemented
(rx, tx, rx/tx, tx+tx, tx+rx,...)

Right now on a raspberry pi 752 distinct spi_messages are executed
in 13 different scenarios.

Configuration of additional test-pattern is easy, so that when
new bugs in drivers get detected the relevant transfer pattern can
also get added to the test framework, so that such situations are
detected in other drivers as well.

The idea behind this driver is to make it possible to also detect
regressions in spi_master implementations when changes occur.
Potentially these tests could get executed automatically in a
test-server-farm.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>