ICP DAS LP-8841 contains a DS-1302 RTC. This driver provides an SPI
master which makes the RTC usable. The driver is not supposed to work
with anything else.

The driver uses the standard MicroWire half-duplex transfer timing.
Master output is set on low clock and sensed by the RTC on the rising
edge. Master input is set by the RTC on the trailing edge and is sensed
by the master on low clock.

Signed-off-by: Sergei Ianovich <ynvich@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

This patch adds support for the AXI SPI Engine controller which is a FPGA
soft-peripheral which is used in some of Analog Devices' reference designs.

The AXI SPI Engine controller is part of the SPI Engine framework[1] and
allows memory mapped access to the SPI Engine control bus. This allows it
to be used as a general purpose software driven SPI controller. The SPI
Engine in addition offers some optional advanced acceleration and
offloading capabilities, which are not part of this patch though and will
be introduced separately.

At the core of the SPI Engine framework is a small sort of co-processor
that accepts a command stream and turns the commands into low-level SPI
transactions. Communication is done through three memory mapped FIFOs in
the register map of the AXI SPI Engine peripheral. One FIFO for the command
stream and one each for transmit and receive data.

The driver translates a spi_message in a command stream and writes it to
the peripheral which executes it asynchronously. This allows it to perform
very precise timings which are required for some SPI slave devices to
achieve maximum performance (e.g. analog-to-digital and digital-to-analog
converters). The execution flow is synchronized to the host system by a
special synchronize instruction which generates a interrupt.

[1] https://wiki.analog.com/resources/fpga/peripherals/spi_engine

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

After removal of legacy PXA DMA code by the commit 6356437e65c2
("spi: spi-pxa2xx: remove legacy PXA DMA bits") the
CONFIG_SPI_PXA2XX_DMA follows the CONFIG_SPI_PXA2XX and cannot be disabled
alone. Therefore remove this config symbol and dead definitions from the
spi-pxa2xx.h.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

adding the spi-loopback-test module to Kconfig and Makefile

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

The bcm2835 has 2 auxiliary spi bus masters spi1 and spi2.

This implements the driver to enable these devices.

The driver does not implement native chip-selects but uses
the aribtrary GPIO-chip-selects provided by the spi-chipselect.

Note that this driver relies on the fact that
the clock is implemented by the clk-bcm2835-aux driver,
which enables/disables the HW block when requesting/releasing
the clock.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>

Add SPI Master controller driver for the SPI interface on XLP8XX,
XLP3XX, XLP2XX, XLP9XX and XLP5XX family of Netlogic XLP MIPS64 processors.

Signed-off-by: Kamlakant Patel <kamlakant.patel@broadcom.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

This patch adds basic spi bus for MT8173.

Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>