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[ Upstream commit 509c583620e9053e43d611bf1614fc3d3abafa96 ]
The original driver by default defines num_chipselects as -1.
This actually allicates an array of 65535 entries in
of_spi_register_master.
There is a side-effect for buggy device trees that (contrary to
dt-binding documentation) have no cs-gpio defined.
This mode was never supported by the driver due to limitations
of native cs and additional code complexity and is explicitly
not stated to be implemented.
To keep backwards compatibility with such buggy DTs we limit
the number of chip_selects to 1, as for all practical purposes
it is only ever realistic to use a single chip select in
native cs mode without negative side-effects.
Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 73b114ee7db1750c0b535199fae383b109bd61d0 ]
On long running tests with a mcp2517fd can controller it showed that
on rare occations the data read shows corruptions for longer spi transfers.
Example of a 22 byte transfer:
expected (as captured on logic analyzer):
FF FF 78 00 00 00 08 06 00 00 91 20 77 56 84 85 86 87 88 89 8a 8b
read by the driver:
FF FF 78 00 00 00 08 06 00 00 91 20 77 56 84 88 89 8a 00 00 8b 9b
To fix this use BCM2835_AUX_SPI_STAT_RX_LVL to determine when we may
read data from the fifo reliably without any corruption.
Surprisingly the only values ever empirically read in
BCM2835_AUX_SPI_STAT_RX_LVL are 0x00, 0x10, 0x20 and 0x30.
So whenever the mask is not 0 we can read from the fifo in a safe manner.
The patch has now been tested intensively and we are no longer
able to reproduce the "RX" issue any longer.
Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Reported-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c7de8500fd8ecbb544846dd5f11dca578c3777e1 ]
This read of the fifo is a potential candidate for a race condition
as the spi transfer is not necessarily finished and so can lead to
an early read of the fifo that still misses data.
So it has been removed.
Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...")
Suggested-by: Hubert Denkmair <h.denkmair@intence.de>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7188a6f0eee3f1fae5d826cfc6d569657ff950ec ]
Sharing more code between polling and interrupt-driven mode.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit bc519d9574618e47a0c788000fb78da95e18d953 ]
The BCM2835 AUX SPI has a shared interrupt line (with AUX UART).
Downstream fixes this with an AUX irqchip to demux the IRQ sources and a
DT change which breaks compatibility with older kernels. The AUX irqchip
was already rejected for upstream[1] and the DT change would break
working systems if the DTB is updated to a newer one. The latter issue
was brought to my attention by Alex Graf.
The root cause however is a bug in the shared handler. Shared handlers
must check that interrupts are actually enabled before servicing the
interrupt. Add a check that the TXEMPTY or IDLE interrupts are enabled.
[1] https://patchwork.kernel.org/patch/9781221/
Cc: Alexander Graf <agraf@suse.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: linux-spi@vger.kernel.org
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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'spi/topic/bcm2835' and 'spi/topic/bcm2835aux' into spi-next
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The auxiliary spi supports only CPHA=0 modes as the first bit is
always output to the pin before the first clock cycle. In CPHA=1
modes the first clock edge outputs the second bit hence the slave
can never read the first bit.
Also the CPHA registers switch between clocking data in/out on
rising/falling edge hence depend on the CPOL setting.
Signed-off-by: Stephan Olbrich <stephanolbrich@gmx.de>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
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When using reverse polarity for clock (spi-cpol) on a device
the clock line gets altered after chip-select has been asserted
resulting in an additional clock beat, which confuses hardware.
This happens due to the fact, the the hardware was initialized
and reset at the begin and end of each transfer which results
in default state for all lines except chip-select which is
handled by the spi-subsystem as gpio-cs is used.
To avoid this situation this patch moves the setup of polarity
(spi-cpol and spi-cpha) outside of the chip-select into
prepare_message, which is run prior to asserting chip-select.
Signed-off-by: Stephan Olbrich <stephanolbrich@gmx.de>
Reviewed-by: Martin Sperl <kernel@martin.sperl.org>
Tested-by: Martin Sperl <kernel@martin.sperl.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
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The tx empty irq can be disabled when all data was copied.
This prevents unnecessary interrupts while the last bytes are sent.
Signed-off-by: Stephan Olbrich <stephanolbrich@gmx.de>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
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The bitmasks for txempty and idle interrupts were interchanged.
Signed-off-by: Stephan Olbrich <stephanolbrich@gmx.de>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Change the initialization order of the HW so that the interrupt
is only requested after the HW is initialized
Also the use of irq_of_parse_and_map is replaced by platform_get_irq.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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There are strange issues with the auxiliary spi device that result
in "lost" data in the RX path if the fifo is filled by too much
(even though the status register is checked if new data can get filled
in).
This has been observed primarily for the interrupt case.
Polling works fine, probably because the RX fifo is pulled immediately
when in the tight polling loop.
For that reason we have to limit the pending bytes to less than 15
when filling the fifo in interrupt mode.
There also was an issue returning the "wrong" last 1/2 bytes
of a transfer when the transfer is not a multiple of 3 bytes.
(this impacted polling and interrupt modes)
Also fixed an overflow in the estimation of the transfer time used
to decide if we run in interrupt or polling mode (found with the
spi-bcm2835.c driver originally).
Reported-by: Georgii Staroselskii <georgii.staroselskii@emlid.com>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
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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>
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