2881 Commits

Author SHA1 Message Date
Andy Shevchenko
9df461eca1 spi: pxa2xx: replace ugly table by approximation
The Quark SoC data sheet describes the baud rate setting using fractional
divider. The subset of possible values represented by a table suggests that the
divisor has one block that could divide by 5. This explains the number of the
beast in some cases in the table. Thus, in this particular case the divisor can
be evaluated as

	5^i * 2^j * 2 * k,

where

	i = [0, 1]
	j = [0, 23]
	k = [1, 256]

There are few cases as mentioned in the data sheet, i.e. better form of the
clock signal will be in case if DDS_CLK_RATE either 2^n or 2/5. It's also
possible to use any value that is less or equal to 0x33333 (1/5/16 = 1/80).

All three cases are compared to each other and the one that suits better is
chosen by the approximation algorithm. Anyone can play with the script [1] that
represents the algorithm.

[1] https://gist.github.com/06b084488b3629898121

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-25 08:30:17 -07:00
Mark Brown
072ac04d31 Merge remote-tracking branches 'spi/fix/dw', 'spi/fix/queue' and 'spi/fix/qup' into spi-linus 2015-03-24 10:38:44 -07:00
Andy Shevchenko
025ffe88ee spi: pxa2xx: shift clk_div in one place
This patch refactors ssp_get_clk_div() and pxa2xx_ssp_get_clk_div() to align
clk_div calculations, i.e. ssp_get_clk_div() and quark_x1000_set_clk_regvals()
will return plain clk_div and it will be shifted to proper position in
pxa2xx_ssp_get_clk_div().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-24 09:32:48 -07:00
Ian Abbott
f20fbaad76 spi: spidev: fix possible arithmetic overflow for multi-transfer message
`spidev_message()` sums the lengths of the individual SPI transfers to
determine the overall SPI message length.  It restricts the total
length, returning an error if too long, but it does not check for
arithmetic overflow.  For example, if the SPI message consisted of two
transfers and the first has a length of 10 and the second has a length
of (__u32)(-1), the total length would be seen as 9, even though the
second transfer is actually very long.  If the second transfer specifies
a null `rx_buf` and a non-null `tx_buf`, the `copy_from_user()` could
overrun the spidev's pre-allocated tx buffer before it reaches an
invalid user memory address.  Fix it by checking that neither the total
nor the individual transfer lengths exceed the maximum allowed value.

Thanks to Dan Carpenter for reporting the potential integer overflow.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 14:00:51 -07:00
Martin Sperl
6935224da2 spi: bcm2835: enable support of 3-wire mode
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 11:54:34 -07:00
Martin Sperl
210b49231a spi: bcm2835: clock divider can be a multiple of 2
The official documentation is wrong in this respect.
Has been tested empirically for dividers 2-1024

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 11:52:26 -07:00
Martin Sperl
4adf312976 spi: bcm2835: fill/drain SPI-fifo as much as possible during interrupt
Implement the recommendation from the BCM2835 data-sheet
with regards to polling drivers to fill/drain the FIFO as much data as possible
also for the interrupt-driven case (which this driver is making use of).

This means that for long transfers (>64bytes) we need one interrupt
every 64 bytes instead of every 12 bytes, as the FIFO is 16 words (not bytes) wide.

Tested with mcp251x (can bus), fb_st7735 (TFT framebuffer device)
and enc28j60 (ethernet) drivers.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 11:48:58 -07:00
Jarkko Nikula
d4f9dcd1ac spi: omap-uwire: Remove needless include asm/irq.h
asm/irq.h is already included by linux/interrupt.h.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 09:43:37 -07:00
Jarkko Nikula
22d1b94d4b spi: pxa2xx: Remove needless includes
These asm/io.h, asm/irq.h and asm/delay.h are needless since they are
already included by linux/io.h via drivers/spi/spi-pxa2xx.h,
linux/interrupt.h and linux/delay.h.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-23 09:43:19 -07:00
Ben Dooks
ea467326e3 spi: atmel: use endian agnostic IO
Use the endian agnositc IO functions instead of the __raw ones for when
the driver is in use on big-endian systems.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-22 18:00:25 +00:00
Martin Sperl
342f948a16 spi: bcm2835: fix all checkpath --strict messages
The following errors/warnings issued by checkpatch.pl --strict have been fixed:
drivers/spi/spi-bcm2835.c:182: CHECK: Alignment should match open parenthesis
drivers/spi/spi-bcm2835.c:191: CHECK: braces {} should be used on all arms of this statement
drivers/spi/spi-bcm2835.c:234: CHECK: Alignment should match open parenthesis
drivers/spi/spi-bcm2835.c:256: CHECK: Alignment should match open parenthesis
drivers/spi/spi-bcm2835.c:271: CHECK: Alignment should match open parenthesis
drivers/spi/spi-bcm2835.c:346: CHECK: Alignment should match open parenthesis
total: 0 errors, 0 warnings, 6 checks, 403 lines checked

In 2 locations the arguments had to get split/moved to the next line so that the
line width stays below 80 chars.

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-20 17:45:35 +00:00
Uwe Kleine-König
391949b6f0 spi: trigger trace event for message-done before mesg->complete
With spidev the mesg->complete callback points to spidev_complete.
Calling this unblocks spidev_sync and so spidev_sync_write finishes. As
the struct spi_message just read is a local variable in
spidev_sync_write and recording the trace event accesses this message
the recording is better done first. The same can happen for
spidev_sync_read.

This fixes an oops observed on a 3.14-rt system with spidev activity
after

	echo 1 > /sys/kernel/debug/tracing/events/spi/enable

.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-03-18 11:34:10 +00:00
Thor Thayer
dd11444327 spi: dw-spi: Convert 16bit accesses to 32bit accesses
Altera's Arria10 SoC interconnect requires a 32-bit write for APB
peripherals. The current spi-dw driver uses 16-bit accesses in
some locations. This patch converts all the 16-bit reads and
writes to 32-bit reads and writes.

Additional Documentation to Support this Change:
The DW_apb_ssi databook states:
"All registers in the DW_apb_ssi are addressed at 32-bit boundaries
to remain consistent with the AHB bus. Where the physical size of
any register is less than 32-bits wide, the upper unused bits of
the 32-bit boundary are reserved. Writing to these bits has no
effect; reading from these bits returns 0." [1]

[1] Section 6.1 of dw_apb_ssi.pdf (version 3.22a)

Request for test with platforms using the DesignWare SPI IP.

Tested On:
Altera CycloneV development kit
Altera Arria10 development kit
Compile tested for build errors on x86_64 (allyesconfigs)

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Reviewed-and-tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-17 12:27:09 +00:00
Mark Brown
db91841b58 spi/omap100k: Convert to runtime PM
Currently the omap100k driver uses prepare and unprepare transfer hardware
to enable and disable clocks for the IP block. Since these functions are
called along with runtime PM and end up duplicating its functionality in a
less flexible fashion we are trying to phase them out so convert this
driver to do runtime PM instead.

While doing so add missing error handling and remove a redundant NULL
assignment.

Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-17 12:25:48 +00:00
Fabian Frederick
0935540232 spi: constify of_device_id array
of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-17 12:15:22 +00:00
Ivan T. Ivanov
1a7b7ee72c spi: Ensure that CS line is in non-active state after spi_setup()
Some devices samples state of the chip select signal during power up
and act differently based on this state, so SPI core should ensure
that CS line is driven in non-active state after spi_setup().

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-16 14:06:48 +00:00
Thor Thayer
2306509605 spi: dw-spi: Single Register read to clear IRQs
Instead of clearing the RxU, RxO, and TxO IRQs individually with
3 register reads, a single read of the ICR register will do the
same thing.

Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:43:44 +00:00
Andy Shevchenko
d744f82683 spi: dw-mid: convert to use dw_dmac instead of intel_mid_dma
intel_mid_dma seems to be unmaintained for a long time. Moreover, the IP block
of DMA itself is the same in both dw_dmac and intel_mid_dma. This patch moves
spi-dw-midpci to use dw_dmac driver.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Andy Shevchenko
f89a6d8f43 spi: dw-mid: move to use core SPI DMA mappings
SPI core has a comprehensive function set to map and unmap a message when it's
needed. This patch converts driver to use that advantage.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Andy Shevchenko
4d5ac1edfd spi: dw-mid: clear ongoing DMA transfers on timeout
This patch shuts up any ongoing DMA transfer in case of error.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Andy Shevchenko
f051fc8f11 spi: dw-mid: take care of FIFO overrun/underrun when do DMA
In according to documentation SPI in DMA mode may encounter underrun/overrun
failures in rare cases. When such failure occurs, an error recovery protocol is
expected to be implemented in the device driver so that the failed transaction
can be restarted.

This patch enables FIFO overrun / underrun interrupts in DMA case and adds a
handler for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Andy Shevchenko
9f14538ecd spi: dw-mid: split dma_setup() from dma_transfer()
The patch splits DMA preparatory code to dma_setup() callback. The change also
converts transfer_one() to program DMA whenever the transfer is DMA mapped. The
change is a follow up of the converion to use SPI core transfer_one_message().
Since the DMA mapped transfers can be interleaved with PIO ones the DMA related
configuration should respect that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Andy Shevchenko
e31abce778 spi: dw-mid: convert value of dma_width to enum dma_slave_buswidth
DMAEngine has a specific type to be used for bus width. This patch converts the
code to use the values of the specific type when configure DMA transfer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:11:13 +00:00
Mark Brown
0365fbd4bb Merge branch 'fix/dw' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi into spi-dw 2015-03-09 18:11:06 +00:00
Michal Simek
38b6484e5b spi: cadence: Remove Kconfig dependency
Remove Kconfig dependency and enable driver for
all ARCHs.
Also update help description.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-09 18:09:30 +00:00
Lars-Peter Clausen
ea022bbb00 spi: Remove support for legacy PM
All SPI drivers have been converted from legacy suspend/resume callbacks to
dev_pm_ops. So we can finally remove support for legacy PM from the SPI
core.

Since there aren't any special bus specific things to do during
suspend/resume and since the PM core will automatically fallback directly to
using the device's PM ops if no bus PM ops are specified there is no need to
have any special SPI bus PM ops.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-08 19:57:55 +00:00
Andy Shevchenko
854d2f241d spi: dw-mid: clear BUSY flag fist and test other one
The logic of DMA completion is broken now since test_and_clear_bit() never
returns the other bit is set. It means condition are always false and we have
spi_finalize_current_transfer() called per each DMA completion which is wrong.

The patch fixes logic by clearing BUSY bit first and then check for the other
one.

Fixes: 30c8eb52cc4a (spi: dw-mid: split rx and tx callbacks when DMA)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-03-07 11:22:02 +00:00
Andy Gross
612762e82a spi: qup: Add DMA capabilities
This patch adds DMA capabilities to the spi-qup driver.  If DMA channels are
present, the QUP will use DMA instead of block mode for transfers to/from SPI
peripherals for transactions larger than the length of a block.

Signed-off-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Ivan T. Ivanov <iivanov@mm-sol.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-07 11:21:20 +00:00
Ivan T. Ivanov
12cb89e37a spi: qup: Fix cs-num DT property parsing
num-cs is 32 bit property, don't read just upper 16 bits.

Fixes: 4a8573abe965 (spi: qup: Remove chip select function)
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-03-07 11:00:51 +00:00
Mark Brown
60c1beeff4 Merge remote-tracking branches 'spi/fix/atmel', 'spi/fix/doc', 'spi/fix/dw', 'spi/fix/img-spfi', 'spi/fix/pl022' and 'spi/fix/ti-qspi' into spi-linus 2015-03-06 21:10:56 +00:00
Andy Shevchenko
c22c62db3f spi: dw: move to SPI core message handling
This patch removes a lot of duplicate code since SPI core provides a nice
message handling.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 20:33:38 +00:00
Mark Brown
3e00803a97 Merge branch 'topic/err' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi into spi-dw 2015-03-06 20:33:19 +00:00
Andy Shevchenko
0b2e8915ea spi: dw: program registers as soon as possible
This patch refactors the code in pump_transfers() to reprogram the registers
immediately when we have a new configuration data. The behaviour is slightly
modified:
 - chip is always disabled and reenabled
 - CTRL0 is always reprogrammed

This change allows to do a further refactoring and simplier conversion to use
SPI core DMA routines in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 20:29:03 +00:00
Andy Shevchenko
45746e82cf spi: dw: make sure SPI controller is enabled
The error handling is partially broken since the controller is disabled on
error and is not re-enabled until condition occurs, i.e. mode (poll, PIO/DMA),
chip (cs_change), or speed (clk_div) is changed. In the result of these changes
we will have a predictable state of the SPi controller independently on how
successfull was a previous transfer.

The patch disables interrupts and re-enables the SPI controller wherever it
needs to be done. Thus most of the time the SPI controller is kept enabled. The
runtime PM, when it will be implemented, must take care of the controller
disabling and re-enabling.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 20:29:03 +00:00
Alexander Sverdlin
cd6fa8d2ca spi: pl022: Fix race in giveback() leading to driver lock-up
Commit fd316941c ("spi/pl022: disable port when unused") introduced a race,
which leads to possible driver lock up (easily reproducible on SMP).

The problem happens in giveback() function where the completion of the transfer
is signalled to SPI subsystem and then the HW SPI controller is disabled. Another
transfer might be setup in between, which brings driver in locked-up state.

Exact event sequence on SMP:

core0                                   core1

                                        => pump_transfers()
                                        /* message->state == STATE_DONE */
                                          => giveback()
                                            => spi_finalize_current_message()

=> pl022_unprepare_transfer_hardware()
=> pl022_transfer_one_message
  => flush()
  => do_interrupt_dma_transfer()
    => set_up_next_transfer()
    /* Enable SSP, turn on interrupts */
    writew((readw(SSP_CR1(pl022->virtbase)) |
           SSP_CR1_MASK_SSE), SSP_CR1(pl022->virtbase));

...

=> pl022_interrupt_handler()
  => readwriter()

                                        /* disable the SPI/SSP operation */
                                        => writew((readw(SSP_CR1(pl022->virtbase)) &
                                                  (~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));

Lockup! SPI controller is disabled and the data will never be received. Whole
SPI subsystem is waiting for transfer ACK and blocked.

So, only signal transfer completion after disabling the controller.

Fixes: fd316941c (spi/pl022: disable port when unused)
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-03-06 19:45:55 +00:00
Alexander Sverdlin
7183d1ebda spi: pl022: Remove dead code
"flag" variable does nothing, remove it.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 19:45:23 +00:00
Alexander Sverdlin
85fa4e1f09 spi: pl022: Don't touch unspecified bits in interrupt mask
PL022 Programmers model explicitely states "do not modify undefined register
bits". Correct the "all enable" interrupt mask so that it only enables defined
ones.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 19:45:20 +00:00
Alexander Sverdlin
45b064d73d spi: pl022: Remove incorrect TxFIFO full reporting
According to PL022 specification, TNF bit states for "Transmit FIFO Not full".
So the logic here is inverted. But "Receive Overrun Interrupt", which is handled
here, is only triggered on Rx errors. So instead of fixing the if statement,
remove the whole message.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 19:45:17 +00:00
Andy Shevchenko
2291793cc4 spi/rockchip: do an error handling in proper time
There was handle_err() callback introduced that is dedicated for error
handling. The patch moves error handling to this callback.

Cc: Heiko Stuebner <heiko@sntech.de>
Cc: linux-rockchip@lists.infradead.org
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 19:41:57 +00:00
Andy Shevchenko
b716c4ffc6 spi: introduce master->handle_err() callback
This callback would be useful to handle an error that occurs in the generic
implementation of transfer_one_message(). The good candidate for this is to
drain FIFO and / or to terminate DMA transfers when timeout happened.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-06 19:41:56 +00:00
Andy Shevchenko
c9dafb27c8 spi: dw-mid: avoid potential NULL dereference
When DMA descriptor allocation fails we should not try to assign any fields in
the bad descriptor. The patch adds the necessary checks for that.

Fixes: 7063c0d942a1 (spi/dw_spi: add DMA support)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-03-06 11:23:26 +00:00
Sifan Naeem
6e0050ec8e spi: img-spfi: Remove udelay in soft reset
Removing the udelay between setting and clearing the soft reset bit in
the spfi control register as it is not required.

Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-03 14:27:01 +00:00
Sifan Naeem
f165ed6337 spi: img-spfi: Verify max spfi transfer length
Maximum transfer length supported by SPFI is 65535, this is limited
by the number of bits available in SPFI TSize register to represent
the transfer size.
For transfer requests larger than the maximum supported the driver
will return an invalid argument error.

Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-03 14:26:34 +00:00
Stefan Agner
e8361f70a8 spi: spi-imx: use correct enumeration type
The fourth argument of dmaengine_prep_slave_sg needs to be of the
enumeration type dma_transfer_direction instead of dma_data_direction.
Since the used enumeration values actually stay the same, this is not
an actual issue at runtime.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-03-03 09:58:24 +00:00
Torsten Fleischer
76e1d14b31 spi: atmel: Fix interrupt setup for PDC transfers
Additionally to the current DMA transfer the PDC allows to set up a next DMA
transfer. This is useful for larger SPI transfers.

The driver currently waits for ENDRX as end of the transfer. But ENDRX is set
when the current DMA transfer is done (RCR = 0), i.e. it doesn't include the
next DMA transfer.
Thus a subsequent SPI transfer could be started although there is currently a
transfer in progress. This can cause invalid accesses to the SPI slave devices
and to SPI transfer errors.

This issue has been observed on a hardware with a M25P128 SPI NOR flash.

So instead of ENDRX we should wait for RXBUFF. This flag is set if there is
no more DMA transfer in progress (RCR = RNCR = 0).

Signed-off-by: Torsten Fleischer <torfl6749@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-02-26 11:34:23 +09:00
Andy Shevchenko
9d239d353c spi: dw: revisit FIFO size detection again
The commit d297933cc7fc (spi: dw: Fix detecting FIFO depth) tries to fix the
logic of the FIFO detection based on the description on the comments. However,
there is a slight difference between numbers in TX Level and TX FIFO size.

So, by specification the FIFO size would be in a range 2-256 bytes. From TX
Level prospective it means we can set threshold in the range 0-(FIFO size - 1)
bytes. Hence there are currently two issues:
  a) FIFO size 2 bytes is actually skipped since TX Level is 1 bit and could be
     either 0 or 1 byte;
  b) FIFO size is incorrectly decreased by 1 which already done by meaning of
     TX Level register.

This patch fixes it eventually right.

Fixes: d297933cc7fc (spi: dw: Fix detecting FIFO depth)
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
2015-02-26 11:09:51 +09:00
Andy Shevchenko
1a18f9f753 spi: dw: always reprogram CTRL0
Instead of an additional reading from the register let's update it even if the
value is kept the same.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-24 23:43:34 +09:00
Andy Shevchenko
341c7dc7c0 spi: dw: refactor code that handles clk_div
This patch does the following changes:

a) the calculation of clk_div is simplified to oneliner;

b) chip->clk_div is updated if clk_div is not zero, therefore the condition is
   simplified by using chip->clk_div in both cases;

c) while here, the redundant parentheses are removed.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-24 23:43:34 +09:00
Andy Shevchenko
ea11370fff spi: dw: get TX level without an additional variable
There is no need to have an additional variable to get a TX level. The patch
refactors this piece of code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-24 23:43:34 +09:00
Andy Shevchenko
39bc03bfec spi: dw: move piece of code out of condition
There is no sense to keep a member assignment in the internal structure inside
the condition which reprograms HW. It makes code readability better if kept
outside of the condition.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-02-24 23:43:33 +09:00