Since the changes to the bitbang driver, there is the possibility we will
be called with either the speed_hz or bpw values zero. We take these to
mean that the default values (8 bits per word, or maximum bus speed).
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the clock rate calculation may round as pleased, which means
that it is possible that we will round down and end up with a faster clock
rate than intended.
Change the calculation to use DIV_ROUND_UP() to ensure that we end up with
a clock rate either the same as or lower than the user requested one.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When data is read through DMA, the last element must be read separately
through the RX register. It cannot be transferred by the DMA. For
further details see e.g. OMAP35x TRM (table 19-16).
Without the fix the driver causes extra clocks to be clocked to the bus
after DMA RX operations. This can cause interesting behaviour with some
devices.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com>
[aaro.koskinen@nokia.com: Simplified the patch while keeping the idea.]
Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently mcspi wake-ups are not enabled. This might cause cases where
OMAP is not waking up on mcspi events.
Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bugfix to spi_bitbang infrastructure: make sure to always set transfer
parameters on the first pass through the message's per-transfer loop.
This can matter with drivers that replace the per-word or per-buffer
transfer primitives, on busses with multiple SPI devices.
Previously, this could have started messages using the settings left after
previous messages. The problem was observed when a high speed chip
(m25p80 type flash) was running very slowly because a low speed device
(avr8 microcontroller) had previously used the bus. Similar faults could
have driven the low speed device too fast, or used an unexpected word
size.
Acked-by: Steven A. Falco <sfalco@harris.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new spi_master.flags word listing constraints relevant to that
controller. Define the first constraint bit: a half duplex restriction.
Include that constraint in the OMAP1 MicroWire controller driver.
Have the mmc_spi host be the first customer of this flag. Its coding
relies heavily on full duplex transfers, so it must fail when the
underlying controller driver won't perform them.
(The spi_write_then_read routine could use it too: use the
temporarily-withdrawn full-duplex speedup unless this flag is set, in
which case the existing code applies. Similarly, any spi_master
implementing only SPI_3WIRE should set the flag.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add two new spi_device.mode bits to accomodate more protocol options, and
pass them through to usermode drivers:
* SPI_NO_CS ... a second 3-wire variant, where the chipselect
line is removed instead of a data line; transfers are still
full duplex.
This obviously has STRONG protocol implications since the
chipselect transitions can't be used to synchronize state
transitions with the SPI master.
* SPI_READY ... defines open drain signal that's pulled low
to pause the clock. This defines a 5-wire variant (normal
4-wire SPI plus READY) and two 4-wire variants (READY plus
each of the 3-wire flavors).
Such hardware flow control can be a big win. There are ADC
converters and flash chips that expose READY signals, but not
many host controllers support it today.
The spi_bitbang code should be changed to use SPI_NO_CS instead of its
current nonportable hack. That's a mode most hardware can easily support
(unlike SPI_READY).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Paulraj, Sandeep" <s-paulraj@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since we renamed the file, we might want to rename the file internals too.
Though we don't bother with changing platform driver name and platform
module alias. The stuff is legacy and hopefully we'll remove it soon.
Suggested-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The driver handles MPC83xx, MPC85xx and MPC86xx SPI controllers, so rename
the file for clarity.
Suggested-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch removes #if 0'ed code, and spi_mpc83xx->busy variable that is
used by that dead snippet only.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mpc83xx_spi_work() is quite large, with up to five indentation levels and
is quite difficult to read.
So, split the function in two parts:
1. mpc83xx_spi_work() now only traverse queued spi messages;
2. mpc83xx_spi_do_one_msg() only manages single messages.
There should be no functional changes.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Checkpatch is spitting errors when seeing the rename patch, so fix the
errors prior to moving.
Following errors and warnings were fixed:
WARNING: Use #include <linux/io.h> instead of <asm/io.h>
#1027: FILE: drivers/spi/spi_mpc8xxx.c:37:
+#include <asm/io.h>
ERROR: "foo * bar" should be "foo *bar"
#1111: FILE: drivers/spi/spi_mpc8xxx.c:121:
+static inline void mpc83xx_spi_write_reg(__be32 __iomem * reg, u32 val)
ERROR: "foo * bar" should be "foo *bar"
#1116: FILE: drivers/spi/spi_mpc8xxx.c:126:
+static inline u32 mpc83xx_spi_read_reg(__be32 __iomem * reg)
ERROR: "foo * bar" should be "foo *bar"
#1125: FILE: drivers/spi/spi_mpc8xxx.c:135:
+ type * rx = mpc83xx_spi->rx; \
ERROR: "foo * bar" should be "foo *bar"
#1135: FILE: drivers/spi/spi_mpc8xxx.c:145:
+ const type * tx = mpc83xx_spi->tx; \
WARNING: suspect code indent for conditional statements (16, 25)
#1504: FILE: drivers/spi/spi_mpc8xxx.c:514:
+ while (((event =
[...]
+ cpu_relax();
Following warnings were left over, since fixing them will hurt the
readability. We'd better fix them by lowering the indentation level by
splitting mpc83xx_spi_work function into two parts.
WARNING: line over 80 characters
#1371: FILE: drivers/spi/spi_mpc8xxx.c:381:
+ status = mpc83xx_spi_setup_transfer(spi, t);
WARNING: line over 80 characters
#1392: FILE: drivers/spi/spi_mpc8xxx.c:402:
+ mpc83xx_spi_chipselect(spi, BITBANG_CS_INACTIVE);
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is needed for some underlaying GPIO controllers that may be a bit
slow, or if chip-select signal need some time to stabilize.
For what it's worth, we already have the similar delay for chip-select
de-assertion case.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a platform is running at high frequencies it's not always possible to
scale-down a frequency to a requested value, and using mmc_spi driver this
leads to the following printk flood during card polling:
...
mmc_spi spi32766.0: Requested speed is too low: 400000 Hz. Will use
520828 Hz instead.
mmc_spi spi32766.0: Requested speed is too low: 400000 Hz. Will use
520828 Hz instead.
...
Fix this by using WARN_ONCE(), it's better than the flood, and also better
than turning dev_err() into dev_dbg(), since we actually want to warn that
some things may not work correctly.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With this patch we'll able to select spi_mpc83xx driver on the MPC86xx
platforms. Let the driver depend on FSL_SOC, so we don't have to worry
about Kconfig anymore.
Also remove the "experimental" dependency, the driver has been tested to
work on a various hardware, and surely not experimental anymore.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Buffer needs not be dma-safe, not rx data length.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a7bb3909b3 ("spi: pxa2xx_spi:
introduce chipselect GPIO to simplify the common cases") introduces
chipselect GPIO, and configures the CS polarity using SPI_CS_HIGH
spi->mode flag. Add SPI_CS_HIGH to the allowed modes.
Signed-off-by: Daniel Ribeiro <drwyrm@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mpc52xx_psc_spi driver is the last user of the legacy activate_cs and
deactivate_cs callbacks, so convert the driver to the cs_control hook and
remove the legacy callbacks from fsl_spi_platform_data struct.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move some common spi_setup() error checks into the SPI framework from the
spi_master controller drivers:
- Add a new "mode_bits" field to spi_master
- Use that in spi_setup to validate the spi->mode value being
requested. Setting this new field is now mandatory for any
controller supporting more than vanilla SPI_MODE_0.
- Update all spi_master drivers to:
* Initialize that field
* Remove current spi_setup() checks using that value.
This is a net minor code shrink.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Start moving some spi_setup() functionality into the SPI core from the
various spi_master controller drivers:
- Make that function stop being an inline;
- Move two common idioms from drivers into that new function:
* Default bits_per_word to 8 if that field isn't set
* Issue a standardized dev_dbg() message
This is a net minor source code shrink, and supports enhancments found in
some follow-up patches.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
bfin_spi_flush() returns limit, which reaches -1 upon timeout. but in
function bfin_spi_pump_transfers() it is compared with 0.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* akpm: (182 commits)
fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset
fbdev: *bfin*: fix __dev{init,exit} markings
fbdev: *bfin*: drop unnecessary calls to memset
fbdev: bfin-t350mcqb-fb: drop unused local variables
fbdev: blackfin has __raw I/O accessors, so use them in fb.h
fbdev: s1d13xxxfb: add accelerated bitblt functions
tcx: use standard fields for framebuffer physical address and length
fbdev: add support for handoff from firmware to hw framebuffers
intelfb: fix a bug when changing video timing
fbdev: use framebuffer_release() for freeing fb_info structures
radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb?
s3c-fb: CPUFREQ frequency scaling support
s3c-fb: fix resource releasing on error during probing
carminefb: fix possible access beyond end of carmine_modedb[]
acornfb: remove fb_mmap function
mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF
mb862xxfb: restrict compliation of platform driver to PPC
Samsung SoC Framebuffer driver: add Alpha Channel support
atmel-lcdc: fix pixclock upper bound detection
offb: use framebuffer_alloc() to allocate fb_info struct
...
Manually fix up conflicts due to kmemcheck in mm/slab.c
Do not take the size of a pointer to determine the size of the pointed-to
type.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin: (27 commits)
Blackfin: hook up new rt_tgsigqueueinfo syscall
Blackfin: improve CLKIN_HZ config default
Blackfin: initial support for ftrace grapher
Blackfin: initial support for ftrace
Blackfin: enable support for LOCKDEP
Blackfin: add preliminary support for STACKTRACE
Blackfin: move custom sections into sections.h
Blackfin: punt unused/wrong mutex-dec.h
Blackfin: add support for irqflags
Blackfin: add support for bzip2/lzma compressed kernel images
Blackfin: convert Kconfig style to def_bool
Blackfin: bf548-ezkit: update smsc911x resources
Blackfin: update aedos-ipipe code to upstream 1.10-00
Blackfin: bf537-stamp: update ADP5520 resources
Blackfin: bf518f-ezbrd: fix SPI CS for SPI flash
Blackfin: define SPI IRQ in board resources
Blackfin: do not configure the UART early if on wrong processor
Blackfin: fix deadlock in SMP IPI handler
Blackfin: fix flag storage for irq funcs
Blackfin: push down exception oops checking
...
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (417 commits)
MAINTAINERS: EB110ATX is not ebsa110
MAINTAINERS: update Eric Miao's email address and status
fb: add support of LCD display controller on pxa168/910 (base layer)
[ARM] 5552/1: ep93xx get_uart_rate(): use EP93XX_SYSCON_PWRCNT and EP93XX_SYSCON_PWRCN
[ARM] pxa/sharpsl_pm: zaurus needs generic pxa suspend/resume routines
[ARM] 5544/1: Trust PrimeCell resource sizes
[ARM] pxa/sharpsl_pm: cleanup of gpio-related code.
[ARM] pxa/sharpsl_pm: drop set_irq_type calls
[ARM] pxa/sharpsl_pm: merge pxa-specific code into generic one
[ARM] pxa/sharpsl_pm: merge the two sharpsl_pm.c since it's now pxa specific
[ARM] sa1100: remove unused collie_pm.c
[ARM] pxa: fix the conflicting non-static declarations of global_gpios[]
[ARM] 5550/1: Add default configure file for w90p910 platform
[ARM] 5549/1: Add clock api for w90p910 platform.
[ARM] 5548/1: Add gpio api for w90p910 platform
[ARM] 5551/1: Add multi-function pin api for w90p910 platform.
[ARM] Make ARM_VIC_NR depend on ARM_VIC
[ARM] 5546/1: ARM PL022 SSP/SPI driver v3
ARM: OMAP4: SMP: Update defconfig for OMAP4430
ARM: OMAP4: SMP: Enable SMP support for OMAP4430
...
This adds a driver for the ARM PL022 PrimeCell SSP/SPI
driver found in the U300 platforms as well as in some
ARM reference hardware, and in a modified version on the
Nomadik board.
Reviewed-by: Alessandro Rubini <rubini-list@gnudd.com>
Reviewed-by: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move all the gpio functions out of <mach/hardware.h> as
this file is for defining the generic IO base addresses
for the kernel IO calls.
Make a new header <mach/gpio-fns.h> to take this and
include it via the chain from <linux/gpio.h> which is
what most of these files should be using (and will be
changed as soon as possible).
Note, this does make minor changes to some drivers but
should not mess up any pending merges.
CC: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
CC: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
setup() may fail before ctldata is set, causing a kernel panic on
cleanup().
Signed-off-by: Daniel Ribeiro <drwyrm@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch-imx is superseeded by the MXC architecture support.
This patch removes arch-imx from the build system.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
On line 944 the return value of flush() is considered as a boolean,
but limit reaches -1 upon timeout which evaluates to true.
On 540, 594, 720 the same occurs for wait_ssp_rx_stall()
On 536 the same occurs for wait_dma_channel_stop()
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If DMA is enabled, any spi_sync call after suspend/resume would block
forever, because DRCMR is lost on suspend. This patch restores DRCMR to
the same values set by probe.
Signed-off-by: Daniel Ribeiro <drwyrm@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The "simplify spi_write_then_read()" patch included two regressions from
the 2.6.27 behaviors:
- The data it wrote out during the (full duplex) read side
of the transfer was not zeroed.
- It fails completely on half duplex hardware, such as
Microwire and most "3-wire" SPI variants.
So, revert that patch. A revised version should be submitted at some
point, which can get the speedup on standard hardware (full duplex)
without breaking on less-capable half-duplex stuff.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: <stable@kernel.org> [2.6.28.x, 2.6.29.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Most SPI peripherals use GPIOs as their chip selects, introduce .gpio_cs
for this.
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With a postfix decrement limit will reach -1 rather than 0, so the warning
will not be issued.
Also, add a cpu_relax() into the busy-wait loop.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Mariusz Ceier <mceier@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1. Rewrite of the non-dma data transfer functions to use only ONE mode
of TIMOD (TIMOD=0x1). With TIMOD=0, it was not possible to set the TX
bit pattern. So the TDBR = 0xFFFF inside the read calls won't work.
2. Clear SPI_RDBR before reading and before duplex transfer.
Otherwise the garbage data in RDBR will get read. Since mmc_spi uses a
lot of duplex transfers, this is the main cause of mmc_spi failure.
3. Poll RXS for transfer completion. Polling SPIF or TXS cannot
guarantee transfer completion. This may interrupt a transfer before it
is finished. Also this may leave garbage data in buffer and affect
next transfer.
[Yi Li <yi.li@analog.com>: add a field "u16 idle_tx_val" in "struct
bfin5xx_spi_chip" to specify the value to transmit if no TX value
is supplied.]
Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for GPIO controlled SPI Chip Selects. To make use of this
feature, set chip_select = 0 and add a proper cs_gpio to your
controller_data.
struct spi_board_info
.chip_select = 0
struct bfin5xx_spi_chip
.cs_gpio = GPIO_P###
There are various SPI devices that require SPI MODE_0, and need to have
the Chip Selects asserted during the entire transfer. Consider using
SPI_MODE_3 (SPI_CPHA | SPI_CPOL) if your device allows it.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Do this because when things crash, we get simple names like "setup" and
"start_queue" which is pretty difficult to trace back to the real thing:
the spi driver
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
According to comments in linux/spi/spi.h:
* All SPI transfers start with the relevant chipselect active. Normally
* it stays selected until after the last transfer in a message. Drivers
* can affect the chipselect signal using cs_change.
*
* (i) If the transfer isn't the last one in the message, this flag is
* used to make the chipselect briefly go inactive in the middle of the
* message. Toggling chipselect in this way may be needed to terminate
* a chip command, letting a single spi_message perform all of group of
* chip transactions together.
*
* (ii) When the transfer is the last one in the message, the chip may
* stay selected until the next transfer. On multi-device SPI busses
* with nothing blocking messages going to other devices, this is just
* a performance hint; starting a message to another device deselects
* this one. But in other cases, this can be used to ensure correctness.
* Some devices need protocol transactions to be built from a series of
* spi_message submissions, where the content of one message is determined
* by the results of previous messages and where the whole transaction
* ends when the chipselect goes intactive.
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This bug can be observed when two SPI devices are sharing the spi bus: One
device is set as SPI CS 7, another one is using SPI CS 4.
In spi_bfin5xx.c: cs_active(), cs_deactive() are used to control SPI_FLG
register. From the debug bellow:
cs_active: flag: 0x7f91, chip->flag: 0x7f80, cs: 7
cs_active: flag: 0xef91, chip->flag: 0xef10, cs: 4
When device A (cs_7) activate CS 7, SPI_FLG is set as 0x7f91 (however,
SPI_FLG should be set as 0x7f80, or 0x6f91 if in broadcast mode).
Due to some HW bug (very possibly), if SPI_FLG is set as 0x7f91, SPISSEL7
is asserted, however SPISSEL4 will be asserted too (I can see this using
the scope). This is unreasonable according to HRM.
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
