Update two points in the SPI interface documentation:
- Update description of the "chip stays selected after message ends"
mode. In some cases it's required for correctness; it isn't just a
performance tweak. (Yes: to use this mode on mult-device busses, another
programming interface will be needed. One draft has been circulated
already.)
- Clarify spi_setup(), highlighting that callers must ensure that no
requests are queued (can't change configuration except between I/Os), and
that the device must be deselected when this returns (which is a key part
of why it's called during device init).
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>
Various documentation updates for the SPI infrastructure, to clarify things
that may not have been clear, to cope with lack of editing, and fix
omissions.
Also, plug SPI into the kernel-api DocBook template, and fix all the
resulting glitches in document generation.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a filesystem API for <linux/spi/spi.h> stack. The initial version of
this interface is purely synchronous.
dbrownell@users.sourceforge.net:
Cleaned up, bugfixed; much simplified; added preliminary documentation.
Works with mdev given CONFIG_SYSFS_DEPRECATED; and presumably udev.
Updated SPI_IOC_MESSAGE ioctl to full spi_message semantics, supporting
groups of one or more transfers (each of which may be full duplex if
desired).
This is marked as EXPERIMENTAL with an explicit disclaimer that the API
(notably the ioctls) is subject to change.
Signed-off-by: Andrea Paterniani <a.paterniani@swapp-eng.it>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds support for the Analog Devices Blackfin processor architecture, and
currently supports the BF533, BF532, BF531, BF537, BF536, BF534, and BF561
(Dual Core) devices, with a variety of development platforms including those
avaliable from Analog Devices (BF533-EZKit, BF533-STAMP, BF537-STAMP,
BF561-EZKIT), and Bluetechnix! Tinyboards.
The Blackfin architecture was jointly developed by Intel and Analog Devices
Inc. (ADI) as the Micro Signal Architecture (MSA) core and introduced it in
December of 2000. Since then ADI has put this core into its Blackfin
processor family of devices. The Blackfin core has the advantages of a clean,
orthogonal,RISC-like microprocessor instruction set. It combines a dual-MAC
(Multiply/Accumulate), state-of-the-art signal processing engine and
single-instruction, multiple-data (SIMD) multimedia capabilities into a single
instruction-set architecture.
The Blackfin architecture, including the instruction set, is described by the
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
http://blackfin.uclinux.org/gf/download/frsrelease/29/2549/Blackfin_PRM.pdf
The Blackfin processor is already supported by major releases of gcc, and
there are binary and source rpms/tarballs for many architectures at:
http://blackfin.uclinux.org/gf/project/toolchain/frs There is complete
documentation, including "getting started" guides available at:
http://docs.blackfin.uclinux.org/ which provides links to the sources and
patches you will need in order to set up a cross-compiling environment for
bfin-linux-uclibc
This patch, as well as the other patches (toolchain, distribution,
uClibc) are actively supported by Analog Devices Inc, at:
http://blackfin.uclinux.org/
We have tested this on LTP, and our test plan (including pass/fails) can
be found at:
http://docs.blackfin.uclinux.org/doku.php?id=testing_the_linux_kernel
[m.kozlowski@tuxland.pl: balance parenthesis in blackfin header files]
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Aubrey Li <aubrey.li@analog.com>
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a bug in the cleanup of an spi_bitbang bus.
The workqueue associated with the bus was destroyed before the call to
spi_unregister_master. That meant that spi devices on that bus would be
unable to do IO in their remove method. The shutdown flag should have been
able to prevent a segfault, but was never getting set. By waiting to
destroy the workqueue until after the master is unregistered, devices are
able to do IO in their remove methods. An added benefit is that neither
the shutdown flag nor a wait for the queue of messages to empty is needed.
Signed-off-by: Chris Lesiak <chris.lesiak@licor.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>
This is adds a simple SPI EEPROM driver, providing access to the EEPROM
through sysfs much like the I2C "eeprom" driver ... except this driver
supports write access, and multiple EEPROM sizes.
From: "Tuppa, Walter" <walter.tuppa@siemens.com>
Since I have EEPROMs on SPI with different address sizing, I made some
changes to your at25.c to support them. Works perfectly. (Also includes a
small bugfix for the "what size address" test.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Walter Tuppa <walter.tuppa@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This clarifies some aspects of the SPI programming interface, based on
feedback from Hans-Peter Nilsson. The in-memory representation of words is
right-aligned, so for example a twelve bit word is stored using sixteen bits
with four undefined bits in the MSB. And controller drivers must reject
protocol tweaking modes they do not support.
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>
I'd like to assign NULL to kfree()d members of a structure. I can't do
that without ugly casting (see the PXA patch) when the structure pointed to
is const-qualified. I don't really see a reason why the cleanup method
isn't allowed to alter the object it should clean up. :-)
No, I didn't test the PXA patch, but I verified that the NULL-assignment
doesn't stop me from doing rmmod/insmodding my own spi_bitbang-based
driver.
Signed-off-by: Hans-Peter Nilsson <hp@axis.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>
This reverts commit 2943ecf2ed.
This should go through the SPI maintainer, it was my fault that it did
not. Especially as it conflicts with other patches he has pending.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Converts from using struct "class_device" to "struct device" making
everything show up properly in /sys/devices/ with symlinks from the
/sys/class directory.
Cc: <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some LCDs like the LS041Y3 require a customized filtering
logic for reliable readings, so make the filtering function
replacable through platform specific hooks.
Signed-off-by: Imre Deak <imre.deak@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Some issues were recently turned up with the current specification of what
it means for spi_transfer.tx_buf to be null, as part of transfers which are
(from the SPI protocol driver perspective) pure reads.
Specifically, that it seems better to change the TX behaviour there from
"undefined" to "will shift zeroes". This lets protocol drivers (like the
ads7846 driver) depend on that behavior. It's what most controller drivers
in the tree are already doing (with one exception and one case of driver
wanting-to-oops), it's what Microwire hardware will necessarily be doing,
and it removes an issue whereby certain security audits would need to
define such a value anyway as part of removing covert channels.
This patch changes the specification to require shifting zeroes, and
updates all currently merged SPI controller drivers to do so.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds earlier initialization of spi_device.mode, as needed
on boards using nondefault chipselect polarity. An example would be
ones using the RS5C348 RTC without an external signal inverter between
the RTC chipselect and the SPI controller.
Without this mechanism, the first setup() call for that chip would
wrongly enable chips, corrupting transfers to/from other chips sharing
that SPI bus.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We need to be able to have a "SPI bus 0" matching chip numbering; but
that number was wrongly used to flag dynamic allocation of a bus number.
This patch resolves that issue; now negative numbers trigger dynamic alloc.
It also updates the how-to-write-a-controller-driver overview to mention
this stuff.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add spi_device hook for LSB-first word encoding, and update all the
(in-tree) controller drivers to reject such devices. Eventually,
some controller drivers will be updated to support lsb-first encodings
on the wire; no current drivers need this.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Renamed bitbang_transfer_setup to follow convention of other exported symbols
from spi-bitbang. Exported spi_bitbang_setup_transfer to allow users of
spi-bitbang to use the function in their own setup_transfer.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This removes superfluous whitespace in the <linux/spi/spi.h> header.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some protocols (like one for some bitmap displays) require different clock
speed or word size settings for each transfer in an SPI message. This adds
those parameters to struct spi_transfer. They are to be used when they are
nonzero; otherwise the defaults from spi_device are to be used.
The patch also adds a setup_transfer callback to spi_bitbang, uses it for
messages that use those overrides, and implements it so that the pure
bitbanging code can help resolve any questions about how it should work.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Providing more accurate coordinates for thumb press requires additional
steps in the filtering logic:
- Ignore samples found invalid by the debouncing logic, or the ones that
have out of bound pressure value.
- Add a parameter to repeat debouncing, so that more then two consecutive
good readings are required for a valid sample.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Acked-by: Juha Yrjola <juha.yrjola@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
The pen down IRQ will toggle during each X,Y,Z measurement cycle.
Even though the IRQ is disabled it will be latched and delivered
when after enable_irq. Thus in the IRQ handler we must avoid
starting a new measurement cycle when such an "unwanted" IRQ happens.
Add a get_pendown_state platform function, which will probably
determine this by reading the current GPIO level of the pen IRQ pin.
Move the IRQ reenabling from the SPI RX function to the timer. After
the last power down message the pen IRQ pin is still active for a
while and get_pendown_state would report incorrectly a pen down state.
When suspending we should check the ts->pending flag instead of
ts->pendown, since the timer can be pending regardless of ts->pendown.
Also if ts->pending is set we can be sure that the timer is running,
so no need to rearm it. Similarly if ts->pending is not set we can
be sure that the IRQ is enabled (and the timer is not).
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Some touchscreens seem to oscillate heavily for a while after touching
the screen. Implement support for sampling the screen until we get two
consecutive values that are close enough.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
