Commit Graph

120 Commits

Author SHA1 Message Date
David Brownell
4b1badf5d9 [PATCH] SPI: define null tx_buf to mean "shift out zeroes"
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>
2006-12-30 10:56:42 -08:00
David Brownell
980a01c9bf [PATCH] SPI: infrastructure to initialize spi_device.mode early
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>
2006-06-28 15:51:01 -07:00
David Brownell
a020ed7521 [PATCH] SPI: busnum == 0 needs to work
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>
2006-05-16 14:33:57 -07:00
David Brownell
ccf77cc4af [PATCH] SPI: devices can require LSB-first encodings
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>
2006-05-16 14:33:57 -07:00
Kumar Gala
ff9f4771b5 [PATCH] SPI: Renamed bitbang_transfer_setup to spi_bitbang_setup_transfer and export it
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>
2006-05-16 14:33:57 -07:00
David Brownell
747d844ee9 [PATCH] SPI: spi whitespace fixes
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>
2006-05-16 14:33:56 -07:00
Imre Deak
4cff33f94f [PATCH] SPI: per-transfer overrides for wordsize and clocking
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>
2006-05-16 14:33:56 -07:00
Imre Deak
d5b415c95f Input: ads7846 - improve filtering for thumb press accuracy
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>
2006-04-26 00:13:18 -04:00
Imre Deak
c9e617a563 Input: ads7846 - handle IRQs that were latched during disabled IRQs
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>
2006-04-11 23:44:05 -04:00
Imre Deak
0b7018aae7 Input: ads7846 - debouncing and rudimentary sample filtering
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>
2006-04-11 23:42:03 -04:00
Andrew Morton
5d870c8e21 [PATCH] spi: remove fastcall crap
gcc4 generates warnings when a non-FASTCALL function pointer is assigned to a
FASTCALL one.  Perhaps it has taste.

Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:56 -08:00
Vitaly Wool
8275c642cc [PATCH] spi: use linked lists rather than an array
This makes the SPI core and its users access transfers in the SPI message
structure as linked list not as an array, as discussed on LKML.

From: David Brownell <dbrownell@users.sourceforge.net>

  Updates including doc, bugfixes to the list code, add
  spi_message_add_tail().  Plus, initialize things _before_ grabbing the
  locks in some cases (in case it grows more expensive).  This also merges
  some bitbang updates of mine that didn't yet make it into the mm tree.

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: Dmitry Pervushin <dpervushin@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:56 -08:00
Mike Lavender
2f9f762879 [PATCH] spi: M25 series SPI flash
This was originally a driver for the ST M25P80 SPI flash.  It's been
updated slightly to handle other M25P series chips.

For many of these chips, the specific type could be probed, but for now
this just requires static setup with flash_platform_data that lists the
chip type (size, format) and any default partitioning to use.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Mike Lavender <mike@steroidmicros.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:55 -08:00
David Brownell
9904f22a72 [PATCH] spi: add spi_bitbang driver
This adds a bitbanging spi master, hooking up to board/adapter-specific glue
code which knows how to set and read the signals (gpios etc).

This code kicks in after the glue code creates a platform_device with the
right platform_data.  That data includes I/O loops, which will usually
come from expanding an inline function (provided in the header).  One goal
is that the I/O loops should be easily optimized down to a few GPIO register
accesses, in common cases, for speed and minimized overhead.

This understands all the currently defined protocol tweaking options in the
SPI framework, and might eventually serve as as reference implementation.

  - different word sizes (1..32 bits)
  - differing clock rates
  - SPI modes differing by CPOL (affecting chip select and I/O loops)
  - SPI modes differing by CPHA (affecting I/O loops)
  - delays (usecs) after transfers
  - temporarily deselecting chips in mid-transfer

A lot of hardware could work with this framework, though common types of
controller can't reach peak performance without switching to a driver
structure that supports pipelining of transfers (e.g.  DMA queues) and maybe
controllers (e.g.  IRQ driven).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:55 -08:00
David Brownell
2e5a7bd978 [PATCH] spi: ads7836 uses spi_driver
This updates the ads7864 driver to use the new "spi_driver" struct, and
includes some minor unrelated cleanup.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:55 -08:00
David Brownell
0c868461fc [PATCH] SPI core tweaks, bugfix
This includes various updates to the SPI core:

  - Fixes a driver model refcount bug in spi_unregister_master() paths.

  - The spi_master structures now have wrappers which help keep drivers
    from needing class-level get/put for device data or for refcounts.

  - Check for a few setup errors that would cause oopsing later.

  - Docs say more about memory management.  Highlights the use of DMA-safe
    i/o buffers, and zero-initializing spi_message and such metadata.

  - Provide a simple alloc/free for spi_message and its spi_transfer;
    this is only one of the possible memory management policies.

Nothing to break code that already works.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:55 -08:00
David Brownell
b885244eb2 [PATCH] spi: add spi_driver to SPI framework
This is a refresh of the "Simple SPI Framework" found in 2.6.15-rc3-mm1
which makes the following changes:

  * There's now a "struct spi_driver".  This increase the footprint
    of the core a bit, since it now includes code to do what the driver
    core was previously handling directly.  Documentation and comments
    were updated to match.

  * spi_alloc_master() now does class_device_initialize(), so it can
    at least be refcounted before spi_register_master().  To match,
    spi_register_master() switched over to class_device_add().

  * States explicitly that after transfer errors, spi_devices will be
    deselected.  We want fault recovery procedures to work the same
    for all controller drivers.

  * Minor tweaks:  controller_data no longer points to readonly data;
    prevent some potential cast-from-null bugs with container_of calls;
    clarifies some existing kerneldoc,

And a few small cleanups.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:54 -08:00
David Brownell
1d6432fe10 [PATCH] spi: mtd dataflash driver
This is a conversion of the AT91rm9200 DataFlash MTD driver to use the
lightweight SPI framework, and no longer be AT91-specific.  It compiles
down to less than 3KBytes on ARM.

The driver allows board-specific init code to provide platform_data with
the relevant MTD partitioning information, and hotplugs.

This version has been lightly tested.  Its parent at91_dataflash driver has
been pretty well banged on, although kernel.org JFFS2 dataflash support was
acting broken the last time I tried it.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:54 -08:00
David Brownell
ffa458c1bd [PATCH] spi: ads7846 driver
This is a driver for the ADS7846 touchscreen sensor, derived from
the corgi_ts and omap_ts drivers.  Key differences from those two:

  - Uses the new SPI framework (minimalist version)
  - <linux/spi/ads7846.h> abstracts board-specific touchscreen info
  - Sysfs attributes for the temperature and voltage sensors
  - Uses fewer ARM-specific IRQ primitives

The temperature and voltage sensors show up in sysfs like this:

  $ pwd
  /sys/devices/platform/omap-uwire/spi2.0
  $ ls
  bus@          input:event0@ power/        temp1         vbatt
  driver@       modalias      temp0         vaux
  $ cat modalias
  ads7846
  $ cat temp0
  991
  $ cat temp1
  1177
  $

So far only basic testing has been done.  There's a fair amount of hardware
that uses this sensor, and which also runs Linux, which should eventually
be able to use this driver.

One portability note may be of special interest.  It turns out that not all
SPI controllers are happy issuing requests that do things like "write 8 bit
command, read 12 bit response".  Most of them seem happy to handle various
word sizes, so the issue isn't "12 bit response" but rather "different rx
and tx write sizes", despite that being a common MicroWire convention.  So
this version of the driver no longer reads 12 bit native-endian words; it
reads 16-bit big-endian responses, then byteswaps them and shifts the
results to discard the noise.

Signed-off-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:54 -08:00
David Brownell
8ae12a0d85 [PATCH] spi: simple SPI framework
This is the core of a small SPI framework, implementing the model of a
queue of messages which complete asynchronously (with thin synchronous
wrappers on top).

  - It's still less than 2KB of ".text" (ARM).  If there's got to be a
    mid-layer for something so simple, that's the right size budget.  :)

  - The guts use board-specific SPI device tables to build the driver
    model tree.  (Hardware probing is rarely an option.)

  - This version of Kconfig includes no drivers.  At this writing there
    are two known master controller drivers (PXA/SSP, OMAP MicroWire)
    and three protocol drivers (CS8415a, ADS7846, DataFlash) with LKML
    mentions of other drivers in development.

  - No userspace API.  There are several implementations to compare.
    Implement them like any other driver, and bind them with sysfs.

The changes from last version posted to LKML (on 11-Nov-2005) are minor,
and include:

  - One bugfix (removes a FIXME), with the visible effect of making device
    names be "spiB.C" where B is the bus number and C is the chipselect.

  - The "caller provides DMA mappings" mechanism now has kerneldoc, for
    DMA drivers that want to be fancy.

  - Hey, the framework init can be subsys_init.  Even though board init
    logic fires earlier, at arch_init ... since the framework init is
    for driver support, and the board init support uses static init.

  - Various additional spec/doc clarifications based on discussions
    with other folk.  It adds a brief "thank you" at the end, for folk
    who've helped nudge this framework into existence.

As I've said before, I think that "protocol tweaking" is the main support
that this driver framework will need to evolve.

From: Mark Underwood <basicmark@yahoo.com>

  Update the SPI framework to remove a potential priority inversion case by
  reverting to kmalloc if the pre-allocated DMA-safe buffer isn't available.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 16:29:54 -08:00