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  1. 07 4月, 2013 1 次提交
    • A
      spi: Initialize cs_gpio and cs_gpios with -ENOENT · 446411e1
      由 Andreas Larsson 提交于 
      The return value from of_get_named_gpio is -ENOENT when the given index
matches a hole in the "cs-gpios" property phandle list. However, the
default value of cs_gpio in struct spi_device and entries of cs_gpios in
struct spi_master is -EINVAL, which is documented to indicate that a
GPIO line should not be used for the given spi_device.

This sets the default value of cs_gpio in struct spi_device and entries
of cs_gpios in struct spi_master to -ENOENT. Thus, -ENOENT is the only
value used to indicate that no GPIO line should be used.
Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
      446411e1
  3. 11 2月, 2013 1 次提交
  5. 09 2月, 2013 1 次提交
    • L
      spi: Add helper functions for setting up transfers · 6d9eecd4
      由 Lars-Peter Clausen 提交于 
      Quite often the pattern used for setting up and transferring a synchronous SPI
transaction looks very much like the following:

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(&msg);

This patch adds two new helper functions for handling this case. The first
helper function spi_message_init_with_transfers() takes a spi_message and an
array of spi_transfers. It will initialize the message and then call
spi_message_add_tail() for each transfer in the array. E.g. the following

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

can be rewritten as

	spi_message_init_with_transfers(&msg, xfers, ARRAY_SIZE(xfers));

The second function spi_sync_transfer() takes a SPI device and an array of
spi_transfers. It will allocate a new spi_message (on the stack) and add all
transfers in the array to the message. Finally it will call spi_sync() on the
message.

E.g. the follwing

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(spi, &msg);

can be rewritten as

	struct spi_transfer xfers[] = {
		...
	};

	ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));

A coccinelle script to find such instances will follow.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
      6d9eecd4
  7. 22 11月, 2012 1 次提交
  9. 28 4月, 2012 1 次提交
  11. 10 3月, 2012 1 次提交
    • S
      spi: Trivial warning fix · 8f53602b
      由 Shubhrajyoti D 提交于 
      The loop count i traverses for ntrans which is unsigned
so make the loop count i also unsigned.

Fix the below warning
In file included from drivers/spi/spi-omap2-mcspi.c:38:
include/linux/spi/spi.h: In function 'spi_message_alloc':
include/linux/spi/spi.h:556: warning: comparison between signed and unsigned integer expressions

Cc: Vitaly Wool <vwool@ru.mvista.com>
Signed-off-by: NShubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
      8f53602b
  13. 08 3月, 2012 1 次提交
    • L
      spi: create a message queueing infrastructure · ffbbdd21
      由 Linus Walleij 提交于 
      This rips the message queue in the PL022 driver out and pushes
it into (optional) common infrastructure. Drivers that want to
use the message pumping thread will need to define the new
per-messags transfer methods and leave the deprecated transfer()
method as NULL.

Most of the design is described in the documentation changes that
are included in this patch.

Since there is a queue that need to be stopped when the system
is suspending/resuming, two new calls are implemented for the
device drivers to call in their suspend()/resume() functions:
spi_master_suspend() and spi_master_resume().

ChangeLog v1->v2:
- Remove Kconfig entry and do not make the queue support optional
  at all, instead be more agressive and have it as part of the
  compulsory infrastructure.
- If the .transfer() method is implemented, delete print a small
  deprecation notice and do not start the transfer pump.
- Fix a bitrotted comment.
ChangeLog v2->v3:
- Fix up a problematic sequence courtesy of Chris Blair.
- Stop rather than destroy the queue on suspend() courtesy of
  Chris Blair.
Signed-off-by: NChris Blair <chris.blair@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Tested-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
      ffbbdd21
  15. 18 11月, 2011 1 次提交
  17. 20 5月, 2011 1 次提交
  19. 22 10月, 2010 1 次提交
  21. 18 8月, 2010 1 次提交
  23. 29 6月, 2010 1 次提交
    • E
      spi/mmc_spi: SPI bus locking API, using mutex · cf32b71e
      由 Ernst Schwab 提交于 
      SPI bus locking API to allow exclusive access to the SPI bus, especially, but
not limited to, for the mmc_spi driver.

Coded according to an outline from Grant Likely; here is his
specification (accidentally swapped function names corrected):

It requires 3 things to be added to struct spi_master.
- 1 Mutex
- 1 spin lock
- 1 flag.

The mutex protects spi_sync, and provides sleeping "for free"
The spinlock protects the atomic spi_async call.
The flag is set when the lock is obtained, and checked while holding
the spinlock in spi_async().  If the flag is checked, then spi_async()
must fail immediately.

The current runtime API looks like this:
spi_async(struct spi_device*, struct spi_message*);
spi_sync(struct spi_device*, struct spi_message*);

The API needs to be extended to this:
spi_async(struct spi_device*, struct spi_message*)
spi_sync(struct spi_device*, struct spi_message*)
spi_bus_lock(struct spi_master*)  /* although struct spi_device* might
be easier */
spi_bus_unlock(struct spi_master*)
spi_async_locked(struct spi_device*, struct spi_message*)
spi_sync_locked(struct spi_device*, struct spi_message*)

Drivers can only call the last two if they already hold the spi_master_lock().

spi_bus_lock() obtains the mutex, obtains the spin lock, sets the
flag, and releases the spin lock before returning.  It doesn't even
need to sleep while waiting for "in-flight" spi_transactions to
complete because its purpose is to guarantee no additional
transactions are added.  It does not guarantee that the bus is idle.

spi_bus_unlock() clears the flag and releases the mutex, which will
wake up any waiters.

The difference between spi_async() and spi_async_locked() is that the
locked version bypasses the check of the lock flag.  Both versions
need to obtain the spinlock.

The difference between spi_sync() and spi_sync_locked() is that
spi_sync() must hold the mutex while enqueuing a new transfer.
spi_sync_locked() doesn't because the mutex is already held.  Note
however that spi_sync must *not* continue to hold the mutex while
waiting for the transfer to complete, otherwise only one transfer
could be queued up at a time!

Almost no code needs to be written.  The current spi_async() and
spi_sync() can probably be renamed to __spi_async() and __spi_sync()
so that spi_async(), spi_sync(), spi_async_locked() and
spi_sync_locked() can just become wrappers around the common code.

spi_sync() is protected by a mutex because it can sleep
spi_async() needs to be protected with a flag and a spinlock because
it can be called atomically and must not sleep
Signed-off-by: NErnst Schwab <eschwab@online.de>
[grant.likely@secretlab.ca: use spin_lock_irqsave()]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Tested-by: NMatt Fleming <matt@console-pimps.org>
Tested-by: NAntonio Ospite <ospite@studenti.unina.it>
      cf32b71e
  25. 30 3月, 2010 1 次提交
    • T
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      由 Tejun Heo 提交于 
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  27. 23 9月, 2009 3 次提交
  29. 01 7月, 2009 2 次提交
    • D
      spi: add spi_master flag word · 70d6027f
      由 David Brownell 提交于 
      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: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      70d6027f
    • D
      spi: new spi->mode bits · b55f627f
      由 David Brownell 提交于 
      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: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: "Paulraj, Sandeep" <s-paulraj@ti.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b55f627f
  31. 19 6月, 2009 2 次提交
  33. 22 4月, 2009 1 次提交
  35. 07 4月, 2009 1 次提交
  37. 06 1月, 2009 1 次提交
  39. 05 1月, 2009 1 次提交
  41. 26 7月, 2008 1 次提交
    • G
      spi: split up spi_new_device() to allow two stage registration. · dc87c98e
      由 Grant Likely 提交于 
      spi_new_device() allocates and registers an spi device all in one swoop.
If the driver needs to add extra data to the spi_device before it is
registered, then this causes problems.  This is needed for OF device
tree support so that the SPI device tree helper can add a pointer to
the device node after the device is allocated, but before the device
is registered.  OF aware SPI devices can then retrieve data out of the
device node to populate a platform data structure.

This patch splits the allocation and registration portions of code out
of spi_new_device() and creates two new functions; spi_alloc_device()
and spi_register_device().  spi_new_device() is modified to use the new
functions for allocation and registration.  None of the existing users
of spi_new_device() should be affected by this change.

Drivers using the new API can forego the use of spi_board_info
structure to describe the device layout and populate data into the
spi_device structure directly.

This change is in preparation for adding an OF device tree parser to
generate spi_devices based on data in the device tree.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NDavid Brownell <dbrownell@users.sourceforge.net>
      dc87c98e
  43. 25 7月, 2008 1 次提交
    • G
      spi: make spi_board_info.modalias a char array · 102eb975
      由 Grant Likely 提交于 
      Currently, 'modalias' in the spi_device structure is a 'const char *'.
The spi_new_device() function fills in the modalias value from a passed in
spi_board_info data block.  Since it is a pointer copy, the new spi_device
remains dependent on the spi_board_info structure after the new spi_device
is registered (no other fields in spi_device directly depend on the
spi_board_info structure; all of the other data is copied).

This causes a problem when dynamically propulating the list of attached
SPI devices.  For example, in arch/powerpc, the list of SPI devices can be
populated from data in the device tree.  With the current code, the device
tree adapter must kmalloc() a new spi_board_info structure for each new
SPI device it finds in the device tree, and there is no simple mechanism
in place for keeping track of these allocations.

This patch changes modalias from a 'const char *' to a fixed char array.
By copying the modalias string instead of referencing it, the dependency
on the spi_board_info structure is eliminated and an outside caller does
not need to maintain a separate spi_board_info allocation for each device.

If searched through the code to the best of my ability for any references
to modalias which may be affected by this change and haven't found
anything.  It has been tested with the lite5200b platform in arch/powerpc.

[dbrownell@users.sourceforge.net: cope with linux-next changes: KOBJ_NAME_LEN obliterated, etc]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      102eb975
  45. 22 7月, 2008 1 次提交
  47. 17 10月, 2007 1 次提交
  49. 01 8月, 2007 2 次提交
  51. 18 7月, 2007 1 次提交
  53. 17 6月, 2007 1 次提交
    • D
      spi doc updates · f5a9c77d
      由 David Brownell 提交于 
      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: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f5a9c77d
  55. 09 5月, 2007 1 次提交
  57. 13 2月, 2007 4 次提交
  59. 08 2月, 2007 2 次提交
  61. 31 12月, 2006 1 次提交
    • D
      [PATCH] SPI: define null tx_buf to mean "shift out zeroes" · 4b1badf5
      由 David Brownell 提交于 
      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: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      4b1badf5