Commit graph

40 commits

Author SHA1 Message Date
David Brownell
673c0c0038 spi: core and gpio expanders use subsys_init
Make the SPI external GPIO expander drivers register themselves at
subsys_initcall() time when they're statically linked, and make the SPI
core do its driver model initialization earlier so that's safe.

SOC-integrated GPIOs are available starting very early -- often before
initcalls start to run, or earily in arch_initcall() at latest -- so this
improves consistency, letting more subsystems rely on GPIOs being usable
by their own subsys_initcall() code.

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>
2008-10-16 11:21:38 -07:00
Vernon Sauder
f9b90e39cb spi: simplify spi_write_then_read()
Modify spi_write_then_read() to use one transfer.  This speeds up all
callers, and is a minor code shrink.

Signed-off-by: Vernon Sauder <Vernon.Sauder@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>
2008-10-16 11:21:38 -07:00
David Brownell
e48880e02e spi: bugfix spi_add_device() with duplicate chipselects
When reviewing a recent patch I noticed a potential trouble spot in the
registration of new SPI devices.  The SPI master driver is told to set
the device up before adding it to the driver model, so that it's always
properly set up when probe() is called.  (This is important, because in
the case of inverted chipselects, this device can make the bus misbehave
until it's properly deselected.  It's got to be set up even if no driver
binds to the device.)

The trouble spot is that it doesn't first verify that no other device
has been added using that chipselect.  If such a device has been added,
its configuration gets trashed.  (Fortunately this has not been a common
error!)

The fix here adds an explicit check, and a mutex to protect the relevant
critical region.

[akpm@linux-foundation.org: make the lock local to spi_add_device()]
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>
2008-08-15 08:35:44 -07:00
Grant Likely
dc87c98e8f spi: split up spi_new_device() to allow two stage registration.
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: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
2008-07-25 22:34:29 -04:00
Grant Likely
102eb97564 spi: make spi_board_info.modalias a char array
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: Grant Likely <grant.likely@secretlab.ca>
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>
2008-07-24 10:47:30 -07:00
Greg Kroah-Hartman
695794ae0c Driver Core: add ability for class_find_device to start in middle of list
This mirrors the functionality that driver_find_device has as well.

We add a start variable, and all callers of the function are fixed up at
the same time.

The block layer will be using this new functionality in a follow-on
patch.


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21 21:54:47 -07:00
David Brownell
3c72426f05 spi core: stop updating dev->power.power_state
Don't update dev->power.power_state any more in the SPI core.  The only
reason to update this scheduled-to-be-removed field was to make the
already-removed /sys/devices/.../power/state files work better.

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>
2008-02-06 10:41:10 -08:00
Ralf Baechle
911f21501f Remove inclusions of <linux/autoconf.h>
Nothing should ever include this file.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: "Mike Frysinger" <vapier.adi@gmail.com>
Acked-by: "Bryan Wu" <cooloney.lkml@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-06 10:41:00 -08:00
Dave Young
5ed2c832ed spi: use class iteration api
Convert to use the class iteration api.

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24 20:40:45 -08:00
Marc Pignat
9b938b7490 spi: simplify spi_sync() calling convention
Simplify spi_sync calling convention, eliminating the need to check both
the return value AND the message->status.  In consequence, this corrects
misbehaviours of spi_read and spi_write (which only checked the former) and
their callers.

Signed-off-by: Marc Pignat <marc.pignat@hevs.ch>
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>
2007-12-05 09:21:18 -08:00
David Brownell
068f407086 SPI: use mutex not semaphore
Make spi_write_then_read() use a mutex not a binary semaphore.

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>
2007-12-05 09:21:18 -08:00
Atsushi Nemoto
350d0076c5 spi: fix double-free on spi_unregister_master
After 49dce689ad, device_for_each_child
iteration hits the master device itself.  Do not call spi_unregister_device()
for the master device.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:39 -08:00
Tony Jones
49dce689ad spi doesn't need class_device
Make the SPI framework and drivers stop using class_device.  Update docs
accordingly ...  highlighting just which sysfs paths should be
"safe"/stable.

Signed-off-by: Tony Jones <tonyj@suse.de>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:10 -07:00
Kay Sievers
7eff2e7a8b Driver core: change add_uevent_var to use a struct
This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.

Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12 14:51:01 -07:00
David Brownell
082c8cb4e5 spi device setup gets better error checking
This updates some error reporting paths in SPI device setup:

 - Move validation logic for SPI chipselects to spi_new_device(),
   which is where it should always have been.

 - In spi_new_device(), emit error messages if the device can't
   be created.  This is LOTS better than a silent failure; though
   eventually, the calling convention should probably change to
   use the <linux/err.h> conventions.

 - Includes one previously-missing check:  SPI masters must always
   have at least one chipselect, even for dedicated busses which
   always keep it selected!

It also adds a FIXME (IDR for dynamic ID allocation) so the issue doesn't live
purely in my mailbox.

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>
2007-07-31 15:39:44 -07:00
Adrian Bunk
149a6501f9 spi.c:scan_boardinfo() mustn't be __init_or_module
WARNING: drivers/built-in.o(.text+0x889735): Section mismatch: reference to .init.text:scan_boardinfo (between 'spi_register_master' and '__unregister')

Signed-off-by: Adrian Bunk <bunk@stusta.de>
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>
2007-07-21 17:49:16 -07:00
Matthias Kaehlcke
9404082898 use mutex instead of semaphore in SPI core/init code
The SPI core/init code uses a semaphore as mutex.  Use the mutex API instead
of the (binary) semaphore.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:05 -07:00
David Brownell
e44a45ae7b SPI dynamic busid generation bugfix
Fix SPI dynamic bus ID assignment to start at 2^15-1 rather than a negative
number.  Valid bus ids are supposed to be positive, and are (now) stored in
an 's16' value.

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>
2007-06-04 13:25:09 -07:00
David Brownell
33e34dc6ee SPI kerneldoc
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>
2007-05-08 11:15:16 -07:00
Adrian Bunk
e9d5a46115 [PATCH] drivers/spi/: fix section mismatches
WARNING: drivers/built-in.o - Section mismatch: reference to .init.text:spi_register_master from .text between 'spi_bitbang_start' (at offset 0x84e11a) and 'bitbang_work'
  WARNING: drivers/built-in.o - Section mismatch: reference to .init.text:spi_alloc_master from .text between 'butterfly_attach' (at offset 0x84e681) and 'at25_remove'
  WARNING: drivers/built-in.o - Section mismatch: reference to .init.text:spi_new_device from .text between 'butterfly_attach' (at offset 0x84e7e4) and 'at25_remove'

Signed-off-by: Adrian Bunk <bunk@stusta.de>
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>
2007-03-27 09:05:15 -07:00
Hans-Peter Nilsson
0ffa028505 [PATCH] SPI cleanup() method param becomes non-const
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>
2007-02-12 09:48:31 -08:00
Greg Kroah-Hartman
07b2463046 Revert "Driver core: convert SPI code to use struct device"
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>
2007-02-07 21:34:08 -08:00
Greg Kroah-Hartman
2943ecf2ed Driver core: convert SPI code to use struct device
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>
2007-02-07 10:37:11 -08:00
Atsushi Nemoto
1e9a51dca1 [PATCH] SPI: alternative fix for spi_busnum_to_master
If a SPI master device exists, udev (udevtrigger) causes kernel crash, due
to wrong kobj pointer in kobject_uevent_env().  This problem was not in
2.6.19.

The backtrace (on MIPS) was:
[<8024db6c>] kobject_uevent_env+0x54c/0x5e8
[<802a8264>] store_uevent+0x1c/0x3c  (in drivers/class.c)
[<801cb14c>] subsys_attr_store+0x2c/0x50
[<801cb80c>] flush_write_buffer+0x38/0x5c
[<801cb900>] sysfs_write_file+0xd0/0x190
[<80181444>] vfs_write+0xc4/0x1a0
[<80181cdc>] sys_write+0x54/0xa0
[<8010dae4>] stack_done+0x20/0x3c

flush_write_buffer() passes kobject of spi_master_class.subsys to
subsys_addr_store(), then subsys_addr_store() passes a pointer to a struct
subsystem to store_uevent() which expects a pointer to a struct
class_device.  The problem seems subsys_attr_store() called instead of
class_device_attr_store().

This mismatch was caused by commit
3bd0f69435, which overrides kset of master
class.  This made spi_master_class.subsys.kset.ktype NULL so
subsys_sysfs_ops is used instead of class_dev_sysfs_ops.

The commit was to fix spi_busnum_to_master().  Here is a patch fixes
this function in other way, just searching children list of
class_device.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-26 13:50:58 -08:00
Hans-Christian Egtvedt
3bd0f69435 [PATCH] spi: set kset of master class dev explicitly
<quote Imre Deak from Thu, 12 Jan 2006 21:18:54 +0200>
  In order for spi_busnum_to_master to work spi master devices must be linked
  into the spi_master_class.subsys.kset list.  At the moment the default
  class_obj_subsys.kset is used and we can't enumerate the master devices.
</quote>

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:33 -08:00
Hans-Christian Egtvedt
4740d387f3 [PATCH] spi: correct bus_num and buffer bug in spi core
Correct the following in driver/spi/spi.c in function spi_busnum_to_master:

 * must allow bus_num 0, the if is really not needed.
 * correct the name buffer which is too small for bus_num >= 10000. It

should be 9 bytes big, not 8.

Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@atmel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:32 -08:00
Jeff Garzik
89fc9a1a79 [PATCH] SPI: improve sysfs compiler complaint handling
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:31 -08:00
Christoph Lameter
e94b176609 [PATCH] slab: remove SLAB_KERNEL
SLAB_KERNEL is an alias of GFP_KERNEL.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:24 -08:00
Andrew Morton
d3e5a938e7 [PATCH] spi section fix
WARNING: vmlinux - Section mismatch: reference to .init.text:spi_register_board_info from __ksymtab_gpl between '__ksymtab_spi_register_board_info' (at offset 0xc032f7d0) and '__ksymtab_spi_alloc_master'

Fix this by removing the export.

Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-03 12:27:58 -08:00
Ingo Molnar
60be6b9a41 [PATCH] lockdep: annotate on-stack completions
lockdep needs to have the waitqueue lock initialized for on-stack waitqueues
implicitly initialized by DECLARE_COMPLETION().  Annotate on-stack completions
accordingly.

Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:09 -07:00
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
dmitry pervushin
ba1a051319 [PATCH] minor SPI doc fix
Because several developers asked me about referenced but missing
spi_add_master(), I think that this patch should be applied ...  it
corrects comments so they refer to spi_register_master() instead.

Signed-off-by: dmitry pervushin <dpervushin@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-21 12:59:19 -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
a9948b6194 [PATCH] SPI: spi bounce buffer has a minimum length
Make sure that spi_write_then_read() can always handle at least 32 bytes
of transfer (total, both directions), minimizing one portability issue.

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
Stephen Street
d2799f083d [PATCH] spi: Fix modular master driver remove and device suspend/remove
Fix two problems in the spi subsystem:

1) spi subsystem core dumps when modular spi master is unloaded.
2) spi subsystem core dumps when spi slave device is suspended/resumed and
   module slave driver is not loaded.

Signed-off-by: Stephen Street <stephen@streetfiresound.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-20 20:00:09 -08:00
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
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
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