Commit Graph

67 Commits

Author SHA1 Message Date
Linus Torvalds 40b42f1ebf Merge branch 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6
* 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6: (44 commits)
  i2c: Delete the i2c-isa pseudo bus driver
  hwmon: refuse to load abituguru driver on non-Abit boards
  hwmon: fix Abit Uguru3 driver detection on some motherboards
  hwmon/w83627ehf: Be quiet when no chip is found
  hwmon/w83627ehf: No need to initialize fan_min
  hwmon/w83627ehf: Export the thermal sensor types
  hwmon/w83627ehf: Enable VBAT monitoring
  hwmon/w83627ehf: Add support for the VID inputs
  hwmon/w83627ehf: Fix timing issues
  hwmon/w83627ehf: Add error messages for two error cases
  hwmon/w83627ehf: Convert to a platform driver
  hwmon/w83627ehf: Update the Kconfig entry
  make coretemp_device_remove() static
  hwmon: Add LM93 support
  hwmon: Improve the pwmN_enable documentation
  hwmon/smsc47b397: Don't report missing fans as spinning at 82 RPM
  hwmon: Add support for newer uGuru's
  hwmon/f71805f: Add temperature-tracking fan control mode
  hwmon/w83627ehf: Preserve speed reading when changing fan min
  hwmon: fix detection of abituguru volt inputs
  ...

Manual fixup of trivial conflict in MAINTAINERS file
2007-07-19 14:24:57 -07:00
Jean Delvare e24b8cb4fa i2c: Delete the i2c-isa pseudo bus driver
There are no users of i2c-isa left, so we can finally get rid of it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-07-19 14:25:20 -04:00
Jean Delvare 4b2643d7d9 i2c: Fix the i2c_smbus_read_i2c_block_data() prototype
Let the drivers specify how many bytes they want to read with
i2c_smbus_read_i2c_block_data(). So far, the block count was
hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense.
Many driver authors complained about this before, and I believe it's
about time to fix it. Right now, authors have to do technically stupid
things, such as individual byte reads or full-fledged I2C messaging,
to work around the problem. We do not want to encourage that.

I even found that some bus drivers (e.g. i2c-amd8111) already
implemented I2C block read the "right" way, that is, they didn't
follow the old, broken standard. The fact that it was never noticed
before just shows how little i2c_smbus_read_i2c_block_data() was used,
which isn't that surprising given how broken its prototype was so far.

There are some obvious compatiblity considerations:
* This changes the i2c_smbus_read_i2c_block_data() prototype. Users
  outside the kernel tree will notice at compilation time, and will
  have to update their code.
* User-space has access to i2c_smbus_xfer() directly using i2c-dev, so
  the changed expectations would affect tools such as i2cdump. In order
  to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA
  a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the
  old numeric value. When i2c-dev receives a transaction with the
  old value, it can convert it to the new format on the fly.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-07-12 14:12:29 +02:00
David Brownell d64f73be1b i2c: Add kernel documentation
Generate I2C kerneldoc; fix various glitches and add "context" sections to
that documentation.  Most I2C and SMBus functions still have no kerneldoc.

Let me suggest providing kerneldoc for all the i2c_smbus_*() functions as
a small and mostly self-contained project for anyone so inclined.  :)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-07-12 14:12:28 +02:00
David Brownell de81d2aaeb i2c: Legacy i2c drivers shouldn't issue uevents
Prevent legacy drivers from issuing uevents for device creation/removal,
so that userspace can't cause modprobing loops for them.  This became a
problem for some legacy PC drivers.  I can't easily see it becoming an
issue with I2C legacy drivers, but consistency-in-paranoia seems likely
to be a good thing here.  For usable i2c-level driver model uevents, just
switch to a new-style driver.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-22 19:49:16 +02:00
Jean Delvare b86a1bc8e3 i2c: Restore i2c_smbus_read_block_data
Add back the i2c_smbus_read_block_data helper function, it is needed
by the upcoming lm93 hardware monitoring driver and possibly others.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:34 +02:00
Jean Delvare b3e820968a i2c: Make i2c_del_driver a void function
Make i2c_del_driver a void function, like all other driver removal
functions. It always returned 0 even when errors occured, and nobody
ever actually checked the return value anyway. And we cannot fail
a module removal anyway.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:32 +02:00
Jean Delvare 12b5053ac5 i2c: Add i2c_new_probed_device()
Add a new helper function to instantiate an i2c device. It is meant as a
replacement for i2c_new_device() when you don't know for sure at which
address your I2C/SMBus device lives. This happens frequently on TV
adapters for example, you know there is a tuner chip on the bus, but
depending on the exact board model and revision, it can live at different
addresses. So, the new i2c_new_probed_device() function will probe the bus
according to a list of addresses, and as soon as one of these addresses
responds, it will call i2c_new_device() on that one address.

This function will make it possible to port the old i2c drivers to the
new model quickly.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:31 +02:00
David Brownell c05646069c i2c: i2c EXPORT_SYMBOL cleanup
Make i2c-core.c obey Documentation/CodingStyle better by snugging
the EXPORT_SYMBOL declarations next to the relevant definitions.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:31 +02:00
David Brownell 6e13e64184 i2c: Add i2c_add_numbered_adapter()
This adds a call, i2c_add_numbered_adapter(), registering an I2C adapter
with a specific bus number and then creating I2C device nodes for any
pre-declared devices on that bus.  It builds on previous patches adding
I2C probe() and remove() support, and that pre-declaration of devices.

This completes the core support for "new style" I2C device drivers.
Those follow the standard driver model for binding devices to drivers
(using probe and remove methods) rather than a legacy model (where the
driver tries to autoconfigure each bus, and registers devices itself).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:31 +02:00
David Brownell 9c1600eda4 i2c: Add i2c_board_info and i2c_new_device()
This provides partial support for new-style I2C driver binding.  It builds
on "struct i2c_board_info" declarations that identify I2C devices on a given
board.  This is needed on systems with I2C devices that can't be fully probed
and/or autoconfigured, such as many embedded Linux configurations where the
way a given I2C device is wired may affect how it must be used.

There are two models for declaring such devices:

 * LATE -- using a public function i2c_new_device().  This lets modules
   declare I2C devices found *AFTER* a given I2C adapter becomes available.
   
   For example, a PCI card could create adapters giving access to utility
   chips on that card, and this would be used to associate those chips with
   those adapters.

 * EARLY -- from arch_initcall() level code, using a non-exported function
   i2c_register_board_info().  This copies the declarations *BEFORE* such
   an i2c_adapter becomes available, arranging that i2c_new_device() will
   be called later when i2c-core registers the relevant i2c_adapter.

   For example, arch/.../.../board-*.c files would declare the I2C devices
   along with their platform data, and I2C devices would behave much like
   PNPACPI devices.  (That is, both enumerate from board-specific tables.)

To match the exported i2c_new_device(), the previously-private function
i2c_unregister_device() is now exported.

Pending later patches using these new APIs, this is effectively a NOP.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:31 +02:00
David Brownell a1d9e6e49f i2c: i2c stack can remove()
More update for new style driver support:  add a remove() method, and
use it in the relevant code paths.

Again, nothing will use this yet since there's nothing to create devices
feeding this infrastructure.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:30 +02:00
David Brownell 7b4fbc50fa i2c: i2c stack can probe()
One of a series of I2C infrastructure updates to support enumeration using
the standard Linux driver model.

This patch updates probe() and associated hotplug/coldplug support, but
not remove().  Nothing yet _uses_ it to create I2C devices, so those
hotplug/coldplug mechanisms will be the only externally visible change.
This patch will be an overall NOP since the I2C stack doesn't yet create
clients/devices except as part of binding them to legacy drivers.

Some code is moved earlier in the source code, helping group more of the
per-device infrastructure in one place and simplifying handling per-device
attributes.

Terminology being adopted:  "legacy drivers" create devices (i2c_client)
themselves, while "new style" ones follow the driver model (the i2c_client
is handed to the probe routine).  It's an either/or thing; the two models
don't mix, and drivers that try mixing them won't even be registered.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:30 +02:00
Jean Delvare 209d27c3b1 i2c: Emulate SMBus block read over I2C
Let the I2C bus drivers emulate the SMBus Block Read and Block Process
Call transactions if they wish. This requires to define a new message
flag, which i2c-core will use to let the underlying I2C bus driver
know that the first received byte will specify the length of the read
message.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:29 +02:00
David Brownell ef2c8321f5 i2c: Rename dev_to_i2c_adapter()
Rename dev_to_i2c_adapter() as to_i2c_adapter(), since the previous
syntax was a surprising and needless difference from normal naming
conventions in Linux.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00
David Brownell 16ffadfc68 i2c: Class attribute cleanup
This patch is a minor cleanup/code shrink, using class infrastructure
in i2c-core to manage the i2c_adapter attribute.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00
David Brownell 4ad4eac606 i2c: i2c_register_driver() cleanup
Minor cleanup in i2c_register_driver():  use list_for_each_entry().

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00
Jean Delvare b31366f439 i2c: i2c_adapter devices need no driver
Kill i2c_adapter_driver as it doesn't make sense and it prevents
further i2c-core cleanups. i2c_adapter devices are virtual devices
(ex-class devices) and as such they don't need a driver.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00
Jean Delvare fccb56e4d8 i2c: Kill i2c_adapter.class_dev
Kill i2c_adapter.class_dev. Instead, set the class of i2c_adapter.dev
to i2c_adapter_class, so that a symlink will be created for every
i2c_adapter in /sys/class/i2c-adapter.

The same change must be mirrored to i2c-isa as it duplicates some
of the i2c-core functionalities.

User-space tools and libraries might need some adjustments. In
particular, libsensors from lm_sensors 2.10.3 or later is required for
proper discovery of i2c adapter names after this change.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:27 +02:00
Jean Delvare fe2c8d51af i2c: Remove the warning on missing adapter device
Now that the i2c_adapter migration plan changed and we are going to
keep i2c_adapter.dev, it's no longer that urgent to add a proper device
to all i2c_adapter drivers. Thus is seems resonable to degrade the
warning asking authors to migrate their driver to a debug message.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-02-13 22:09:04 +01:00
David Brownell f37dd80ac2 i2c: Add driver suspend/resume/shutdown support
Driver model updates for the I2C core:

 - Add new suspend(), resume(), and shutdown() methods.  Use them in the
   standard driver model style; document them.

 - Minor doc updates to highlight zero-initialized fields in drivers, and
   the driver model accessors for "clientdata".

If any i2c drivers were previously using the old suspend/resume calls
in "struct driver", they were getting warning messages ... and will
now no longer work.  Other than that, this patch changes no behaviors;
and it lets I2C drivers use conventional PM and shutdown support.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-02-13 22:09:00 +01:00
Jean Delvare b8d6f45b32 i2c: completion header cleanups
i2c-core and i2c-isa use completions without including
<linux/completion.h>. Fix it.

i2c-powermac includes <linux/completion.h> but doesn't use any
completion. Fix it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Brownell <david-b@pacbell.net>
2007-02-13 22:09:00 +01:00
David Brownell b119dc3f99 i2c: Migration aids for i2c_adapter.dev removal
Flag i2c_adapter.dev for removal after userspace tools get upgraded, and
include a near-term code migration aid to facilitate this:

 - The class device gets the name attribute it should have had.  This
   was previously (wrongly) associated with the i2c_adapter.dev node.
   Sysfs based tools and libraries can start converting right away.

 - Issue a warning for legacy adapter drivers that don't provide any
   physical device node; so systems with those drivers will know to
   fix this problem earlier.

This is one of a series of patches to help the I2C stack become a better
citizen of the Linux Driver Model world.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-01-04 13:07:04 +01:00
Jean Delvare 7b77d065d1 i2c: Use the __ATTR macro where possible
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:31 +01:00
David Brownell 438d6c2c01 i2c: Whitespace cleanups
Remove extraneous whitespace from various i2c headers and core files,
like space-before-tab and whitespace at end of line.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:31 +01:00
Jiri Kosina 6ea23039cb i2c: Add support for nested i2c bus locking
This patch adds the 'level' field into the i2c_adapter structure, which is 
used to represent the 'logical' level of nesting for the purposes of 
lockdep. This field is then used in the i2c_transfer() function, to 
acquire the per-adapter bus_lock with correct nesting level.

Signed-off-by: Jiri Kosina <jikos@jikos.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-12-10 21:21:30 +01:00
Jean Delvare 77ed74da26 [PATCH] i2c: Prevent deadlock on i2c client registration
Delay the call to adapter->client_register() until after we are
certain that the client registration is a success. At this point the
client is fully initialized and we no longer hold the adapter->clist
mutex, so this should prevent the deadlocks if the client_register()
callback needs to take that mutex too, as is the case for the bttv
driver.

This fixes bug #7234.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30 10:58:47 -07:00
Jean Delvare 114fd18397 i2c: Warn on i2c client creation failure
i2c: Warn on i2c client creation failure

Warn when an i2c client creation fails. If we don't, the user will
never know something wrong happened, as i2c client creation is
typically called through an attach_adapter callback, those return value
we currently ignore for technical reasons.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:52 -07:00
Jean Delvare 7eff82c8b1 i2c-core: Drop useless bitmaskings
i2c-core: Drop useless bitmaskings

The code generated is exactly the same.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:52 -07:00
Jean Delvare b119c6c952 i2c: __must_check fixes (core drivers)
i2c: __must_check fixes (core drivers)

Check for error on sysfs file creation.
Check for error on device registration.
Check for error on class device registration.

Greg, I am not familiar with completion, can you please tell me if I
need to take care of it in the error paths (as I did in this patch,
see /* Needed? */ comments), or if it isn't needed?

These patches were tested, including forced errors, so they should work
fine. But of course more testing can't hurt.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-26 15:38:50 -07:00
Mark M. Hoffman 2369df933f [PATCH] i2c: Fix 'ignore' module parameter handling in i2c-core
This patch fixes a bug in the handling of 'ignore' module parameters of I2C
client drivers.

Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-07-12 15:43:06 -07:00
Krzysztof Halasa 46f5ed753f [PATCH] i2c: Mark block write buffers as const
The attached patch marks i2c_smbus_write_block_data() and
i2c_smbus_write_i2c_block_data() buffers as const.

Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-22 11:10:34 -07:00
Jean Delvare 7eebcb7c0f [PATCH] i2c: Optimize core_lists mutex usage
Stop holding the core_lists mutex when we don't actually need it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:53 -08:00
Ingo Molnar 5c085d369c [PATCH] i2c: Semaphore to mutex conversions, part 2
semaphore to mutex conversion.

the conversion was generated via scripts, and the result was validated
automatically via a script as well.

build tested.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:51 -08:00
Jean Delvare 7656032b90 [PATCH] i2c: Speed up block transfers
Speed up i2c_smbus_write_block_data and i2c_smbus_read_i2c_block_data
a bit by using memcpy instead of an explicit loop.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:51 -08:00
Arjan van de Ven b3585e4f5b [PATCH] I2C: Convert i2c to mutexes
The patch below converts a few i2c semaphores to mutexes

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-23 14:21:49 -08:00
Jean Delvare 21bbd69182 [PATCH] I2C: Resurrect i2c_smbus_write_i2c_block_data.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2006-02-06 12:02:14 -08:00
Russell King b864c7d5d1 [PATCH] Add i2c_bus_type probe and remove methods
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-13 11:26:07 -08:00
Jean Delvare 3fb81a3df6 [PATCH] i2c: I2C_DF_NOTIFY removal comment cleanups
The removal of I2C_DF_NOTIFY left some out of date comments in the
code. Drop them.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:27 -08:00
Greg Kroah-Hartman de59cf9ed4 [PATCH] I2C: Make i2c_add_driver automatically set the proper module owner
This prevents i2c drivers from messing up and forgetting to set the
module owner of their driver.  It also reduces the size of their drivers
by one line :)

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jean Delvare <khali@linux-fr.org>
2006-01-05 22:16:24 -08:00
Laurent Riffard 35d8b2e6b8 [PATCH] i2c: Drop i2c_driver.{owner,name}, 1 of 11
We should use the i2c_driver.driver's .name and .owner fields
instead of the i2c_driver's ones.

This patch updates the core of the i2c drivers: it removes .name and
.owner fields from the struct i2c_device and modify various
functions to use struct device fields instead.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:22 -08:00
Jean Delvare cf02df7702 [PATCH] i2c: Rework client usage count, 3 of 3
Do not limit the usage count of i2c clients to 1. In other words,
change the client usage count behavior from the old I2C_CLIENT_ALLOW_USE
to the old I2C_CLIENT_ALLOW_MULTIPLE_USE. The rationale is that no
driver actually needs the limiting behavior, and the unlimiting
behavior is slightly easier to implement.

Update the documentation to reflect this change.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:22 -08:00
Jean Delvare cde7859bda [PATCH] i2c: Rework client usage count, 2 of 3
Make I2C_CLIENT_ALLOW_USE the default for all i2c clients. It doesn't
hurt if the usage count is actually never used for any given driver,
and allows for nice code simplifications in i2c-core.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:22 -08:00
Jean Delvare cb748fb201 [PATCH] i2c: Rework client usage count, 1 of 3
No i2c client uses the I2C_CLIENT_ALLOW_MULTIPLE_USE flag, drop it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:22 -08:00
Jean Delvare 8a9947552d [PATCH] i2c: Drop i2c_driver.flags, 2 of 3
Just about every i2c chip driver sets the I2C_DF_NOTIFY flag, so we
can simply make it the default and drop the flag. If any driver really
doesn't want to be notified when i2c adapters are added, that driver
can simply omit to set .attach_adapter. This approach is also more
robust as it prevents accidental NULL pointer dereferences.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-05 22:16:21 -08:00
Russell King d052d1beff Create platform_device.h to contain all the platform device details.
Convert everyone who uses platform_bus_type to include
linux/platform_device.h.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-29 19:07:23 +01:00
Jean Delvare 421ef47be2 [PATCH] i2c: SMBus PEC support rewrite, 2 of 3
This is my rewrite of the SMBus PEC support. The original
implementation was known to have bugs (credits go to Hideki Iwamoto
for reporting many of them recently), and was incomplete due to a
conceptual limitation.

The rewrite affects only software PEC. Hardware PEC needs very little
code and is mostly untouched.

Technically, both implementations differ in that the original one
was emulating PEC in software by modifying the contents of an
i2c_smbus_data union (changing the transaction to a different type),
while the new one works one level lower, on i2c_msg structures (working
on message contents). Due to the definition of the i2c_smbus_data union,
not all SMBus transactions could be handled (at least not without
changing the definition of this union, which would break user-space
compatibility), and those which could had to be implemented
individually. At the opposite, adding PEC to an i2c_msg structure
can be done on any SMBus transaction with common code.

Advantages of the new implementation:

* It's about twice as small (from ~136 lines before to ~70 now, only
  counting i2c-core, including blank and comment lines). The memory
  used by i2c-core is down by ~640 bytes (~3.5%).

* Easier to validate, less tricky code. The code being common to all
  transactions by design, the risk that a bug can stay uncovered is
  lower.

* All SMBus transactions have PEC support in I2C emulation mode
  (providing the non-PEC transaction is also implemented). Transactions
  which have no emulation code right now will get PEC support for free
  when they finally get implemented.

* Allows for code simplifications in header files and bus drivers
  (patch follows).

Drawbacks (I guess there had to be at least one):

* PEC emulation for non-PEC capable non-I2C SMBus masters was dropped.
  It was based on SMBus tricks and doesn't quite fit in the new design.
  I don't think it's really a problem, as the benefit was certainly
  not worth the additional complexity, but it's only fair that I at
  least mention it.

Lastly, let's note that the new implementation does slightly affect
compatibility (both in kernel and user-space), but doesn't actually
break it. Some defines will be dropped, but the code can always be
changed in a way that will work with both the old and the new
implementations. It shouldn't be a problem as there doesn't seem to be
many users of SMBus PEC to date anyway.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:14 -07:00
Laurent Riffard 6586bcd7b2 [PATCH] Owner field additions to many i2c drivers, 4 of 5
This patch updates the .owner field for the i2c core struct xxxx_driver
variables.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:11 -07:00
Jean Delvare 30dac74697 [PATCH] i2c: Drop I2C_SMBUS_I2C_BLOCK_MAX
Drop I2C_SMBUS_I2C_BLOCK_MAX, use I2C_SMBUS_BLOCK_MAX instead.

I2C_SMBUS_I2C_BLOCK_MAX has always been defined to the same value as
I2C_SMBUS_BLOCK_MAX, and this will never change: setting it to a lower
value would make no sense, setting it to a higher value would break
i2c_smbus_data compatibility. There is no point in changing
i2c_smbus_data to support larger block transactions in SMBus mode, as
no SMBus hardware supports more than 32 byte blocks. Thus, for larger
transactions, direct I2C transfers are the way to go.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-10-28 14:02:10 -07:00
Hideki Iwamoto 5c50d18859 [PATCH] i2c: Several PEC-related fixes in software SMBus emulation
Fix several errors in I2C SMBus emulation when PEC is used:
* Weird logic error in SMBus Write Word transactions.
* Wrong buffer size, affecting SMBus Block Write transactions.
* Potential buffer overrun in SMBus Block Write transactions.

From: Hideki Iwamoto <h-iwamoto@kit.hi-ho.ne.jp>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/i2c/i2c-core.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
2005-10-28 14:02:07 -07:00