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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Move the check for SMBUS_QUICK in i2c_probe() after the forced
addresses have been handled. This makes it possible for a driver to
leave the probed address lists empty, only providing forced addresses,
and get i2c_probe to work even if the bus doesn't support SMBUS_QUICK.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/i2c/i2c-core.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
In PM v1, all devices were called at SUSPEND_DISABLE level. Then
all devices were called at SUSPEND_SAVE_STATE level, and finally
SUSPEND_POWER_DOWN level. However, with PM v2, to maintain
compatibility for platform devices, I arranged for the PM v2
suspend/resume callbacks to call the old PM v1 suspend/resume
callbacks three times with each level in order so that existing
drivers continued to work.
Since this is obsolete infrastructure which is no longer necessary,
we can remove it. Here's an (untested) patch to do exactly that.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jean Delvare