While writing the i2c-imc driver, I noticed that the warning message
when the i2c core can't figure out how to probe is mostly useless.
This trivial patch improves it.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

i2c_put_adapter dereferences i2c_adapter pointer passed without check
for NULL. This adds a check for non-NULL pointer to allow i2c_put_adapter
called with NULL and behave the same way i2c_release_client does already.
It allows to simplify drivers where you need to release the adapter
during probe failures.
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This reverts commit c80f5284.
Regressions have been found and also run time based instantiation would
fail. We need more thoughts on this.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This tries to address an issue found when writing an MFD driver
for the Nomadik STw481x PMICs: as the platform is using device
tree exclusively I want to specify the driver matching like
this:

static const struct of_device_id stw481x_match[] = {
	{ .compatible = "st,stw4810", },
	{ .compatible = "st,stw4811", },
	{},
};

static struct i2c_driver stw481x_driver = {
	.driver = {
		.name	= "stw481x",
		.of_match_table = stw481x_match,
	},
	.probe		= stw481x_probe,
	.remove		= stw481x_remove,
};

However that turns out not to be possible: the I2C probe code
is written so that the probe() call is always passed a match
from i2c_match_id() using non-devicetree matches.

This is probably why most devices using device tree for I2C
clients currently will pass no .of_match_table *at all* but
instead just use .id_table from struct i2c_driver to match
the device. As you realize that means that the whole idea with
compatible strings is discarded, and that is why we find strange
device tree I2C device compatible strings like "product" instead
of "vendor,product" as you could expect.

Let's figure out how to fix this before the mess spreads. This
patch will allow probeing devices with only an of_match_table
as per above, and will pass NULL as the second argument to the
probe() function. If the driver wants to deduce secondary info
from the struct of_device_id .data field, it has to call
of_match_device() on its own match table in the probe function
device tree probe path.

If drivers define both an .of_match_table *AND* a i2c_driver
.id_table, the .of_match_table will take precedence, just
as is done in the i2c_device_match() function in i2c-core.c.

I2C devices probed from device tree should subsequently be
fixed to handle the case where of_match_table() is
used (I think none of them do that today), and platforms should
fix their device trees to use compatible strings for I2C devices
instead of setting the name to Linux device driver names as is
done in multiple cases today.

Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Grant Likely <grant.likely@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0.  If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.

Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.

To reduce overall code bloat, make the changes described above.
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NKevin Hilman <khilman@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>

i2c: suppress lockdep warning on delete_device

Since commit 846f9974 the following lockdep
warning is thrown in case i2c device is removed (via delete_device sysfs
attribute) which contains subdevices (e.g. i2c multiplexer):

=============================================
[ INFO: possible recursive locking detected ]
3.8.7-0-sampleversion-fct #8 Tainted: G           O
---------------------------------------------
bash/3743 is trying to acquire lock:
  (s_active#110){++++.+}, at: [<ffffffff802b3048>] sysfs_hash_and_remove+0x58/0xc8

but task is already holding lock:
  (s_active#110){++++.+}, at: [<ffffffff802b3cb8>] sysfs_write_file+0xc8/0x208

other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(s_active#110);
   lock(s_active#110);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

4 locks held by bash/3743:
  #0:  (&buffer->mutex){+.+.+.}, at: [<ffffffff802b3c3c>] sysfs_write_file+0x4c/0x208
  #1:  (s_active#110){++++.+}, at: [<ffffffff802b3cb8>] sysfs_write_file+0xc8/0x208
  #2:  (&adap->userspace_clients_lock/1){+.+.+.}, at: [<ffffffff80454a18>] i2c_sysfs_delete_device+0x90/0x238
  #3:  (&__lockdep_no_validate__){......}, at: [<ffffffff803dcc24>] device_release_driver+0x24/0x48

stack backtrace:
Call Trace:
[<ffffffff80575cc8>] dump_stack+0x8/0x34
[<ffffffff801b50fc>] __lock_acquire+0x161c/0x2110
[<ffffffff801b5c3c>] lock_acquire+0x4c/0x70
[<ffffffff802b60cc>] sysfs_addrm_finish+0x19c/0x1e0
[<ffffffff802b3048>] sysfs_hash_and_remove+0x58/0xc8
[<ffffffff802b7d8c>] sysfs_remove_group+0x64/0x148
[<ffffffff803d990c>] device_remove_attrs+0x9c/0x1a8
[<ffffffff803d9b1c>] device_del+0x104/0x1d8
[<ffffffff803d9c18>] device_unregister+0x28/0x70
[<ffffffff8045505c>] i2c_del_adapter+0x1cc/0x328
[<ffffffff8045802c>] i2c_del_mux_adapter+0x14/0x38
[<ffffffffc025c108>] pca954x_remove+0x90/0xe0 [pca954x]
[<ffffffff804542f8>] i2c_device_remove+0x80/0xe8
[<ffffffff803dca9c>] __device_release_driver+0x74/0xf8
[<ffffffff803dcc2c>] device_release_driver+0x2c/0x48
[<ffffffff803dbc14>] bus_remove_device+0x13c/0x1d8
[<ffffffff803d9b24>] device_del+0x10c/0x1d8
[<ffffffff803d9c18>] device_unregister+0x28/0x70
[<ffffffff80454b08>] i2c_sysfs_delete_device+0x180/0x238
[<ffffffff802b3cd4>] sysfs_write_file+0xe4/0x208
[<ffffffff8023ddc4>] vfs_write+0xbc/0x160
[<ffffffff8023df6c>] SyS_write+0x54/0xd8
[<ffffffff8013d424>] handle_sys64+0x44/0x64

The problem is already known for USB and PCI subsystems. The reason is that
delete_device attribute is defined statically in i2c-core.c and used for all
devices in i2c subsystem.

Discussion of original USB problem:
http://lkml.indiana.edu/hypermail/linux/kernel/1204.3/01160.html

Commit 356c05d5 introduced new macro to suppress
lockdep warnings for this special case and included workaround for USB code.

LKML discussion of the workaround:
http://lkml.indiana.edu/hypermail/linux/kernel/1205.1/03634.html

As i2c case is in principle the same, the same workaround could be used here.
Signed-off-by: NAlexander Sverdlin <alexander.sverdlin@nsn.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

CONFIG_HOTPLUG is going away as an option, cleanup CONFIG_HOTPLUG
ifdefs in i2c files.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

i2c_del_adapter() is usually called from a drivers remove callback. The Linux
device driver model does not allow the remove callback to fail and all resources
allocated in the probe callback need to be freed, as well as all resources which
have been provided to the rest of the kernel(for example a I2C adapter) need to
be revoked. So any function revoking such resources isn't allowed to fail
either. i2c_del_adapter() adheres to this requirement and will never fail. But
i2c_del_adapter()'s return type is int, which may cause driver authors to think
that it can fail. This led to code constructs like:

	ret = i2c_del_adapter(...);
	BUG_ON(ret);

Since i2c_del_adapter() always returns 0 the BUG_ON is never hit and essentially
becomes dead code, which means it can be removed. Making the return type of
i2c_del_adapter() void makes it explicit that the function will never fail and
should prevent constructs like the above from re-appearing in the kernel code.

All callers of i2c_del_adapter() have already been updated in a previous patch
to ignore the return value, so the conversion of the return type from int to
void can be done without causing any build failures.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Currently i2c_del_adapter() returns -EINVAL when it gets an adapter which is not
registered. But none of the users of i2c_del_adapter() depend on this behavior,
so for the sake of being able to sanitize the return type of i2c_del_adapter
argue, that the purpose of i2c_del_adapter() is to remove an I2C adapter from
the system. If the adapter is not registered in the first place this becomes a
no-op. So we can return success without having to do anything.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

The detach_adapter callback has been deprecated for quite some time and has no
user left. Keeping it alive blocks other cleanups, so remove it.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Add i2c bus recovery infrastructure to i2c adapters as specified in the i2c
protocol Rev. 03 section 3.1.16 titled "Bus clear".

http://www.nxp.com/documents/user_manual/UM10204.pdf

Sometimes during operation i2c bus hangs and we need to give dummy clocks to
slave device to start the transfer again. Now we may have capability in the bus
controller to generate these clocks or platform may have gpio pins which can be
toggled to generate dummy clocks. This patch supports both.

This patch also adds in generic bus recovery routines gpio or scl line based
which can be used by bus controller. In addition controller driver may provide
its own version of the bus recovery routine.

This doesn't support multi-master recovery for now.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
[wsa: changed gpio type to int and minor reformatting]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

This allows you to get the equivalent functionality of
i2c_add_numbered_adapter() with all data in the device tree and no
special case code in your driver.  This is a common device tree
technique.

For quick reference, the FDT syntax for using an alias to provide an
ID looks like:
  aliases {
    i2c0 = &i2c_0;
    i2c1 = &i2c_1;
  };
Signed-off-by: NDoug Anderson <dianders@chromium.org>
[wsa: removed one check from static function. We know our callers]
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

MAX_IDR_MASK is another weirdness in the idr interface.  As idr covers
whole positive integer range, it's defined as 0x7fffffff or INT_MAX.

Its usage in idr_find(), idr_replace() and idr_remove() is bizarre.
They basically mask off the sign bit and operate on the rest, so if
the caller, by accident, passes in a negative number, the sign bit
will be masked off and the remaining part will be used as if that was
the input, which is worse than crashing.

The constant is visible in idr.h and there are several users in the
kernel.

* drivers/i2c/i2c-core.c:i2c_add_numbered_adapter()

  Basically used to test if adap->nr is a negative number which isn't
  -1 and returns -EINVAL if so.  idr_alloc() already has negative
  @start checking (w/ WARN_ON_ONCE), so this can go away.

* drivers/infiniband/core/cm.c:cm_alloc_id()
  drivers/infiniband/hw/mlx4/cm.c:id_map_alloc()

  Used to wrap cyclic @start.  Can be replaced with max(next, 0).
  Note that this type of cyclic allocation using idr is buggy.  These
  are prone to spurious -ENOSPC failure after the first wraparound.

* fs/super.c:get_anon_bdev()

  The ID allocated from ida is masked off before being tested whether
  it's inside valid range.  ida allocated ID can never be a negative
  number and the masking is unnecessary.

Update idr_*() functions to fail with -EINVAL when negative @id is
specified and update other MAX_IDR_MASK users as described above.

This leaves MAX_IDR_MASK without any user, remove it and relocate
other MAX_IDR_* constants to lib/idr.c.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: "Marciniszyn, Mike" <mike.marciniszyn@intel.com>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: NWolfram Sang <wolfram@the-dreams.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Wolfram Sang <wolfram@the-dreams.de>
Tested-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

i2c_smbus_process_call has no users in the kernel, so this can be
removed. Documentation for the same has been updated accordingly.

Fixes following sparse warning.
drivers/i2c/i2c-core.c:1871:5: warning: symbol 'i2c_smbus_process_call'
was not declared. Should it be static?

[wsa: updated the documentation]
Signed-off-by: NTushar Behera <tushar.behera@linaro.org>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

ACPI 5 introduced I2cSerialBus resource that makes it possible to enumerate
and configure the I2C slave devices behind the I2C controller. This patch
adds helper functions to support I2C slave enumeration.

An ACPI enabled I2C controller driver only needs to call acpi_i2c_register_devices()
in order to get its slave devices enumerated, created and bound to the
corresponding ACPI handle.
Signed-off-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Convert the struct i2c_msg initialization to C99 format. This makes
maintaining and editing the code simpler. Also helps once other fields
like transferred are added in future.
Signed-off-by: NShubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

To avoid name conflicts:

  drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined

While at it, also make the other names more consistent and add
parentheses.

[akpm@linux-foundation.org: repair fallout]
[sfr@canb.auug.org.au: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change]
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: walter harms <wharms@bfs.de>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If kernel is compiled with CONFIG_PROVE_LOCKING the
validator raises an error when a multiplexer is removed
via sysfs and sub-clients are connected to it. This is a
false positive.
Documentation/lockdep-design.txt recommends to handle this
via calls to mutex_lock_nested().

Based on an earlier fix from Michael Lawnick.

Note that the extra code resolves to nothing unless
CONFIG_DEBUG_LOCK_ALLOC=y.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Michael Lawnick <ml.lawnick@gmx.de>

Adapter drivers might support only a subset of the SMBus operations
natively. Those drivers currently have to manually emulate unsupported
operations using I2C.

Make the i2c_smbus_xfer() function fall back to
i2c_smbus_xfer_emulated() when the adapter's .smbus_xfer() operation
returns -EOPNOTSUPP, like it already does when the .smbus_xfer()
operation isn't available at all.

[JD: Minor optimization.]
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

SCCB is a serial communication bus developed by Omnivision. Its 2-wire
mode is very similar to SMBus byte data transactions, but requires the
controller to ignore the ACK bit and to insert a stop condition after
each message.

Add a device SCCB flag and a message stop flag to be passed to
controller drivers.

[JD: Kill rogue definition in go7007 driver.]
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Some drivers (in particular for TV cards) need exclusive access to
their I2C buses for specific operations. Export an unlocked flavor
of i2c_transfer to give them full control.

The unlocked flavor has the following limitations:
* Obviously, caller must hold the i2c adapter lock.
* No debug messages are logged. We don't want to log messages while
  holding a rt_mutex.
* No check is done on the existence of adap->algo->master_xfer. It
  is thus the caller's responsibility to ensure that the function is
  OK to call.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This converts a struct device * to a struct i2c_adapter * while verifying
that the device really is an I2C adapter. Just like i2c_verify_client.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

Signed-off-by: NJean Delvare <khali@linux-fr.org>

Fix that. Also convert this and the related comment to proper commenting
style.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

10-bit addresses overlap with traditional 7-bit addresses, leading in
device name collisions. Add an arbitrary offset to 10-bit addresses to
prevent this collision. The offset was chosen so that the address is
still easily recognizable.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>

Currently, if an i2c bus driver supports both static and dynamic bus
ids, it needs to choose between calling i2c_add_numbered_adapter() and
i2c_add_adapter().  This patch makes i2c_add_numbered_adapter()
redirect to i2c_add_adapter() if the requested bus id is -1.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

When warning on the use of deprecated i2c_driver methods
attach_adapter and detach_adapter, mention the name of the driver
which needs to be updated.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

The last legitimate user of i2c_driver.attach_adapter and
.detach_adapter is gone, so we can finally deprecate these callbacks.
The last few drivers which still use these will have to be updated to
make use of standard I2C device instantiation ways instead.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Introduce i2c_for_each_dev(), an i2c device iterator with proper
locking for use by i2c-dev. This is needed so that we can get rid of
the attach_adapter and detach_adapter legacy callback functions.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Rename the parameter of i2c_get_adapter() to "nr", to make it clear we
are passing an adapter number and not an adapter ID (which have gone
away by now.)
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Having conditional around the of_match_table and the of_node pointers
turns out to make driver code use ugly #ifdef blocks.  Drop the
conditionals and remove the #ifdef blocks from the affected drivers.

Also tidy up minor whitespace issues within the same hunks.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>

Since the PM core wishes to transition away from the legacy suspend
and resume methods and since removing them makes using PM core features
like runtime PM much easier start warning when a driver is registered
using the legacy methods.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

When devices use dev_pm_ops the I2C API is implementing standard functionality
for integration with runtime PM and for checking for the presence of a per
device op. The PM core provides pm_generic_ functions implementing this
behaviour - use them to reduce coupling with future PM updates.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Remove real devices first and dummy devices last. This gives device
driver which instantiated dummy devices themselves a chance to clean
them up before we do.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Tested-by: NHans Verkuil <hverkuil@xs4all.nl>
Cc: stable@kernel.org

Helper functions for I2C and SMBus transactions don't modify the
i2c_client that is passed to them, so it can be marked const.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Make sure I2C adapters being registered have the required struct
fields set. If they don't, problems will happen later.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

Check the class flags before allocating the temporary i2c_client
structure, to avoid allocating it when we don't need it.

Also optimize the inner loop a bit.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>

The "new_device" sysfs interface has been there for quite some time
now, nobody complained about it so it must be good enough. Time to
remove the warning and call it stable.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NMichael Lawnick <ml.lawnick@gmx.de>