This will aid the seamless removal of the current probe()'s, more
commonly unused than used second parameter. Most I2C drivers can
simply switch over to the new interface, others which have DT
support can use its own matching instead and others can call
i2c_match_id() themselves. This brings I2C's device probe method
into line with other similar interfaces in the kernel and prevents
the requirement to pass an i2c_device_id table.
Suggested-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[Kieran: fix rebase conflicts and adapt for dev_pm_domain_{attach,detach}]
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When there was no other way to match a I2C device to driver i2c_match_id()
was exclusively used. However, now there are other types of tables which
are commonly supplied, matching on an i2c_device_id table is used less
frequently. Instead of _always_ calling i2c_match_id() from within the
framework, we only need to do so from drivers which have no other way of
matching. This patch makes i2c_match_id() available to the aforementioned
device drivers.
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Currently the I2C framework insists on devices supplying an I2C ID
table. Many of the devices which do so unnecessarily adding quite a
few wasted lines to kernel code. This patch allows drivers a means
to 'not' supply the aforementioned table and match on DT match tables
instead.
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This function provides a single call for all I2C devices which need to
match firstly using traditional OF means i.e by of_node, then if that
fails we attempt to match using the supplied I2C client name with a
list of supplied compatible strings with the '<vendor>,' string
removed. The latter is required due to the unruly naming conventions
used currently by I2C devices.
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
[Kieran: Fix static inline usage on !CONFIG_OF]
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
A great deal of I2C devices are currently matched via DT node name, and
as such the compatible naming convention of '<vendor>,<device>' has gone
somewhat awry - some nodes don't supply one, some supply an arbitrary
string and others the correct device name with an arbitrary vendor prefix.
In an effort to correct this problem we have to supply a mechanism to
match a device by compatible string AND by simple device name. This
function strips off the '<vendor>,' part of a supplied compatible string
and attempts to match without it.
It is also used for sysfs, where a user can choose to instantiate a
device on an i2c bus using the sysfs interface by providing a string and
address to match and communicate with the device on the bus. Presently
this string is only matched against the old i2c device id style strings,
even in the presence of full device tree compatible strings with vendor
prefixes.
Providing a vendor-prefixed string to the sysfs interface will not match
against the device tree of_match_device() calls as there is no device
tree node to parse from the sysfs interface.
This function can match both vendor prefixed and stripped compatible
strings on the sysfs interface.
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Here we're providing dereference protection for i2c_match_id(), which
saves us having to do it each time it's called. We're also stripping
out the (now) needless checks in i2c_device_match(). This patch paves
the way for other, similar code trimming.
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Kieran Bingham <kieran@bingham.xyz>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Kieran Bingham <kieran@bingham.xyz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Race condition between registering an I2C device driver and
deregistering an I2C adapter device which is assumed to manage that
I2C device may lead to a NULL pointer dereference due to the
uninitialized list head of driver clients.
The root cause of the issue is that the I2C bus may know about the
registered device driver and thus it is matched by bus_for_each_drv(),
but the list of clients is not initialized and commonly it is NULL,
because I2C device drivers define struct i2c_driver as static and
clients field is expected to be initialized by I2C core:
i2c_register_driver() i2c_del_adapter()
driver_register() ...
bus_add_driver() ...
... bus_for_each_drv(..., __process_removed_adapter)
... i2c_do_del_adapter()
... list_for_each_entry_safe(..., &driver->clients, ...)
INIT_LIST_HEAD(&driver->clients);
To solve the problem it is sufficient to do clients list head
initialization before calling driver_register().
The problem was found while using an I2C device driver with a sluggish
registration routine on a bus provided by a physically detachable I2C
master controller, but practically the oops may be reproduced under
the race between arbitraty I2C device driver registration and managing
I2C bus device removal e.g. by unbinding the latter over sysfs:
% echo 21a4000.i2c > /sys/bus/platform/drivers/imx-i2c/unbind
Unable to handle kernel NULL pointer dereference at virtual address 00000000
Internal error: Oops: 17 [#1] SMP ARM
CPU: 2 PID: 533 Comm: sh Not tainted 4.9.0-rc3+ #61
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
task: e5ada400 task.stack: e4936000
PC is at i2c_do_del_adapter+0x20/0xcc
LR is at __process_removed_adapter+0x14/0x1c
Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
Control: 10c5387d Table: 35bd004a DAC: 00000051
Process sh (pid: 533, stack limit = 0xe4936210)
Stack: (0xe4937d28 to 0xe4938000)
Backtrace:
[<c0667be0>] (i2c_do_del_adapter) from [<c0667cc0>] (__process_removed_adapter+0x14/0x1c)
[<c0667cac>] (__process_removed_adapter) from [<c0516998>] (bus_for_each_drv+0x6c/0xa0)
[<c051692c>] (bus_for_each_drv) from [<c06685ec>] (i2c_del_adapter+0xbc/0x284)
[<c0668530>] (i2c_del_adapter) from [<bf0110ec>] (i2c_imx_remove+0x44/0x164 [i2c_imx])
[<bf0110a8>] (i2c_imx_remove [i2c_imx]) from [<c051a838>] (platform_drv_remove+0x2c/0x44)
[<c051a80c>] (platform_drv_remove) from [<c05183d8>] (__device_release_driver+0x90/0x12c)
[<c0518348>] (__device_release_driver) from [<c051849c>] (device_release_driver+0x28/0x34)
[<c0518474>] (device_release_driver) from [<c0517150>] (unbind_store+0x80/0x104)
[<c05170d0>] (unbind_store) from [<c0516520>] (drv_attr_store+0x28/0x34)
[<c05164f8>] (drv_attr_store) from [<c0298acc>] (sysfs_kf_write+0x50/0x54)
[<c0298a7c>] (sysfs_kf_write) from [<c029801c>] (kernfs_fop_write+0x100/0x214)
[<c0297f1c>] (kernfs_fop_write) from [<c0220130>] (__vfs_write+0x34/0x120)
[<c02200fc>] (__vfs_write) from [<c0221088>] (vfs_write+0xa8/0x170)
[<c0220fe0>] (vfs_write) from [<c0221e74>] (SyS_write+0x4c/0xa8)
[<c0221e28>] (SyS_write) from [<c0108a20>] (ret_fast_syscall+0x0/0x1c)
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Instantiated I2C device nodes are marked with OF_POPULATE. This was
introduced in 4f001fd301. On unloading, loaded device nodes will of
course be unmarked. The problem are nodes that fail during
initialisation: If a node fails, it won't be unloaded and hence not be
unmarked.
If a I2C driver module is unloaded and reloaded, it will skip nodes that
failed before.
Skip device nodes that are already populated and mark them only in case
of success.
Fixes: 4f001fd301 ("i2c: Mark instantiated device nodes with OF_POPULATE")
Signed-off-by: Ralf Ramsauer <ralf@ramses-pyramidenbau.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[wsa: use 14-digit commit sha]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
This includes the device tree binding and I2C core changes to support
the i2c-bus subnode that I2C masters can use to describe their slaves
in a separate namespace and therefore avoid clashing with potentially
other subnodes.
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Merge tag 'tegra-for-4.8-i2c' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into i2c/for-next
[wsa: fell through the cracks, applied to 4.9 now]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
i2c: 'i2c-bus' node support for v4.8-rc1
This includes the device tree binding and I2C core changes to support
the i2c-bus subnode that I2C masters can use to describe their slaves
in a separate namespace and therefore avoid clashing with potentially
other subnodes.
This routine is only used together with lockdep for nested locking.
The number of lock subclasses is limited to 8 as defined in lockdep.h
Emit a warning if the adapter depth exceeds the maximum number of
lockdep subclasses.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Peter Rosin <peda@axentia.se>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
For crazy setups in which an i2c gpio expander is behind an i2c gpio
multiplexer controlled by a gpio provided a second expander using the
same device driver we need to explicitly tell lockdep how to handle
nested locking.
Export i2c_adapter_depth() as public API to be reused outside of i2c
core code.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Peter Rosin <peda@axentia.se>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When enumerating I2C devices connected to an I2C adapter we scan the whole
namespace (as it is possible to have devices anywhere in that namespace,
not just below the I2C adapter device) and add each found device to the I2C
bus in question.
Now after commit 525e6fabea ("i2c / ACPI: add support for ACPI
reconfigure notifications") checking of the adapter handle to the one found
in the I2cSerialBus() resource was moved to happen after resources of the
I2C device has been parsed. This means that if the I2cSerialBus() resource
points to an adapter that does not exists in the system we still parse
those resources. This is problematic in particular because
acpi_dev_resource_interrupt() tries to configure GSI if the device also has
an Interrupt() resource. Failing to do that results errrors like this to be
printed on the console:
[ 10.409490] ERROR: Unable to locate IOAPIC for GSI 37
To fix this we pass the I2C adapter to i2c_acpi_get_info() and make sure
the handle matches the one in the I2cSerialBus() resource before doing
anything else to the device.
Reported-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
It's better to have strings in the code like they appeared in the output.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This makes it trivial to constify them, so do that.
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
ACPI 5 specification doesn't have property for the I2C bus speed but
I2cSerialBus resource descriptor which define each controller-slave
connection define the maximum speed supported by that connection.
Thus finding the maximum safe speed for the bus is to walk through all
I2cSerialBus resources that are associated to I2C controller and use the
speed of slowest connection.
Add function i2c_acpi_find_bus_speed() to the i2c-core that adapter
drivers can call prior registering itself to core.
This implies two-step walk through the I2cSerialBus resources: call to
i2c_acpi_find_bus_speed() does the first scan and finds the safe bus
speed that adapter drivers can set up. Adapter driver registration does
the second scan when i2c-core creates the I2C slaves by calling the
i2c_acpi_register_devices(). In that way the bus speed is set in case
slave device probe gets called during registration and does communication.
Previous version commit 55d38d060e ("i2c: core: Add function for finding
the bus speed from ACPI") got reverted due merge conflicts from
commit 525e6fabea ("i2c / ACPI: add support for ACPI reconfigure
notifications").
This version is a bit bigger than previous version but is still sharing
the lowest and complicated part of I2cSerialBus lookup routines with the
existing code.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
I2C ACPI enumeration was originally implemented in another module under
drivers/acpi/ but was later moved into i2c-core with added support for
I2C ACPI operation region.
Rename these acpi_i2c_ prefixed functions, structures and defines in
i2c-core to i2c_acpi_ in order to have more consistent name space.
This is updated version from commit a7003b6580 ("i2c: core: Cleanup I2C
ACPI namespace") that got reverted due merge conflicts from
commit 525e6fabea ("i2c / ACPI: add support for ACPI reconfigure
notifications").
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This unifies usage with i2c_lock_bus and i2c_unlock_bus, and paves the
way for the next patch which looks a bit saner with this preparatory
work taken care of beforehand.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull i2c updates from Wolfram Sang:
"Here is the I2C pull request for 4.8:
- the core and i801 driver gained support for SMBus Host Notify
- core support for more than one address in DT
- i2c_add_adapter() has now better error messages. We can remove all
error messages from drivers calling it as a next step.
- bigger updates to rk3x driver to support rk3399 SoC
- the at24 eeprom driver got refactored and can now read special
variants with unique serials or fixed MAC addresses.
The rest is regular driver updates and bugfixes"
* 'i2c/for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (66 commits)
i2c: i801: use IS_ENABLED() instead of checking for built-in or module
Documentation: i2c: slave: give proper example for pm usage
Documentation: i2c: slave: describe buffer problems a bit better
i2c: bcm2835: Don't complain on -EPROBE_DEFER from getting our clock
i2c: i2c-smbus: drop useless stubs
i2c: efm32: fix a failure path in efm32_i2c_probe()
Revert "i2c: core: Cleanup I2C ACPI namespace"
Revert "i2c: core: Add function for finding the bus speed from ACPI"
i2c: Update the description of I2C_SMBUS
i2c: i2c-smbus: fix i2c_handle_smbus_host_notify documentation
eeprom: at24: tweak the loop_until_timeout() macro
eeprom: at24: add support for at24mac series
eeprom: at24: support reading the serial number for 24csxx
eeprom: at24: platform_data: use BIT() macro
eeprom: at24: split at24_eeprom_write() into specialized functions
eeprom: at24: split at24_eeprom_read() into specialized functions
eeprom: at24: hide the read/write loop behind a macro
eeprom: at24: call read/write functions via function pointers
eeprom: at24: coding style fixes
eeprom: at24: move at24_read() below at24_eeprom_write()
...
This reverts commit a7003b65801e17a19617a509b2dbae3442ddd709.There were
too heavy merge conflicts and the driver code making use of this was not
ready yet anyhow. So, we wait one cycle.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This reverts commit 55d38d060e. There were
too heavy merge conflicts and the driver code making use of this was not
ready yet anyhow. So, we wait one cycle.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
ACPI 5 specification doesn't have property for the I2C bus speed but
I2cSerialBus resource descriptors which define each controller-slave
connection define the maximum speed supported by that connection.
Thus finding the maximum safe speed for the bus is to walk all
I2cSerialBus resources that are associated to I2C controller and use
the speed of slowest connection.
Add function i2c_acpi_find_bus_speed() to the i2c-core that adapter
drivers can call prior registering itself to core.
This implies two-step walk through the I2cSerialBus resources: call to
i2c_acpi_find_bus_speed() does the first scan and finds the safe bus
speed that adapter drivers can set up. Adapter driver registration does
the second scan when i2c-core creates the I2C slaves by calling the
i2c_acpi_register_devices(). In that way the bus speed is set in case
slave device probe gets called during registration and does
communication.
Implement this by reusing the existing ACPI I2C walk routines in the
i2c-core. Extend them so that slowest connection speed is saved during
the walk and I2C slaves are registered only when calling through the
i2c_acpi_register_devices() with the i2c_adapter pointer.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
I2C ACPI enumeration was originally implemented in another module under
drivers/acpi/ but was later moved into i2c-core with added support for
I2C ACPI operation region.
Rename these acpi_i2c_ prefixed functions, structures and defines in
i2c-core to i2c_acpi_ in order to have more consistent name space.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Now that we revisited all error messages, we can use pr_fmt for the
remaining pr_* messages to ensure consistent output.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use a warning loglevel instead of info and switch to dev_* for device
info. Also print which client was accessed.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Use dev_err instead of pr_err for more details.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Switch to WARN if no adapter name is given, otherwise we won't know who
missed to do that. Add error message if device registration fails.
Update error message for missing algo to match style of the others.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Move recovery init to a seperate function to let have
i2c_register_adapter() less lines and to avoid goto and a label.
Refactor string handling there for consistency and to save some bytes.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
On error, we should give idr back to the pool in any case.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds supports for I2C device enumeration and removal via
ACPI reconfiguration notifications that are send as a result of an
ACPI table load or unload operation.
The code is very similar with the device tree reconfiguration code
with only small differences in the way we test and set the enumerated
state of the device:
* the equivalent of device tree's OF_POPULATED flag is the
flags.visited field in the ACPI device and the following
wrappers are used to manipulate it: acpi_device_enumerated(),
acpi_device_set_enumerated() and acpi_device_clear_enumerated()
* the device tree code checks of status of the OF_POPULATED flag to
avoid trying to create duplicate Linux devices in two places: once
when the controller is probed, and once when the reconfigure event
is received; in the ACPI code the check is performed only once when
the ACPI namespace is searched because this code path is invoked in
both of the two mentioned cases
The rest of the enumeration handling is similar with device tree: when
the Linux device is unregistered the ACPI device is marked as not
enumerated; also, when a device remove notification is received we
check that the device is in the enumerated state before continuing
with the removal of the Linux device.
Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the 'i2c-bus' device-tree node is present for an I2C adapter then
parse this subnode for I2C slaves.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Some I2C devices have multiple addresses assigned, for example each address
corresponding to a different internal register map page of the device.
So far drivers which need support for this have handled this with a driver
specific and non-generic implementation, e.g. passing the additional address
via platform data.
This patch provides a new helper function called i2c_new_secondary_device()
which is intended to provide a generic way to get the secondary address
as well as instantiate a struct i2c_client for the secondary address.
The function expects a pointer to the primary i2c_client, a name
for the secondary address and an optional default address. The name is used
as a handle to specify which secondary address to get.
The default address is used as a fallback in case no secondary address
was explicitly specified. In case no secondary address and no default
address were specified the function returns NULL.
For now the function only supports look-up of the secondary address
from devicetree, but it can be extended in the future
to for example support board files and/or ACPI.
Signed-off-by: Jean-Michel Hautbois <jean-michel.hautbois@veo-labs.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
A custom recovery function doesn't need these pointers to be populated
because it may work differently internally.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Peter Griffin <peter.griffin@linaro.org>
With a i2c topology like the following
GPIO ---| ------ BAT1
| v /
I2C -----+----------+---- MUX
| \
EEPROM ------ BAT2
there is a locking problem with the GPIO controller since it is a client
on the same i2c bus that it muxes. Transfers to the mux clients (e.g. BAT1)
will lock the whole i2c bus prior to attempting to switch the mux to the
correct i2c segment. In the above case, the GPIO device is an I/O expander
with an i2c interface, and since the GPIO subsystem knows nothing (and
rightfully so) about the lockless needs of the i2c mux code, this results
in a deadlock when the GPIO driver issues i2c transfers to modify the
mux.
So, observing that while it is needed to have the i2c bus locked during the
actual MUX update in order to avoid random garbage on the slave side, it
is not strictly a must to have it locked over the whole sequence of a full
select-transfer-deselect mux client operation. The mux itself needs to be
locked, so transfers to clients behind the mux are serialized, and the mux
needs to be stable during all i2c traffic (otherwise individual mux slave
segments might see garbage, or worse).
Introduce this new locking concept as "mux-locked" muxes, and call the
pre-existing mux locking scheme "parent-locked".
Modify the i2c mux locking so that muxes that are "mux-locked" locks only
the muxes on the parent adapter instead of the whole i2c bus when there is
a transfer to the slave side of the mux. This lock serializes transfers to
the slave side of the muxes on the parent adapter.
Add code to i2c-mux-gpio and i2c-mux-pinctrl that checks if all involved
gpio/pinctrl devices have a parent that is an i2c adapter in the same
adapter tree that is muxed, and request a "mux-locked mux" if that is the
case.
Modify the select-transfer-deselect code for "mux-locked" muxes so
that each of the select-transfer-deselect ops locks the mux parent
adapter individually.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Instead of checking for i2c parent adapters for every lock/unlock, simply
override the locking for muxes to always lock/unlock the parent adapter
directly.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add i2c_lock_bus() and i2c_unlock_bus(), which call the new lock_bus and
unlock_bus ops in the adapter. These funcs/ops take an additional flags
argument that indicates for what purpose the adapter is locked.
There are two flags, I2C_LOCK_ROOT_ADAPTER and I2C_LOCK_SEGMENT, but they
are both implemented the same. For now. Locking the root adapter means
that the whole bus is locked, locking the segment means that only the
current bus segment is locked (i.e. i2c traffic on the parent side of
a mux is still allowed even if the child side of the mux is locked).
Also support a trylock_bus op (but no function to call it, as it is not
expected to be needed outside of the i2c core).
Implement i2c_lock_adapter/i2c_unlock_adapter in terms of the new locking
scheme (i.e. lock with the I2C_LOCK_ROOT_ADAPTER flag).
Locking the root adapter and locking the segment is the same thing for
all root adapters (e.g. in the normal case of a simple topology with no
i2c muxes). The two locking variants are also the same for traditional
muxes (aka parent-locked muxes). These muxes traverse the tree, locking
each level as they go until they reach the root. This patch is preparatory
for a later patch in the series introducing mux-locked muxes, which behave
differently depending on the requested locking. Since all current users
are using i2c_lock_adapter, which is a wrapper for I2C_LOCK_ROOT_ADAPTER,
we only need to annotate the calls that will not need to lock the root
adapter for mux-locked muxes. I.e. the instances that needs to use
I2C_LOCK_SEGMENT instead of i2c_lock_adapter/I2C_LOCK_ROOT_ADAPTER. Those
instances are in the i2c_transfer and i2c_smbus_xfer functions, so that
mux-locked muxes can single out normal i2c accesses to its slave side
and adjust the locking for those accesses.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
When using a certain I2C device with runtime PM enabled on
a certain I2C bus adaper the following happens:
struct amba_device *foo
\
struct i2c_adapter *bar
\
struct i2c_client *baz
The AMBA device foo has its device PM struct set to ignore
children with pm_suspend_ignore_children(&foo->dev, true).
This makes runtime PM work just fine locally in the driver:
the fact that devices on the bus are suspended or resumed
individually does not affect its operation, and the hardware
does not power up unless transferring messages.
However this child ignorance property is not inherited into
the struct i2c_adapter *bar.
On system suspend things will work fine.
On system resume the following annoying phenomenon occurs:
- In the pm_runtime_force_resume() path of
struct i2c_client *baz, pm_runtime_set_active(&baz->dev); is
eventually called.
- This becomes __pm_runtime_set_status(&baz->dev, RPM_ACTIVE);
- __pm_runtime_set_status() detects that RPM state is changed,
and checks whether the parent is:
not active (RPM_ACTIVE) and not ignoring its children
If this happens it concludes something is wrong, because
a parent that is not ignoring its children must be active
before any children activate.
- Since the struct i2c_adapter *bar does not ignore
its children, the PM core thinks that it must indeed go
online before its children, the check bails out with
-EBUSY, i.e. the i2c_client *baz thinks it can't work
because it's parent is not online, and it respects its
parent.
- In the driver the .resume() callback returns -EBUSY from
the runtime_force_resume() call as per above. This leaves
the device in a suspended state, leading to bad behaviour
later when the device is used. The following debug
print is made with an extra printg patch but illustrates
the problem:
[ 17.040832] bh1780 2-0029: parent (i2c-2) is not active
parent->power.ignore_children = 0
[ 17.040832] bh1780 2-0029: pm_runtime_force_resume:
pm_runtime_set_active() failed (-16)
[ 17.040863] dpm_run_callback():
pm_runtime_force_resume+0x0/0x88 returns -16
[ 17.040863] PM: Device 2-0029 failed to resume: error -16
Fix this by letting all struct i2c_adapter:s ignore their
children: i2c children have no business doing keeping
their parents awake: they are completely autonomous
devices that just use their parent to talk, a usecase
which must be power managed in the host on a per-message
basis.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Jan reported this:
===
After enabling CONFIG_I2C_DEBUG_CORE my system was broken
(no network, console login not possible). System log was
flooded with the this message:
...
[ 608.052077] rtc-ds1307 0-0068: uevent
[ 608.052500] rtc-ds1307 0-0068: uevent
[ 608.052925] rtc-ds1307 0-0068: uevent
...
The culprit is the dev_dbg printk in the i2c uevent handler.
If this is activated (for instance by CONFIG_I2C_DEBUG_CORE)
it results in an endless loop with systemd-journald.
This happens if user-space scans the system log and reads the uevent
file to get information about a newly created device, which seems fair
use to me. Unfortunately reading the "uevent" file uses the same
function that runs for creating the uevent for a new device,
generating the next syslog entry.
Ideally user-space would implement a recursion detection and
after reading the same device file for the 1000th time call it a
day, but nevertheless I think we should avoid this problem by
removing the debug print completely or using another print variant.
The same problem seems to be reported here:
https://bugs.freedesktop.org/show_bug.cgi?id=76886
===
His patch converted the message to pr_debug, but I think the debug can
simply go. We have other means to see code paths these days. This
enables us to clean up the function some more while we are here.
Reported-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Tested-by: Jan Glauber <jglauber@cavium.com>
Mark the i2c bus as registered right after the the bus_register call,
not at the end of init. Otherwise, we can't register our own dummy
driver.
Reported-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: 95026658c4 ("i2c: do not use internal data from driver core")
The variable p is a data structure which is used by the driver core
internally and it is not expected that busses will be directly accessing
these driver core internal only data.
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[wsa: removed the unlikely()]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The adapter device is a logical device. Because of that, it already uses
pm_runtime_no_callbacks() in the core. To ensure proper propagation from
the children (i2c devices) to the parent of the adapter (the HW device),
make sure RuntimePM is enabled in any case.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This function used to be DT only, so it lived inside a CONFIG_OF block.
Now it uses device attributes and must be moved outside of it. No
further code changes, only one whitespace improvement.
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Inspired from the i2c-rk3x driver (thanks guys!) but refactored and
extended. See built-in docs for further information.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch fixes obvious copy-past error in wake up irq parsing
code which leads to the fact that dev_pm_set_wake_irq() will
be called with wrong IRQ number when "wakeup" IRQ is not
defined in DT.
Fixes: 3fffd12839 ("i2c: allow specifying separate wakeup interrupt in device tree")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: <stable@vger.kernel.org> # v4.3
Pull i2c updates from Wolfram Sang:
- New drivers: UniPhier (with and without FIFO)
- some drivers got some bigger rework: ismt, designware, img-scb (rcar
had to be reverted because issues were showing up just lately)
- ACPI: reworked the device scanning and added support for muxes
... and quite a lot of driver bugfixes and cleanups this time. All
files touched outside of the i2c realm have proper acks.
* 'i2c/for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (70 commits)
i2c: rcar: Revert the latest refactoring series
i2c: pnx: remove superfluous assignment
MAINTAINERS: i2c: drop i2c-pnx maintainer
MAINTAINERS: i2c: mark also subdirectories as maintained
i2c: cadence: enable driver for ARM64
i2c: i801: Document Intel DNV and Broxton
i2c: at91: manage unexpected RXRDY flag when starting a transfer
i2c: pnx: Use setup_timer instead of open coding it
i2c: add ACPI support for I2C mux ports
acpi: add acpi_preset_companion() stub
i2c: pxa: Add support for pxa910/988 & new configuration features
i2c: au1550: Convert to devm_kzalloc and devm_ioremap_resource
i2c-dev: Fix I2C_SLAVE ioctl comment
i2c-dev: Fix typo in ioctl name reference
i2c: sirf: tune the divider to make i2c bus freq more accurate
i2c: imx: Use -ENXIO as error in the NACK case
i2c: i801: Add support for Intel Broxton
i2c: i801: Add support for Intel DNV
i2c: mediatek: add i2c resume support
i2c: imx: implement bus recovery
...
Although I2C mux devices are easily enumerated using ACPI (_HID/_CID or
device property compatible string match), enumerating I2C client devices
connected through an I2C mux needs a little extra work.
This change implements a method for describing an I2C device hierarchy that
includes mux devices by using an ACPI Device() for each mux channel along
with an _ADR to set the channel number for the device. See
Documentation/acpi/i2c-muxes.txt for a simple example.
To make this work the ismt, i801, and designware pci/platform devs now
share an ACPI companion with their I2C adapter dev similar to how it's done
in OF. This is done on the assumption that power management functions will
not be called directly on the I2C dev that is sharing the ACPI node.
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Dustin Byford <dustin@cumulusnetworks.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The way we currently scan I2C devices behind an I2C host controller does not
work in cases where the I2C device in question is not declared directly below
the host controller ACPI node.
This is perfectly legal according the ACPI 6.0 specification and some existing
systems are doing this.
To be able to enumerate all devices which are connected to a certain I2C host
controller we need to rework the current I2C scanning routine a bit. Instead of
scanning directly below the host controller we scan the whole ACPI namespace
for present devices with valid I2cSerialBus() connection pointing to the host
controller in question.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Dustin Byford <dustin@cumulusnetworks.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
A change of return status was introduced in commit 3fffd12839
("i2c: allow specifying separate wakeup interrupt in device tree")
The commit prevents the defer status being passed up the call stack
appropriately when dev_pm_domain_attach returns -EPROBE_DEFER.
Catch the PROBE_DEFER and clear up the IRQ wakeup status
Signed-off-by: Kieran Bingham <kieranbingham@gmail.com>
Fixes: 3fffd12839 ("i2c: allow specifying separate wakeup interrupt in device tree")
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
