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>
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>
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>
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>
SMBus Host Notify allows a slave device to act as a master on a bus to
notify the host of an interrupt. On Intel chipsets, the functionality
is directly implemented in the firmware. We just need to export a
function to call .alert() on the proper device driver.
i2c_handle_smbus_host_notify() behaves like i2c_handle_smbus_alert().
When called, it schedules a task that will be able to sleep to go through
the list of devices attached to the adapter.
The current implementation allows one Host Notification to be scheduled
while an other is running.
Tested-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
.alert() is meant to be generic, but there is currently no way
for the device driver to know which protocol generated the alert.
Add a parameter in .alert() to help the device driver to understand
what is given in data.
This patch is required to have the support of SMBus Host Notify protocol
through .alert().
Tested-by: Andrew Duggan <aduggan@synaptics.com>
For hwmon:
Acked-by: Guenter Roeck <linux@roeck-us.net>
For IPMI:
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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>
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>
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>
Drivers do this in various ways, let's use one standard way of doing it.
Note: I2C_M_RD is bit 0, so the code could be simplified. To be extremly
robust and to advertise good coding practices, I still use the ternary
operator and let the compilers do the optimizing job.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
In commit f309d44431 ("platform_device:
better support builtin boilerplate avoidance") we introduced the
builtin_driver macro.
Here we use that support and extend it to I2C driver registration,
so where a driver is clearly non-modular and builtin-only, we can
register it in a similar fashion. And existing code that is clearly
non-modular can be updated with the simple mapping of
module_i2c_driver(...) ---> builtin_i2c_driver(...)
We've essentially cloned the former to make the latter, and taken
out the remove/module_exit parts since those never get used in a
non-modular build of the code.
A similar thing was done in commit b4eb6cdbbd
("PCI: Add builtin_pci_driver() to avoid registration boilerplate").
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This patch adds a i2c_check_quirks helper function to check the quirk flags
of an i2c adapter, in a similar way to i2c_check_functionality.
Signed-off-by: Nicola Corna <nicola@corna.info>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Add I2C_AQ_NO_CLK_STRETCH quirk flag, to be used when clock stretching is
not supported.
Signed-off-by: Nicola Corna <nicola@corna.info>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
There are devices that need to handle block transactions
regardless of the capabilities exported by the adapter.
For performance reasons, they need to use i2c read blocks
if available, otherwise emulate the block transaction with word
or byte transactions.
Add support for a helper function that would read a data block
using the best transfer available: I2C_FUNC_SMBUS_READ_I2C_BLOCK,
I2C_FUNC_SMBUS_READ_WORD_DATA or I2C_FUNC_SMBUS_READ_BYTE_DATA.
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
of_find_i2c_adapter_by_node() call requires quite often missing
put_device(), and i2c_put_adapter() releases a device locked by
i2c_get_adapter() only. In general module_put(adapter->owner) and
put_device(dev) are not interchangeable.
This is a common error reproduction scenario as a result of the
misusage described above (for clearness this is run on iMX6 platform
with HDMI and I2C bus drivers compiled as kernel modules):
root@mx6q:~# lsmod | grep i2c
i2c_imx 10213 0
root@mx6q:~# lsmod | grep dw_hdmi_imx
dw_hdmi_imx 3631 0
dw_hdmi 11846 1 dw_hdmi_imx
imxdrm 8674 3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
drm_kms_helper 113765 5 dw_hdmi,imxdrm,imx_ipuv3_crtc,imx_ldb
root@mx6q:~# rmmod dw_hdmi_imx
root@mx6q:~# lsmod | grep i2c
i2c_imx 10213 -1
^^^^^
root@mx6q:~# rmmod i2c_imx
rmmod: ERROR: Module i2c_imx is in use
To fix existing users of these interfaces and to avoid any further
confusion and misusage in future, add one more interface
of_get_i2c_adapter_by_node(), it is similar to i2c_get_adapter() in
sense that an I2C bus device driver found and locked by user can be
correctly unlocked by i2c_put_adapter().
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull power management and ACPI updates from Rafael Wysocki:
"These are mostly fixes and cleanups all over, although there are a few
items that sort of fall into the new feature category.
First off, we have new callbacks for PM domains that should help us to
handle some issues related to device initialization in a better way.
There also is some consolidation in the unified device properties API
area allowing us to use that inferface for accessing data coming from
platform initialization code in addition to firmware-provided data.
We have some new device/CPU IDs in a few drivers, support for new
chips and a new cpufreq driver too.
Specifics:
- Generic PM domains support update including new PM domain callbacks
to handle device initialization better (Russell King, Rafael J
Wysocki, Kevin Hilman)
- Unified device properties API update including a new mechanism for
accessing data provided by platform initialization code (Rafael J
Wysocki, Adrian Hunter)
- ARM cpuidle update including ARM32/ARM64 handling consolidation
(Daniel Lezcano)
- intel_idle update including support for the Silvermont Core in the
Baytrail SOC and for the Airmont Core in the Cherrytrail and
Braswell SOCs (Len Brown, Mathias Krause)
- New cpufreq driver for Hisilicon ACPU (Leo Yan)
- intel_pstate update including support for the Knights Landing chip
(Dasaratharaman Chandramouli, Kristen Carlson Accardi)
- QorIQ cpufreq driver update (Tang Yuantian, Arnd Bergmann)
- powernv cpufreq driver update (Shilpasri G Bhat)
- devfreq update including Tegra support changes (Tomeu Vizoso,
MyungJoo Ham, Chanwoo Choi)
- powercap RAPL (Running-Average Power Limit) driver update including
support for Intel Broadwell server chips (Jacob Pan, Mathias Krause)
- ACPI device enumeration update related to the handling of the
special PRP0001 device ID allowing DT-style 'compatible' property
to be used for ACPI device identification (Rafael J Wysocki)
- ACPI EC driver update including limited _DEP support (Lan Tianyu,
Lv Zheng)
- ACPI backlight driver update including a new mechanism to allow
native backlight handling to be forced on non-Windows 8 systems and
a new quirk for Lenovo Ideapad Z570 (Aaron Lu, Hans de Goede)
- New Windows Vista compatibility quirk for Sony VGN-SR19XN (Chen Yu)
- Assorted ACPI fixes and cleanups (Aaron Lu, Martin Kepplinger,
Masanari Iida, Mika Westerberg, Nan Li, Rafael J Wysocki)
- Fixes related to suspend-to-idle for the iTCO watchdog driver and
the ACPI core system suspend/resume code (Rafael J Wysocki, Chen Yu)
- PM tracing support for the suspend phase of system suspend/resume
transitions (Zhonghui Fu)
- Configurable delay for the system suspend/resume testing facility
(Brian Norris)
- PNP subsystem cleanups (Peter Huewe, Rafael J Wysocki)"
* tag 'pm+acpi-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (74 commits)
ACPI / scan: Fix NULL pointer dereference in acpi_companion_match()
ACPI / scan: Rework modalias creation when "compatible" is present
intel_idle: mark cpu id array as __initconst
powercap / RAPL: mark rapl_ids array as __initconst
powercap / RAPL: add ID for Broadwell server
intel_pstate: Knights Landing support
intel_pstate: remove MSR test
cpufreq: fix qoriq uniprocessor build
ACPI / scan: Take the PRP0001 position in the list of IDs into account
ACPI / scan: Simplify acpi_match_device()
ACPI / scan: Generalize of_compatible matching
device property: Introduce firmware node type for platform data
device property: Make it possible to use secondary firmware nodes
PM / watchdog: iTCO: stop watchdog during system suspend
cpufreq: hisilicon: add acpu driver
ACPI / EC: Call acpi_walk_dep_device_list() after installing EC opregion handler
cpufreq: powernv: Report cpu frequency throttling
intel_idle: Add support for the Airmont Core in the Cherrytrail and Braswell SOCs
intel_idle: Update support for Silvermont Core in Baytrail SOC
PM / devfreq: tegra: Register governor on module init
...
This patch changes type of input parameter for
prepare/unprepare_recovery() callbacks from struct i2c_bus_recovery_info
* to struct i2c_adapter *. This allows to simplify implementation of
these callbacks and avoid type conversations from i2c_bus_recovery_info
to i2c_adapter. The i2c_bus_recovery_info can be simply retrieved from
struct i2c_adapter which contains pointer on it. There are no users
currently, so this is safe to do.
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
After more discussion, brave users, and additional datasheet evaluation,
some API updates for the new I2C slave framework became imminent. The
slave events now get some easier to understand naming. Also, the event
handling has been simplified to only need a single call to the slave
callback when an action by the backend is required.
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Now that we have struct fwnode_handle, we can use that to point to
ACPI companions from struct device objects instead of pointing to
struct acpi_device directly.
There are two benefits from that. First, the somewhat ugly and
hackish struct acpi_dev_node can be dropped and, second, the same
struct fwnode_handle pointer can be used in the future to point
to other (non-ACPI) firmware device node types.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
The number of I2C adapters which are not fully I2C compatible is rising,
sadly. Drivers usually do handle the flaws, still the user receives only
some errno for a transfer which normally can be expected to work. This
patch introduces a formal description of flaws. One advantage is that
the core can check before the actual transfer if the messages could be
transferred at all. This is done in the next patch. Another advantage is
that we can pass this information to the user so the restrictions are
exactly known and further actions can be based on that. This will be
done later after some stabilization period for this description.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Ray Jui <rjui@broadcom.com>
Tested-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Tested-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Tested-By: Ludovic Desroches <ludovic.desroches@atmel.com>
Pull i2c updates from Wolfram Sang:
"Summary:
- legacy PM code removed from the core, there were no users anymore
(thanks to Lars-Peter Clausen)
- new driver for Broadcom iProc
- bigger driver updates for designware, rk3x, cadence, ocores
- a bunch of smaller updates and bugfixes"
* 'i2c/for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (31 commits)
i2c: ocores: rework clk code to handle NULL cookie
i2c: designware-baytrail: another fixup for proper Kconfig dependencies
i2c: fix reference to functionality constants definition
i2c: iproc: Add Broadcom iProc I2C Driver
i2c: designware-pci: update Intel copyright line
i2c: ocores: add common clock support
i2c: hix5hd2: add COMPILE_TEST
i2c: clarify comments about the dev_released completion
i2c: ocores: fix clock-frequency binding usage
i2c: tegra: Maintain CPU endianness
i2c: designware-baytrail: use proper Kconfig dependencies
i2c: designware: Do not calculate SCL timing parameters needlessly
i2c: do not try to load modules for of-registered devices
i2c: designware: Add Intel Baytrail PMIC I2C bus support
i2c: designware: Add i2c bus locking support
of: i2c: Add i2c-mux-idle-disconnect DT property to PCA954x mux driver
i2c: designware: use {readl|writel}_relaxed instead of readl/writel
i2c: designware-pci: no need to provide clk_khz
i2c: designware-pci: remove Moorestown support
i2c: imx: whitespace and checkpatch cleanup
...
