Commit Graph

66 Commits

Author SHA1 Message Date
Heiner Kallweit 7159dbdae3 i2c: core: improve return value handling of i2c_new_device and i2c_new_dummy
Currently i2c_new_device and i2c_new_dummy return just NULL in error
case although they have more error details internally. Therefore move
the functionality into new functions returning detailed errors and
add wrappers for compatibility with the current API.

This allows to use these functions with detailed error codes within
the i2c core or for API extensions.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: rename new functions and fix minor kdoc issues]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-05-17 19:28:31 +02:00
Linus Torvalds 45182e4e1f Merge branch 'i2c/for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:

 - API for late atomic transfers (e.g. to shut down via PMIC). We have a
   seperate callback now which is called under clearly defined
   conditions. In-kernel users are converted, too.

 - new driver for the AMD PCIe MP2 I2C controller

 - large refactoring for at91 and bcm-iproc (both gain slave support due
   to this)

 - and a good share of various driver improvements anf fixes

* 'i2c/for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (57 commits)
  dt-bindings: i2c: riic: document r7s9210 support
  i2c: imx-lpi2c: Use __maybe_unused instead of #if CONFIG_PM_SLEEP
  i2c-piix4: Add Hygon Dhyana SMBus support
  i2c: core: apply 'is_suspended' check for SMBus, too
  i2c: core: ratelimit 'transfer when suspended' errors
  i2c: iproc: Change driver to use 'BIT' macro
  i2c: riic: Add Runtime PM support
  i2c: mux: demux-pinctrl: use struct_size() in devm_kzalloc()
  i2c: mux: pca954x: allow management of device idle state via sysfs
  i2c: mux: pca9541: remove support for unused platform data
  i2c: mux: pca954x: remove support for unused platform data
  dt-bindings: i2c: i2c-mtk: add support for MT8516
  i2c: axxia: use auto cmd for last message
  i2c: gpio: flag atomic capability if possible
  i2c: algo: bit: add flag to whitelist atomic transfers
  i2c: stu300: use xfer_atomic callback to bail out early
  i2c: ocores: enable atomic xfers
  i2c: ocores: refactor setup for polling
  i2c: tegra-bpmp: convert to use new atomic callbacks
  i2c: omap: Add the master_xfer_atomic hook
  ...
2019-05-09 14:41:55 -07:00
Linus Torvalds 82463436a7 Merge branch 'i2c/for-current-fixed' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
 "I2C driver bugfixes and a MAINTAINERS update for you"

* 'i2c/for-current-fixed' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: Prevent runtime suspend of adapter when Host Notify is required
  i2c: synquacer: fix enumeration of slave devices
  MAINTAINERS: friendly takeover of i2c-gpio driver
  i2c: designware: ratelimit 'transfer when suspended' errors
  i2c: imx: correct the method of getting private data in notifier_call
2019-05-03 11:42:01 -07:00
Wolfram Sang 5d756112da i2c: core: apply 'is_suspended' check for SMBus, too
We checked I2C calls, but not SMBus. Refactor the helper to an inline
function and use it for both, I2C and SMBus.

Fixes: 9ac6cb5fbb ("i2c: add suspended flag and accessors for i2c adapters")
Reported-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-05-03 16:44:51 +02:00
Wolfram Sang 4db61c2a16 i2c: core: ratelimit 'transfer when suspended' errors
There are two problems with WARN_ON() here. One: It is not ratelimited.
Two: We don't see which adapter was used when trying to transfer
something when already suspended. Implement a custom ratelimit once per
adapter and use dev_WARN there. This fixes both issues. Drawback is that
we don't see if multiple drivers are trying to transfer with the same
adapter while suspended. They need to be discovered one after the other
now. This is better than a high CPU load because a really broken driver
might try to resend endlessly.

Fixes: 9ac6cb5fbb ("i2c: add suspended flag and accessors for i2c adapters")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@vger.kernel.org # v5.1+
2019-05-03 15:25:00 +02:00
Jarkko Nikula 72bfcee11c i2c: Prevent runtime suspend of adapter when Host Notify is required
Multiple users have reported their Synaptics touchpad has stopped
working between v4.20.1 and v4.20.2 when using SMBus interface.

The culprit for this appeared to be commit c5eb119007 ("PCI / PM: Allow
runtime PM without callback functions") that fixed the runtime PM for
i2c-i801 SMBus adapter. Those Synaptics touchpad are using i2c-i801
for SMBus communication and testing showed they are able to get back
working by preventing the runtime suspend of adapter.

Normally when i2c-i801 SMBus adapter transmits with the client it resumes
before operation and autosuspends after.

However, if client requires SMBus Host Notify protocol, what those
Synaptics touchpads do, then the host adapter must not go to runtime
suspend since then it cannot process incoming SMBus Host Notify commands
the client may send.

Fix this by keeping I2C/SMBus adapter active in case client requires
Host Notify.

Reported-by: Keijo Vaara <ferdasyn@rocketmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203297
Fixes: c5eb119007 ("PCI / PM: Allow runtime PM without callback functions")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Keijo Vaara <ferdasyn@rocketmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-05-02 18:42:15 +02:00
Linus Torvalds cf67690884 gcc-9: don't warn about uninitialized variable
I'm not sure what made gcc warn about this code now.  The 'ret' variable
does end up initialized in all cases, but it's definitely not obvious,
so the compiler is quite reasonable to warn about this.

So just add initialization to make it all much more obvious both to
compilers and to humans.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-01 11:07:40 -07:00
Wolfram Sang 63b96983a5 i2c: core: introduce callbacks for atomic transfers
We had the request to access devices very late when interrupts are not
available anymore multiple times now. Mostly to prepare shutdown or
reboot. Allow adapters to specify a specific callback for this case.
Note that we fall back to the generic {master|smbus}_xfer callback if
this new atomic one is not present. This is intentional to preserve the
previous behaviour and avoid regressions. Because there are drivers not
using interrupts or because it might have worked "accidently" before.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Stefan Lengfeld <contact@stefanchrist.eu>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-16 13:08:11 +02:00
Wolfram Sang 83c42212d2 i2c: core: use I2C locking behaviour also for SMBUS
If I2C transfers are executed in atomic contexts, trylock is used
instead of lock. This behaviour was missing for SMBUS, although a lot of
transfers are of SMBUS type, either emulated or direct. So, factor out
the locking routine into a helper and use it for I2C and SMBUS.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-16 13:08:11 +02:00
Wolfram Sang bae1d3a05a i2c: core: remove use of in_atomic()
Commit cea443a81c ("i2c: Support i2c_transfer in atomic contexts")
added in_atomic() to the I2C core. However, the use of in_atomic()
outside of core kernel code is discouraged and was already[1] when this
code was added in early 2008. The above commit was a preparation for
commit b7a3670131 ("i2c-pxa: Add polling transfer"). Its commit
message says explicitly it was added "for cases where I2C transactions
have to occur at times interrup[t]s are disabled". So, the intention was
'disabled interrupts'. This matches the use cases for atomic I2C
transfers I have seen so far: very late communication (mostly to a PMIC)
to powerdown or reboot the system. For those cases, interrupts are
disabled then. It doesn't seem that in_atomic() adds value.

After a discussion with Peter Zijlstra[2], we came up with a better set
of conditionals to match the use case.

The I2C core will soon gain an extra callback into bus drivers
especially for atomic transfers to make them more generic. The code
deciding which transfer to use (atomic/non-atomic) should mimic the
behaviour which locking to use (trylock/lock). This is why we add a
helper for it.

[1] https://lwn.net/Articles/274695/
[2] http://patchwork.ozlabs.org/patch/1067437/

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Stefan Lengfeld <contact@stefanchrist.eu>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-16 13:08:05 +02:00
Wolfram Sang bf263c35b2 i2c: add extra check to safe DMA buffer helper
Make sure we report 'no buffer' for 0-length messages. This can only
happen if threshold is set to 0 which is kind of bogus but we should
still handle this situation. Update the docs and add a debug message
to educate callers of this function.

Reported-by: Hsin-Yi Wang <hsinyi@chromium.org>
Fixes: e94bc5d18b ("i2c: add helpers to ease DMA handling")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Hsin-Yi Wang <hsinyi@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-03-13 18:03:26 +01:00
Jim Broadus 93b6604c5a i2c: Allow recovery of the initial IRQ by an I2C client device.
A previous change allowed I2C client devices to discover new IRQs upon
reprobe by clearing the IRQ in i2c_device_remove. However, if an IRQ was
assigned in i2c_new_device, that information is lost.

For example, the touchscreen and trackpad devices on a Dell Inspiron laptop
are I2C devices whose IRQs are defined by ACPI extended IRQ types. The
client device structures are initialized during an ACPI walk. After
removing the i2c_hid device, modprobe fails.

This change caches the initial IRQ value in i2c_new_device and then resets
the client device IRQ to the initial value in i2c_device_remove.

Fixes: 6f108dd70d ("i2c: Clear client->irq in i2c_device_remove")
Signed-off-by: Jim Broadus <jbroadus@gmail.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
[wsa: this is an easy to backport fix for the regression. We will
refactor the code to handle irq assignments better in general.]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-02-24 14:43:22 +01:00
Wolfram Sang 9ac6cb5fbb i2c: add suspended flag and accessors for i2c adapters
A few drivers open code the handling of suspended adapters. It could be
handled by the core, though, to ensure generic handling. This patch adds
the flag and accessor functions. The usage of these helpers is optional,
though. See the kerneldoc in this patch. Using the new flag, we now
reject further transfers if the adapter is already marked suspended.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-01-08 21:01:07 +01:00
Charles Keepax 6f108dd70d i2c: Clear client->irq in i2c_device_remove
The IRQ will be mapped in i2c_device_probe only if client->irq is zero and
i2c_device_remove does not clear this. When rebinding an I2C device,
whos IRQ provider has also been rebound this means that an IRQ mapping
will never be created, causing the I2C device to fail to acquire its
IRQ. Fix this issue by clearing client->irq in i2c_device_remove,
forcing i2c_device_probe to lookup the mapping again.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-10-31 23:33:34 +00:00
Charles Keepax b9bb3fdf4e i2c: Remove unnecessary call to irq_find_mapping
irq_create_mapping calls irq_find_mapping internally and will use the
found mapping if one exists, so there is no need to manually call this
from i2c_smbus_host_notify_to_irq.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-10-31 23:33:14 +00:00
Linus Torvalds 57dbde63f2 Merge branch 'i2c/for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
 "I2C has not so much stuff this time. Mostly driver enablement for new
  SoCs, some driver bugfixes, and some cleanups"

* 'i2c/for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (35 commits)
  MAINTAINERS: add maintainer for Renesas RIIC driver
  i2c: sh_mobile: Remove dummy runtime PM callbacks
  i2c: uniphier-f: fix race condition when IRQ is cleared
  i2c: uniphier-f: fix occasional timeout error
  i2c: uniphier-f: make driver robust against concurrency
  i2c: i2c-qcom-geni: Simplify irq handler
  i2c: i2c-qcom-geni: Simplify tx/rx functions
  i2c: designware: Set IRQF_NO_SUSPEND flag for all BYT and CHT controllers
  i2c: mux: mlxcpld: simplify code to reach the adapter
  i2c: mux: ltc4306: simplify code to reach the adapter
  i2c: mux: pca954x: simplify code to reach the adapter
  i2c: core: remove level of indentation in i2c_transfer
  i2c: core: remove outdated DEBUG output
  i2c: zx2967: use core to detect 'no zero length' quirk
  i2c: tegra: use core to detect 'no zero length' quirk
  i2c: qup: use core to detect 'no zero length' quirk
  i2c: omap: use core to detect 'no zero length' quirk
  i2c: Convert to using %pOFn instead of device_node.name
  i2c: brcmstb: Allow enabling the driver on DSL SoCs
  eeprom: at24: fix unexpected timeout under high load
  ...
2018-10-29 14:44:03 -07:00
Stephen Boyd 34d1b82cd1 i2c: Fix kerneldoc for renamed i2c dma put function
This function was renamed in commit 82fe39a6bc ("i2c: refactor
function to release a DMA safe buffer") but this kernel doc wasn't
updated to point at the new function. Rename it.

Fixes: 82fe39a6bc ("i2c: refactor function to release a DMA safe buffer")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-10-11 22:59:57 +02:00
Wolfram Sang cc52612ec0 i2c: core: remove level of indentation in i2c_transfer
Using the common kernel pattern to bail out at the beginning if some
conditions are not met, we can save a level of indentation. No
functional change.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-10-05 18:13:37 +02:00
Wolfram Sang a7163dc213 i2c: core: remove outdated DEBUG output
The usefulness of this debug output is questionable. It covers only
direct i2c_transfer calls and no SMBUS calls, neither direct nor
emulated ones. And the latter one is largely used in the kernel, so a
lot of stuff is missed. False positives are also generated in case the
locking later fails. Also, we have a proper tracing mechanism for all
these kinds of transfers in place for years now. Remove this old one.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-10-05 18:12:43 +02:00
Wolfram Sang 82fe39a6bc i2c: refactor function to release a DMA safe buffer
a) rename to 'put' instead of 'release' to match 'get' when obtaining
   the buffer
b) change the argument order to have the buffer as first argument
c) add a new argument telling the function if the message was
   transferred. This allows the function to be used also in cases
   where setting up DMA failed, so the buffer needs to be freed without
   syncing to the message buffer.

Also convert the only user.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-08-30 23:13:15 +02:00
Wolfram Sang 0c36dd37d5 i2c: remove deprecated attach_adapter callback
There aren't any users left. Remove this callback from the 2.4 times.
Phew, finally, that took years to reach...

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-08-24 14:42:45 +02:00
Linus Torvalds 99cc7ad46b Merge branch 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:

 - the core has now a lockless variant of i2c_smbus_xfer. Some open
   coded versions of this got removed in drivers. This also enables
   proper SCCB support in regmap.

 - locking got a more precise naming. i2c_{un}lock_adapter() had to go,
   and we know use i2c_lock_bus() consistently with flags like
   I2C_LOCK_ROOT_ADAPTER and I2C_LOCK_SEGMENT to avoid ambiguity.

 - the gpio fault injector got a new delicate testcase

 - the bus recovery procedure got fixed to handle the new testcase
   correctly

 - a new quirk flag for controllers not able to handle zero length
   messages together with driver updates to use it

 - new drivers: FSI bus attached I2C masters, GENI I2C controller, Owl
   family S900

 - and a good set of driver improvements and bugfixes

* 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (77 commits)
  i2c: rcar: implement STOP and REP_START according to docs
  i2c: rcar: refactor private flags
  i2c: core: ACPI: Make acpi_gsb_i2c_read_bytes() check i2c_transfer return value
  i2c: core: ACPI: Properly set status byte to 0 for multi-byte writes
  dt-bindings: i2c: rcar: Add r8a774a1 support
  dt-bindings: i2c: sh_mobile: Add r8a774a1 support
  i2c: imx: Simplify stopped state tracking
  i2c: imx: Fix race condition in dma read
  i2c: pasemi: remove hardcoded bus numbers on smbus
  i2c: designware: Add SPDX license tag
  i2c: designware: Convert to use struct i2c_timings
  i2c: core: Parse SDA hold time from firmware
  i2c: designware-pcidrv: Mark expected switch fall-through
  i2c: amd8111: Mark expected switch fall-through
  i2c: sh_mobile: use core to detect 'no zero length read' quirk
  i2c: xlr: use core to detect 'no zero length' quirk
  i2c: rcar: use core to detect 'no zero length' quirk
  i2c: stu300: use core to detect 'no zero length' quirk
  i2c: pmcmsp: use core to detect 'no zero length' quirk
  i2c: mxs: use core to detect 'no zero length' quirk
  ...
2018-08-21 17:40:46 -07:00
Andy Shevchenko 4717be73c2 i2c: core: Parse SDA hold time from firmware
There are two drivers already using the SDA hold time setting.
It might be more in the future, thus, make I2C core to parse the setting
for us if provided by firmware.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-08-08 22:28:52 +02:00
Wolfram Sang d9cfe2ce24 i2c: quirks: add zero length checks
Some adapters do not support a message length of 0. Add this as a quirk
so drivers don't have to open code it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-08-04 23:24:03 +02:00
Peter Rosin 7b94ea5051 i2c/mux, locking/core: Annotate the nested rt_mutex usage
If an i2c topology has instances of nested muxes, then a lockdep splat
is produced when when i2c_parent_lock_bus() is called.  Here is an
example:

  ============================================
  WARNING: possible recursive locking detected
  --------------------------------------------
  insmod/68159 is trying to acquire lock:
    (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]

  but task is already holding lock:
    (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]

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

          CPU0
          ----
     lock(i2c_register_adapter#2);
     lock(i2c_register_adapter#2);

    *** DEADLOCK ***

    May be due to missing lock nesting notation

  1 lock held by insmod/68159:
    #0:  (i2c_register_adapter#2){+.+.}, at: i2c_parent_lock_bus+0x32/0x50 [i2c_mux]

  stack backtrace:
  CPU: 13 PID: 68159 Comm: insmod Tainted: G           O
  Call Trace:
    dump_stack+0x67/0x98
    __lock_acquire+0x162e/0x1780
    lock_acquire+0xba/0x200
    rt_mutex_lock+0x44/0x60
    i2c_parent_lock_bus+0x32/0x50 [i2c_mux]
    i2c_parent_lock_bus+0x3e/0x50 [i2c_mux]
    i2c_smbus_xfer+0xf0/0x700
    i2c_smbus_read_byte+0x42/0x70
    my2c_init+0xa2/0x1000 [my2c]
    do_one_initcall+0x51/0x192
    do_init_module+0x62/0x216
    load_module+0x20f9/0x2b50
    SYSC_init_module+0x19a/0x1c0
    SyS_init_module+0xe/0x10
    do_syscall_64+0x6c/0x1a0
    entry_SYSCALL_64_after_hwframe+0x42/0xb7

Reported-by: John Sperbeck <jsperbeck@google.com>
Tested-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Deepa Dinamani <deepadinamani@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Chang <dpf@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Link: http://lkml.kernel.org/r/20180720083914.1950-3-peda@axentia.se
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-25 11:22:20 +02:00
Wolfram Sang c4ae05b976 i2c: recovery: make pin init look like STOP
When we initialize the pins, make sure it looks like STOP by dividing
the delay into halves. It shouldn't matter because SDA is expected to be
held low by a device, but for super-safety, let's do it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-07-21 00:11:05 +02:00
Wolfram Sang f7ff75e2a8 i2c: recovery: rename variable for easier understanding
While refactoring the routine before, it occurred to me that this will
make the code much easier to understand.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-07-17 10:48:45 +02:00
Wolfram Sang 7ca5f6be79 i2c: recovery: add get_bus_free callback
Some IP cores have an internal 'bus free' logic which may be more
advanced than just checking if SDA is high. Add a separate callback to
get this status. Filling it is optional.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-07-17 10:46:51 +02:00
Wolfram Sang 0b71026c69 i2c: recovery: refactor recovery function
After exiting the while loop, we checked if recovery was successful and
sent a STOP to the clients. Meanwhile however, we send a STOP after
every pulse, so it is not needed after the loop. If we move the check
for a free bus to the end of the while loop, we can shorten and simplify
the logic. It is still ensured that at least one STOP will be sent to
the wire even if SDA was not stuck low.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-07-17 10:42:48 +02:00
Wolfram Sang ffc59c496b i2c: recovery: require either get_sda or set_sda
For bus recovery, we either need to bail out early if we can read SDA or
we need to send STOP after every pulse. Otherwise recovery might be
misinterpreted as an unwanted write. So, require one of those SDA
handling functions to avoid this problem.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-07-17 10:41:55 +02:00
Wolfram Sang abe41184ab i2c: recovery: if possible send STOP with recovery pulses
I2C clients may misunderstand recovery pulses if they can't read SDA to
bail out early. In the worst case, as a write operation. To avoid that
and if we can write SDA, try to send STOP to avoid the
misinterpretation.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
2018-07-12 23:38:18 +02:00
Linus Torvalds 9bca19a01d Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:

 - mainly feature additions to drivers (stm32f7, qup, xlp9xx, mlxcpld, ...)

 - conversion to use the i2c_8bit_addr_from_msg macro consistently

 - move includes to platform_data

 - core updates to allow the (still in review) I3C subsystem to connect

 - and the regular share of smaller driver updates

* 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (68 commits)
  i2c: qup: fix building without CONFIG_ACPI
  i2c: tegra: Remove suspend-resume
  i2c: imx-lpi2c: Switch to SPDX identifier
  i2c: mxs: Switch to SPDX identifier
  i2c: busses: make use of i2c_8bit_addr_from_msg
  i2c: algos: make use of i2c_8bit_addr_from_msg
  i2c: rcar: document R8A77980 bindings
  i2c: qup: Add command-line parameter to override SCL frequency
  i2c: qup: Correct duty cycle for FM and FM+
  i2c: qup: Add support for Fast Mode Plus
  i2c: qup: add probe path for Centriq ACPI devices
  i2c: robotfuzz-osif: drop pointless test
  i2c: robotfuzz-osif: remove pointless local variable
  i2c: rk3x: Don't print visible virtual mapping MMIO address
  i2c: opal: don't check number of messages in the driver
  i2c: ibm_iic: don't check number of messages in the driver
  i2c: imx: Switch to SPDX identifier
  i2c: mux: pca954x: merge calls to of_match_device and of_device_get_match_data
  i2c: mux: demux-pinctrl: use proper parent device for demux adapter
  i2c: mux: improve error message for failed symlink
  ...
2018-06-14 16:21:46 +09:00
Boris Brezillon 0478226564 i2c: Retain info->of_node in i2c_new_device()
Currently, of_i2c_register_devices() is responsible for retaining
info->of_node, but we're about to expose a function to parse I2C board
info without registering the I2C device.

We could possibly let this function retain ->of_node, but this approach
is prone to reference leak since people will have to remember to call
of_node_put() if something goes wrong between the OF node parsing and
the registration step.
Let's just retain the ->of_node in i2c_new_register() instead.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-05-22 13:40:25 +02:00
Boris Brezillon 4fad8868af i2c: Get rid of i2c_board_info->archdata
The only user of i2c_board_info->archdata is the OF parsing code and it
just pass a zero-initialized object which has the same effect as leaving
->archdata to NULL since the client object is allocated with kzalloc().

Get rid of this useless field.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-05-15 10:42:20 +02:00
Ulf Hansson e6a20b6cd2 i2c: Respect all error codes from dev_pm_domain_attach()
The limitation of being able to check only for -EPROBE_DEFER from
dev_pm_domain_attach() has been removed. Hence let's respect all error
codes and bail out accordingly.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-14 22:58:45 +02:00
Ard Biesheuvel 1eace8344c i2c: add param sanity check to i2c_transfer()
The API docs describe i2c_transfer() as taking a pointer to an array
of i2c_msg containing at least 1 entry, but leaves it to the individual
drivers to sanity check the msgs and num parameters. Let's do this in
core code instead.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[wsa: changed '<= 0' to '< 1']
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-04-11 23:33:46 +02:00
Davidlohr Bueso 50888b015d i2c: Update i2c_trace_msg static key to modern api
No changes in refcount semantics -- key init is false; replace

static_key_slow_inc|dec   with   static_branch_inc|dec
static_key_false          with   static_branch_unlikely

Added a '_key' suffix to i2c_trace_msg, for better self
documentation.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-04-03 19:20:26 +02:00
Ahbong Chang 4a3f7691e2 i2c: fix parameter of trace_i2c_result
According to the event i2c_result defined in include/trace/events/i2c.h,
the second parameter should be the number of messages instead of the
ended loop index. The value of ended loop index is the same as ret.

Signed-off-by: Ahbong Chang <cwahbong@google.com>
Reviewed-by: Todd Poynor <toddpoynor@google.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-04-03 16:37:45 +02:00
Wolfram Sang 398432edde i2c: make i2c_check_addr_validity() static
After previous refactoring, there is only one user in the same file
left. Make the function static now.

[wsa: added 'int' to bare 'unsigned']
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-03-24 14:07:23 +01:00
Wolfram Sang 8efb11adee Merge branch 'i2c-mux/for-next' of https://github.com/peda-r/i2c-mux into i2c/for-4.17
"These patches verify the device id of the PCA984x mux chips using
standardized (but rarely implemented) i2c device identification."
2018-03-17 21:11:23 +01:00
Peter Rosin dde67eb1be i2c: add i2c_get_device_id() to get the standard i2c device id
Can be used during probe to double check that the probed device is
what is expected.

Loosely based on code from Adrian Fiergolski <adrian.fiergolski@cern.ch>.

Tested-by: Adrian Fiergolski <adrian.fiergolski@cern.ch>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>
2018-03-06 10:57:59 +01:00
Javier Martinez Canillas af503716ac i2c: core: report OF style module alias for devices registered via OF
The buses should honor the firmware interface used to register the device,
but the I2C core reports a MODALIAS of the form i2c:<device> even for I2C
devices registered via OF.

This means that user-space will never get an OF stype uevent MODALIAS even
when the drivers modules contain aliases exported from both the I2C and OF
device ID tables. For example, an Atmel maXTouch Touchscreen registered by
a DT node with compatible "atmel,maxtouch" has the following module alias:

$ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias
i2c:maxtouch

So udev won't be able to auto-load a module for an OF-only device driver.
Many OF-only drivers duplicate the OF device ID table entries in an I2C ID
table only has a workaround for how the I2C core reports the module alias.

This patch changes the I2C core to report an OF related MODALIAS uevent if
the device was registered via OF. So for the previous example, after this
patch, the reported MODALIAS for the Atmel maXTouch will be the following:

$ cat /sys/class/i2c-adapter/i2c-8/8-004b/modalias
of:NtrackpadT<NULL>Catmel,maxtouch

NOTE: This patch may break out-of-tree drivers that were relying on this
      behavior, and only had an I2C device ID table even when the device
      was registered via OF. There are no remaining drivers in mainline
      that do this, but out-of-tree drivers have to be fixed and define
      a proper OF device ID table to have module auto-loading working.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Dmitry Mastykin <mastichi@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-03-05 16:25:32 +01:00
Linus Torvalds 4141cf676b Merge branch 'i2c/for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
 "I2C has the following changes for you:

   - new flag to mark DMA safe buffers in i2c_msg. Also, some
     infrastructure around it. And docs.

   - huge refactoring of the at24 driver led by the new maintainer
     Bartosz

   - update I2C bus recovery to send STOP after recovery

   - conversion from gpio to gpiod for I2C bus recovery

   - adding a fault-injector to the i2c-gpio driver

   - lots of small driver improvements, and bigger ones to
     i2c-sh_mobile"

* 'i2c/for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (99 commits)
  i2c: mv64xxx: Add myself as maintainer for this driver
  i2c: mv64xxx: Fix clock resource by adding an optional bus clock
  i2c: mv64xxx: Remove useless test before clk_disable_unprepare
  i2c: mxs: use true and false for boolean values
  i2c: meson: update doc description to fix build warnings
  i2c: meson: add configurable divider factors
  dt-bindings: i2c: update documentation for the Meson-AXG
  i2c: imx-lpi2c: add runtime pm support
  i2c: rcar: fix some trivial typos in comments
  i2c: davinci: fix the cpufreq transition
  i2c: rk3x: add proper kerneldoc header
  i2c: rk3x: account for const type of of_device_id.data
  i2c: acorn: remove outdated path from file header
  i2c: acorn: add MODULE_LICENSE tag
  i2c: rcar: implement bus recovery
  i2c: send STOP after successful bus recovery
  i2c: ensure SDA is released in recovery if SDA is controllable
  i2c: add 'set_sda' to bus_recovery_info
  i2c: add identifier in declarations for i2c_bus_recovery
  i2c: make kerneldoc about bus recovery more precise
  ...
2018-02-04 10:57:43 -08:00
Lixin Wang e0638fa400 i2c: core: decrease reference count of device node in i2c_unregister_device
Reference count of device node was increased in of_i2c_register_device,
but without decreasing it in i2c_unregister_device. Then the added
device node will never be released. Fix this by adding the of_node_put.

Signed-off-by: Lixin Wang <alan.1.wang@nokia-sbell.com>
Tested-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
2018-01-17 15:23:31 +01:00
Wolfram Sang 2806e6ad77 i2c: send STOP after successful bus recovery
If we managed to get a client release SDA again, send a STOP afterwards
to make sure we have a consistent state on the bus again.

Tested-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-01-16 00:04:42 +01:00
Wolfram Sang 72b08fcc15 i2c: ensure SDA is released in recovery if SDA is controllable
If we have a function to control SDA, we should ensure that SDA is not
held down by us. So, release the GPIO in this case.

Tested-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-01-16 00:04:30 +01:00
Wolfram Sang 8092178ffe i2c: add 'set_sda' to bus_recovery_info
This will be needed when we want to create STOP conditions, too, later.
Create the needed fields and populate them for the GPIO case if the GPIO
is set to output.

Tested-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-01-16 00:04:19 +01:00
Wolfram Sang 8a91732b3b i2c: refactor i2c_master_{send_recv}
Those two functions are very similar, the only differences are that one
needs the I2C_M_RD flag for its message while the other one needs the
buffer casted to drop the const. Introduce a generic helper which allows
to specify the flags (also needed later for DMA safe variants of these
calls) and let the casting be done in the inlining functions which are
now calling the new helper function.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-03 21:22:29 +01:00
Wolfram Sang e94bc5d18b i2c: add helpers to ease DMA handling
One helper checks if DMA is suitable and optionally creates a bounce
buffer, if not. The other function returns the bounce buffer and makes
sure the data is properly copied back to the message.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-12-03 20:47:44 +01:00
Phil Reid 10c9ef045a i2c: core: fix compile issue related to incorrect gpio header
The correct header to include for the gpiod interface is
<linux/gpio/consumer.h>.

Fixes: 3991c5c80b ("i2c: Switch to using gpiod interface for gpio bus recovery")
Signed-off-by: Phil Reid <preid@electromag.com.au>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-11-28 10:44:00 +01:00