linux-toradex.git/drivers/i2c/i2c-mux.c, branch v6.11

i2c: mux: Remove class argument from i2c_mux_add_adapter()

2024-05-13T14:13:19+00:00

99a741aa7a2d ("i2c: mux: gpio: remove support for class-based device
instantiation") removed the last call to i2c_mux_add_adapter() with a
non-null class argument. Therefore the class argument can be removed.

Note: Class-based device instantiation is a legacy mechanism which
shouldn't be used in new code, so we can rule out that this argument
may be needed again in the future.

Signed-off-by: Heiner Kallweit 
Reviewed-by: Thomas Zimmermann 
Acked-by: Peter Rosin 
Reviewed-by: Laurent Pinchart 
Acked-by: Jonathan Cameron 
Acked-by: Rob Herring (Arm) 
Signed-off-by: Wolfram Sang

i2c: mux: Avoid potential false error message in i2c_mux_add_adapter

2023-09-25T06:22:02+00:00

I2C_CLASS_DEPRECATED is a flag and not an actual class.
There's nothing speaking against both, parent and child, having
I2C_CLASS_DEPRECATED set. Therefore exclude it from the check.

Signed-off-by: Heiner Kallweit 
Acked-by: Peter Rosin 
Signed-off-by: Wolfram Sang

i2c: mux: harden i2c_mux_alloc() against integer overflows

2022-09-21T20:12:06+00:00

A couple years back we went through the kernel an automatically
converted size calculations to use struct_size() instead.  The
struct_size() calculation is protected against integer overflows.

However it does not make sense to use the result from struct_size()
for additional math operations as that would negate any safeness.

Fixes: 1f3b69b6b939 ("i2c: mux: Use struct_size() in devm_kzalloc()")
Signed-off-by: Dan Carpenter 
Acked-by: Peter Rosin 
Reviewed-by: Gustavo A. R. Silva 
Signed-off-by: Wolfram Sang

i2c: mux: add sysfs header

2019-06-22T05:32:33+00:00

We are using sysfs functions directly, so we should include the header.

Signed-off-by: Wolfram Sang 
Signed-off-by: Peter Rosin

i2c: mux: Use struct_size() in devm_kzalloc()

2019-06-10T07:28:46+00:00

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
    int stuff;
    struct boo entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Peter Rosin

i2c: mux: populate the new *_atomic callbacks

2019-04-16T11:08:12+00:00

If the parent adapter has atomic_xfer callbacks, populate them for the
mux adapter as well. We can use the same translation function as for the
non-atomic xfer callback.

Signed-off-by: Wolfram Sang 
Reviewed-by: Peter Rosin 
Reviewed-by Andy Shevchenko 
Signed-off-by: Wolfram Sang

Merge branch 'i2c/for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

2018-08-22T00:40:46+00:00

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
  ...

i2c/mux, locking/core: Annotate the nested rt_mutex usage

2018-07-25T09:22:20+00:00

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 
Tested-by: John Sperbeck 
Signed-off-by: Peter Rosin 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Davidlohr Bueso 
Cc: Deepa Dinamani 
Cc: Greg Kroah-Hartman 
Cc: Linus Torvalds 
Cc: Peter Chang 
Cc: Peter Zijlstra 
Cc: Philippe Ombredanne 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: Wolfram Sang 
Link: http://lkml.kernel.org/r/20180720083914.1950-3-peda@axentia.se
Signed-off-by: Ingo Molnar

i2c: mux: make use of __i2c_smbus_xfer

2018-07-03T20:57:55+00:00

Calling the __i2c_smbus_xfer wrapper in __i2c_mux_smbus_xfer provides
retries and thus makes the parent-locked case consistent with the both
mux-locked (i2c_mux_smbus_xfer) and the I2C transfer cases.

Signed-off-by: Peter Rosin 
Signed-off-by: Wolfram Sang

i2c: mux: improve error message for failed symlink

2018-05-24T11:42:40+00:00

Trivial, but still: the failed symlink is not *for* the channel but a
link *to* the channel.

Signed-off-by: Wolfram Sang 
Signed-off-by: Peter Rosin